VTechWorks Repository :: Browsing by Author "Aust, W. Michael"

Browsing by Author "Aust, W. Michael"

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Agroforestry opportunities and constraints in the Água de Gato Watershed, Santiago, Cape Verde Islands
Delgado, Orlando Jesus (Virginia Tech, 1996-08-23)
The objectives of this study were to determine the opportunities, constraints, and willingness of the inhabitants and non-resident landowners to adopt a new land-use system in the Agua de Gato Watershed, to determine the degree of agroforestry technical support available to farmers in the watershed, and to determine suitable agroforestry systems which can be adapted to the watershed according to its biological and physical conditions. A random group of farmers of the Agua de Gato Watershed and a group of technicians working on the island of Santiago were interviewed in order to get individual and general information about the farms the and practice of agroforestry in the watershed. Only 56% of the technicians knew or had some knowledge about agroforestry, and the farmers think that they do not have enough technical support for better development of agriculture in the watershed. Although most of the farmers had a small piece of land, averaging 1.1 ha, most of them, 92%, were willing to adopt an agroforestry system as a new land use system for their farms.
An Analysis of Log Truck Turn Times at Harvest Sites and Mill Facilities
Dowling, Tripp N. (Virginia Tech, 2010-04-19)
The raw forest products transportation sector is inherently unique when compared to other transportation industries. The loggers and contractors who transport raw forest products are at a competitive disadvantage. Older equipment is also commonly used by the raw forest products transportation industry in harsh working environments. The average log truck age is 9.7 years while all trucks average only 3.9 years. Nineteen percent of log trucks are 15 years old or older while only 5.9% of all trucks are older than 8 years. Log trucks are regulated by both the Federal Motor Carrier Safety Administration and the state that the truck operates in, thus making interstate transportation more difficult. In addition to these challenges, there is a lack of information concerning efficiency and productivity improvement opportunities related to transporting forest products. This study evaluated truck turn times at both the harvesting site and mill facilities in order to identify important trucking productivity factors and efficiency improvement opportunities. Regression equations were created to estimate truck turn times at harvesting sites and mill facilities. Gross level studies found that 1268 truck turns at the tract scale averaged 1.40 hours while 576 truck turns at the mill scale averaged 0.56 hours. Elemental time studies at four harvesting locations found that log trucks were idle 32% of the time. Trucks spent 29% of time being loaded and 26% of the time waiting. Elemental time studies at mill facilities found that trucks were idle 27% of the time. Trucks spent the greatest amount of time unloading while unbinding was the second greatest contributor to turn times. Reductions in loading and waiting times can have significant effects on the overall turn time. Harvesting contractors could benefit from maintaining balanced harvesting crews. Estimates indicate that harvesting contractors could earn an additional profit of $106,500 over a period of five years by purchasing an additional skidder for those crews whose production is limited due to a lack of skidding capacity. It is estimated that if adding an additional trailer to harvesting crews would allow an additional 2 loads to be transported to the mill each day, harvesting crews could earn an additional $22,100 per year of profit. Road construction can also affect harvesting contractors profits. By minimizing road construction through the use of easements and improved pre-harvest planning, harvesting contractors could reduce road construction costs by as much as $14,000 per tract. With tools available to estimate truck turn around times, harvesting contractors, fleet managers, and truck drivers will be able to make more informed decisions regarding fleet management. This will enable those owning and operating trucks to operate in more efficient and profitable manners. The models created during this study will allow managers to estimate tract and mill turn times so as to better allocate trucking resources.
An Analysis of Palustrine Mitigation Wetlands in the Virginia Coastal Plain
Cummings, Angela R. (Virginia Tech, 1999-05-13)
In recent years, the success of wetland mitigation projects and their ability to function as natural systems has been questioned. This study was conducted (i) to characterize and examine differences between mitigation and natural wetlands, (ii) to examine differences in soil morphology along a wetness gradient in mitigation and natural wetlands, and (iii) to observe changes in mitigation wetlands with time. Site characteristics, including soil properties, hydrology, and vegetation, were analyzed for three mitigation-reference wetland pairs located in the Virginia Coastal Plain. Hydrologic regimes of mitigation areas, when compared to reference areas, generally showed larger differentials between seasonal high and low watertables. Mitigation areas, dominated by herbaceous vegetation, tended to be lower in C and N levels and higher in soil pH, and much higher in bulk density than the mature forested reference wetland. Initially low levels of C and N did not increase significantly over the five-year study period. Soils in the mitigation area were more uniform and considerably less differentiated when compared to those of the reference area. Testing for Fe(II) with alpha-alpha, dipyridyl dye solution produced mixed results, obtaining both positive and negative reactions to saturated samples. Oxidized rhizospheres, associated with active root channels in surface horizons, formed in less than ten years under the current hydrologic conditions. These features were more abundant and more prominent in areas saturated at or above the surface for longer periods of time. Overall, site differences between mitigation and reference areas are mainly due to construction practices and a lack of organic matter accumulation. Better design methods should incorporate the addition of organic amendments, with attempts to minimize soil compaction.
An analysis of solute transport on a harvested hillslope in the southern Appalachian Mountains
Moore, Erin Amanda (Virginia Tech, 2008-04-30)
Interest in transport of dissolved nitrogen (N) and carbon (C) in forested ecosystems is growing because of potential effects of these solutes on streamwater quality and implications for C sequestration. Additional research will further the understanding about the dynamics of these soil solutes, particularly in response to harvesting of forests. Also, the purported role of riparian buffers, where logging is restricted along stream channels, in retaining soil solutes is not well studied in the steeply sloping terrain of the southern Appalachian Mountains. I examined solute transport in a first-order watershed in the Nantahala National Forest in North Carolina that was harvested in February 2006 with retention of a 10-m riparian buffer. To quantify the movement of dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON), and dissolved organic carbon (DOC), four transects of lysimeters, approximately 30 m apart, were installed perpendicular to the stream on one hillslope. Porous ceramic cup (2-bar) lysimeters were installed in each transect 1, 4, 10, 16, 30, and 50 m from the stream in the A horizon and B horizon, and 4, 16, and 50 m from the stream in the saprolite layer. Samples were removed from the lysimeters 24 hr after 50 centibars of tension were placed on them, and riparian groundwater well and stream samples were collected at the same time as lysimeter samples. Collection of samples from the lysimeters, wells, and stream occurred every four to six weeks for one calendar year beginning March 2007. A 16-wk laboratory N mineralization study was conducted on A horizon soils. Mean nitrate values in the soil solution of the A horizon in the spring were 1.53mg-N/L and decreased through the growing season to 0.030mg-N/L. Mean soil solution nitrate values in the B horizon and saprolite layer were 0.40mg-N/L in the spring and summer and decreased to 0.031mg-N/L in the winter. Mean soil solution ammonium concentrations were higher in the A horizon (0.090mg-N/L) than the B horizon and saprolite layer (0.034mg-N/L) and were lowest during the summer and fall. Dissolved organic C was significantly higher in the A horizon, with values ranging from 2.3mg/L to 599mg/L, than in the relatively stable B horizon and saprolite (1.9mg/L to 36.6mg/L). Dissolved organic C was logarithmically correlated to DON (r2 = 0.64), and DON values were highest in the A horizon (0.70mg/L). Cumulative N mineralization potential ranged from 48.1mg-N/kg to 75.6mg-N/kg and was not a useful predictor for nitrate soil solution values. Nitrate leached vertically, and a large percentage of nitrate was stored in the B horizon and saprolite. Ammonium, DON, and DOC did not appear to leach vertically because they did not increase in the B horizon or saprolite layer. Ammonium, DON, and DOC are less mobile in soil solution than nitrate. The 10-m riparian zone had little impact on nitrate, ammonium, DON, and DOC removal. Nitrate remaining in the A horizon was likely removed through plant uptake in the harvested area before reaching the riparian zone. There was no detectable difference between ammonium concentrations in the harvested area and riparian zone likely because of limited mobility. The riparian zone did not remove excess DON or DOC, and in some transects was a source of DON and DOC. Nitrate and DOC concentrations were highly variable among transects and locations within transects. This may be caused by sensitivity of these solutes to site heterogeneity. This suggests that a large number of lysimeters should be used to account for this variability in future studies to ensure accuracy. This study observed limited vertical leaching of ammonium, DON, and DOC through the profile. However, excess nitrate was observed moving from the A horizon into the B horizon and saprolite layer, suggesting the potential for delivery to the stream via subsurface transport and the need for attenuation of nitrate by the riparian zone. Because of low concentrations of nitrate entering the riparian zone during this study, the capacity for riparian attenuation of nitrate was not demonstrated.
Anticipated Impact of a Vibrant Wood-to-Energy Market on the U.S. South's Wood Supply Chain
Conrad, Joseph Locke IV (Virginia Tech, 2011-08-11)
Recent emphasis on producing energy from woody biomass has raised questions about the impact of a vibrant wood-to-energy market on the southern wood supply chain, which consists of forest landowners, forest industry mills, and harvesting contractors. This study utilized two surveys of southern wood supply chain participants and a designed operational study of an energywood harvest to investigate the impact of an expanded wood-to-energy market on each member of the southern wood supply chain. First, a survey of consulting foresters was conducted to examine how harvest tract size, forest ownership, and forest industry structure have changed within the U.S. South and how foresters expect the wood-to-energy market to impact the wood supply chain in the future. Second, this study employed a mail survey of forest landowners, forest industry mills, and wood-to-energy facilities from the thirteen southern states in order to investigate expected competition for resources, wood supply chain profitability, and landowner willingness to sell timber to energy facilities. Third, this study conducted a designed operational study on a southern pine clearcut in the Coastal Plain of North Carolina, with three replications of three harvest prescriptions to measure harvesting productivity and costs when harvesting woody biomass for energy. The three treatments were: a Conventional roundwood only harvest (control), an Integrated harvest in which roundwood was delivered to traditional mills and residuals were chipped for energy, and a Chip harvest in which all stems were chipped for energy use. Results from the two surveys suggest that timber markets are inadequate in many areas of the South as a result of expanded timber supply and reduced forest products industry capacity. Only 12% of responding landowners and foresters had sold wood to an energy facility, indicating that wood-to-energy markets are non-existent in many areas of the South. Nonetheless, 98% of consulting foresters and 90% of landowners reported a willingness to sell timber to an energy facility if the right price were offered. Consulting foresters expected wood-to-energy facilities to provide an additional market for wood, and not displace forest products industry capacity. However, two-thirds of consulting foresters, wood-to-energy facilities, and private landowners expected competition between mills and energy facilities while 95% of fibermills (pulp/paper and composite mills) expected competition. Fibermills were much more concerned about competition for resources and increases in wood costs than any other member of the southern wood supply chain. The operational study documented the challenges facing some harvesting contractors in economically producing energywood. Onboard truck roundwood costs increased from $9.35 green t-1 in the Conventional treatment to $10.98 green t-1 in the Integrated treatment as a result of reduced felling and skidding productivity. Energy chips were produced for $19.19 green t-1 onboard truck in the Integrated treatment and $17.93 green t-1 in the Chip treatment. Energywood harvesting costs were higher in this study than in previous research that employed loggers with less expensive, more fuel efficient equipment. This suggests that high capacity, wet-site capable loggers may not be able to economically harvest and transport energywood without a substantial increase in energywood prices. This study suggests that the southern wood supply chain is in position to benefit from a vibrant wood-to-energy market. Landowners should benefit from an additional market for small-diameter stems. This study shows that high production, wet-site capable loggers should not harvest energywood until prices for this material appreciate considerably. Wet-site loggers have very expensive equipment with high hourly fuel consumption rates and this study documented that energywood production was not sufficiently high to offset the high hourly cost of owning and operating this equipment. Nevertheless, a wood-to-energy market should benefit harvesting contractors in general because unless the forest products industry contracts further, loggers can continue to harvest and deliver roundwood to mills as they do at present and those properly equipped for energywood harvesting at low cost may be able to profit from a new market. The forest products industry has the largest potential downside of any member of the southern wood supply chain. This study documents widespread anticipation of competition between the forest products and wood-to-energy industries. However, to date there has been minimal wide-scale competition between the forest products and wood-to-energy industries. It is possible that the wood-to-energy industry will complement, rather than compete with the forest products industry, and thereby benefit each member of the southern wood supply chain.
Assessing and Evaluating Recreation Resource Impacts: Spatial Analytical Approaches
Leung, Yu-Fai (Virginia Tech, 1998-02-09)
It is generally recognized that the magnitude of recreation resource impacts should be judged by their severity and spatial qualities, including extent, distribution, and association. Previous investigations, however, have primarily focused on assessing the severity of impacts, with limited examination of spatial qualities. The goal of this dissertation was to expand our understanding of the spatial dimension of recreation resource impacts and their assessment and evaluation. Two empirical data sets collected from a comprehensive recreation impact assessment and monitoring project in Great Smoky Mountains National Park provided the basis for the analyses. Three spatial issues were examined and presented as three papers, designed for journal submission. The purpose of the first paper was to improve our understanding of the dimensional structure and spatial patterns of camping impacts by means of multivariate analyses and mapping. Factor analysis of 195 established campsites on eight impact indicator variables revealed three dimensions of campsite impact: land disturbance, soil and groundcover damage, and tree-related damage. Cluster analysis yielded three distinctive campsite types that characterize both the intensity and areal extent of camping impacts. Spatial patterns and site attributes of these three campsite types and an additional group of primitive campsites were illustrated and discussed. The purpose of the second paper was to examine the influence of sampling interval on the accuracy of selected trail impact indicator estimates for the widely applied systematic point sampling method. A resampling-simulation method was developed and applied. Simulation results indicated that using systematic point sampling for estimating lineal extent of trail impact problems can achieve an excellent level of accuracy at sampling intervals of less than 100 m, and a reasonably good level of accuracy at intervals between 100 and 500 m. The magnitude of accuracy loss could be higher when the directions of loss are not considered. The responses of accuracy loss on frequency of occurrence estimates to increasing sampling intervals were consistent across impact types, approximating an inverse asymptotic curve. These findings suggest that systematic point sampling using an interval of less than 500 m can be an appropriate method for estimating the lineal extent, but not for estimating occurrence of trail impacts. Further investigations are called for to examine the generalizability of these results to other areas. The purpose of the third paper was to expand the scope of indices used for evaluating recreation resource impacts. Two specific objectives were to synthesize the recreation ecology and recreation resource management literature on the use of spatial indicators and indices, and to propose and apply selected spatial indices that are mostly lacking in the literature. Three spatial indices primarily adapted from the geography and ecology literature were proposed for application in recreation impact evaluation. Application results demonstrated that the Lorenz curve and associated Gini coefficient, and the linear nearest-neighbor analysis and associated LR ratio were effective in quantifying the spatial distribution patterns of trail impacts at landscape and trail scales, respectively. Application results of the third index, the impact association index, were less promising and require further refinements. Management implications and future directions of research were discussed in light of the findings of this dissertation. As the field of recreation ecology is emerging, this dissertation has demonstrated: (1) the value of recreation impact assessment and monitoring programs in providing data for examining the spatial dimension of impacts, and (2) the utility of spatial analytical approaches in understanding recreation impact assessment and evaluation.
Assessing the Cost and Operational Feasibility of "Green" Hardwood Winter Inventory for Southeastern Pulp Mills
Gallagher, Thomas V. (Virginia Tech, 2003-05-23)
Procuring hardwood pulpwood during the winter months for a pulp mill in the Southeast can be difficult. Saturated soils and low soil strength make logging difficult or impossible on many sites, forcing companies to store large volumes of hardwood pulpwood in woodyards for retrieval during wet weather. Hardwood fiber readily available in large volumes on ground that is operable during wet periods at a location near the pulp mill could provide a valuable alternative wood source. Thus, the objectives of this study are to 1) develop a decision model for a manager to use to determine the feasibility of strategically located, intensively-managed, short-rotation hardwood fiber farms as pulp mill furnish, 2) use the model to estimate wood costs for a hypothetical eastern cottonwood plantation, and 3) use the model to determine if a fiber farm grown on drier, upland sites ("green" inventory) could be used to reduce woodyard winter inventories and economically supply a nearby pulp mill during a wood shortage, thus reducing high cost, emergency "spot market" wood purchases. The decision model is incorporated in a spreadsheet and includes all the costs typical for a fiber farm. The model is tested using current establishment and management costs from the literature and yields from an experimental fiber farm in the southeast. Under current yields, delivered costs from the fiber farm averages $71/ton. With potential increased yields that could occur with genetic improvements and operational optimizations, delivered cost for fiber farm wood could be reduced to $56/ton. In comparison, the highest cost wood purchased by the three cooperating pulp mills during the study period was $50.23/ton. The net present values of a fiber farm as "green" inventory were determined using actual wood cost and inventory levels from three cooperating southeastern pulp mills. For the "green" inventory analysis, all three pulp mills would have lowered their overall wood cost using a fiber farm (with higher yield) as "green" inventory, primarily by reducing the amount of wood required as dry inventory on woodyards. Savings accrued during "dry" years offset the higher cost of hardwood plantation deliveries. A sensitivity analysis was performed to determine the optimal size fiber farm for one of the cooperating pulp mills and indicated that 800 acres would be the most beneficial.
Assessment of silvicultural practices to improve survival and growth of pioneer and mid-successional hardwoods on old field restoration sites
Steele, Jason Keith (Virginia Tech, 2020-07-01)
Survival and growth of planted trees are common indices used to evaluate success of wetland restoration efforts used to compensate for wetland losses. Restoration efforts on marginal agricultural lands typically result in less than satisfactory survival and growth of desired tree species. This study evaluated seed source ecotype, greenhouse preconditioning and combinations of five mechanical site preparation techniques (mound, bed, rip, disk, pit), four levels of planting stock (gallon, tubeling, bare root, and direct seed), and three planting aids (mat, tube, none) on the survival and growth of American sycamore (Platanus occidentalis L.) and willow oak (Quercus phellos L.) planted on an old field riparian area in the Virginia Piedmont. American sycamore seedlings subjected to greenhouse flood preconditioning had 25% greater height and willow oak seedlings grown under normal greenhouse conditions had 18% greater diameter, but these greenhouse adaptations did not confer greater survivability or growth after field planting. American sycamore seeds sourced from dry ecotypes were 14% taller than wet ecotype seeds, and willow oak acorns sourced from wet ecotypes were 11% taller than dry ecotype acorns, indicating that parental ecotype may influence survivability and growth. The combination of mounding site preparation and gallon planting stock increased mean survival to 100% and aboveground dry biomass (5.44 Mg/ha/yr) in American sycamore. Willow oak had 45% greater woody stem volume with mounding site preparation 80% greater woody stem volume with gallon and bare root planting stock. Tubeling planting stock provided significant benefit relative to the low planting stock cost for American sycamore, while bare root seedlings were shown to be an effective planting stock for willow oak. The use of appropriate ecotype seed sources, use of mounding mechanical site preparation techniques and planting of species appropriate planting stock increased survival and growth of common early and mid-successional Piedmont tree species on marginal agricultural lands. Treatments that appear to be economically viable for restoration and mitigation efforts could potentially offer other economic incentives such as short rotation woody crops and timber value, which might induce additional private landowners to attempt restoration efforts in marginal old field riparian areas.
Carbon Pools and Fluxes as an Indicator of Riparian Restoration
Giese, Laura (Virginia Tech, 2001-01-12)
Riparian forests are integral components of the landscape. The inherent biogeochemical processes that occur in such forests provide numerous benefits to wildlife and society. Maintaining good water quality is a major benefit from riparian forests and therefore, the maintenance, creation, or restoration of riparian forests is indispensable. This study was designed to broaden current knowledge of the complex, interrelated biogeochemical processes and determine indices for riparian forest restoration based on the various carbon pools/fluxes that may represent restoration success. This study was implemented on the Savannah River Site, an Environmental Research Park, where several riparian forests are recovering from thermal disturbances. The streams in these forests were subjected to thermal discharges that increased flows and resulted in removal of soil and a decline in the amount of woody vegetation. Two of these riparian forests are at different ages post-disturbance and represent different stages of recovery, which provides an exceptional opportunity to study successional processes in riparian forests and enhance restoration efforts. Linear transects perpendicular to the main stream channels were established in 2 recovering riparian forests of different ages (two areas in Pen Branch ~ 8 years post-disturbance; Fourmile Branch ~ 12 years post disturbance) and an undisturbed (thermally) more mature riparian forest (Meyer's Branch ~ 60 years). Along these transects quantitative data were obtained on above and belowground carbon pools and fluxes. Carbon pools exhibited a close correlation with riparian forest development. Biomass and carbon pools increased with increasing riparian forest stand age. The importance of the herbaceous carbon pool declined relative to the total above ground biomass, and the root carbon pool increased with forest age/succession. In general, net primary production (NPP) in young riparian forests (~8-10 years) rapidly approached and even exceeded NPP of more mature riparian forests. Once the herbaceous stage of succession was surpassed, the litterfall component of NPP plays a greater role riparian forests. As a woody overstory became established (after ~ 8-10 years), annual litterfall rates as a function of NPP were independent of forest age. Establishment of woody species occurred ~8 to 10 years after thermal disturbance and litterfall amount in young riparian forests rapidly became comparable to mature riparian forests. Lateral litter movement from the riparian forest toward the stream was less than the amount of litter (carbon pool) deposited from upstream into the riparian forest during a flood event. Overall lateral litter movement supplied less energy to the stream system than vertical inputs. A decline in riparian forest floor biomass was observed with increasing riparian forest development. However, a difference in foliar forest floor percent carbon lended itself to a minimal increase in the forest floor carbon pool with increasing riparian forest age. Woody debris in riparian forests comprised a relatively small carbon pool compared to tree and soil carbon pools. The species composition of litter appeared to be more of an overriding factor influencing decomposition rates than forest age. The influence of litter quality was evident in the decomposition rates of the different litter composites used in this study. In all 4 sites the litter composite from the mature riparian forest decomposed significantly more than the litter composites from the younger riparian forests. The fairly rapid decomposition of red maple (Acer rubrum L.), which was one of the main components in the mature riparian forest litter composite, influenced the greater decomposition rate. The litter composites from the younger riparian forests were similar and both included more decomposition resistant litter types, specifically waxmyrtle (Myrica cerifera L.) and alder (Alnus serrulata (Ait.) Willd.). Decomposition rates did not differ between the individual successional stages. Riparian forests are intimately associated with their hydroperiod. During flood events the riparian forest receives inputs of organic matter and sediment, and the amount of deposition may decrease along a distance gradient from the main stream channel. The differential amount of inputs could affect forest productivity. However, in these riparian forests, a distance gradient effect was not observed. Trends in herbaceous biomass were evident along a microtopographic moisture gradient. The ridge and swale microtopography prevalent in the younger riparian forests counteracted a distance from the stream channel gradient effect across the riparian forest. This study provided knowledge of how carbon pools and fluxes change with riparian forest recovery from disturbance as well as through different seral stages. Implementing the findings of this study will enhance restoration evaluation efforts to ensure that these areas continue to provide the numerous benefits gleamed from them.
Changes in Soil Nitrogen Following Biosolids Application to Loblolly Pine (Pinus Taeda L.) Forest in the Virginia Piedmont
Arellano Ogaz, Eduardo (Virginia Tech, 2009-01-12)
Application of biosolids as an alternative source of Nitrogen (N) is becoming a common silviculture practices on loblolly pine forest. However, little is known about how biosolids type, application rate, and timing affect forest floor and soil N availability in pine plantations. The objectives of this study were to determine the effect of different types, rates, and season of application of biosolids on forest floor and soil N. The study was established in a 17-year-old loblolly pine plantation in Amelia County, VA. Anaerobically digested (AD225), lime stabilized (LS225), and pelletized (Pellet225) biosolids and a conventional inorganic urea plus diammonium phosphate fertilizer (U+DAP225) were surface applied at a rate of 225 kg ha-1 based on Plant Available Nitrogen (PAN) between March 5th and 10th, 2006. Anaerobically digested biosolids were also surface applied at the rates of 900 kg PAN ha-1 and 1800 kg PAN ha^-
Characterization of the Vegetation and Soil of the Forest Communities at Camp Brookside in Summers County, West Virginia
Mitchem, David O. (Virginia Tech, 2004-12-07)
Camp Brookside, a seasonal island, is located on the floodplain of the New River in Summers County, West Virginia. This island hosts several rare plant species and a rare plant community known as a riverside flat rock plant community (FRPC). The FRPC is characterized by flat resistant sandstone shelves above water that are generally associated with rapids. Flooding has historically maintained the FRPC by scouring any soil off of the bedrock and leaving sand deposits in cracks or depressions. However, since the Bluestone Dam was built in 1950, organic material accumulation and soil development has gone unabated. Measurements were taken of the overstory, lower canopy, regeneration layers, and soils found at Camp Brookside. Our overstory data indicated that there are five distinct plant communities on the island. The FRPC has an overstory of eastern redcedar (Juniperus virginiana), Virginia pine (Pinus virginiana), and white ash (Fraxinus americana). The FRPC has an average soil depth of 1.8 cm, a loamy sand soil texture, and a soil pH of 3.9. A xeric pine community dominated by Virginia pine and eastern redcedar was found along the riverside portion of the island. Historically, this community was part of the FRPC. The xeric pine community has an average soil depth of 17.6 cm, a loamy sand soil texture, and a soil pH of 4.6. Our results indicate that soil and organic material is accumulating in the FRPC, and that some type of disturbance will be needed to maintain this community.
Comparing Sediment Trap Data With Erosion Models for Evaluation of Forest Haul Road Stream Crossing Approaches
Lang, A. J.; Aust, W. Michael; Bolding, M. Chad; McGuire, Kevin J.; Schilling, Erik B. (American Society of Agricultural & Biological Engineers, 2017-01-01)
Soil erosion and sediment delivery models have been developed to estimate the inherent complexities of soil erosion, but most models are not specifically modified for forest operation applications. Three erosion models, the Universal Soil Loss Equation for forestry (USLE-Forest), Revised Universal Soil Loss Equation Version 2 (RUSLE2), and Water Erosion Prediction Project (WEPP), were compared to one year of trapped sediment data for 37 forest haul road stream crossings. We assessed model performance from five variations of the three erosion models: USLE-Roadway, USLE-Soil Survey, RUSLE2, WEPP-Default, and WEPP-Modified. Each road approach was categorized into one of four levels of erosion (very low, low, moderate, and high) based on trapped erosion rate data and erosion rates reported in recent peerreviewed literature. Model performance metrics included: (1) summary statistics and nonparametric analysis, (2) linear relationships, (3) percent agreement within erosion categories and tolerable error ranges, and (4) contingency table metrics. Sediment trap data varied from negligible (<0.1) to hundreds of Mg ha-1 year-1. The soil erosion models evaluated could estimate erosion within 5 Mg ha-1year-1 for most approaches having erosion rates less than 11.2 Mg ha-1 year-1, while models estimates varied widely for approaches that eroded at rates above 11.2 Mg ha-1year-1. Kruskal-Wallis nonparametric analyses revealed that only WEPP-Modified estimates were not significantly different from trapped sediment data (p ≥ 0.107). While WEPP-Modified ranked best for most model performance metrics, the time, effort, modeling expertise, and uncertainty associated with model results may discourage the use of WEPP as a forest management tool. WEPP is better suited for researchers and government agencies that have the capability to measure extensive parameter data. Additional sensitivity analysis is needed to expand default parameters for forest roads within the WEPP and USLE models.
Comparing sediment trap data with the USLE-forest, RUSLE2, and WEPP-road erosion models for evaluation of bladed skid trail BMPs
Wade, Charles R.; Bolding, M. Chad; Aust, W. Michael; Lakel, William A.; Schilling, Erik B. (American Society of Agricultural and Biological Engineers, 2012)
Three erosion models, the Universal Soil Loss Equation for Forestry (USLE-Forest), the Revised Universal Soil Loss Equation Version 2 (RUSLE2), and the Water Erosion Prediction Project for Forest Roads (WEPP-Road), were compared to sediment trap data for bladed skid trail best management practices (BMPs). The bladed skid trail BMPs evaluated were: (1) water bar only (control treatment); (2) water bar + lime, fertilizer, and grass seed (seed treatment); (3) seed + straw mulch (mulch treatment); (4) control + piled hardwood slash (hardwood slash treatment); and (5) control + piled pine slash (pine slash treatment). This study used three erosion models to evaluate the BMPs while also using linear regression, model efficiency (NSE), and percent bias (PBIAS) to compare the prediction accuracy and applicability of the models to monthly erosion collected in sediment traps from six replications of the five treatments. Results showed significant treatment differences due to the BMPs, with the control treatment being the most erosive, followed generally by the seed, hardwood slash, pine slash, and mulch treatments. Model predictions indicated that all models were suitable for ranking erosion rates for the skid trail closure treatments for simple hazard or BMP ratings. However, the older and simpler USLE-Forest and RUSLE2 models had satisfactory NSE and PBIAS values, whereas WEPP-Road did not. Results indicate that WEPP-Road needs additional enhancement with regard to skid trail parameters before it can be effectively used for erosion prediction on bladed skid trails.
A Comparison of Chipper Productivity, Chip Characteristics, and Nutrient Removals from Two Woody Biomass Harvesting Treatments
Groover, Miles Clark (Virginia Tech, 2011-11-30)
Increased costs of fossil fuels, regulatory policies, and investments by federal and state governments have caused increased interest and incentive for the use of wood as a renewable form of energy. As a result, landowners and forest managers are considering chipping whole trees and harvesting residues as a means to meet increased demand of wood chips as a renewable source of energy. However, the profitability, productivity gains, and sustainability of these alternative harvesting methods continue to be an area of research. The objective of this study was to compare two biomass harvesting treatments with regard to the characteristics of the chips they produced, chipper productivity, nutrient removals, and site disturbance. The first biomass harvesting treatment was an integrated harvest where roundwood was merchandized and hauled to the appropriate mill and limbs, tops, and small stems (residues) were chipped for hog fuel. The second biomass harvesting treatment simulated a scenario where biomass markets were competing with pulpwood markets and landowners could choose to sell wood for energy or pulp wood. In this treatment whole trees and small stems were chipped for hog fuel. A third harvesting treatment was a conventional roundwood harvest where no wood was chipped, and this treatment was used as a control for comparison of nutrient removals and site disturbance. The chips produced from both harvesting treatments were very similar, but those produced from whole trees tended to be slightly smaller than those produced from residues. Chipper productivity was significantly higher when chipping whole trees and it was also much more efficient in terms of fuel use. Estimations of nutrient removals showed that there was very little difference in the amount of nutrient removed from the biomass harvesting treatments, but both treatments removed significantly more N and Ca than the conventional roundwood harvesting treatment. There was significantly more downed and standing material left on the site after harvesting in the conventional treatment, but this did not translate into a large amount of additional nutrients left on the site. There was little difference in soil disturbance between all three treatments, and due to the dry soil conditions during harvesting, there was very little visual soil disturbance at all during harvesting.
A comparison of crown attributes for six genotypes on Pinus taeda as affected by site and management intensity
Carbaugh, Eric Douglas (Virginia Tech, 2015-10-19)
This study was designed to investigate the development of the crown architecture of six genotypes of loblolly pine across a variety of growing conditions, and also to investigate the stability of the crown ideotype for these genotypes over a range of site and silvicultural management regimes. The objectives were to determine whether the crown dimensions that determine the crown ideotype of four clones, a mass-control-pollinated family, and an open-pollinated family of Pinus taeda L. are consistent within their respective genotypes, and to determine whether those same crown dimensions and genotypes follow consistent patterns even when established on different sites with contrasting qualities and different silvicultural regimes. The study was conducted on a 5-year-old plantation with an initial spacing of 1,235 trees per hectare. The plots had not reached crown closure, which provided the opportunity to assess the crown characteristics of individual trees of each genotype and how they developed over in a variety of growing conditions, without the interactions of other individuals. The study was a split-split plot design with the whole plot divided between two sites of contrasting quality; one site established in the Virginia Piedmont and a second site established in the North Carolina Coastal Plain. The sub plots were divided between high and low intensity silviculture. The sub-sub plots were divided among the six genotypes of loblolly pine. Seventeen tree and crown characteristics were measured, and means were compared using analysis of variance and Tukey's HSD test. We hypothesized that the branch and crown attributes would follow consistent patterns among these genotypes on the two sites and between the two silvicultural regimes. The results generally confirm these hypotheses. When the genotypes were compared, interactions only occurred with total branches, internode length, total foliage mass, and total leaf area. Tree height, diameter at breast height (dbh), stem volume, and crown volume averaged 4.8 m, 7.5 cm, 0.03 m3, and 7.1 m3, respectively at the site in Virginia, compared to values of 4.1 m, 6.2 cm, 0.02 m3, and 4.9 m3 at the site in North Carolina. Tree height, dbh, stem volume, branch diameter, branch length, and crown volume averaged 4.7 m, 7.5 cm, 0.03 m3, 1.3 cm, 90.3 cm, and 7.3 m3, respectively under high intensity silviculture compared to values of 4.3 m, 6.2 cm, 0.02 m3, 1.1 cm, 68.7 cm, and 4.7 m3 under low intensity silviculture. There were differences among the genotypes in branch diameter, branch length, and crown volume, with the branch diameter of clones 1 and 3 averaging 1.2 cm compared to an average of 1.3 cm for clones 2 and 4. Branch length for clone 1 averaged 72.4 cm and clone 3 averaged 77.0 cm, while branch length for clone 2 averaged 83.3 cm and clone 4 averaged 86.7 cm. Crown volume for clone 1 averaged 4.9 m3 and clone 3 averaged 6.3 m3, while clone 2 averaged 7.1 m3 and clone 4 averaged 7.2 m3. These differences conform to the crown ideotype for these clones, where clones 1 and 3 were considered narrow crowned and clones 2 and 4 were considered broad crowned. The branch diameter and branch length of the open pollinated family (OP) was similar in size to the broad crowned clones (1.3 cm and 84 cm, respectively), while the branch diameter and branch length of the mass control pollinated (MCP) family was smaller than the narrow crowned clones (1.1 cm and 71.2 cm, respectively). Crown volume for the OP family was intermediate between the clonal ideotypes, averaging 5.9 m3, while the MCP family had the smallest crown volume, averaging 4.7 m3. A single-degree-of-freedom ANOVA comparing the two clonal ideotypes yielded similar results. There were interactions with branch diameter, total branches, internode length, and total leaf area, but the broad crown ideotype was larger in every measured parameter than the narrow crown ideotype. The lack of interactions and the general conformity to crown ideotype in this study indicated stability among these genotypes across this variety of growing conditions.
Components of logging costs
Loving, Easton (Virginia Tech, 1991-06-15)
Twenty-four independent logging businesses in the Southeastern United States were analyzed in a general systems approach to document the components of logging costs for mechanized operations, assess the sensitivity of these components to external stimuli, and to identify and describe the business management techniques adopted by contractors to insure survival and profitability. The contractors' cost records for 1988 and 1989 were analyzed to meet the study's first two objectives and interviews with each participant facilitated identification of survival and profitability strategies. The general interviews and on-site observations of the harvesting systems provided background information for evaluating the costs and identifying business management techniques. The contractors' records were summarized into six cost components: 1) consumable supplies, 2) labor, 3) equipment,4) insurance. 5) contract hauling, and 6) administrative overhead. Contractors were stratified by trucking strategy, ranging from those who hauled all of their own wood to contractors relying exclusively on contract truckers. Consumable supplies, labor, and equipment accounted for approximately 75% of total costs for the average contractor in 1988 and 1989. The concept of excess logging capacity was evaluated. Analyses indicate that excess capacity exists in many areas of the Southeastern U.S., and excess capacity influences cost structures and survival strategies. Discussion with most contractors and evaluation of direct costs of excess capacity indicated that contractors are unable to achieve marginal efficiencies due to the large number of suppliers in some areas. Four major business survival strategies were identified during the study. Equity dissolution and diversification were the prevalent strategies, suggesting that the late 1980s and early 1990s favor harvesting systems that are downwardly elastic in terms of production.
A Computer Simulation Model for Predicting the Impacts of Log Truck Turn-Time on Timber Harvesting System Productivity
Barrett, Scott M. (Virginia Tech, 2001-01-18)
A computer simulation model was developed to represent a logging contractor's harvesting and trucking system of wood delivery from the contractor's in-woods landing to the receiving mill. The Log Trucking System Simulation model (LTSS) focuses on the impacts to logging contractors as changes in truck turn times cause an imbalance between harvesting and trucking systems. The model was designed to serve as a practical tool that can illustrate the magnitude of cost and productivity changes as the delivery capacity of the contractor's trucking system changes. The model was used to perform incremental analyses using an example contractor's costs and production rates to illustrate the nature of impacts associated with changes in the contractor's trucking system. These analyses indicated that the primary impact of increased turn times occurs when increased delivery time decreases the number of loads per day the contractor's trucking system can deliver. When increased delivery times cause the trucking system to limit harvesting production, total costs per delivered ton increase. In cases where trucking significantly limits system production, total costs per delivered ton would decrease if additional trucks were added. The model allows the user to simulate a harvest with up to eight products trucked to different receiving mills. The LTSS model can be utilized without extensive data input requirements and serves as a user friendly tool for predicting cost and productivity changes in a logging contractor's harvesting and trucking system based on changes in truck delivery times.
Consider Logging Residue Needs for BMP Implementation When Harvesting Biomass for Energy
Barrett, Scott M.; Aust, W. Michael; Bolding, M. Chad (Virginia Cooperative Extension, 2014-08-07)
This publication reviews the Best Management Practices (BMP) on harvesting forestry operations particularly when harvesting biomass.
Consider logging residue needs for BMP implementation when harvesting biomass for energy
Barrett, Scott M.; Aust, W. Michael; Bolding, M. Chad (Virginia Cooperative Extension, 2019)
Logging residues for Best Management Practices. Residue can be used for slash or for water protection.
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.

Browsing by Author "Aust, W. Michael"

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