30 research outputs found
Soil Morphological, Physical, and Chemical Parameters Affecting Longleaf Pine (Pinus palustris) Site Quality and Ecosystem Restoration Potential in East Texas
There has been a large decline in coverage of longleaf pine (Pinus palustris Mill.) within its range in the southeastern United States since the time of European settlement. Due to this decline, interest has developed in the re-establishment of this species on suitable sites. However, many attempts have been unsuccessful in re-establishment, likely in part due to the lack of emphasis on selection of suitable soils. Historically, longleaf pine was found on soils with a wide range of soil properties, including higher quality soils, due to frequent fires which kept many competing species suppressed. Decline in longleaf pine coverage has been attributed to many factors, including both site conversion and fire exclusion. Much of the land that originally supported longleaf pine in the southeastern United States has been converted to agricultural use, loblolly pine (Pinus taeda Mill.) plantations, and urban development. Fire has often been excluded from longleaf pine ecosystems in recent history due to concern for human health, safety, and liability. Because of limited funding and reduced opportunities for prescribed fire use, longleaf pine ecosystem restoration efforts might be best focused on more marginal soils that have characteristics that naturally restrain herbaceous and hardwood competition. However, there is a need to quantify the potential productivity for longleaf
pine on these marginal soils and to develop understandings of edaphic factors limiting their growth.
Soil morphological, physical, and chemical properties in existing longleaf pine ecosystems on three soil series in the Angelina and Sabine National Forests in east Texas were evaluated to develop a better understanding of how variation in soil properties may affect longleaf pine site quality. Analysis of variance and regression techniques were used to compare soil properties for three different soil mapping units: Letney (Arenic Paleudults), Stringtown (Typic Hapludults), and Tehran (Grossarenic Paleudults). These soils all support natural longleaf pine stands, but vary in texture, depth to argillic horizons, nutrient availability, available water capacity, and other parameters which are likely related to site quality, as measured by site index, of longleaf pine.
Longleaf pine site index was influenced by depth to E horizon, depth to first argillic B horizon, texture of B horizon, and nutrients in the B horizon. B horizon physical and chemical variables appeared to be most influential on observed site index values for longleaf pine on the soils in the study
Forage Yields in Turkey Hill Wilderness in East Texas for White-tailed Deer
Wilderness areas are often considered quality areas where natural processes occur without human activity. It is often assumed that these unmanaged areas will provide and support quality wildlife habitat. The objective of this study was to evaluate the forage production and stocking potential of an unmanaged wilderness area in east Texas. Four different community types were evaluated for forage yield, forage availability, and browse utilization for white-tailed deer. Results show that although a wide range of forage yields were measured in the spring, summer forage yield did not differ among the various communities. Availability also differed between community types, but utilization within each community appears to be lower than what could be supported
Relationships of Selected Soil Properties and Community Species Composition in Turkey Hill Wilderness Area in East Texas
-Sixty-nine different stands within 15 different previously managed communities were sampled in what is now the Turkey Hill Wilderness of the Angelina National Forest. Within each stand, 0.04 ha plots were randomly located, and the height, diameter, crown class and species of each tree recorded. Soil samples were collected in two locations within each plot, and the soil type confirmed at plot center. Soil samples were analyzed for selected soil chemical and physical properties. Due to the low occurrence (less than 4 times) of some communities, only six community types were analyzed Analysis of the vegetation and soil data using Cluster, Principle Component and Pearson’s Correlation Analyses showed some relationships between vegetation communities, species and the soil properties. This information may be useful toward development of better understanding about plant community relationships
Survival of Longleaf and Loblolly Pines Planted at Two Spacings in an East Texas Bahiagrass Silvopasture
The practice of combining intensive timber and forage production on the same site, a silvopasture system, offers landowners the potential for diversification of income. The establishment of such a system in a pasture setting offers unique challenges compared with traditional timber or forage systems. In 2003, a silvopasture demonstration was established south of Carthage, Texas, in a pasture dominated by bahiagrass (Paspalum notatum). Four replications of treatments composed of open pasture, longleaf (Pinus palustris) and loblolly (Pinus taeda) pine planted at a traditional spacing, and longleaf and loblolly pine planted at a silvopasture spacing were established. Due to high mortality rates, replanting of trees occurred in 2004 and 2005. Third-year seedling survival was highest for loblolly pine in both planting systems, and forage production levels did not significantly differ among treatments. Wild hog damage contributed to the low longleaf pine seedling survival rates
Effects of Ponderosa Pine Ecological Restoration on Forest Soils and Understory Vegetation in Northern Arizona
The human exclusion of wildfire and overgrazing by livestock since settlement have caused dramatic changes in ponderosa pine (Pinus ponderosa Dougl ex Laws) forest ecosystems. These changes include increased numbers of tree stems, reduced understory cover and diversity, and the introduction of invasive, non-native understory species. This study evaluated the coverage and species composition of understory vegetation present in the “cool-season” (late spring and early summer) in a ponderosa pine forest on grazed and ungrazed plots that had undergone restoration treatments on three different soil/geologic parent material types near Flagstaff, Arizona, twelve years after tree thinning and grazing exclosure treatments were applied. Several measured soil properties, such as soil respiration and temperature, were also evaluated in this study. Species richness of “cool-season” vegetation was influenced more by grazing practices than restoration treatments. Differences could be less or greater when vegetation that is active later in the season is measured. Vegetative cover was significantly influenced by restoration treatments (9.3% cover under open canopies and 6.5% under dense canopies), probably due to differences in competition for light and other resources (i.e. soil moisture and nutrients). Unlike finding by Abella et al. (2015), who studied “warm-season” vegetation, “cool-season” understory cover was not influenced by soil parent material type in this study, which might suggest that differences in understory cover due to soil properties are only seen shortly after restoration treatments are applied, or the time of year vegetation is evaluated may play a role in the differences seen. Soil respiration was highest on limestone soil parent material type (3.3 g C-CO2 m-2 day-1), and soil temperature was lowest under closed canopy treatments (15°C)
Soil and Nutrient Loss Following Site Preparation Burning
Sediment loss and nutrient concentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinus taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff samples indicated that the prescribed burn caused increased losses of N, P, K, Ca, and Mg from treatment plots. Preliminary results indicate a significant increase in sediment concentration and sediment loss following the prescribed burning application. The data indicate a gradual decline in sediment loss and nutrient concentration over time corn treatment plots with respect to control plots. Sediment loss following treatment was within the range of sediment loss for an undisturbed forest in the south
Structural Control of Mesic Vegetation Communities within the Owl and Bear Creek Watersheds, Fort Hood Military Installation, Texas
The Fort Hood Military Installation is a karst landscape, dominated by Lower Cretaceous carbonates of the Trinity and Fredericksburg groups. The study area is the northeastern peninsula known as the Owl Mountain Province, utilized by the U.S. Army for troop maneuvers and training. The geomorphic evolution of the province has been controlled by the structural development of incised canyons in the Owl and Bear creek watersheds, following the deformational trend of the Balcones/Ouachita fault system and the transverse Belton High-Central Texas Reef Trend. These trends control cave development in the subsurface, karst manifestations at the surface, joints in outcrop, stream orientation, and vegetation associations. Previous transect vegetation surveys identified nine discrete areas of Acer grandidentatum habitat confined to mesic slot canyons in the watersheds. Traditional vegetation modeling has relied heavily on slope and aspect as key elements controlling ecological associations and soil moisture; in karst landscapes, permeability and solutional widening of conduits formed by local and regional deformation events can influence the location and ecological stability of these vegetation communities. Orientation trends derived from geologic mapping and spatial analyses of this karst landscape support the hypothesis that regional deformation events have exerted structural control on the relict mesic vegetation population
Fuel loading prediction models developed from aerial photographs of the Sangre de Cristo and Jemez mountains of New Mexico, USA
Fuel load prediction equations that made use of aerial photographs were developed for Mixed Conifer, Ponderosa Pine (Pinus ponderosa Dougl. ex Laws.) and Pinyon-Juniper (Pinus edulis Engelm.)-(Juniperusmonosperma Engelm.) cover types from one-time measurements made in the Santa Fe watershed (SFWS) located in the Sangre de Cristo Mountains of northern New Mexico, and at Los Alamos National Laboratory (LANL) located in the Jemez Mountains of northern New Mexico. The results of the watershed data set were favorable and exhibited a high degree of relative accuracy. The results from the LANL data set did not share the same degree of accuracy, but rather exhibited a high degree of error. Use of these or similar prediction equations may be limited to certain regions and community types that exhibit similar regional characteristics such as terrain, soil, and weather conditions. Applied use of the prediction equations required less time than traditional fuel sampling performed onsite, but suffered from a loss of accuracy. It is strongly suggested that additional study of this method be undertaken to generate more accurate and reliable equations. Hopefully, more accurate equations may augment existing fuel sampling techniques and be put to practical use for fire planning purposes
Quantifying Land Cover Change Due to Petroleum Exploration and Production in the Haynesville Shale Region Using Remote Sensing
The Haynesville Shale lies under areas of Louisiana and Texas and is one of the largest gas plays in the U.S. Encompassing approximately 2.9 million ha, this area has been subject to intensive exploration for oil and gas, while over 90% of it has traditionally been used for forestry and agriculture. In order to detect the landscape change in the past few decades, Landsat Thematic Mapper (TM) imagery for six years (1984, 1989, 1994, 2000, 2006, and 2011) was acquired. Unsupervised classifications were performed to classify each image into four cover types: agriculture, forest, well pad, and other. Change detection was then conducted between two classified maps of different years for a time series analysis. Finally, landscape metrics were calculated to assess landscape fragmentation. The overall classification accuracy ranged from 84.7% to 88.3%. The total amount of land cover change from 1984 to 2011 was 24%, with 0.9% of agricultural land and 0.4% of forest land changed to well pads. The results of Patch-Per-Unit area (PPU) index indicated that the well pad class was highly fragmented, while agriculture (4.4-8.6 per sq km) consistently showed a higher magnitude of fragmentation than forest (0.8-1.4 per sq km)