A canopy-related stratification of a southern pine forest using LANDSAT digital data

An investigation was undertaken to determine if a consistent stratification of a Southern pine forest could be obtained by using LANDSAT multispectral scanner data to assess crown closure. Winter and summer LANDSAT scenes of the North Carolina coastal region were analyzed individually and then registered and merged to take advantage of temporal changes in the forest canopy. Three levels of pine crown closure were accurately delineated. The applicability of this stratification as supplemental input to a forest inventory system is also discussed

Qualitative and Quantitative Aquatic Algal Data Compilation to Determine Macrotrends- III

A data base of the algae of Arkansas ecoregions has been established by the use of a relational data base management system (dBase III plus). The system was chosen to be readily available for a variety of microcomputers using MS- and PC-DOS. The data base contains taxonomic fields from division through variety, synonymy, authors, initial description, date and definitive descriptive source. The data are cross-referenced by ecoregion, Round\u27s community and subcommunity designations. The data base contains approximately 1,500 taxonomic records in all divisions and classes of freshwater algae. The data are sortable by any of the included parameters. The data have been used to initiate the publication of the algal flora of Arkansas. The listing of the Cyanophyta/Cyanobacteria or blue-green algae is presently available. Other taxonomic lists are in preparation

Effect of Removal of Woody Biomass after Clearcutting and Intercropping Switchgrass (Panicum virgatum) with Loblolly Pine (Pinus taeda) on Rodent Diversity and Populations

Plant-based feedstocks have long been considered viable, potential sources for biofuels. However, concerns regarding production effects may outweigh gains like carbon savings. Additional information is needed to understand environmental effects of growing feedstocks, including effects on wildlife communities and populations. We used a randomized and replicated experimental design to examine initial effects of biofuel feedstock treatment options, including removal of woody biomass after clearcutting and intercropping switchgrass (Panicum virgatum), on rodents to 2 years post-treatment in regenerating pine plantations in North Carolina, USA. Rodent community composition did not change with switchgrass production or residual biomass removal treatments. Further, residual biomass removal had no influence on rodent population abundances. However, Peromyscus leucopus was found in the greatest abundance and had the greatest survival in treatments without switchgrass. In contrast, abundance of invasive Mus musculus was greatest in switchgrass treatments. Other native species, such as Sigmodon hispidus, were not influenced by the presence of switchgrass. Our results suggest that planting of switchgrass, but not biomass removal, had species-specific effects on rodents at least 2 years post-planting in an intensively managed southern pine system. Determining ecologicalmechanisms underlying our observed species associations with switchgrass will be integral for understanding long-term sustainability of biofuels production in southern pine forest

A reduction in ag/residential signature conflict using principal components analysis of LANDSAT temporal data

Methods to accurately delineate the types of land cover in the urban-rural transition zone of metropolitan areas were considered. The application of principal components analysis to multidate LANDSAT imagery was investigated as a means of reducing the overlap between residential and agricultural spectral signatures. The statistical concepts of principal components analysis were discussed, as well as the results of this analysis when applied to multidate LANDSAT imagery of the Washington, D.C. metropolitan area

Habitat Influences on Nongame Bird Nest Success in a Managed and Fragmented Southern Pine Forest.

We confirmed the breeding-season presence of 52 bird species and assessed the reproductive quality of a fragmented southern pine forest managed for natural resource extraction on Barksdale Air Force Base in northwest Louisiana, USA. We also conducted point counts to assess relative abundance, richness, and diversity among four habitat discontinuity types (timber harvests, pipeline corridors, access roads, and natural gas wells). Each parameter was greater on study plots adjacent to gas wells than on those adjacent to roads. We determined the fate of 817 nests of 42 species between 1996 and 1998 and determined Mayfield daily nest success (MDNS) for each species with sufficient nests. Half (50.5%) of the 657 open-constructed nests were successful and most (87.4%) failures resulted from predation. MDNS differed among habitat discontinuity types, years of the study, differentially fragmented sectors of the study area, and between interior and edge habitats. MDNS for the full open-nesting community was greater in 1996 than in 1998 and Neotropical migrant MDNS was greater in 1996 and 1997 than in 1998. These differences corresponded with drastic differences in precipitation across the years of the study. Northern Cardinals (Cardinalis cardinalis) and Kentucky Warblers (Oporornis formosus) were most abundant on plots adjacent to recent timber harvests and natural gas wells. Cardinal MDNS was greater adjacent to pipeline corridors and access roads than to timber harvests and natural gas wells. Kentucky Warbler nestling-stage MDNS was greater adjacent to timber harvests, pipelines, and roads, than to wells. Cardinal and Hooded Warbler (Wilsonia citrina ) MDNS was lower for nests located near edges than for those located more than 62.75 m from discontinuities, but results were opposite for Kentucky Warblers. Full-community and Hooded Warbler MDNS was greater in the least fragmented sector of the study area than in the more fragmented sectors. Recent prescribed burning of the understory had no discernible effect on MDNS. Ground and canopy nests had greater MDNS than shrub nests and better-concealed nests of four species had greater MDNS than nests with less concealment. We conclude that MDNS can be positively influenced through management of habitat discontinuities

Fall Forestry Camp

The 1994 fall camp at the Solon Dixon Forestry Education Center in southern Alabama could not have been better. Though it went quickly, the three weeks that we spent down there were unforgettable

Forest Soil Carbon and Nitrogen Cycles under Biomass Harvest: Stability, Transient Response, and Feedback

Biomass harvest generates an imbalance in forest carbon (C) and nitrogen (N) cycles and the nonlinear biogeochemical responses may have long-term consequences for soil fertility and sustainable management. We analyze these dynamics and characterize the impact of biomass harvest and N fertilization on soil biogeochemistry and ecosystem yield with an ecosystem model of intermediate complexity that couples plant and soil C and N cycles. Two harvest schemes are modeled: continuous harvest at low intensity and periodic clear-cut harvest. Continuously-harvested systems sustain N harvest at steady-state under net mineralization conditions, which depends on the C:N ratio and respiration rate of decomposers. Further, linear stability analysis reveals steady-state harvest regimes are associated with stable foci, indicating oscillations in C and N pools that decay with time after harvest. Modeled ecosystems under periodic clear-cut harvest operate in a limit-cycle with net mineralization on average. However, when N limitation is strong, soil C–N cycling switches between net immobilization and net mineralization through time. The model predicts an optimal rotation length associated with a maximum sustainable yield (MSY) and minimum external N losses. Through non-linear plant–soil feedbacks triggered by harvest, strong N limitation promotes short periods of immobilization and mineral N retention, which alter the relation between MSY and N losses. Rotational systems use N more efficiently than continuous systems with equivalent biomass yield as immobilization protects mineral N from leaching losses. These results highlight dynamic soil C–N cycle responses to harvest strategy that influence a range of functional characteristics, including N retention, leaching, and biomass yield

Impact of Preservative Treatments and Fungal Exposure on Phenolic Fiber Reinforced Polymer (FRP) Composite Material Utilized in Wood Reinforcement

When wood products are exposed to environmental conditions conducive to biodeterioration, wood preservation becomes a necessity, especially when long-term utilization is desired. Although considerable literature exists on the treatment of laminated timbers and wood composites with wood preservatives, almost no information is available on the exposure of Fiber Reinforced Polymer (FRP) composites to wood preservative chemicals. In this work, FRP material was treated with common preservative chemicals and the effect of wood preservative treatments on mechanical properties of FRP material were investigated. Although the longitudinal elastic modulus was unaffected, some longitudinal strength losses were recorded for CCA and CDDC (water borne) treated FRP coupons. These results were supported by Scanning Electron (SEM) and light microscopy analyses of single glass fibers taken from preservative treated FRP coupons. A further study evaluated the susceptibility of E-glass fiber reinforced polymer (FRP) /phenolic pultruded composite material to fungal degradation. Since the phenolic FRP material was designed for use as reinforcement with wood, two common wood decay fungi, a brown rot and a white rot, were chosen for exposure of the FRP material. Light, fluorescent and Scanning Electron Microscopy (SEM) indicated that both wood decay h g i actively grew and penetrated into the FRP material, especially in high-void content areas. The experimental results indicate that, the mechanical property evaluation technique (ILSS) is promising and sensitive enough to detect the effects of fungal degradation in phenolic FRP materials. The durability of adhesive bonds on wood/FRP interfaces poses a continuing problem for the wood products industry. Wood preservative chemicals are known to interfere with adhesion mechanisms between wood laminates as well as wood/FRP interfaces. The purpose of the third part of this study was to determine the effects of various wood preservative treatments and manufacturing processes (pre- and post-treatment) on wood/FRP bond durability, shear strength and surface energy characteristics of wood and phenolic FRP material. While pre-treatment of individual laminates with oil borne (copper naphthenate, creosote and pentachlorophenol) and water borne (CCA and CDDC) preservatives increased the delamination between the wood and FRP, the post treatments had limited effects on delamination