نتایج جستجو برای: stands
تعداد نتایج: 21645 فیلتر نتایج به سال:
Plots in an unmanaged loblolly-shortleaf pine (Pinus taeda L.-P. echinata Mill.) stand that had been cutover I5 yrpreviously were established to representfive stocking levels: 10, 20, 30, 40, and 50%. The stand was on a good site (site indexLob = 90 ft at 50 yr) and had uneven-aged character. Two competition control treatments (none and individual tree release using herbicide) were also assigne...
Invasive, non-indigenous, phytophagous insects have caused widespread declines in several dominant tree species. The decline in dominant tree species may lead to cascading effects on other tree and microbial species and their interactions, affecting forest recovery following the decline. In the eastern USA, eastern hemlock (Tsuga canadensis (L.) Carr) is declining because of infestation by the ...
1 Former human practices can persistently influence forest ecosystems, particularly by altering the distribution and abundance of vegetation. Previous research has focused on the role of colonization success in governing plant community patterns in abandoned forests, but few studies have explored how changes in the performance of adult plants may contribute to changes in plant populations. 2 We...
In this study, some silvicultural and growth characteristics of Cercis siliqustrum L. were assessed at Pol-dokhtar and Shineh in northwest and southwest of Khoramabad in Lorestan province. The study areas were delimitated on topographic map by field observations and using GPS. Data were collected from 30 circular plots of 0.1 ha area, by random sampling design. Quantitative and qualitative ch...
Intensive pine (Pinus spp.) management is a primary land use in the southeastern United States. In eastern North Carolina, intensively managed pine stands often occur on land previously ditched and drained. Because modification of natural vegetation and water sources are known to affect dipteran community structure, we studied effects of intensive pine management on abundance and diversity of d...
Forest scientists advocate the use of natural disturbance-based forest management for restoring the characteristics of old-growth forests to younger second-growth northern hardwood stands. However, prescriptions rely upon studies that have (1) not spanned the full range of conditions and species assemblages, and (2) focused primarily on contrasting old-growth andmature second-growth stands at a...
Rodent and avian consumption of Holm Oak, Quercus ilex, acorns were examined in central Spain during two high-production seasons, 1990-1991 and 1993-1994, in 1 and 3 large stands and in 6 and 10 small stands (0.2-12 ha) respectively, to study the effects of vertebrate predation on seedling recruitment. Previous data indicate that wood mouse abundance is much higher in small stands. Tree size, f...
The natural forest and range stands of Zanjan province are located in mountainous areas. Inventorying and mapping of natural forest and range stands in mountainous areas are difficult and costly. Satellite data are suitable for this purpose. The Landsat ETM+ image data of 2002 are used for classification and mapping of natural forest stands in Zanjan province. For the purpose of data reduction ...
The natural forest and range stands of Zanjan province are located in mountainous areas. Inventorying and mapping of natural forest and range stands in mountainous areas are difficult and costly. Satellite data are suitable for this purpose. The Landsat ETM+ image data of 2002 are used for classification and mapping of natural forest stands in Zanjan province. For the purpose of data reduction ...
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