VTechWorks Repository :: Browsing by Author "Smith, David William"

Browsing by Author "Smith, David William"

Now showing 1 - 20 of 38

Applying the diagnosis and recommendation integrated system(DRIS) to Fraser fir Christmas trees
Kopp, Virginia Ann (Virginia Tech, 1988-05-15)
The process of diagnosing the foliar nutrient status of Fraser fir [Abies fraseri (Pursh)Poir.] Christmas trees and prescribing fertilizers is not well understood. Agricultural researchers have established critical yield levels for agronomic crops that are objective measures of crop quality and have associated these yields with nutrient status; however, Christmas tree quality is subjective and not well associated with nutrient status. A nutrient-sensitive tree response factor that reflects tree quality is needed for a proper diagnosis. The purpose of this study was to determine the relationship between nutrient balance and indices of tree quality and to evaluate how nutrient balance and tree quality can be manipulated by fertilizer inputs based on the Diagnosis and Recommendation Integrated System. In 1984 a factorial N, P, pH, fertilizer source, and fertilizer frequency trial was installed in northwestern North Carolina. A randomized complete block design with factorial combinations of all five factors was used. After three years, the fertilizer trial was analyzed to study the effects of fertilizer additions on foliar nutrient balance and tree quality. Several tree response factors were measured in the fall after dormancy. Statistical methods such as correlations and multivariate discriminant analysis were used to determine which response factors were correlated with foliar nutrients and which factor most governed tree quality. DRIS indices were calculated for six independent plots of different fertility treatments. Basal diameter (BD) was the strongest discriminator of tree quality and was used as a substitute for yield in the DRIS analyses. The importance of nutrient intensity was demonstrated since significant nutrient / dry matter ratios were calculated for N, P, K, and Mg. Balance was shown to be important since the indices for N, K, and Mg were a function of the four other nutrient ratios other than dry matter, and the P and Ca indices were a function of three nutrient ratios other than dry matter. Nutrient balance was also shown to be important by the significant relationship of BD as a function of the nutrient balance index (NBI). When NBI had a relatively small value, large BD trees were produced; as NBI values increased, BD decreased. Fertilizer additions that created nutrient imbalances also decreased BD, in spite of the high nutrient intensities found in the foliage. These results show that nutrient balance in Fraser fir foliage, as well as nutrient intensity, is important for producing optimal Christmas tree quality.
Bald eagle habitat use on B. Everett Jordan Lake and Falls Lake, North Carolina
Chester, Dennis Nathan (Virginia Tech, 1988-06-30)
I examined the roosting and perching habitat preferences of a nonbreeding population of bald eagles in North Carolina during 1986 and 1987. I characterized roosting habitat at 2 scales; those of forest stands and individual roost trees. Eagles chose roost areas that were less dense, had less canopy cover, were closer to forest edges, and had larger trees than random forest areas (P < 0.05). Within roost areas eagles choose trees that were larger (height and dbh) than random trees. Additionally. eagles roosting at the Morgan Creek roost preferred dead hardwoods close to the forest edge and eagles at the Mason Point roost preferred trees farther from a frequently used dirt road within the roost. Suitable perch trees were the most important attribute of perching habitat. Eagles preferred loblolly pines and trees with leafless crowns (P < 0.05), which relates to their accessible crown structures. Perch trees were larger (height and dbh, P < 0.05) than adjacent trees along the shore. Eagles utilized the bottom of tree crowns during summer but used treetops during fall and winter. I found no evidence that eagles selected perches in relation to forest stand characteristics within 20 m of perch trees, forest cover types in 1 ha blocks surrounding perches, or habitat disturbances. Management recommendations include techniques to enhance bald eagle habitat on the study area. Primary emphasis should be toward managing for roosting habitat because of its apparent scarcity. Perch trees are plentiful but long-term management is desirable. Future nesting seems likely and management techniques for potential nesting habitat are suggested.
Biological studies of shiitake logs and associated mycoflora in the Virginia highlands
Guevara-Guerrero, Gonzalo (Virginia Tech, 1991-12-05)
Shiitake growers in Virginia are experiencing considerable diminution of the fruiting life of oak logs, due primarily to Ascomycetous, competing, wood-rotting, contaminating "weed fungi" that either invade the logs after trees are felled or are present in tree tissues before felling. We surveyed several shiitake farms, and, although the fungal flora differed among them, the predominant colonizing fungi were identified as Graphostroma platystoma (also identified as Diatrype stygma), Eutypa spinosa and Slereum aff. complicatum. Other less frequently observed fungi were Stereum ostrea, Schizophyllum commune, Hymenochaete sp., Poria sp., Hypoxylon atropunctatum and Hypoxylon punctulatum. Site and means of invasion (colonization) of these "weed fungi" were studied by monitoring endophytic fungal populations in stressed and non-stressed oak trees in the Jefferson National Forest Montgomery County, Virginia. Twenty-six samples from Poverty Creek (non-stressed) and 23 from Brush Mountain (stressed) were studied. Fifty percent of the samples from the non-stressed were sterile, 23% yielded Paecilomyces variota., and 27% were colonized by other fungi. On the other hand, 100% of the samples from stressed trees (Brush Mountain) were colonized by fungi; 74% yielded P. variotii and 26% by other fungi. Thirty samples from a pin oak (Quercus paluslris) plot at Virginia Tech (non-stressed) were 74% sterile, 16% colonized by an unidentified yeast, and 10% colonized by other unknown fungi.
Characterization of Vascular Plant Species Composition and Relative Abundance in Southern Appalachian Mixed-Oak Forests
Hammond, Daniel N. Jr. (Virginia Tech, 1997-12-16)
Eight study sites were established in mid-elevation, south aspect, mixed-oak forests in the Ridge and Valley and Allegheny Mountain physiographic provinces of Southwestern Virginia and West Virginia to address questions concerning the variability in species composition, richness, and relative abundance of vascular plant species in those communities. All forest strata were sampled using a nested plot design. Variability in species richness and species composition was found to be high. Total species richness values ranged from 84 to 273, and Sorrenson's Coefficient of Similarity index values indicated that approximately 46, 38, and 51 percent of the species in the overstory, mid-story, and herb stratum were the same among sites, respectively. However, despite differences in composition and richness, K-S tests revealed significant differences in the distribution of ranked relative abundance only in the mid-story at two sites. Differences did occur in the relative abundance of twelve growth form categories. While tree seedlings and perennial herbs dominated, on average, woody vines and fern species represented substantial coverage on sites in the Allegheny Mountains. Correlations among forest strata were weak. The greatest amount of variation in species richness was attributiable to the standard deviation of a forest site quality index (FSQI), which was thought to represent the variation in microtopography across each site. The lack of correlation and high variability in plant species richness and composition, despite similarities in topographic characteristics, reinforce the inherent weaknesses involved with using the chronosequence approach to studying ecological responses in the Southern Appalachian mixed-oak region. Future remeasurement and long term monitoring of these study sites, following the implementation of silvicultural manipulations, will provide the information needed to make inference on the effects of forest management practices on Southern Appalachian mixed-oak forests.
A description of floral diversity in the southern Appalachians with forest management considerations for conservation
Brown, Maryfrances McGrath (Virginia Tech, 1994-05-04)
Biological diversity is the variety of plant and animal life, habitats and ecosystems, and the biological processes and functions within them. It is this simple yet profoundly important concept in biology which in recent years has become an issue of great concern to the lay public and scientific community alike. The cause for this concern lies in the current rapid destruction and transformation of many ecosystems worldwide. From temperate and tropical rain forests to coral reefs, the loss of habitat due to the pressures of an expanding human population threatens the existence of numerous species of plants and animals. It is suspected that thousands of species of plants and animals are being lost before ever being described, let alone tested for their usefulness as medicines or crops (Wilson 1988). Over 25% of prescription drugs available today contain active compounds that are extracted directly from plants (Ledig 1988). In addition, the cross breeding of domesticated crop species with wild relatives has resulted in improved disease resistance in crops such as barley, rice, cassava, sugarcane, and com (Plotkin 1986). Thus, the loss of habitat and the possible extirpation or extinction of plant and animal species may mean the loss of potential life-saving drugs and crop-enhancing wild relatives.
Desired Future Conditions of Riparian Areas on Southeastern National Forests
Pert, Heather Anne (Virginia Tech, 2000-12-06)
Development of goals (desired future conditions (DFCs)) based on substantial public involvement is critical to the success of ecosystem management on public lands. I evaluated DFCs of riparian areas on national forests in the southern Appalachian mountains and evaluated a process for involving the public in development of DFCs for riparian areas on the Jefferson National Forest. First, I identified the major components, structures, and functions that are essential to riparian health through a literature review. Second, I examined how the key components, structures, and functions identified in the literature review were addressed in the DFCs and standards and guidelines for eight southeastern national forest management plans. In reviewing forest plans, I found a clear shift from emphasizing water quality in older forest plans to a more comprehensive incorporation of the values and functions of riparian areas in more recent plans. Riparian attributes included in DFCs varied widely and disparities between DFCs for forest plans and measurable criteria in the standards and guidelines often occurred. Finally, I designed, tested, and evaluated a public involvement process that identified public values for use in the development of DFCs for riparian areas on the Jefferson National Forest. I used a combination of alternative dispute resolution techniques and the Analytic Hierarchy Process (AHP), a participatory decision-making tool. I used surveys before and after the riparian meetings to evaluate the effectiveness of the public involvement process. Survey respondents generally were middle-aged, well-educated, high-income males who were long-time residents of the area. Riparian meeting participants indicated that the DFC for riparian areas on the JNF should strongly emphasize water quality and quantity, protection of riparian-dependent species and their habitats, and maintenance of the integrity of the relationship between riparian areas and the surrounding environment. Participants indicated recreational and commodity uses of riparian areas could occur as long as they did not negatively affect the other, more highly valued characteristics of riparian areas. Participants felt that the meetings were fair, that diverse interests were represented, that they had enough information to participate in the process, and that it was a wise use of their time.
Development of a method for implementing group selection in Appalachian hardwoods
Boucher, Britt A. (Virginia Tech, 1989-05-05)
A method is described for implementing group selection regeneration in Appalachian hardwoods. The diverse set of definitions of the method, and the current forest demands are combined to form a flexible system of implementation that can accommodate public as well as private forests. Group selection is used where an uneven-aged silvicultural system is required and multiple objectives demanded. Several types of information are collected in a sample of the forest and then used to make the selection decision of which groups of trees to remove, and which groups to leave.
Ecology and Control of Rhododendron (Rhododendron ponticum L.) in Turkish Eastern Beech (Fagus orientalis Lipsky) Forests
Esen, Derya (Virginia Tech, 2000-06-28)
Purple-flowered rhododendron (Rhododendron ponticum L.) and yellow-flowered rhododendron (R. flavum Don.) are two dominant shrub species of the eastern beech (Fagus orientalis L.) understories in the eastern and western Black Sea Region (BSR), respectively. These invasive woody species significantly reduce beech growth and can preclude tree regeneration. The ecological consequence is an aging beech overstory with little or no regeneration to replace the mature trees. Great rhododendron (R. maximum L.) has been increasing in the forests of the Southern Appalachians of the United States, reducing tree regeneration and growth. The BSR and Southern Appalachians bear noteworthy similarities in climate, topography, and the forest flora. Purple-flowered and great rhododendrons also show important similarities in their ecology and the forest vegetation problems they can cause. Current rhododendron-dominated and threatened BSR forests may provide an advanced ecological picture of the forests of the Southern Appalachians in which great rhododendron now thrives. Therefore, new information gained on the ecology and effective and cost-efficient control of purple-flowered rhododendron may significantly improve forest management practices, not only for the current rhododendron-invaded BSR ecosystem, but also for other parts of the world. This dissertation consists of five separate yet related chapters. The first gives relevant literature reviewed for the dissertation. The second chapter focuses on various environmental and disturbance factors that may have shaped the current purple-flowered rhododendron-dominated beech forests of the BSR of Turkey. Chapter 3 assesses the effects of various manual and herbicidal woody control techniques on purple-flowered and yellow-flowered rhododendron in two field experiments in the BSR. The fourth chapter relates a study of uptake and translocation behavior of triclopyr ester and imazapyr in great rhododendron. This information is used to determine the optimum herbicide-surfactant combinations for the greatest active ingredient uptake and root translocation in great rhododendron. The last chapter is a synthesis of the information gained in all of these different experiments.
Effect of season of harvest and site quality on hardwood regeneration on the Virginia Piedmont
Kays, Jonathan (Virginia Tech, 1985-03-05)
Many existing Piedmont hardwood stands are composed of trees that are largely under 45 cm in diameter and contain a desirable oak component, as well as large amounts of undesirable red maple and sourwood. In stands under even-aged silviculture, season of harvest can be used as an effective management tool to favor different species compositions. If oak or other hardwood production is the management objective a dormant season harvest will result in increased sprout vigor of all oak as well as non-oak species. If pine conversion is the objective then a growing season harvest will reduce the vigor of all hardwood species and allow for easier competition control. The higher densities of all classes of regenerants on better sites indicates control will be more difficult.
Effects of Clearcutting with Whole Tree Harvesting on Woody and Herbaceous Plant Diversity After 17-Years of Regrowth in a Southern Appalachian Forest
Wright, David Kenyon (Virginia Tech, 1997-12-15)
This study examines the effects of clearcut regeneration with whole-tree harvesting on plant diversity. Three approaches were used to study changes in species composition and structure: (1) forest level, (2) stand level, and (3) diversity indices. Within each approach the forest was stratified into three horizontal vegetative regions based upon height: herb (< 1 m), shrub (between 1 and 5 m), and tree (> 5 m). Between the pre-harvest and 17-year-old forest, the relative percent cover of 3 out of 45 herbaceous and 2 out of 34 woody species were found to be significantly different (df = 3; a = 0.10) in the herb stratum; the importance value (average of relative basal area and stem density) of 2 out of 25 woody species in the shrub stratum; and 1 out of 21 woody species in the tree stratum. Within stands, the three lower quality, 17-year-old stands (SI50 = 12.2, 15.2, and 18.3 m) most resembled their pre-harvest composition; however, increases in ericaceous species were observed in the herb and shrub strata potentially inhibit the future regeneration of tree species. The SI50 = 21.3 m stand incurred the greatest changes in composition potentially due to the lack of fire as a disturbance mechanism. The major mechanism that has caused the shifts in species composition and structure is the change in the microenvironment due to the removal of the overstory, which has shifted the competitive advantages from one species to another. In all cases, diversity indices were not found to be significantly different between the 17-year-old and pre-harvest forests. Diversity indices were therefore determined to have limited use if a manager wants to know specific compositions and/or abundance of species.
Effects of group selection and clearcut openings on wildlife in Appalachian hardwood forests
Kerpez, Theodore A. (Virginia Tech, 1994-03-15)
Group selection has recently emerged as an alternative silvicultural system to clearcutting in Appalachian hardwood forests, but there is little, if any, information on the effects of group selection on wildlife. Thus, I studied and compared the effects of group selection and clearcut openings on wildlife in the Jefferson National Forest, Virginia. Breeding birds were censused 1 year before and 2 years after harvesting at 20 group selection openings, 4 clearcut openings, 18 sites in the mature even-aged forest adjacent to the openings, and 29 control sites. I also compared use of group selection openings and clearcut openings by white-tailed deer. The number of species and the total number of birds decreased at the openings and in the forest adjacent to the openings after harvesting with both methods. (Seven species increased and 9 species decreased in the openings after harvesting. Four species decreased in the forest adjacent to the openings after harvesting. Indigo buntings and rufous-sided towhees increased more at the interior of clearcut openings than at the edge of clearcut openings or in group selection openings. Sites within the clearcut openings where groups of trees were left uncut were not used more by birds than clearcut sites without trees. (The number and proportion of stumps with sprouts browsed by white-tailed deer was greater in group selection openings than in clearcut openings. Clearcut and large group selection openings provided breeding habitat for the same bird species. The smaller group selection openings were not used by some species found in the clearcut openings. However, creating a variety of opening sizes probably will provide the maximum benefit for all wildlife species that use early successional habitat. The same species were negatively affected, and to a similar degree, by group selection and clearcut openings. Both types of openings had negative impacts on forest-interior bird species in the adjacent forest. However, if the same acreage is harvested, group selection will affect a greater area of adjacent forest than clearcutting, because smaller openings have greater edge to area ratios.
The effects of growth medium acidity, exogenous growth regulators, and nitrogen fertilizer on the acceleration of Fraser fir seedling growth
Bryan, James Alfred (Virginia Tech, 1988-08-05)
Three factors were tested in an attempt to accelerate the growth of Abies fraseri seedlings grown in containers in a greenhouse: growth medium acidity. foliar application of growth regulators. and supply of nitrogen fertilizer. Sphagnum peat growth medium was adjusted with a to 8 kg dolomitic limestone/m3 compressed packaged peat to initial pH ranging from 3.9 to 6.7. Best growth (21.2 cm mean height at 19 months) was achieved with 1 kg/m³ and 2 kg/m³â ¢ with initial mean pH 4.2 and 4.5. respectively. Seedlings with 4 and 8 kg/m³ grew more slowly (17.4 and 9.5 cm. respectively. in 19 months). and many were chlorotic. with poor root development. Three growth regulators were sprayed on seedlings: benzylaminopurine (BAP). gibberellic acid (G~. and indolebutyric acid (IBA). BAP stimulated terminal bud activity. decreasing the periods of rest between active growth. BAP increased height and diameter of new shoot growth up to 19% and 32% respectively. BAP reduced root growth 22% when applied at the higher concentration (100 ppm). GA3 had no main effect on either shoot or root growth. However. GA3 did increase shoot growth slightly in the absence of BAP. IBA increased root growth up to 26%. IBA had no significant effect on shoot growth. Nitrogen fertilizer was supplied weekly in concentrations of 200. 400. and 600 ppm. At six months age there was no treatment effect on seedling growth. At nine months age 400 ppm N had produced 9% more shoot growth than either 200 or 600 ppm N. Nine-month-old seedlings with 400 ppm fertilizer averaged 8.9 cm in height.
Effects of gypsy moth defoliation on acorn production and viability, litterfall, and litter layer depth and biomass in north-central Virginia and western Maryland
McConnell, Steven P. (Virginia Tech, 1988-05-05)
The effects of gypsy moth defoliation on acorn production (the seed source for oak regeneration), and the forest floor regeneration environment were investigated. Parameters measured included: acorn quantity, weight, development, and viability; litterfall; and forest floor depth and biomass. Nineteen plots in north-central Virginia and western Maryland on which trees suffered heavy, moderate, or no defoliation were monitored over a two-year period.
Effects of Low-Input Vegetation Management on Pine-Hardwood Mixed Stands in the Northern Piedmont
Heinze, Jason A. (Virginia Tech, 1999-11-05)
In an attempt to provide low-cost, low-input alternatives for regenerating pine-hardwood mixtures, this study examined several mechanisms that influence the growth of pine-hardwood stands. The Regeneration Alternatives Study is an ongoing experiment that was designed to gain biological and economical information concerning the growth and yield of loblolly pine and mixed hardwood species. Low-cost herbicide applications (stump treatment, basal stem spray, release, and soil spot release) were used to control competing vegetation during the study. The four even-aged regeneration treatments applied to loblolly pine and mixed hardwood stands of this study had a significant effect on their growth. Loblolly pine growth increased and mixed hardwood growth decreased as the intensity of herbicide treatment increased for all age classes. In general, loblolly pine was more productive with more intense treatment applications on poorer sites following a growing season harvest. Hardwood species were more productive with less intense treatment applications on higher-quality sites following a dormant season harvest for all age classes. Loblolly pine planting following clearfelling, coupled with a herbicide stump and release treatment (treatment 4), resulted in the highest yields of loblolly pine, the greatest economic returns, and the greatest level of site utilization. However, treatment 4 also resulted in the lowest yield of mixed hardwoods and the lowest level of species richness. Loblolly pine planting following clearfelling, with (treatment 3) and without (treatment 2) a hardwood stump treatment application, resulted in a more even distribution of pines and hardwoods, depending on the treatment. Treatment 3 favored loblolly pine growth, especially following a growing season harvest on poor sites. Treatment 2 favored mixed hardwood growth, especially following a dormant season harvest on good sites. There were no differences between methods of release (basal spray or soil spot herbicide application). Economically, treatments 2 and 3 did not realize a profit on returns. Pine yields, dbh, and basal area were all significantly greater following a summer season harvest as opposed to pine growth following a winter harvest with the same chemical treatments. The pine growth data indicated that less intense chemical treatments following a summer harvest can achieve the same or greater growth results than more intense chemical treatments following a winter harvest. The results of this study indicate a significant biological and economic tradeoff, depending on the level of hardwood control applied and the time of harvesting.
Equations for Estimating Above-Ground Phytomass in the Understory of Appalachian Oak Forests
Martin, Wayne L.; Sharik, Terry L.; Oderwald, Richard G.; Smith, David William (Virginia Tech. Division of Forestry and Wildlife Resources, 1981)
Regression equations were developed for estimating total aboveground phytomass for 17 tree and shrub species in the understory of second growth Appalachian oak forest stands in southwest Virginia. All possible combinations of three functional forms of the equation and three independent variables, singly and in combination, were tested. The linear model, with stem basal area as the independent variable, provided the best fit to the data for 15 of the 17 species. The exceptions were the blueberries (vaccinium stamineum and v. vacillans), where crown area performed better than basal area as the independent variable.
Evaluation of Ranked Set Sampling for Estimating Shrub Phytomass in Appalachian Oak Forests
Martin, Wayne L.; Sharik, Terry L.; Oderwald, Richard G.; Smith, David William (Virginia Tech. Division of Forestry and Wildlife Resources, 1980)
Ranked set sampling was introduced by McIntyre (1952) in estimating pasture yields. As described by McIntyre, the ranked set sampling procedure is implemented by first selecting a set of n elements at random from a population, and then raking those elements from lowest to highest by inspection of the variable of interest. The lowest ranked element is then measured. A second set of n elements is selected and ranked, and the second lowest element is measured. This process is continued until n such sets have been selected and n elements have been measured. The entire procedure can be repeated as many times as deemed necessary. McIntyre claimed that the ranked set estimator of the population mean was unbiased regardless of errors in ranking, and that with perfect ranking the variance of the mean from ranked set sampling would be less than that of random sampling when the number of measured elements is the same for both methods. Halls and Dell (1966) concluded that ranked set sampling was more efficient than simple random sampling in estimating pasture yields. A theoretical underpinning for ranked set sampling was provided by Dell and Clutter (1972), who also demonstrated that ranked set sampling is more efficient than random sampling even when errors in ranking are present. Ranked set sampling is clearly advantageous when measurement of an element is time consuming or costly and sample elements can be reliably ranked. The effectiveness of this technique has already been demonstrated for estimating forage and pasture yields. The objective of this study is to evaluate the effectiveness of ranked set sampling for estimating shrub phytomass in forest stands.
Factors affecting loblolly pine growth following site preparation
Needham, Ted Daniel (Virginia Polytechnic Institute and State University, 1986)
Site preparation is a required silvicultural practice for establishing loblolly pine plantations in the Piedmont physiographic region of the southeastern U.S.; however, relatively little is known about its effect on soil and site factors that influence growth and yield. In this study, the effect of seven different site preparation prescriptions on competing vegetation, tree nutrition, and the spatial distribution of planted seedlings was examined. Three treatments had a soil tillage component and differed with respect to the number of operations employed in removing residual trees and logging slash prior to discing. One treatment involved roller chopping and broadcast burning, one an application of the herbicide glyphosate followed by a broadcast-burn, one involved shearing all raking fogging-debris into windows, and one was no site preparation prior to planting. All treatments were applied to 12 sites in the South Carolina and Georgia Piedmont. After four years in the field, 756 trees within the site preparation treatment areas were randomly selected for analysis of foliar nutrients, soil nutrients, and competing vegetation. Herbaceous, woody shrub, and hardwood competition levels were not significantly different among site preparation treatment areas after four years. However, hardwood competition levels had increased at a faster rate during the last two growing seasons on chopped and disced areas than on the other areas. Hardwood competition became the predominant factor limiting pine basal diameter when 83% of the total basal area was in hardwoods or hardwood basal area levels exceeded 3.5 m²ha⁻¹. Potassium was identified as the most limiting nutrient 38% of the time, compared to 28% for phosphorus, 14 % for nitrogen, 7% for calcium, aiid 13% for magnesium. A significant linear relationship between soil and foliar nutrients confirmed these results. No treatment effect on nutrient deficiencies was evident. Foliar nutrient critical levels were derived using the Diagnosis and Recommendation Integrated System (DRIS) and were the same as those reported in the literature for nitrogen, phosphorous, and magnesium while potassium and calcium critical levels were determined to be twice as high as those reported (0.52% and 0.19%, respectively). The spatial distribution of seedlings at planting and after 2 years was determined. Spatial patterns varied from uniform to random as the degree of logging slash removal decreased. After two years, the spatial distribution shifted toward random and clustered. The degree of change was similar in all but the herbicide burn and untreated areas, which exhibited the greatest change and whose mortality tended to be clustered.
Fertilization and Woody Plant Nutrition in the Context of the Urban Forest
Watkins, James R. (Virginia Tech, 1998-10-05)
Fertilization of urban trees is often based on traditional forestry objectives. These objectives and resultant attributes may not be desired in urban trees. The majority of research and the ensuing recommendations regarding fertilizer amounts and formulations comes from agricultural models, pomology, and industrial forestry - very little from arboriculture. Lack of water and inadequate soil volumes are responsible for many of the problems that beset urban trees. More research is needed in water deficit mitigation, establishing nutrient sufficiency and deficiency levels in urban trees, the role of fertilization in disease remediation and increased pathogenesis, and the effects of long term fertilization on trees in the urban landscape.
Five-year fertilizer and ground cover effects on surface-mine soils and pine growth
Klemp, Mary Therese (Virginia Tech, 1988-06-05)
During the last three years, 80% of mining permits in Virginia listed forestland as the post-mining land use. Adequate stocking and growth of tree stands at time of bond-release eligibility and beyond is an important beginning for returning mined lands to a productive state. In order to ensure reforestation success, biological constraints, including low mine soil fertility and competition from herbaceous ground cover, must be overcome. The effect of cultural treatments on the growth of three commercial pine species on reclaimed surface-mined land in southwestern Virginia was studied. In June, 1981, containerized seedlings of loblolly (Pinus taeda L.), Virginina (P. virginiana Mill.), and eastern white (P. strobus L.) pines were planted on a flat bench site (Site I) and a site returned to approximate original contour (Site I1). Seedlings were artificially inoculated with Pisolithus tinctorius ((Pers.) Coker and Couch), fertilized with slow-release fertilizer pellets at time of planting and broadcast with N fertilizer prior to the fourth growing season, and the ground cover around them was controlled with herbicides through the third growing season. Survival and growth of these seedlings after the first and second growing seasons were reported by Schoenholtz and Burger (1984). The response of these pines to treatments at the end of the third and fifth growing seasons were evaluated in this study. Treatment effects on foliar nutrient levels and soil properties were also examined. At the end of five years, loblolly and Virginia pines have been successfully established and are performing as well as trees in stands growing don natural soils in the southeastern U.S. Eastern white pine grows slowly the first three years and was just beginning to exhibit a response to treatment. Ground-cover control had the greatest effect on loblolly pine volume-index and elicited as much as an 86% increase in volume-index at the end of five growing seasons. Volume-index of Virginia pine was improved with ground-cover control on Site I and with fertilization on Site II. All species show an additive growth response to the combined treatments. At age five, white pine responded synergistically to combined fertilizer and ground-cover control treatments. The peak response to treatments occurred generally at age two for both loblolly and Virginia pines, while white pine response never peaked. The status of foliar and soil nutrients corroborated the importance of these cultural treatments in improving growth. Negative relationships between volume-index and foliar N and mineralizable N showed that N was not limiting pine growth at this time. Mature stands of serecia lespedeza may have supplied adequate N. A positive relationship between white pine volume-index and foliar P levels suggested that insufficient P may have limited growth of this species. As mine soils in this region age, soil P tends to be fixed by Fe-oxides present in the spoil, making competition for low levels of available-P even greater. Fertilization and ground-cover control will improve tree growth on reforested surface mines by alleviating complex interacting water and nutrient deficiencies. These treatments, implemented during establishment, were still evident at age five, a time that coincides with bond-release eligibility, and response curves suggested that response to treatments will continue as the stands develop.
Forest soil and vegetation characteristics in two forest types following wildfire in the Shenandoah National Park, Virginia
Groeschl, David A. (Virginia Tech, 1991-01-05)
A wildfire of variable intensity occurred in mid-July of 1988 in the Shenandoah National Park and adjacent private lands. This study was established to measure post-fire forest soil and vegetation characteristics in both the mixed pine and mixed oak forest types occurring on Dovel Mountain in the Shenandoah National Park, Virginia. Vegetation and soil results represent one (1989) and two (1990) growing seasons following fire occurrence in the mixed pine forest type, whereas only second year results are reported for the mixed oak forest type. Forest floor and mineral soil parameters differed among burn levels and followed similar trends for both forest types. Forest floor depth and weight were significantly less on low and high burn areas as compared to unburned areas. Low intensity fires removed the Oi-Oe layer while leaving the Oa layer relatively intact. Conversely, high intensity fifes resulted in the consumption of the entire forest floor. Total carbon, nitrogen, and nutrient differences between low and unburned areas for the entire forest floor (Oi-Oe + Oa) were negligible. However, loss of these constituents were much greater following high intensity fifes. Differences in the surface 10 cm of mineral soil were also detected following following high intensity fifes. Differences in the sulface 10 cm of mineral soil were also detected following low and high intensity fires. Mineral soil acidity was lower while exchangeable cation concentrations were higher in burned areas compared to unburned areas. Total carbon and nitrogen levels were higher in low burn areas, whereas total carbon and nitrogen levels were lower on high bum areas. Inorganic nitrogen levels were higher in both low and high burn areas compared to unburned areas.

Browsing by Author "Smith, David William"

Results Per Page

Sort Options