Recent Publications of the Southern
Research Station
Announcement of Publications - June 1998
Focus-Loblolly Pine Publication Updates and Expands Knowledge
Base
Dr. Robert P. Schultz, former assistant director of
the Southern Forest Experiment Station in New Orleans, has authored an immediate classic, Loblolly Pine-The Ecology and Culture of Loblolly Pine (Pinus
taeda L.). Since W.G. Wahlenberg's 1960 monograph about the loblolly, almost 6,000
publications had been written about the species. Schultz's work, Agriculture Handbook 713,
encompasses genetics, tree improvement, field inventory and analysis, and international
forestry, as well as ecology, direct seeding, and planting.
Loblolly pine ranks as a highly valuable tree for its pulp, paper,
and lumber products. In the South, loblolly is planted more than any other conifer. Robert
E. Buckman, professor of forestry at Oregon State University, was Deputy Chief for Forest
Service Research in 1985 when Schultz began working on the loblolly book. Buckman, who
wrote the foreword for Loblolly Pine - The Ecology and Culture of Loblolly Pine (Pinus
taeda L.) considers loblolly to be the most important tree species in the United
States. When cotton and other agricultural crops were abandoned, loblolly proved its worth
for erosion control and commodity production. Nontimber uses of loblolly include wildlife
habitat, grazing, watershed protection, and rehabilitation of cutover, degraded lands. The
loblolly grows better than any other southern pine and enjoys tremendous popularity
internationally. China plants more than half a million trees each year; Brazil, Argentina,
and other South American countries also plant the loblolly widely.
Schultz retired from the Forest Service in 1992 and continued to
work as a volunteer on the updated monograph of the loblolly pine. He acknowledges the
work of scientists, editors, and administrators who contributed to making Loblolly Pine
- The Ecology and Culture of Loblolly Pine (Pinus taeda L.) a reality.
Together, they have produced a book that adds to the technical foundations laid by Ashe
(1915) and Wahlenberg (1960). It highlights individual tree, stand, and land management
alternatives useful to resource managers, students, researchers, and others.
Southern Research Scientists Contribute to Collection of Studies on
the South's Changing Environment
The Productivity and Sustainability of Southern Forest
Ecosystems in a Changing Environment, a new volume in Springer-Verlag's Ecological Studies
Series, describes five years of research conducted by the Southern Global Change Program,
one of the regional research cooperatives of the Forest Service Global Change Program. The
Global Change Program provides a sound scientific basis for making regional, national, and
international management and policy decisions regarding forest ecosystems in the context
of global change challenges. The research described in this volume was conducted by
scientists and support personnel of the USDA Forest Service, the U.S. Environmental
Protection Agency, the U.S. Department of Energy, other Federal and Sate agencies, and
universities throughout the southern United States. The editors, based in Raleigh, NC, are
Robert A. Mickler of ManTech Environmental Technology, Inc., and Susan Fox of the Southern
Research Station. "We are very proud to have this work in publication, which includes
the studies of many scientists from the Southern Research Station," said Pete
Roussopoulos, Director of the Southern Research Station. "This prestigious volume
contributes to our understanding of the growth and physiological processes present in
forest ecosystems in the southern United States."
Forty-seven chapters comprise The Productivity and Sustainability of
Southern Forest Ecosystems in a Changing Environment. Six sections cover: 1) an
introduction to southern forests in a changing environment; 2) global change impacts on
tree physiology and growth; 3) modeling the biophysical effects of global change; 4) the
effects of climate change on forest soils; 5) disturbance interactions with global change;
6) global change and disturbance in southern forest ecosystems. Chapters authored or
co-authored by Southern Research Station scientists include:
4. Influence of Drought Stress on the Response of Shortleaf Pine to
Ozone; Richard B. Flagler; John C. Brissette; and James P. Barnett
6. Environmental Stresses and Reproductive Biology of Loblolly Pine
(Pinus taeda L.) and Flowering Dogwood (Cornus florida L.); Kristina F.
Connor; Timothy C. Prewitt; Franklin T. Bonner; William W. Elam; and Robert C. Parker
11. Ecophysiological Response of Managed Loblolly Pine to Changes in
Stand Environment; Mary A. Sword; Jim L. Chambers; Dennis A. Gravatt; James D. Haywood;
and James P. Barnett
17. A Linked Model for Simulating Stand Development and Growth
Processes of Loblolly Pine; V. Clark Baldwin, Jr.; Phillip M. Dougherty; and Harold E.
Burkhart
18. MAESTRO Simulations of the Response of Loblolly Pine to Elevated
Temperatures and Carbon Dioxide; Wendell P. Cropper, Jr.; Kelly Peterson; and Robert O.
Teskey
22. Predictions and Projections of Pine Productivity and Hydrology
in Response to Climate Change Across the Southern United States; Steven G. McNulty; James
A Vose; and Wayne T. Swank
26. Summary of Simulated Forest Responses to Climate Change in the
Southeastern United States; David A. Weinstein; Wendell P. Cropper, Jr.; and Steven G.
McNulty
28. Influence of Microclimate on Short-term Litter Decomposition in
Loblolly Pine Ecosystems; B. Graeme Lockaby; Arthur H. Chappelka; Mary A. Sword; and Allan
E. Tiarks
29. Soil Organic Matter and Soil Productivity: Searching for the
Missing Link; Felipe G. Sanchez
32. Environmental Effects on Pine Tree Carbon Budgets and Resistance
to Bark Beetles; Richard T. Wilkens; Matthew P. Ayres; Peter L. Lorio, Jr.; and John D.
Hodges
33. Predictions of Southern Pine Beetle Populations Using a Forest
Ecosystem Model; Steven G. McNulty; Peter L. Lorio, Jr.; Matthew P. Ayres; and John D.
Reeve
34. Soil Effects Mediate Interaction of Dogwood Anthracnose and
Acidic Precipitation; Kerry O. Britton; Paul C. Berrang; and Erika Mavity
35. Effects of Temperature and Drought Stress on Physiological
Processes Associated With Oak Decline; Theodor D. Leininger
36. Effects of Global Climate Change on Biodiversity in Forests of
the Southern United States; Margaret S. Devall and Bernard R. Parresol
38. Detecting and Predicting Climatic Variation from Old-Growth
Baldcypress; Gregory A. Reams and Paul C. Van Deusen
39. Modeling the Differential Sensitivity of Loblolly Pine to
Climatic Change Using Tree Rings; Edward R. Cook; Warren L. Nance; Paul J. Krusic; and
James Grissom
40. Global Change and Disturbance in Southern Forest Ecosystems;
Matthew P. Ayres and Gregory A. Reams
44. An Integrated Assessment of Climate Change on Timber Markets of
the Southern United States; Joseph E. de Steiguer and Steven G. McNulty
47. Economics and Global Climate Change; David N. Wear
The Productivity and Sustainability of Southern Forest Ecosystems in
a Changing Environment is available from Springer-Verlag New York, Inc., 175 Fifth Avenue,
New York, NY 10010. The book costs $162.00. Call Springer-Verlag at 800-Springer
(800-777-4643). You can visit Springer-Verlag at www.Springer-NY.com
The Tannin in Your Life
Whether you realize or not, you are familiar with tannins. It may be
from their historical use for leather manufacture. It may be from a nice cup of tea or
from the wonderful palate tannins impart to a fine red wine. Even the simple pleasure of a
piece of chocolate candy (at least, for some of us) is centered on tannin. Tannins are
important to forestry because these compounds make up over one-third of the weight of most
tree barks, are the major constituents of nut shell husks, and are important components of
the leaves of most woody plants. Those of us in the South are familiar with the brown
coloration of our streams and lakes due in large part to the leaching of these
water-soluble polymers from leaves and bark of our southern forest plants. These few
examples illustrate the broad distribution of tannins in plants and the impact of this
family of naturally occurring compounds on our lives.
The condensed tannins, such as those found in your tea or in tree
bark, are second only to wood lignins in their abundance of phenolic compounds on earth.
According to Dr. Richard W. Hemingway of the Southern Research Station's Forest Products
Research Unit at Pineville, LA, "Condensed tannins are infinitely more interesting
than lignins because tannins are more reactive, they challenge our ability to sort out
complexities involved in their stereochemistry, and they hold broad-spectrum biological
and ecological significance." Their biological significance rests with their potent
antioxidant properties and their propensity to form complexes with proteins and metal
ions.
Working with scientists from around the U.S. and many other
countries, Hemingway and the Southern Research Station have invested more than 25 years in
the study of condensed tannins. Hemingway's work has focused on understanding the basic
structure, reactions, and physical properties of condensed tannins. Dr. Hemingway has
distinguished himself as one of the world's leading scientists studying this important
class of natural products. His research has expanded our knowledge of these polymers, and
those results have helped other scientists and technologists identify new ways to use
tannins.
At the beginning of Hemingway's work in 1972, the Forest Service
began an effort to try to use tannins from southern pine bark. Little was known of the
structure or reactions of condensed tannins. However, both the chemical and forest
products industries demonstrated significant interest in the potential for tannins' use as
a renewable source of materials, especially for the manufacture of wood adhesives. Aided
by the great patience of Peter Koch and collaboration with Professor G. W. McGraw,
Louisiana College, Pineville, Hemingway first concentrated on defining the structure and
reactions of the condensed tannins.
Some of Hemingway's more applied research efforts, conducted with
Dr. Roland E. Kreibich, illustrate the value of knowing about the structure and reactions
of condensed tannins. Utilizing tannins isolated from the waste bark generated from
southern pine or pecan nut processing waste streams, the two scientists developed adhesive
systems capable of forming finger-jointed lumber without the need for external heat to
cure the adhesive. The wood used can be from green end-trim or from previously dried
lumber. This development has important implications in maximizing the use of wood in the
manufacture of premium-quality, high-value wood products from processing wastes that would
otherwise be used as pulp chips or sold as defective low-quality lumber.
About 15 years ago, Dr. Hemingway began researching the premise that
the properties of tannins are influenced not only by their chemical structure but just as
importantly by their conformational properties. The ability of these molecules to change
their three-dimensional shape depending on the environment being experienced is important
to explaining their biological activity. Through collaborations with Professor Frank R.
Fronczek at Louisiana State University, Professor Fred L. Tobiason at Pacific Lutheran
University, and Professor Wayne L. Mattice at the Institute of Polymer Science, University
of Akron, our Southern Research Station laboratory provided much of the basic crystal
structure and molecular mechanics data needed to understand the shape and flexibility of
these molecules.
The purchase of a 300MHz NMR spectrometer for the Forest Products
Research Unit was a major step in helping the Southern Research Station remain competitive
in this science. An example of the progress made possible by ready access to this
sophisticated analytical tool is the work done in collaboration Dr. T. Hatano, faculty of
pharmaceutical sciences, University of Okayama, Japan). Scientists and technicians have
provided physical data from NMR experiments that show what regions of a polypeptide chain
interact with different parts of tannin molecules. This information is needed to
understand their biological activity and help exploit those properties for high-value
specialty chemicals.
Hemingway, who helped organized and edited the results of he first
two tannin conferences, is working with Professor Georg Gross, the University of Ulm,
Germany, and Dr. Takashi Yoshida, Okayama University of Okayama, Japan, to organize the
3rd Tannin Conference. Scheduled for July 20-25, 1998, in Bend, OR, this conference has
attracted more than 125 contributions from scientists working in 22 countries. The topics
to be addressed include: 1) structure and synthesis of hydrolyzable tannins; 2) structure
and synthesis of condensed tannins; 3) biotechnology; 4) anti-oxidant properties and heart
disease; 5) conformation, complexation, and anti-microbial properties; 6) polyphenols and
cancer; and 7) commercial and ecological significance. Contributions to this conference
that are co-authored by Hemingway include:
- Interaction of flavanoids with peptides and proteins, and
conformations of dimeric flavanoids in solution; T. Hatano; T. Yoshida; and R. W.
Hemingway
- Tannin-based ``honeymoon' adhesives for finger-jointing dry, wet, and
green structural lumber; R.E. Kreibich and R.W. Hemingway
- Phenolation of (+)-catechin with mineral acids. Identification of new
reaction products; W. Peng; R. W. Hemingway; and A. H. Conner
- Modeling the conformation of polyphenols and their complexation with
polypeptides; F. L. Tobiason; R. W. Hemingway; and G. Vergoten
Abstracts of all contributions have been compiled into a 229
page book titled Abstracts of the 3rd Tannin Conference, published by Phytochemical
Connections, Inc., P.O. Box 12522, Alexandria, LA 71315. Plenum Press will publish Plant
Polyphenols: Chemistry and Biology, comprised of 55 contributions to this meeting. The
book should be in print by mid-1999.
Practical Guidelines for Producing Longleaf Pine Seedlings in
Containers--Clarification
The February 1998 issue of Recent Publications of the Southern
Research Station included an error in the description of GTR SRS-14 Practical
Guidelines for Producing Longleaf Pine Seedlings in Containers. Authors James P.
Barnett and John M. McGilvray state that the longleaf pine does not require full sun, but
it does perform much better with full sun. When planted in the field, the longleaf is so
sensitive to shade from competition that it could take 5 to 8 years for the seedling to
reach a stem diameter of 1 inch, at which point it goes into height growth. Barnett and
McGilvray's methods provide the longleaf pine seedling with the best opportunity to grow
quickly in the field and compete well with other southern pines.
RECENT PUBLICATIONS-JUNE 1998
Achtemeier, Gary L. 1998. First remote measurements of smoke on
the ground at night. In: Second symposium on fire and forest meteorology; 1998 January
11-16; Phoenix, AZ. Boston, MA: American Meteorology Society: 165-169.
The author discusses the measurement of smoke
movement on the ground at night. Small amounts of smoke from smouldering heavy fuels can
become trapped near the ground and carried several miles without much dispersion. In
addition, smoke entrapped within moist shallow valleys can initiate or enhance local fog.
Visibility impairment by smoke or smoke/fog over roadways can create serious hazards to
transportation. The Talladega Smoke Study reveals a proven technology that uses an
intensified multispectral video camera for airborne remote sensing of smoke moving near
ground at night; the need for a smoke sensing technology that can be used routinely to
monitor smoke movement at night; and, based on a comparison of ground observations with
smoke images collected from the airborne remote sensing part of the Talladega project,
some shallow layers of dense smoke escapes detection.
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Baker, James B.; Shelton, Michael G. 1998. Rehabilitation of
Understocked Loblolly-Shortleaf Pine StandsC I. Recently Cutover Natural Stands.
South. J. Appl. For. 22(l):35-40.
Two loblolly/shortleaf pine (Pinus taeda L.-P. echinata
Mill.) stands were cut to stocking levels of 10, 20, 30, 40, and 50 percent to simulate
recently cutover, understocked, uneven-aged stands. Number of trees ranged from 38 per
acre for 10 percent stocking to 213 per acre for 50 percent stocking; comparable total
basal areas were 4 and 16 ft2/ac, respectively. One stand was on a good site
(site index = 90ft at age 50), the other on a medium site (site index = 75 ft at age 50).
As a rehabilitation treatment, all hardwoods 1 in. groundline diameter and larger were
injected with an herbicide. At 2, 5, 10, and 15 years after treatment, the stands were
inventoried to determine: (1) rate at which the understocked stands recovered, and (2)
minimum stocking levels required for successful rehabilitation.
During 15 years of rehabilitation, the understocked stands changed
dramatically, and because of rapid growth of residual pines, stocking levels, basal areas,
and tree volumes increased markedly. Stands having at least 20 percent residual stocking
and 5 ft2/ac of pine basal area reached an acceptable stocking level of 60
percent (based on number and size of trees), or 45 ft2/ac of basal area within
15 years. Stands at this minimum stocking threshold produced 4,600 bd ft(Doyle)/ac
of sawtimber volume on the good site and 3,000 bd ft/ac of sawtimber volume on the medium
site during the 15 year period.
The study indicates that recently cutover, or damaged, understocked
stands with at least 20 percent to 30 percent stocking or 5 to 10 ft2/ac of
pine basal area can be rehabilitated to produce respectable sawtimber volumes. This
management strategy provides a low-cost alternative to establishing a new stand at
considerable cost to the landowner.
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Baker, James B.; Shelton, Michael G. 1998. Rehabilitation of
Understocked Loblolly Shortleaf Pine StandsCII. Development of Intermediate and Suppressed
Trees Following Release in Natural Stands. Southern Journal of Applied Forestry.
22(1):41-46.
Development of 86 intermediate and suppressed loblolly pine (Pinus
taeda L.) trees, that had been recently released from overtopping pines and hardwoods,
was monitored over a 15 year period. The trees were growing in natural stands on good
sites (site index = 90 ft at 50 years) that had been recently cut to stocking levels
ranging from 10 to 50 percent. At time of release, the trees averaged 26 years in age, 4.8
in. in d.b.h., and 37 ft in height. The trees had averaged only 0.5 in. in d.b.h. growth
the 5 years prior to release (0.1 in./yr).
After 15 years, the 77 surviving trees averaged 59 ft in height and
12.9 in. in d.b.h., increasing 21 ft in height and 8.1 in. in d.b.h. During the 15 year
period, crown dimensions of the trees increased markedly as well. On average, crown
lengths increased 11 ft (from 16 to 27 ft); crown widths nearly tripled from 9 to 25ft;
and crown volumes increased 11 fold from 608 to 6,700ft3. The majority of the
trees had good form and would produce high-quality sawtimber. Satisfactory response to
release was best predicted by initial d.b.h. and live-crown ratio.
Results of the study suggest that trees with at
least a 20 percent live-crown ratio should satisfactorily respond to release, even though
they had developed in lower crown positions of fully stocked uneven-aged stands for 10 to
50 years. Responding trees rapidly expanded their crowns and accelerated in height and
diameter growth.
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Baker, James B.; Shelton, Michael G. 1998. Rehabilitation of
Understocked Loblolly-Shortleaf Pine StandsCIII. Natural Stands Cutover 15 Years
Previously but Unmanaged. Southern Journal of Applied Forestry. 22(1):47-52.
Plots in an unmanaged loblolly-shortleaf pine (Pinus taeda
L.-P. echinata Mill.) stand that had been cutover 15 years previously were
established to represent five stocking levels: 10, 20, 30, 40, and 50 percent. The stand
was on a good site (site index Lob = 90 ft at 50 years) and had uneven-aged
character. Two competition control treatments (none and individual tree release using
herbicide) were also assigned. Three, five, and nine years later, the plots were
reinventoried to determine: (1) the rate at which the understocked stands recovered, (2)
the minimum stocking level required for successful rehabilitation, and (3) the effects of
release on pine growth.
The pine release treatment did not enhance stand development during
the 9 year rehabilitation period, primarily because only 18 percent of the pines
(representing 5 percent of total pine basal area) were overtopped by hardwoods and were
thus in need of release. However, results suggest that stands having an initial stocking
of 20 to 30 percent, or a total basal area of 10 to 15 ft2/ac, can reach an
acceptable stocking (levels of 60 percent for stocking, 45 ft2/ac for basal
area, and 2,500 bd ft(Doyle)/ac for sawlog volume) within 15 years or less.
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Baker, James B.;Shelton, Michael G. 1998. Rehabilitation of
understocked loblolly-shortleaf pine standsCIV. Natural and planted seedling/sapling
stands. Southern Journal of Applied Forestry. 22(1)53-59.
A 3- to 6-year-old naturally regenerated, even-aged loblolly pine (Pinus
taeda L.) stand and a 5 year-old loblolly pine plantation on good sites (SILob
= 85 to 90 ft at 50 years) were cut to density levels of 50, 90, 180, 270, and 360
seedlings and/or saplings/ac. Two pine release treatments (none and individual tree
release with an herbicide) were applied to the natural stand, but were not imposed in the
plantation because site preparation treatments were applied before planting. At 2, 5, and
10 years after installation, plots were inventoried to determine: (1) the lowest threshold
of seedling/sapling density that was feasible to manage, (2) the time required for poorly
stocked seedling/sapling stands to reach an acceptable stocking level, and (3) whether
release treatments would improve survival and growth of understocked, natural
seedling/sapling stands.
Results indicated that loblolly pine plantations on good sites
having at least 180 trees/ac (30 percent stocking) reached an acceptable stocking level of
60 percent by age 10 and produced up to 1,500 ft3/ac (19 cd/ac) of merchantable
volume by age 15. By this age, trees in plantations with 2 70 and 360 trees/ac displayed
good form, but at densities of 180, 90, and 50 trees/ac the trees still retained large
branches nearly to the ground.
Natural stands having at least 180 trees/ac that were released from
overtopping by hardwood at age 5 reached 60 percent stocking by age 15 but produced only
627 ft3/lac (8 cd/ac) of merchantable volume. When pines in the natural stand were not
released, only plots with 360 trees/ac reached an acceptable 60 percent stocking level by
age15 but only produced 539 ft3/ac (7cd/ac) of merchantable volume. The
observed differences in recovery rates in the understocked pine stands principally
reflected the levels of competing hardwoods.
Results suggest that understocked, natural stands or plantations of
pine seedlings/saplings with fewer than 180 trees/ac (less than 30 percent stocking), at
age 5, should probably be liquidated and a new stand established unless the landowner is
willing to sacrifice significant reductions in early volume production.
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Bolstad, Paul V.; Swank, Wayne T. 1997. Cumulative impacts of
landuse on water quality in a Southern Appalachian watershed. Journal of American
Water Resource Association. 33(3): 519-533.
Water quality variables were sampled over 109 weeks along Coweeta
Creek, a fifth-order stream located in the Appalachian Mountains of western North
Carolina. The purpose of this study was to observe any changes in water quality, over a
range of flow conditions, with concomitant downstream changes in the mix of landuses.
Variables sampled include pH, HC032-, conductivity, N03--N,
NH4+-N, P043--P, Cl-, Na+,
K+, Ca2+ Mg2+, SO4 2-, SiO2,
turbidity, temperature, dissolved oxygen, total and fecal coliform, and fecal
streptococcus. Landcover/landuse was interpreted from 1:20,000 aerial photographs and
entered in a GIS, along with information on total and paved road length, building location
and density, catchment boundaries, hydrography, and slope. Linear regressions were
performed to relate basin and near-stream landscape variables to water quality.
Consistent, cumulative, downstream changes in water quality
variables were observed along Coweeta Creek, concomitant with downstream, human-caused
changes in landuse. Furthermore, larger downstream changes in water quality variables were
observed during stormflow when compared to baseflow, suggesting cumulative impacts due to
landscape alteration under study conditions were much greater during storm events.
Although most water quality regulations, legislation, and sampling are promulgated for
baseflow conditions, this work indicates they should also consider the cumulative impacts
of physical, chemical, and biological water quality during stormflow.
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Bridgwater, F. E.; Bramlett, D. L.; Byram, T.D.; Lowe, W. J.
1998. Controlled mass pollination in loblolly pine to increase genetic gains. The
Forestry Chronicle. 74(2): 185-189.
Controlled mass pollination (CMP) is one way to increase genetic
gains from traditional wind-pollinated seed orchards. Methodology is under development by
several forestry companies in the southern USA. Costs of CMP depend on the efficient
installation, pollination, and removal of inexpensive paper bags. Even in pilot-scale
studies, these costs seem reasonable. Net present values from CMP in a sample of 67
loblolly pine (Pinus taeda L.) seed orchards in the Western Gulf Forest Tree
Improvement Program are conservatively expected to average $108 per acre of plantation
established with seedlings from CMP among the best six parents in each of five breeding
regions and $154 per acre for CMP among the best pair of parents in each breeding region.
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Cain, Michael D. 1997. Woody and herbaceous competition effects
on the growth of naturally regenerated loblolly and shortleaf pines through 11 years.
New Forests 14: 107-125.
Four levels of vegetative competition were used to quantify the
growth of loblolly and shortleaf pines (Pinus taeda L. and P. echinata
Mill.) in naturally regenerated, even-aged stands on the Upper Coastal Plain of
southeastern Arkansas, USA. Treatments included: (1) no competition control, (2) woody
competition control, (3) herbaceous competition control, and (4) total control of nonpine
vegetation. After pines became established from natural seeding, herbicides were used to
control herbaceous plants for 4 consecutive years and woody plants for 5 consecutive
years. Even though 89 percent of crop pines on untreated check plots were free-to-grow 11
years after establishment, crop pines on vegetation control plots were larger (P<0.001)
in mean d.b.h., total height, and volume per tree. From age 5 through 11 years, crop pine
diameter growth increased on woody control plots and decreased on herbaceous control plots
because of hardwood competition in the latter treatment. At age 11, crop pine volume
production averaged 207 m3/ha on total control plots, 158 m3/ha on
herbaceous control plots, 130 m3/ha on woody control plots, and 102 m3/ha
on untreated check plots.
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Cain, Michael D.; Shelton, Michael G. 1997. Loblolly and
shortleaf pine seed viability through 21 months of field storage: Can carry-over occur
between seed crops? Canadian Journal of Forest Research. 27:1901-1904.
To assess the potential for carry-over of loblolly pine (Pinus
taeda L.) and shortleaf pine (Pinus echinata Mill.) seeds from one year to the
next, seed viability was determined by germination tests following field storage for up to
21 months. Treatments included seeds stored (i) in a freezer, (ii) on the forest floor,
(iii) 1.8 m above the forest floor and exposed to precipitation, and (iv) 1.8 m above the
forest floor and sheltered from precipitation. The germinative capacity of seeds stored in
a freezer exceeded 95 percent for both loblolly and shortleaf pines after 7, 9, 19, and 21
months. Because seeds stored on the forest floor germinated naturally, laboratory
germination after 7 months storage averaged less than 1 percent for both species. Loblolly
pine seeds stored above the forest floor and exposed to precipitation had the highest
germinative capacity (98 percent and 56 percent germination after 7 and 21 months,
respectively). Relative ranking of viability retention for the remaining treatments was
loblolly seeds sheltered from precipitation > shortleaf seeds sheltered from
precipitation > shortleaf seeds exposed to precipitation.
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Conner, Richard N.; Rudolph, D. Craig; Schaefer, Richard R.; Saenz,
Daniel. 1997. Long-distance dispersal of Red-cockaded Woodpeckers in Texas. Wilson
Bulletin. 109(1):157-160.
The red-cockaded woodpecker (Picoides borealis)
is a cooperatively breeding species indigenous to the mature pine forests of the
Southeastern United States. Continued loss and fragmentation of the mature forests of the
South have increased the isolation of extant woodpecker groups throughout the range of
this endangered species. The authors discuss long-distance dispersal, which is likely
highly sensitive to population density because birds tend to keep moving until they find a
breeding vacancy.
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Conner, Richard N.; Saenz, Daniel; Rudolph, D. Craig; Coulson,
Robert N. 1998. Southern pine beetle-induced mortality of pines with natural and
artificial red-cockaded woodpecker cavities in Texas. Wilson Bulletin. 110(l):100-109.
Southern pine beetle (Dendroctonus frontalis)
infestation is the major cause of mortality for red-cockaded woodpecker (Picoides
borealis) cavity trees in loblolly (Pinus taeda) and shortleaf (P. echinata)
pines. Recent intensive management for red-cockaded woodpeckers includes the use of
artificial cavity inserts. Between 1991 and 1996 the authors examined southern pine beetle
infestation rates of pines with natural versus artificial cavities in loblolly and
shortleaf pine habitat on the northern portion of the Angelina National Forest. No
significant difference existed in the rate at which southern pine beetles infested and
killed pines with natural cavities versus those with artificial cavity inserts (c2
= 0.84, P > 0.05). Southern pine beetles infested and killed 20 natural cavity
trees (25.6 percent) during the 5-year study (78 cavity-tree years) and 19 artificial
cavity trees (18.8 percent; 101 cavity-tree years). Data for the entire Angelina National
Forest indicate that 40 percent (25 of 62) of the cavity trees killed by southern pine
beetles between 1984 and 1996 had been the nest tree during the preceding breeding season.
The annual infestation rate of cavity trees appears to be related to southern pine beetle
population levels of the surrounding forest. Use of artificial cavities is essential to
maintain sufficient numbers of usable cavities for red-cockaded woodpeckers in Texas. Why
southern pine beetles appear to preferentially infest active red-cockaded woodpecker
cavity trees is still unknown, but may be related to southern pine beetle attraction to
resin volatiles produced when woodpeckers excavate resin wells and/or changes in the
levels of infestation-inhibiting tree volatiles as a result of cavity and resin well
excavation.
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Conner, Richard N.; Saenz, Daniel; Rudolph, D. Craig; and others.
1998. Red-cockaded woodpecker nest-cavity selection: relationships with cavity age and
resin production. The Auk. 115(2): 447-454.
The authors evaluated selection of nest sites by
male red-cockaded woodpeckers (Picoides borealis) in Texas relative to the age of
the cavity when only cavities excavated by the woodpeckers were available and when both
naturally excavated cavities and artificial cavities were available. They also evaluated
nest-cavity selection relative to the ability of naturally excavated cavity trees to
produce resin, which is used by the woodpeckers to maintain a barrier against predation by
rat snakes (Elaphe spp.). Longleaf pines (Pinus palustris) selected by
breeding males as nest trees produced significantly greater resin yields at 2, 8, and 24
hours post-wounding than cavity trees used for roosting by other group members. This
preference was observed in loblolly pine (P. taeda) and shortleaf pine (P.
echinata) cavity trees only at the 2 hour resin-sampling period. When only naturally
excavated cavities were available, red-cockaded woodpeckers in both longleaf pine and
loblolly-shortleaf pine habitat selected the newest cavities available for their nest
sites, possibly as a means to reduce parasite loads. When both naturally excavated and
artificial cavity inserts were available, red-cockaded woodpeckers continued to select the
newest cavity for nesting in loblolly-shortleaf pine habitat but not in longleaf pine
habitat. Resin production in existing longleaf pine nest trees remained sufficient for
continued use, whereas resin production in loblolly pine and shortleaf pine nest trees
decreased through time, probably because of woodpecker activity at resin wells. For these
latter tree species, breeding males switched to newer cavities and/or cavity trees with
higher resin yields.
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Conner, William H.; Buford, Marilyn A. 1998. Southern deepwater
swamps. In: Messina, Michael G.; Conner H., eds. Southern forested wetlands ecology
and management. Boca Raton, FL: CRC Press: 261-287.
The authors define, classify, and analyze the
economic significance of southern deepwater swamps. They discuss the physical environment,
vegetational communities, animal communities, management issues, and research needs for
this complex resource.
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Dean, Thomas J.; Baldwin, Jr., V. Clark. 1996. Crown management
and stand density. In: Carter, Mason C., ed. Growing trees in a greener world:
industrial forestry in the 21st century; 35th LSU forestry
symposium. Baton Rouge, LA: Louisiana State University Agricultural Center, Louisiana
Agricultural Experiment Station: 148-159a-e.
Stand density management allows a forester to
utilize mortality and promote individual tree vigor. However, even after four decades of
spacing studies, planning for stand-density management remains a difficult problem. Forest
management approaches the problem with sophisticated analysis, but the heart of the
analysis depends on statistical growth models fit to data from empirical field trials.
Statistical growth-and-yield simulators interface poorly at times with modern forest
management analyses (Chang 1984). Even though no better predictor of the next rotation
exists than the performance of the previous rotation, history data does not exist for
every stand, and the combinations of species, density management, soils, and topography
create a matrix too large to test with spacing studies. Furthermore, changes in cultural
treatments, product specifications, and the physical environment diminish the predictive
value of field trials. Theories are emerging from recent work to support dens
density-management planning. These theories focus on the dynamics of crown dimensions in
relationship to stand development and average tree spacing and may aid in developing sound
density-management decisions and managing for desired stand qualities. In addition, they
may aid in overcoming some of the deleterious effects climate change, air quality, and
site degradation. Mechanistic linkages between the crown and the stem suggest new uses for
traditional treatments that may stimulate productivity and improve value.
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Ensign, William E.; Leftwich; Angermeier; Dolloff, C. Andrew. 1997. Factors
influencing stream fish recovery following a large-scale disturbance. Transactions of
the American Fisheries Society 126:895-907.
The authors examined fish distribution and abundance
in erosional habitat units in South Fork Roanoke River, VA, following a fish kill by using
a reachwide sampling approach for 3 species and a representative-reach sampling approach
for 10 species. Qualitative (presence-absence) and quantitative (relative abundance)
estimates of distribution and abundance provided consistent measures of fish recovery for
2 of 3 species at the reachwide scale and 8 of 10 species at the representative-reach
scale. Combining results across scales and estimator types showed that distributions and
abundances of 5 of 11 species in the reach affected by the kill were similar to those
observed in unaffected upstream and downstream reaches 8 to 11 months following the
perturbation. Differences in distribution and abundance between the affected reach and
unaffected reaches indicate that 4 of 11 species had not fully recovered during the same
time period; results were equivocal for 2 other species. The scientists attribute
differences in recovery rates between these two groups to differences in parental
investment in offspring. Species exhibiting rapid recovery either engage in extensive
spawning site preparation or guard the spawning site following egg deposition and
fertilization; species that had not recovered in the year following the kill show limited
spawning site preparation and do not guard the spawning site.
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Franco, Peter A.; Weaver, Peter L.; Eggen-McIntosh, Susan. 1997. Forest
resources of Puerto Rico, 1990. Resour. Bull. SRS-22. Asheville, NC: U.S. Department
of Agriculture, Forest Service, Southern Research Station. 45 p.
The principal findings of the second forest survey
of Puerto Rico (1990) and changes that have occurred since the survey was established in
1980 are presented. The forest inventory estimates describe the timber resource found
within the potential commercial region designated in the first survey. The timber resource
addressed consists primarily of regrown areas on abandoned pastures and cropland,
including coffee production areas. The status and trends of the timber resource are
presented for the two Life Zones occurring in the commercial region, as well as for
various forest classes, which are based on stand history and origin. Topics discussed
include forest area, timberland area, basal area, species composition, timber volume,
growing-stock volume, and sawtimber volume. Results of the 1990 survey are promising,
showing increases in numbers of trees across all diameter classes and substantial
increases in volume. These trends offer evidence that Puerto Rico's forest are continuing
to recover following a dramatic decline of the late 19th and early 20th
centuries.
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Johnson, Tony G. 1998. The Southeast's timber industryBan
assessment of timber product output and use, 1995. Resour. Bull. SRS-24. Asheville,
NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 24p.
In 1995, volume of roundwood products removed from
southern forests totaled 3.7 billion cubic feetB5 percent more than in 1992. Mill
byproducts generated from primary manufacturers was down 2 percent to 1.3 billion cubic
feet. Almost all plant residues were used, mostly for fuel and fiber products. Pulpwood
was the leading roundwood product at 1.8 billion cubic feet; saw logs are ranked second at
1.6 billion cubic feet; veneer logs were third with 238 million cubic feet. The number of
primary processing plants declined from 1,144 in 1992 to 1,028 in 1995. Total receipts
increased 3 percent to 3.8 billion cubic feet.
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Johnson, Tony G.; Steppleton, Carolyn D. 1997. Southern pulpwood
production, 1996. Resour. Bull. SRS-21. Asheville, NC: U.S.
Department of Agriculture, Forest Service, Southern Research Station. 34 p.
In 1996, the South's production of pulpwood
decreased 6 percent to 68.5 million cords. Roundwood production decreased to 49.6 million
cords and accounted for 72 percent of the total pulpwood production. The use of wood
residue declined to 19.0 million cords. Alabama leads the South in total production,
number of mills, and pulping capacity. Currently, 105 mills are operating and drawing wood
from the 13 Southern States. Southern mills' pulping capacity of 137,160 tons per day
accounts for more than two-thirds of the Nation's total pulping capacity.
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Kaiser, H. Fred; Granskog, James E. 1996. Raw materials from the
public lands in century 21. In: Carter, Mason C., ed. Growing trees in a greener
world: industrial forestry in the 21st century; 35th LSU forestry
symposium. Baton Rouge, LA: Louisiana State University Agricultural Center, Louisiana
Agricultural Experiment Station: 254-261.
Forest management on public lands is undergoing
fundamental change. To understand forest management on U.S. public lands in the future, an
understanding of the concept of ecosystem management will be needed. Ecosystem management
is not a goal unto itself, but a means to an endCand that end goal is sustainability of
all resources. A number of commitments have been made by U.S. Government officials to use
ecosystem management principles in managing the Nation's forest resources. At the June
1992 United Nations Conference on Environment and Development (UNCED) meeting in Rio de
Janeiro, the United States announced a policy of ecosystem management for natural
resources. President Clinton in the April 1993 "Forest Plan for a Sustainable Economy
and a Sustainable Environment" (Forest Plan) announced that ecosystem principles will
be used in forest planning. And in the September 1993 report, "Creating a Government
That Works Better and Costs Less," Vice President Gore directed that ecosystem
planning and management be used by federal land management agencies. The authors discuss
timber production from public and private lands, both from a historical view and within
the framework of ecosystem management.
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Kard, Brad. 1998. Termiticide field tests continue moving
forward. [a] Stainless steel meshCan alternative termite barrier? [b] 1998. Pest
Control. February 1998. [page numbers unknown]
The author reports on existing and candidate
termiticide field tests and the value of stainless steel mesh as an alternative barrier.
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Kilgo, John C.; Sargent, Robert A. 1998. Effect of stand width
and adjacent habitat on breeding bird communities in bottomland hardwoods. Journal of
Wildlife Management. 620(1): 72-83.
Bottomland hardwood forests support an abundant and
diverse avifauna, but area of this forest type has been reduced, and current projections
indicate continued declines. The authors compared breeding bird abundance indices and
species richness among bottomland hardwood stands ranging in width from <50 m to
>1,000 m and enclosed by forested habitat. They also compared avian abundance indices
and richness among stands enclosed by pine (Pinus spp.) forest and stands enclosed
by field-scrub habitats. Total species richness and species richness of Neotropical
migrants were associated positively (P < 0.05) with stand width in all years. Total
bird counts differed among width classes in all years, with counts generally greatest in
width classes <50 m and >1,000 m. Counts of Neotropical migrants differed (P
< 0.05) among width classes in 1993 and 1995 and followed the same general trend as
total bird count. Acadian flycatcher (Empidonax virescens), blue-gray gnatcatcher (Polioptila
caerulea), and red-eyed vireo (Vireo olivaceous) were more abundant in smaller
width classes (P < 0.05), whereas the opposite was true for white-eyed vireo (Vireo
griseus) and northern parula (Parula americana). Probability of occurrence was
associated positively (P < 0.05) with stand width for 12 species and negatively with
stand width for 1 species. Total bird count and the counts of blue-gray gnatcatcher in
1995 and of northern cardinal (Cardinalis cardinalis) in both years were higher in
field-enclosed stands (FES) than in pine-enclosed stands (PES). No species analyzed was
more abundant in PES than in FES. The authors conclude that even narrow riparian zones can
support an abundant and diverse avifauna, but that conservation of wide ($500 m) riparian
zones is necessary to maintain the complete avian community characteristic of bottomland
hardwood forests in South Carolina.
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Klepzig, K.D. 1998. Competition between a biological control
fungus, Ophiostoma piliferum, and symbionts of the southern pine beetle.
Mycologia. 90(1): 69-75.
A colorless isolate of O. piliferum was paired in a series of
competitive interactions with three fungal symbionts of Dendroctonus frontalis, the
southern pine beetle. Two of these fungi, Ceratocystiopsis ranaculosus and Entomocorticium
sp. A, are considered to be mutualists of the southern pine beetle. The third fungal
symbiont, O. minus, is considered to be an antagonist. The author strong evidence
of differential competition between O. piliferum and all three symbionts. In
primary and secondary resource capture contests on an artificial medium, O. piliferum
outcompeted all three fungi. In inoculations of natural substrate, O. piliferum
outcompeted the two mutualists but did not outcompeted O. minus. The ability of O.
piliferum to outcompeted beetle mutualists on both artificial and natural substrates
indicates promise for this fungus as a biological control agent of the southern pine
beetle. However, it may not be able to always prevent colonization by O. minus and
the resultant discoloration of colonized wood.
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Leftwich, Kevin N.; Angermeier, Paul L.; Dolloff, C. Andrew. 1997. Factors
influencing behavior and transferability of habitat models for a benthic stream fish.
Transactions of the American Fisheries Society. 126: 725-734.
The authors examined the predictive power and
transferability of habitat-based models by comparing associations of tangerine darter Percina
aurantiaca and stream habitat at local and regional scales in North Fork Holston River
(NFHR) and Little River, VA. The models correctly predicted the presence or absence of
tangerine darters in NFHR for 64 percent (local model) and 78 percent (regional model) of
the sampled habitat units (i.e., pools, runs, riffles). The distribution of tangerine
darters apparently was influenced more by regional variables than local variables. Data
from Little River and 37 historical records from VA were used to assess transferability of
models developed from NFHR data. In general, the models did not transfer well to Little
River; all models predicted that either no (regional model) or few (local model) habitat
units in Little River would contain tangerine darter, even though the species was observed
in 83 percent of the habitat units sampled. Conversely, the regional model correctly
predicted presence of tangerine darters for 95 percent of the historical records.
Principal components analysis showed extensive overlap in NFHR and Little River habitat,
which suggests that the two streams are ecologically similar. The suitability of Little
River for tangerine darters was shown more clearly by principal components analysis than
by the authors' models. Because different limiting factors may apply in different systems,
the elimination of potentially important ecological variables may compromise model
transferability. A hierarchical approach to habitat modeling, with regard to variable
retention, may improve transferability of habitat models.
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Leininger, T.D.; McCasland, C.S. 1997. Oak decline in the
midsouth U.S.A.: a summary from 1986 to 1996 [Abstract]. Phytopathology 87(6):S57.
From 1986 to 1988, oak decline research plots were
set up at 11 sites (three upland and eight bottomland) in the Midsouth region of the
U.S.A. Plots either had (D) or did not have (ND) decline when they were set up. Data were
collected to examine relationships between oak crown conditions and various site and stand
variables, especially numbers of diseases and indicators of wood-boring insects on plot
trees. Percentages of crowns with decline symptoms were greater on D plots than on ND
plots initially, in 1992, and 1996; and were greater at two of the upland sites compared
to other sites. Percentages of crowns with decline symptoms had increased on 8 ND sites by
1996. Twenty to 40 percent of oaks on D plots had died by 1996, compared to 5 to 10
percent on ND plots. Percent mortality increased over time on D and ND plots. Oaks on D
and ND plots averaged about 0.2 diseases and about 3 insect borer scars. Numbers of
diseases and insect borer scars were highly variable so that no relationship was
established between these and crown decline symptoms. Interestingly, 7 of 10 D plots had
more red oaks (>60 percent of all species), than 8 of 11 ND plots (approximately 50
percent of all species). The importance of these findings are discussed for aging oak
forests of the region.
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Lemly, A. Dennis. 1997. Ecosystem recovery following selenium
contamination in a freshwater reservoir. Ecotoxicology and Environmental Safety.
36:275-281.
Belews Lake, North Carolina, was contaminated by
selenium in wastewater released from a coal-fired electric generating facility during
1974-1985. Selenium bioaccumulated in aquatic food chains and caused severe reproductive
failure and teratogenic deformities in fish. Beginning in 1986, the electric utility
company changed its ash disposal practices and selenium-laden wastewater no longer entered
the lake. A survey of selenium present in the water, sediments, benthic invertebrates,
fish, and aquatic birds was conducted in 1996. Concentrations were compared to pre-1986
levels to determine how much change occurred during the decade since selenium inputs
stopped. The data were also examined using a hazard assessment protocol to determine if
ecosystem-level hazards to fish and aquatic birds had changed as well. Results reveal that
waterborne selenium fell from a peak of 20 Fg/liter before 1986, to <1 Fg/liter in
1996; concentrations in biota were 85 to 95 percent lower in 1996. Hazard ratings indicate
that high hazard existed prior to 1986 and that moderate hazard is still present,
primarily due to selenium in the sediment-detrital food pathway. Concentrations of
selenium in sediments have fallen by about 65 to 75 percent, but remain sufficiently
elevated (1-4 Fg/g) to contaminate benthic food organisms of fish and aquatic birds. Field
evidence confirmed the validity of the hazard ratings. Developmental abnormalities in
young fish indicate that selenium-induced teratogenesis and reproductive impairment are
occurring. Moreover, the concentrations of selenium in benthic food organisms are
sufficient to cause mortality in young bluegill and other centrarchids because of Winter
Stress Syndrome. At the ecosystem level, recovery has been slow. Toxic effects are still
evident 10 years after selenium inputs were stopped. The sediment-associated selenium will
likely continue to be a significant hazard to fish and aquatic birds for years.
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Lemly, A. Dennis. 1997. Environmental implications of excessive
selenium: a review. Biomedical and Environmental Sciences. 10: 415-435.
Selenium is a naturally occurring trace element that is
nutritionally required in small amounts, but it can become toxic at concentrations only
twice those required. The narrow margin between beneficial and harmful levels has
important implications for human activities that increase the amount of selenium in the
environment. Two of these activities, disposal of fossil fuel wastes and agricultural
irrigation of arid, seleniferous soils, have poisoned fish and wildlife, and threatened
public health at several locations in the United States. Research studies of these
episodes have generated a data base that clearly illustrates the environmental hazard of
excessive selenium. It is strongly bioaccumulated by aquatic organisms, and even slight
increases in waterborne concentrations can quickly result in toxic effects such as
deformed embryos and reproductive failure in wildlife. The selenium data base has been
very beneficial in developing hazard assessment procedures and establishing
environmentally sound water quality criteria. The two faces of selenium, required nutrient
and potent toxin, make it a particularly important trace element in the health of both
animals and man. Because of this paradox, environmental selenium in relation to
agriculture, fisheries, and wildlife will continue to raise important land and water
management issues for decades to come. If these issues are dealt with using prudence and
the available environmental selenium data base, adverse impacts to natural resources
and-public health can be avoided.
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Lemly, A. Dennis. 1997. Risk assessment as an environmental
management tool: considerations for freshwater wetlands. Environmental Management.
21(3): 343-358.
This paper presents a foundation for improving the risk assessment
process for freshwater wetlands. Integrating wetland science, i.e., use of an
ecosystem-based approach, is the key concept. Each biotic and abiotic wetland component
should be identified and its contribution to ecosystem functions and societal values
determined when deciding whether a stressor poses an unreasonable risk to the
sustainability of a particular wetland. Understanding the major external and internal
factors that regulate the operational conditions of wetlands is critical to risk
characterization. Determining the linkages between these factors, and how they influence
the way stressors affect wetlands, is the basis for an ecosystem approach. Adequate
consideration of wetland ecology, hydrology, geomorphology, and soils can greatly reduce
the level of uncertainty associated with risk assessment and lead to more effective risk
management. In order to formulate effective solutions, wetland problems must be considered
at watershed, landscape, and ecosystem scales. Application of an ecosystem approach can be
greatly facilitated if wetland scientists and risk assessors work together to develop a
common understanding of the principles of both disciplines.
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Lemly, A. Dennis. 1998. A position paper on selenium in
ecotoxicology: a procedure for defining site-specific water quality criteria.
Ecotoxicology and Environmental Safety. 39: 1-9.
This paper describes a method for deriving site-specific water
quality criteria for selenium using a two-step process: 1) gather information on selenium
residues and biological effects at the site and in down-gradient systems; and 2) examine
criteria based on the degree of bioaccumulation, the relationship between measured
residues and threshold concentrations for reproductive effects in fish and wildlife, and
any observed reproductive impacts. Several outcomes are possibleCcriteria can be left
unmodified, adjusted upward by a fixed amount (50 percent), or adjusted downward by one of
three amounts (25, 50, or 75 percent). A criterion (existing or proposed) is lowered or
raised by an amount that is proportional to the magnitude of bioaccumulation and toxic
effects presentCi.e., the degree of biological hazard. Criteria can be modified under two
circumstances: 1) diagnostic residues and toxic effects must be coupled (present)
in order to lower a criterion; or 2) diagnostic residues and toxic effects must be
coupled (absent) in order to raise a criterion. Coupling residues and effects makes the
procedure sensitive to the natural inter- and intraspecific variation in bioaccumulation
and toxic responses exhibited by fish and wildlife in aquatic ecosystems. The goal is to
establish criteria that keep food-chain bioaccumulation below levels that result in
toxicity to fish and wildlife. Precautions are given for those attempting to apply the
generic EPA model for implementing national water quality criteria to a site-specific
selenium criterion.
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Lemly, A. Dennis. 1998. Pathology of selenium poisoning in fish.
In: Frankenberger, Jr., William T.; Engberg, Richard A., eds. Environmental chemistry of
selenium. New York: Marcel Dekker, Inc.: 281-296.
Selenium presents an interesting paradox in the field of aquatic
toxicology because it is both a nutrient and a poison. As a nutrient, it is required in
the diet of fish at concentrations of about 0. 1 to 0. 5 Fg/g dry weight. Selenium is
necessary for proper formation and functioning of glutathione peroxidase, which is a major
cellular antioxidant enzyme. This enzyme protects cell membranes from damage or lysis due
to lipid peroxidation. Without adequate selenium, normal cellular and organ metabolism
break down because of peroxides produced as a by-product of digestion. Symptoms of
selenium deficiency in fish include reduced growth, anemia, exudative diathesis, muscular
dystrophy, and increased mortality. Thus, the beneficial effects of proper selenium in the
diet of fish are firmly established.
At dietary concentrations of only 7 to 30 times those required >3
Fg/g), selenium becomes a poison. Some of the major toxic effects are due to a simple
principle of cell biology. From a biochemical perspective, selenium is very similar to
sulfur, and cells do not discriminate well between the two when carrying out one of their
key functionsCprotein synthesis. When present in excessive amounts, selenium is
erroneously substituted for sulfur in proteins that are being formed inside the cells.
Sulfur-to-sulfur linkages (ionic disulfide bonds) are necessary for protein molecules to
coil into their tertiary (helix) structure which, in turn, is necessary for proper
functioning of the protein, either as a cellular building block or as a component of
enzymes. Substitution of selenium for sulfur disrupts the normal chemical bonding,
resulting in improperly formed and dysfunctional proteins or enzymes.
Thresholds for dietary selenium toxicity in fish are
easily reached and exceeded in contaminated aquatic systems. Excessive selenium can cause
a wide variety of toxic effects at the biochemical, cellular, organ, and system levels.
This chapter examines the most prominent outward manifestation of selenium
toxicosisCteratogenic deformitiesCand discusses the use of this pathological symptom as a
diagnostic tool for evaluating reproductive impairment and assessing impacts to fish
populations in contaminated aquatic habitats.
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Lester, D.G.; Wilson, A.D. 1997. Novel USDA Forest Service
pest-image softwares for the rapid identification of southern hardwood pests [Abstract].
Phytopathology 87(6):S113.
The accurate and rapid identification of forest
pests is necessary for selecting successful controls for most forest health problems. To
facilitate this process, new softwares were developed in Visual Basic (for Windows) to
access and display images from pest libraries of selected hardwood hosts or specific
diseases, including: ash pests, oak pests, cottonwood pests, and oak wilt of southern
oaks. Each [pest image] library contains 90 to 200 full color images arranged by topic.
Images take about 5 s to load and display on a 100 MHz computer, may be downloaded for use
in other graphic softwares, and are in the public domain. A zoom feature is included for
extra detail. Topics include insects, diseases, and abiotic incitants of forest pest
problems. The oak wilt library includes sections on current Federal research results and
control methods. The softwares, available on CD-ROM, are the first CDs produced entirely
in-house by the USDA Forest Service. They operate on 486 or faster IBM-compatible
computers with SVGA monitor, Windows 3.x or 95, mouse or graphics tablet, and 2 or faster
CD-ROM drive. [Ed. note: Contact A.D. Wilson, Stoneville, MS, at 601-686-3180 to
purchase any pest image CD; a charge of $12.50 per CD is provided to cover production
costs.]
Loeb, Susan C.; Hooper, Robert G. 1997. An experimental test of
interspecific competition for red-cockaded woodpecker cavities. Journal of Wildlife
Management. 61(4): 1268-1280.
To test whether the presence of nest boxes near
red-cockaded woodpecker (RCW, Picoides borealis) cavity trees reduced cavity use by
other species and improved RCW reproductive success on the Francis Marion National Forest
in coastal South Carolina, the authors placed 3 nest bows in each of 62 experimenta1 boxes
clusters and designated 61 clusters as controls. Observations of nest box and cavity use
showed that nest boxes were somewhat effective in reducing cavity use and that eastern
bluebirds (Sialia sialis) and southern flying squirrels (Glaucomys volans)
were the most frequent users of' nest boxes and cavities. Bluebirds preferred nest boxes
to cavities in both years and flying squirrels showed significant preference for nest
boxes in 1992. Pretreatment monitoring (1990) of RCW reproductive performance showed no
significant difference between control and experimental groups. However, posttreatment
monitoring showed that in 1991 RCW's in experimental clusters were significantly more
likely to nest than RCW's in control clusters; in 1991 and 1992, they were more likely to
fledge $1 young. Further, RCW's were less likely to initiate a nest if $1 cavity was
occupied by a non-RCW species than if no cavities in the cluster were occupied by a
non-RCW species. These results indicate that RCW cavities were subject to interspecific
competition and that nest boxes may be an effective means of reducing competition,
particularly when the number of cavities is limited.
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McAlister, Robert H.; Clark, III, Alexander; Saucier, Joseph R.
1997. The effect of age at harvest on bending and tensile properties of loblolly pine
from the Coastal Plain. Forest Products Journal. 47(5): 85-88.
The effect of rotation age on strength and stiffness of lumber
produced from unthinned loblolly pine stands in the Coastal Plain of Georgia was examined.
Six stands representing 22-, 28-, and 40-year-old rotations were sampled. A stratified
random sample of trees 8 to 16 inches in diameter at breast height was selected from each
stand and processed into lumber. Dimension lumber from the study was tested for strength
and stiffness in both static bending and tension according to the provisions of the
American Society for Testing and Materials standard method D 198. The strength and
stiffness in both bending and tension generally increased with increasing rotation age.
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McTague, John Paul; Tinus, Richard W. 1996. The effects of
seedling quality and forest site weather on field survival of ponderosa pine. Tree
Planters' Notes. 47(1): 16-23.
In this study, the authors report field survival
results of an analysis of the USDA Forest Service Reforestation Improvement Program. The
field survival of 3 test plantings of ponderosa pine (Pinus ponderosa Laws. var. ponderosa)
were modeled with regression analysis using a modified logit transformation. The initial
predictor variables tested included nursery seedling morphological traits such as height,
diameter, and stem and root weights; several performance attributes such as root growth
potential, cold hardiness, and root exposure stress tests; and days since planting of the
seedlings. Forest site weather variables measured during the first growing season reduced
confounding between seedling quality tests and field survival measurements. Root growth
potential was consistently important as a performance attribute in explaining survival of
three field tests of ponderosa pine. The root exposure stress test was a useful measure
for predicting survival of seedlings planted on warm sites, and the mean initial height of
seedlings was an important predictor for survival on warm and very dry sites.
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McElreath, S.D.; Tainter, F.H.; Birrenkott, G.P.;and others. Polyclonal
antibodies to wetwood bacteria from egg yolk of immunized hens [Abstract]. 1997.
Phytopathology 87(6):S113-114.
[Ed. note: Leininger, T.D. is SRS author.]
Four Leghorn hens were immunized with
formaldehyde-treated whole cells of Ervinia chrysanthemi and a Clostridium
sp. isolated from a wetwood-affected black oak. Two hens received each antigen and were
immunized either subcutaneously (SQ) at the base of the neck or intramuscularly (IM) in
the pectoralis muscle. Boosters were given at 2, 4, and 10 weeks. IgY antibodies were
isolated from yolks collected weeks 1 to 16. Homologous antibody titers were measured by
ELISA using a donkey anti-chicken antibody conjugated with alkaline phosphatase. The
greatest dilution which gave an ELISA A410 of 0.9 to 1.0 was 1/800 with Erwinia
chrysanthemi at 7 weeks and 1/400 with the Clostridium sp. at 13 weeks. Gross
and histological pathology of tissues around the injection sites revealed similar
inflammatory responses that were less extensive around the base-of-the-neck injections. An
ELISA system for detection of these bacteria in sap and wood samples is under development.
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Parresol, Bernard R.; Vissage, John S. 1998. White pine site
index for the southern forest survey. Res. Pap. SRS-10. Asheville, NC: U.S.
Department of Agriculture, Forest Service, Southern Research Station. 8 p.
A base-age invariant polymorphic site index equation
was used to model the white pine (Pinus strobus L.) Site-quality data provided by
Frothingham (1914). These data are the accepted standard used by the Southern Forest
Inventory and Analysis unit of the U.S. Department of Agriculture, Forest Service. An all
possible growth intervals data structure was used, and autocorrelation parameters were
incorporated into the site index model. It has recently been shown that these measures are
necessary to obtain unbiased, efficient parameter estimates. The model is invertible,
hence site index can be explicitly determined without the need for a numerical evaluation
procedure. The site index model can be solved to provide an equation for any base age,
hence it is applicable regardless of the choice of rotation age. Site index curves are
graphed for base ages 25 and 50 years, and example calculations are provided.
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Peng, Weiling; Conner, Anthony H.; Hemingway, Richard W. 1997. Phenolation
of (+)-catechin with mineral acids. II. Identification of new reaction products. Journal
of Wood Chemistry and Technology. 17(4):341-360.
To investigate the reactions that occur in the flavanoid unit during
the liquefaction of tannin in phenol, the phenolysis of (+)-catechin was studied using
either H2SO4, HCl, or BF3 2H2O as acid
catalyst. In addition to
2-[3-(3,4-dihydroxyphenyl)-2-hydroxy-3-(4-hydroxyphenyl)propyl]-1,3,5-benzenetriol (1) and
2-[(3,4-dihydroxyphenyl)(4-hydroxyphenyl)methyl]-2,3-dihydro-4,6-benzofurandiol (3) that
have been described previously, eight additional reaction products were isolated, four of
which were compounds that have not been described previously. The novel compounds
described here are:
2-[3-(3,4-dihydroxyphenyl)-2-hydroxy-3(2-hydroxyphenyl)propyl]-1,3,5-benzenetriol (2),
2-[(3,4-dihydroxyphenyl)(2-hydroxyphenyl)methyl]-2,3-dihydro-4,6-benzofurandiol (4),
2-[(3,4-dihydroxyphenyl)(4-hydroxyphenyl)methyl]-2,3-dihydro-7-(4-hydroxyphenyl)methyl-4,6-benzofurandiol
(5), and
2-(1,3,5-trihydroxyphenyl)methyl-3-(3,4-dihydroxyphenyl)-6-[(3,4-dihydroxyphenyl)-
-(4-hydroxyphenyl)methyl]-2,3,5,6-tetrahydrobenzo[1,2-b:5,4-b']-difuran-4-ol (6).
The structures of these and other previously
described products are consistent with opening of the pyran ring of catechin and reaction
at C-2 by either the para or the ortho position of phenol. Additional
products resulting from reaction between pyran ring cleavage products and catechin, and
from reaction of cleavage products were found. Similar reactions would be expected to take
place during the phenolysis of condensed tannins.
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Perry, Roger W.; Mangini, Alex. 1997. A comparison of trap versus
ground collection of acorns to assess insect infestation. Journal of Entomological
Science. 32(4): 412-415.
Oak (Quercus spp.) species are a significant
portion of the forest in the Eastern United States. Oaks provide valuable timber products
and habitat for many wildlife species. Acorns are essential for oak regeneration and are a
major food source for more than 186 species of birds and mammals. Great variation in
annual acorn production causes dramatic fluctuations in seed availability for food and oak
regeneration. Although total annual production may have the greatest effect on acorn
abundance, availability can be dramatically reduced by insects. During years of high
production, insect losses are usually low in proportion to abundance; however, insects can
destroy most acorns during years of low production. Loss of acorns to insects can vary
from as low as 6 percent to more than 80 percent. Thus, studies seeking information on oak
regeneration and studies involving wildlife food availability may be biased when insect
predation is not considered. To provide information on acorn abundance and loss to
insects, most studies have used acorns collected from traps. However, traps are costly to
build and maintain, require many hours to install, and provide limited sampling areas and
high variance. Collecting acorns from the ground is a quick and inexpensive method of
obtaining large samples of acorns. Given the high costs associated with trapping acorns,
the authors tested whether insect infestation level differed according to collection
method to determine whether collecting acorns from the ground is a viable alternative to
trapping.
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Powers, R.F.; Tiarks, A.E.; Burger, J.A.; Carter, M.C. Sustaining
the productivity of planted forests. 1996. In: Carter, Mason C., ed. Growing trees in
a greener world: industrial forestry in the 21st century; 35th LSU
forestry symposium. Baton Rouge, LA: Louisiana State University Agricultural Center,
Louisiana Agricultural Experiment Station: 97-134
Conversion of natural forests to plantations,
particularly in the tropics, has drawn global attention and concern. Moreover, plantation
forestry is on the rise, especially in tropical and subtropical regions where growth rates
are rapid. Even in the United States, where even-age silviculture is being deemphasized on
public land (only about 15 percent of all plantings in recent years), the area in new
plantings on all ownership has averaged 1.11 million ha annually for the last decade,
ranging from a low of 979 thousand ha in 1993 to the all-time high of 1.37 million ha in
1988 (Moulton, et al. 1996). Most of this is in the southern pine region. Since global and
domestic demands for wood products will continue to rise in the 21st century,
deemphasis of timber management on public forests and the reclassification of much natural
forest to protected status places an unprecedented burden on planted forests on private
lands to meet the needs of a wood-demanding public. Pressures will bear particularly on
industrial plantations of the South and Pacific Northwest to be more productive than ever.
But there is much skepticism that high rates of plantation productivity can be maintained
for long periods with repeated cropping. Addressing this criticism requires a definition
and understanding of productivity that cuts across all intended uses of plantations.
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Prestemon, Jeffrey P. 1997. The effects of NAFTA expansion on US
forest products exports. Journal of Forestry. 95(7): 26-32.
When Mexico began liberalizing its domestic market and foreign trade
a decade ago, the U.S. Government hoped U.S. exporters would gain easier access to the
Nation's third most important foreign market, after Japan and Canada. Having just
completed a free trade accord with Canada, U.S. trade officials sought to solidify changes
in Mexico and encourage further economic reform by negotiating the North American Free
Trade Agreement (NAFTA). Similar economic and political motivations are behind current
U.S. Government interest in adding other countries to NAFTA or establishing an
Americas-wide free trade area. Latin American leaders have themselves expressed a desire
to create a regional free trade area by 2005.
If new countries join NAFTA or if hemispheric free trade is
accomplished in another way, among the new signatories might be relatively large producers
and consumers of forest products Ca prospect that should draw the attention of U.S. forest
products manufacturers and consumers. Some have suggested that growth in the forest
sectors of Latin American countries might raise competitive pressures on North American
forest products producers. Others have simply indicated the region's potential for
substantially increased forest products output.
No research, however, has been published on how
NAFTA expansion to include other major forest products producers would affect competition.
Given the current structure of trade in the Americas and the existing constraints to trade
in forest products between the United States and the other countries, how would expansion
of NAFTA change the situation?
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Prestemon, Jeffrey P. 1998. Estimating tree grades for Southern
Appalachian natural forest stands. Forest Science 44(1): 73-86.
Log prices can vary significantly by grade: grade 1 logs are often
several times the price per unit of grade 3 logs. Because tree grading rules derive from
log grading rules, a model that predicts tree grades based on tree and stand-level
variables might be useful for predicting stand values. The model could then assist in the
modeling of timber supply and in economic optimization. Grade models are estimated for10
species groups found in the Southern Appalachians, using data from several thousand trees
and permanent plots in the USDA Forest Service's Forest Inventory and Analysis (FIA)
database. The models correctly predicted grades of a majority of trees in both a test and
a validation data set, and predictions of grade proportions across a sample of the
population were usually within 3 percentage points of actual grade proportions. But
success of models varied across species and diameter groups. Considering several measures
of modeling success, the most accurate models were those predicting tree grades for
softwoods and larger hardwoods.
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Schultz, Robert P. 1997. Loblolly pine: the ecology and
culture of loblolly pine (Pinus taeda L.). Agriculture Handbook 713.
Washington, D.C.: U.S. Department of Agriculture, Forest Service. 493 p.
Loblolly pine ranks as a highly valuable tree for its pulp, paper,
and lumber products. In the South, loblolly is planted more than any other conifer. Loblolly
PineCThe Ecology and Culture of Loblolly Pine (Pinus taeda L.) adds to the
technical foundations laid by Ashe (1915) and Wahlenberg (1960). Agriculture Handbook 713
encompasses genetics, tree improvement, field inventory and analysis, and international
forestry, as well as ecology, direct seeding, and planting. Loblolly Pine: The
Ecology and Culture of Loblolly Pine (Pinus taeda L.) highlights individual
tree, stand, and land management alternatives useful to resource managers, students,
researchers, and others. [Ed. Note: Although the number of copies for initial
distribution are limited, this publication will be offered for sale by the Government
Printing Office.]
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Seixas, Fernando; McDonald, Tim. 1997. Soil compaction effects of
forwarding and its relationship with 6- and 8-wheel drive machines. Forest Products
Journal. 47(11/12): 46-52.
A study was done to determine the impact, if any, of
a range of drive train options on the soil compaction effects of forwarders. The purpose
of the study was to evaluate the cost of optional forwarder equipment versus its ability
to reduce detrimental soil physical property changes. Tests were done on forwarders
equipped with wide and narrow tires, rear steel tracks, and 6 or 8 tires. The
configurations differed, at the extremes, by a factor of about 2 in expected ground
pressure. Despite that, results showed little difference in bulk density, soil strength,
rut formation, or porosity changes (pre- versus post-traffic) between any of the tested
options. The implication was that, for the moisture conditions encountered in the study,
the use of the tested options did not alter soil compaction impacts substantially. A drop
in macroporosity was observed, however, which may have been evidence that traffic affected
soil structure without compacting it by a detectable amount.
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Shackelford, Clifford E.; Conner, Richard N. 1997. Woodpecker
abundance and habitat use in three forest types in eastern Texas. Wilson Bulletin.
109(4): 614-629.
Woodpeckers were censused in 60 fixed-radius (300 m)
circular plots (divided into eight 45B-arc pie-shaped sectors) in mature
forests (60 to 80 years-old) of three forest types (20 plots per type) in eastern Texas:
bottomland hardwood forest; longleaf pine (Pinus palustris) savanna; and mixed
pine-hardwood forest. A total of 2,242 individual woodpeckers of eight species was
detected in 144 h of censusing. Vegetation characteristics in plot sectors with and
without woodpeckers were compared. Woodpecker presence and abundance were primarily
associated with the occurrence of large snags and logs. Red-bellied woodpeckers (Melanerpes
carolinus) were the most abundant and widespread species, especially in areas
containing more hardwoods than pines. Red-cockaded woodpeckers (Picoides borealis)
were the least abundant and most habitat-restricted woodpecker, occurring only in the
longleaf pine savanna. Pileated woodpeckers (Dryocopus pileatus) were the most
evenly distributed species among the forest types, but occurred primarily in mature
forests with large snags and logs. Bottomland hardwood forests were important for northern
flickers (Colaptes auratus), redheaded woodpeckers (Melanerpes erythrocephalus),
and yellow-bellied sapsuckers (Sphyrapicus varius) during the fall and winter, and
for downy woodpeckers (Picoides pubescens) during the summer and winter. The hairy
woodpecker (P. villosus) was most frequently encountered in areas of recent
disturbance in the mixed pine-hardwood forests, especially in fall. Vocal imitation of a
barred owl (Strix varia) increased the number of woodpecker detections by 71
percent.
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Shelton, Michael G.; Murphy, Paul A. 1997. Growth after thinning
a 35-year-old natural stand to different loblolly pine and hardwood basal areas.
Southern Journal of Applied Forestry. 21(4): 168-174.
Growth was monitored for 4 years in a thinned stand
in southern Arkansas with three pine basal areas (70, 85, and 100 ft2/ac) and
three hardwood basal areas (0, 15, and 30 ft2/ac); pretreatment basal areas
averaged 119 and 33 ft2/ac for pines and hardwoods, respectively. Treatments
were arranged in a 3 x 3 factorial randomized complete block design with three replicates,
yielding 27 permanent 0.20 acre plots. Growth variables were regressed with residual pine
and hardwood basal areas. Pine basal area and volume growth increased with the pine
stocking level after thinning and decreased with the level of retained hardwoods. For
basal area and merchantable volume, hardwood growth largely compensated for losses in the
pine component, and thus, hardwood retention had little net effect on the total growth of
the stand. The greatest impact of hardwood retention was on the stand's sawtimber growth,
because hardwoods did not contribute to this product class. Each 1 ft2/ac of
retained hardwood basal area reduced pine sawtimber growth by 6 to 10 bd ft( Doyle/ac/yr,
depending on the pine stocking. Because large differences existed in the value of timber
products, retaining 15 and 30 ft2/ac of hardwoods reduced the value of' timber
production by 13 and 24 percent, respectively, at 4 years after thinning..
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Shupe, Todd F.; Hse, Chung Y.; Grozdits, George A.; Choong, Elvin T.
1997. Effects of silvicultural practice and veneer layup on some mechanical properties
of loblolly pine plywood. Forest Products Journal. 47(10): 101-106.
Loblolly pine three-ply plywood was manufactured from veneer
obtained from silviculturally different stands. Panels from each site were assembled with
four different veneer grade arrangements and tested in wet and dry conditions. Stiffness
properties in both the wet and dry conditions and strength properties in the dry condition
were all significantly affected by silvicultural practice; veneer grade arrangement also
showed significant differences. Shear strength and bending properties (MOR and MOE) were
most favorable with panels manufactured from all A-grade veneer (AAA). Strength properties
were found to be very similar between panels manufactured with A-grade veneer on one face
and C-grade veneer on the other face and in the core (ACC), and A-grade veneer on both
faces and C grade veneer in the core (ACA).
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Solomon, J.D. and others. 1997. Oak pests: a guide to major
insects, diseases, air pollution and chemical injury. R8-PR 7. Atlanta, GA: U.S.
Department of Agriculture, Forest Service, Southern Region, Southern Research Station. 69
p.
This 1997 revision contains additional research and evaluations that
provide new data about oak pests. The oak wilt and decline section has been changed; Texas
live oak decline has been replaced with oak decline, and the oak wilt section has been
updated and expanded. Corticium and Texas root rots have been deleted, and dryadeus root
rot has been added. Figure 28c in the root damage by Prionus sp. section has been
replaced. Pesticide information has been revised to conform with current recommendations.
The most current taxonomic classifications of pathogenic fungi and disease names are not
always indicated in the text of individual disease descriptions. To keep the reader
current on the presently accepted scientific and disease names, a list of new names that
are synonyms of the old ones is provided.
The oaks (Quercus spp.) are among our most valuable hardwood
resources, amounting to one-third of the hardwood sawtimber volume in the United States.
Over half the annual cut of oak lumber is produced in the 13 Southern States. Oaks are
best known for their timber production and resulting fine furniture, beautiful flooring,
and other products. Yet, aesthetics, watershed management, recreation, and wildlife are
goals now given equal or greater priority by many. The oaks are valued for shade and
ornamental purposes - a single tree sometimes adds thousands of dollars to real estate
values.
Insects, diseases, and pollutants present a continuing threat to
oaks. A major portion of the acorn crop is destroyed during some years - hampering
regeneration efforts. Seedling mortality and dieback add to this problem. Terminal and top
injury adversely affect tree form. Repeated defoliations cause growth loss and mortality.
Borers and decay cause defect and degrade amounting to an annual loss of millions of
dollars. Indirect losses occur through disruption of sustained forestry practices,
regulation of forest types, and altered wildlife habitat. Homeowners may incur the expense
of chemical control and possibly the cost of tree removal if mortality occurs. Nuisances
created by numerous insects decrease tourist use and revenue. It is far better to prevent
attack by insects and disease than it is to remedy them after they occur. Be aware of, and
use, cultural practices that maintain and promote tree vigor. Match tree species to the
proper site. Assure sufficient water, nutrients, space, and sunlight. Avoid accidental
injuries such as cuts, bruises, and broken limbs. Use practices that favor natural
controls such as birds and other predators, parasites, and insect pathogens. Practices
such as "pick-up and destroy" and "prune-out and destroy" can help
reduce hibernating forms and inoculum reservoirs. When all else fails, chemical controls
may become necessary.
This booklet will help nurserymen, forest woodland
managers, pest control operators, and homeowners to identify and control pest problems on
oaks. The major insect and disease pests of oaks in the South are emphasized. Descriptions
and illustrations of the pests and their damage are provided to aid in identification.
Brief notes are given on biology and control to aid in predicting damage and making
control decisions. A list of chemical controls is provided. Chemical controls are subject
to change as certain compounds are banned and new materials approved. Thus, the chemical
control section can be removed (tear sheet) and discarded when outdated. For further
information on pesticides, contact your State Forester, county agent, or the nearest
office of State and Private Forestry, USDA Forest Service.
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Stelzer, H.E.; Foster, G.S.; Shaw, D.V.; McRae, J.B. 1998. Ten-year
growth comparison between rooted cuttings and seedlings of loblolly pine. Canadian
Journal of Forest Research. 28: 69-73.
Rooted cuttings and seedlings of loblolly pine (Pinus
taeda L.) were established in a central Alabama field trial. Five, full-sib families,
with an average number of six clones per family, were evaluated. Mean cutting/seedling
height ratios revealed that despite initial differences in size, relative growth rates of
both propagule types stabilized and were equal by age 7 years. Through age 10 years,
results show virtually no difference in height, diameter at breast height, volume, or stem
taper between the rooted cuttings and seedlings.
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Steynberg, Petrus J.; Steynberg, Jan P.; Hemingway, Richard W.; and
others. 1997. Acid-catalyzed rearrangements of flavan-4-phloroglucinol derivatives to
novel 6-hydroxyphenyl-6a,llb-dihydro-6H-[1]benzofuro[2,3-c]-chromenes and
hydroxyphenyl-3,2'-spirobi[dihydro[l]benzofurans]. Journal of Chemical Society, Perkin
Transactions I. 2395-2403.
Acetic acid-catalyzed cleavage of proanthocyanidins
in the presence of phloroglucinol gives a series of 2R procyanidin- and
prodelphinidin-phloroglucinol adducts together with a novel 2S all-cis
derivative implicating cleavage of the pyran ring and subsequent inversion of
stereochernistry at C-2c. These flavan-4-phloroglucinol adducts also suffer
dehydration to products with novel fused dihydrobenzopyrandihydrobenzofuran rings. In
addition, cleavage of the flavan C-10A-C-4c bond followed by
dehydration results in unique 3,2'-spirobi[dihydro[l]benzofurans].
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Sung, S.S.; Black, C.C.; Kormanik, T.L. [and others]. 1997. Fall
nitrogen fertilization and the biology of Pinus taeda seedling development.
Canadian Journal of Forest Research. 27:1406-1412.
In mid-September when stems and roots of
nursery-grown loblolly pine (Pinus taeda L.) seedlings are actively accumulating
dry weight (DW), an extra 10, 20, or 40 kg NH4NO3@ha-1
(10N, 20N, 4ON) was applied. Seedlings receiving no extra N (0N) were the controls. The
temporal patterns of seedling growth, nutrient concentrations, and sugar-metabolizing
enzyme activities were determined during that fall and winter to assess the dynamics of
seedling vigor. The 40N-treated seedlings had significantly fewer culls and greater
first-order lateral root numbers, root collar diameter, DW of needle, stem, and root, and
N concentration (percentage of DW) and content (milligrams per seedling) than controls and
the 10N-treated seedlings. However, the temporal patterns of DW allocation, sugar
metabolism, or the concentrations of P, K, Mg, and Ca were not affected by fall N
fertilization. These results fit the hypothesis that basic plant morphological and
biochemical processes, e.g., periodicity in stem and root DW growth or in stem and root
sucrolysis and glycolysis, were not altered by human-made changes such as fall N
fertilization. Fall N fertilization near 40 kg N@ha-1 is a beneficial treatment
because it decreased the number of culls and increased seedling N concentrations and DW
without causing nutrient imbalance or detectably disturbing seedling development.
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Swallow, Stephen K.; Talukdar, Piyali; Wear, David N. 1997. Spatial
and temporal specialization in forest ecosystem management under sole ownership. 1997.
American Journal of Agricultural Economics. 79: 311-326.
"Ecosystem management" complicates forest
management considerably. In this paper the authors extend the economic analysis of
forestry to capture both the temporal and the spatial dimensions, allowing optimization of
timber harvest decisions throughout an ecosystem. Dynamic programming simulations
illustrate the implications for the simplest ecosystem, consisting of two forest
management units. Results indicate that explicit recognition of ecological interactions,
even between identical forest stands, may prescribe specialization through time and across
space. Such spatial and temporal specialization leverages opportunities to provide
ecosystem goods that may be foregone through reliance on "rules of thumb"
derived from models that focus on the single stand.
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Swank, Wayne T.; Vose, James M. 1997. Long-term nitrogen dynamics
of Coweeta forested watersheds in the southeastern United States of America. Global
Biogeochemical Cycles. 2(4):657-671.
The authors analyzed long-term (23 years) data of inorganic N
deposition and loss for an extensive network of mature mixed hardwood covered watersheds
in the Southern Appalachians of North Carolina to assess trends and dynamics of N in
baseline ecosystems. They also assessed watershed N saturation in the context of altered N
cycles and stream inorganic N responses associated with management practices (cutting
prescriptions, species replacement, and prescribed burning) and with natural disturbances
(drought and wet years, insect infestations,
hurricane damage, and ozone events) on reference watersheds.
Reference watersheds were characterized as highly conservative of inorganic N with
deposition < 9.0 kg ha-1 yr-1 and stream water exports below 0.25
kg ha-1 yr-1. However, reference watersheds appeared to be in a
transition phase between stage 0 and stage 1 of watershed N saturation, as evidenced by
significant time trend increases in annual flow-weighted concentrations of NO3-
in stream water and increases in the seasonal amplitude and duration of NO3
concentrations during 1972 to 1994. These stream water chemistry trends were partially
attributed to significant increases in NO3- and NH4+
concentrations in bulk precipitation over the some period and/or reduced biological demand
due to forest maturation. Levels and annual patterns of stream NO3-
concentrations and intra-annual seasonal patterns characteristic of latter phases of
stages 1and 2 of watershed N saturation were found for low-elevation and high-elevation
clear-cut watersheds, respectively, and were related to the dynamics of microbial
transformations of N and vegetation uptake. Evidence for stage 3 of N saturation, where
the watershed is a net source of N rather than an N sink, was found for the most
distributed watershed at Coweeta (hardwood converted to grass, fertilized, limed, treated
with herbicide, and subsequently characterized by successional vegetation). Compared to
other intensive management practices, prescribed burning had little effect on stream
water, NO3- concentrations, and stream NO3-
losses associated with natural disturbances are small and short lived.
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Thompson, Michael T.; Sheffield, Raymond M. 1997. Forest
statistics for Southeast Georgia, 1996. Resour. Bull. SRSB23. Asheville,
NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 59 p.
This report summarizes a 1996 inventory of the
forest resources of a 35-county area of Georgia. Major findings are highlighted in text
and graphs; detailed data are presented in 51 tables.
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Vissage, John S.; Hoffard, William H. 1997. Summary report:
forest health monitoring in the South, 1992. Resour. Bull. SO-195.
Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station.
27 p.
In 1990, the U.S. Department of Agriculture, Forest
Service and the U.S. Environmental Protection Agency launched a cooperative program,
Forest Health Monitoring, to monitor the health of the Nation's forest. Several indicators
of forest health have been measured on permanent plots in 14 States. Data gathered from
Alabama, Georgia, and Virginia in 1992 are summarized in this report. Simple percentage
distributions of crown ratings and damage data from sample plots do not suggest any
widespread problems in these States. Crown ratings were poor for only 1 percent of the
sample trees. A synopsis of forest insect and disease surveys in the southern region shows
that these pests continue to cause substantial damage.
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Wilson, A.D.; Lester, D.G. 1997. Use of an electronic-nose device
for profiling headspace volatile metabolites to rapidly identify phytopathogenic microbes
[Abstract]. Phytopathology 87:S116.
A new electronic-nose device (AromaScan A32S), consisting of an
organic matrix-coated polymer-type 32-detector array, was tested as a novel tool for the
detection, identification, and discrimination of phytopathogenic microbes. The sensor
array detects the unique mixture of volatile metabolites released by microbes growing on
standardized growth media by measuring electrical resistance across detector paths. A
unique aroma profile (signature pattern) is produced, defined by the normalized response
intensities of each detector, that is specific to the types and amounts of compound(s)
present in the sample gas. The device was sensitive to sample concentration and
differences in relative humidity (RH) between sample and reference gases. Control of
sample gas RH to within 2 to 3 percent above reference RH yielded the best results. The
instrument provides rapid results (run time 90 to 220 s) and effectively discriminated
prokaryotes and fungi to species and even strain depending on how extensively the neural
net was taught pattern recognition from reference databases of known microbes.
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