Wiregrass (Aristida beyrichiana) may limit woody plant encroachment in longleaf pine (Pinus palustris) ecosystems

Wiregrass (Aristida beyrichiana) is a dominant groundcover species that facilitates fire in southeastern U.S.A. pine savannas, thereby limiting woody plant cover and maintaining a herbaceous dominated understory. In December 1993 two of us planted a plot of wiregrass (Aristida beyrichiana) in the midst of fire-maintained little bluestem (Schizachyrium scoparium) longleaf pine (Pinus palustris) savanna in the outer Coastal Plain of South Carolina. The plot and the surrounding area burned three times in the following 20 y. Vegetation sampling carried out in late summer 2013 indicated wiregrass dominated the plot and the majority of little bluestem had disappeared. The wiregrass plot was comparatively open and grass dominated, whereas the surrounding formerly bluestem dominated stand had filled in with loblolly pine (Pinus taeda) saplings as well as hardwood trees and shrubs. In addition wiregrass had reproduced and established away from the original planted area, most noticeably within a soil-disturbed plow line. A subsequent prescribed fire in spring 2014 burned with higher intensity within the wiregrass plot than in the surrounding area. Our observations suggest suppression of woody plant encroachment by dense wiregrass in pine savannas even during long fire free periods, which should reduce the likelihood of transition to hardwood dominated ecosystems

Woody cover in wet and dry African savannas after six decades of experimental fires

Fire is an integral process in savannas ecosystems as it alters the extent of woody cover in these systems. This study examined the effects of varying fire frequencies and fire exclusion over a 60-year time period in South Africa. The presence of fire, irrespective of frequency, was influential in lowering tree abundance in the wet savanna, whilst the effect of fire in the dry savanna was limited. This study suggests that vegetation responses to fire are most likely influenced by rainfall, thus it is recommended that management strategies should take account of whether a savanna is a wet or dry system when implementing fire management regimes

Large-scale synchrony of gap dynamics and the distribution of understory tree species in maple-beech forests

Large-scale synchronous variations in community dynamics are well documented for a vast array of organisms, but are considerably less understood for forest trees. Because of temporal variations in canopy gap dynamics, forest communities—even old-growth ones—are never at equilibrium at the stand scale. This paucity of equilibrium may also be true at the regional scale. Our objectives were to determine (1) if nonequilibrium dynamics caused by temporal variations in the formation of canopy gaps are regionally synchronized, and (2) if spatiotemporal variations in canopy gap formation aVect the relative abundance of tree species in the understory. We examined these questions by analyzing variations in the suppression and release history of Acer saccharum Marsh. and Fagus grandifolia Ehrh. from 481 growth series of understory saplings taken from 34 mature stands. We observed that (1) the proportion of stems in release as a function of time exhibited a U-shaped pattern over the last 35 years, with the lowest levels occurring during 1975–1985, and that (2) the response to this in terms of species composition was that A. saccharum became more abundant at sites that had the highest proportion of stems in release during 1975–1985. We concluded that the understory dynamics, typically thought of as a stand-scale process, may be regionally synchronized

Nest Site Selection and Nest Survival of Eastern Wild Turkeys in a Pyric Landscape

Pine (Pinus spp.)-dominated forests are commonly managed with prescribed fire in the southeastern United States to reduce fuel loads, maintain diverse plant communities, and increase habitat quality for wildlife. Prescribed fire alters understory vegetation, which is a key component of nesting habitat for ground-nesting birds. We assessed the influences of vegetation, prescribed fire, and landscape features (e.g., roads, edge) on nest site selection and nest survival of eastern wild turkeys (Meleagris gallopavo silvestris) in a pine-dominated ecosystem in west-central Louisiana. We radio-marked 55 female wild turkeys and evaluated vegetation and landscape characteristics associated with 69 nests during the 2014 and 2015 reproductive periods. We used conditional logistic regressions with matched-pairs case-control sampling and information-theoretic approaches to determine if vegetation characteristics within 15m of a nest site, distances to surrounding vegetation communities and edges, and prescribed fire history of patches where a nest was located influenced nest site selection. We calculated hazard ratios for covariates in our top-performing models to determine if any of these characteristics affected nest site survival. Turkeys in our study had a longer reproductive season and higher nesting and renesting rates relative to other populations in the southeastern United States. At the local scale, turkeys nested in areas with higher percent ground cover vegetation. At the landscape scale, turkeys nested closer to roads and farther from edges of 2 plant communities. Turkeys selected to nest in forest stands burned 2 years prior. Nest survival was not affected by percent ground cover, distance to roads, or distance to edge but was negatively associated with time-since fire; turkey nests in stands burned ≥3 years prior had lower survival than nests in stands burned the current year. We suggest that burning on a 3-year fire return interval is compatible with management for wild turkeys in southeastern pine-dominated forests. Includes supporting information

Temporal, spatial, and structural patterns of adult trembling aspen and white spruce mortality in Quebec's boreal forest

Temporal, spatial, and structural patterns of adult trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) mortality were studied in intact 150-year-old stands in the southwestern boreal forest of Quebec. For both species, mortality decreases (number of dead trees/total number of trees) with distance from the lake edge until 100-150 m, from which point it slightly increases. Strong peaks in mortality were found for 40- to 60-year-old aspen mainly between 1974 and 1992. Such mortality in relatively young aspen is likely related to competition for light from the dominant canopy trees. Also, the recruitment of this young aspen cohort is presumably the result of a stand breakup that occurred when the initial aspen-dominated stand was between 90 and 110 years old. For spruce, strong peaks in mortality were found in 110- to 150-year-old trees and they occurred mainly after 1980. No clear explanation could be found for these peaks, but we suggest that they may be related to senescence or weakening of the trees following the last spruce budworm outbreak. Suppressed and codominant aspen had a much higher mortality ratio than spruce in the same height class, while more surprisingly, no difference in mortality rate was found between dominant trees of the two species. Most spruce trees were found as standing dead, which leads us to reject the hypothesis that windthrow is an important cause of mortality for spruce in our forests

Setting Times for Torah Study in R. Shneur Zalman of Liady's Thought

This study presents the ideas about setting times for Torah study in the writings of R. Shneur Zalman of Liady (Rashaz) as one of the elements that formed the inclusive concept of mystical experience in the Ḥabad movement. The article argues that in his teachings Rashaz invested common experiences and the precepts of normative, non-mystical Judaism with mystical meanings, and thus proposed a new, inclusive concept of mystical experience. The reinterpretation of the precept of setting times for Torah study in Rashaz's writings was one of the factors that greatly contributed to the re-evaluation of the role of ordinary people in religious life, and to shaping Ḥabad's inclusivist vision of mysticism

Growth rate, tree form and bark texture of Quercus falcata Michx. and Q. falcata variety pagodaefolia E11. in four stands in Southern East Texas

Quercus falcata Michx. growth rate, importance (basal area), tree form, and bark texture were examined over a local gradient in soil moisture (as inferred from site vegetation, slope position and soil texture) . At drier sites, growth rate was found to be slower, bark was found to be rougher, and the maximum tree height was found to be smaller. Quercus falcata basal area also differed greatly between study sites. However, contrary to expectation, changes in basal area did not parallel changes in diameter growth rate, suggesting the possible importance of historical factors in determining the distribution of this species. The frequency of occurrence of the two varieties of Quercus falcata, variety falcata and Q. falcata var. pagodaefblia Ell., was compared among the four study sites, and within one study site. As was found by Caplenor et al. (1968), variety falcata reaches its maximum abundance under drier conditions, while variety pagodaefolia is most abundant in moister environments

SUCCESSION IN A BEECH-MAGNOLIA FOREST IN EAST TEXAS

Successional change following logging and major natural disturbance was investigated through the use of stand history reconstruction and population monitoring in an east Texas mixed pine-hardwood forest. Establishment of intolerant loblolly pine (Pinus taeda), white oak (Quercus alba) and water oak (Q. nigra) was limited to a relatively brief (10-20 yrs) period after a selective pine cut in 1910-1930. Establishment of shade tolerant beech (Fagus grandifolia) and southern magnolia (Magnolia grandiflora), initially suppressed after logging, began to increase as reproduction of less tolerant species declined, and is relatively abundant in the current forest. Timing of red maple (Acer rubrum) establishment was intermediate between these extremes. Current establishment is mostly occurring beneath patches of water oak, white oak and pine, rather than beneath beech and magnolia. Beech and magnolia trees and saplings are growing faster and mortality of young trees and saplings is lower than for other hardwood species. Thus, through a variety of mechanisms, the importance of beech and magnolia in the current forest appears to be increasing relative to pine and less tolerant hardwoods. Though the data are less complete, similar processes have apparently occurred after major natural disturbance

The Forest Service\u27s Bait and Switch: A Case Study on Bear Baiting and the Service\u27s Struggle to Adopt a Reasoned Policy on a Controversial Hunting Practice Within the National Forests

The USFS’s reluctant and haphazard attempts to develop a national policy on bear baiting and the resulting legal challenges