نتایج جستجو برای: oak decline
تعداد نتایج: 100201 فیلتر نتایج به سال:
Zagros vegetation zone is one of the most important forest regions in Iran, which consists of a diverse group of arboreal species, especially oaks (Quercus spp.). Ilam province located in west of Iran and in Zagros vegetation zone which has 641000 ha of oak forests that its dominant species is Persian oak (Q. brantii). Oak trees decline is a complicated phenomenon that may result from different...
This study was accomplished with the aim of investigating the effects of tree decline and slope aspect on leaf morphological traits and determining the indicator morphological traits that indicate the leaf diversity of Persian oak trees in relation to habitat conditions and environmental stresses in Mellah Siah forests of Ilam. Two forest habitats were selected on the northern and southern slop...
A spatially explicit forest succession and disturbance model is used to delineate the extent and dispersion of oak decline under two fire regimes over a 150-year period. The objectives of this study are to delineate potential current and future oak decline areas using species composition and age structure data in combination with ecological land types, and to investigate how relatively frequent...
Current ecological, economic, and social conditions present unique challenges to natural resource managers seeking to maintain the resilience of disturbance-dependent ecosystems, such as oak (Quercus spp.) forests. Oak-dominated ecosystems throughout the U.S. have historically been perpetuated through periodic disturbance, such as fire, but more recently show decline given shifting disturbance ...
Oak decline, the precipitous mortality of mature oak trees, has been a chronic problem in xeric oak ecosystems and is reaching unprecedented levels in red oak group (Quercus section Lobatae) species in the Ozark Highlands. The high rates of mortality are leading to rapid changes in species composition, forest structure, and related changes in fire risk, insect populations, and colonization patt...
Black oak (Quercus velutina Lam.) and scarlet oak (Quercus coccinea Muenchh.)—two major components (44% of total stand basal area) of upland oak forests—are suffering severe decline and mortality in the Ozark Highlands, Missouri. However, factors influencing their survival (mortality) are not well understood. In this study we quantified how stand and tree-level predisposing factors are associat...
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 ...
Decline phenomenon is one of the most important reasons for the destruction and mortality of oak trees in Zagros forests due to the wide variety and diversity of the topography of its determination through track and field operations is not readily possible. Changes in an ecosystem are often gradual changes, but sometimes changes occur in an ecosystem in a short time. This change can cause a ...
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