نتایج جستجو برای: stands
تعداد نتایج: 21645 فیلتر نتایج به سال:
Eastern hemlock (Tsuga canadensis (L.) Carr.) is an evergreen conifer that is widely dispersed in the northeastern United States. Loss of the hemlock component in the eastern forest due to the introduced hemlock woolly adelgid (Adelges tsugae) will have long-term consequences for terrestrial and aquatic ecosystems. Some of the functional attributes of hemlock (vertical structure diversity, ever...
A new Faustmann optimal rotation harvesting stands’ problem under Brown geometric price and Logistic and Gompertz wood stock, diffusions is presented. The optimal cut policies for the stochastic Faustmann model and the single harvest rotation or Vicksell model are evaluated in the case of a Chilean Radiata pine forest company. The company cut policy validates the Vicksell model, its optimal cut...
Original oak (Quercus) forests in the southwestern Carpathian Mountains, Slovakia, were replaced by non-forest cover or managed stands often containing introduced non-native tree species. We compared the composition, richness, and abundance of litter-dwelling beetle (Coleoptera) communities in 30 stands across three management types: (i) reserved stands that most closely approximate the pre-cle...
Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlak...
Surface lignite coal mines in east Texas are commonly reforested using loblolly pine (Pinus taeda L.) following mining and reclamation activities. Due to the nature of such an extreme disturbance, altered growth patterns, growth rates, and productivity could be expected. We destructively sampled aboveand belowground tissue to develop prediction equations specific to these sites. These predictio...
mental evidence obtained by a 5-year experiment with harvesting in a cornfield takes centuries to obtain from a forest. Most foresters have careers that last only 30–40 years. Changes may be occurring in productivity too slowly to be detected by any one generation of foresters. Periodic comparison of long-term controls and harvested forests can show unequivocally whether forest management activ...
Another experiment was carried out in which the opposite environmental conditions were obtained, viz., those of waterlogging. In this a comparison was made between applying Ceresan on the cutting and on the soil. Co.290 was planted, and after planting, 11 inches of rain fell in 18 days; the field was under water for some considerable time. In a previous paperreference was made to the beneficial...
Statistical models explaining students' ratings of photographs of withinstand forest scenes were constructed for 99 forest inventory plots in east Texas pine and oak-pine forest types. Models with parameters that are sensitive to visual preference yet compatible with forest management and timber inventories are presented. The models suggest that the density of sawtimber-sized trees and the prop...
A method for extracting forest parameters is described in this paper. The 3D point clouds derived from phase difference laser scanners in forests were processed in a step-wise separation. The first step contains basic filter methods to reduce raw data which, separates isolated points or deletes those artefacts resulting from the ambiguity problem. The next step includes using algorithms to isol...
Edwards et al. 1 revisited well-known studies reporting power-laws in the frequency distribution of flight duration of wandering albatrosses 2,3 , and concluded that no Lévy process 4,5 could model recent observations with higher resolution. Here we show that this re-analysis 1 suffers from a conceptual misunderstanding, and that the new albatross data remain consistent with a biological Lévy f...
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