نتایج جستجو برای: Oak decline

تعداد نتایج: 100201  

Determination of soil chemical properties variability that affected tree tolerance to stresses can help to manage this environmental phenomenon. In this investigation, for detection of this variation trend, area of affected decline oak trees divided to four groups of control (without Oak decline), slight, middle and severe Oak decline based on tree and branch number per soil surface unit. In ea...

Oak decline is an eminent factor, which has a significant role in degradation and change in Zagros forests. The goal of present study was to assess the crown surface area of oak trees in Sarableh forests, Ilam province. For this purpose, permanent sample plots were used. Eighty sample plots with 10 Ar area were applied based on systematic-random method in a 150×200 survey network in 120 ha. The...

The phenomenon of Oak decline is one of worrying phenomena that has been occurred in Zagros forests, and the extent of the infected forest areas is spread increasingly. The present study aims to investigate the symptoms of Oak decline on the individuals and its effect on the secondary compounds of Quercus brantii leaves. For this purposes, three forest regions including Abolivafa, Miankouh and ...

In this study, all the papers about oak decline phenomena in forests of Iran have been reviewed. One hundred and twelve papers from 51 journals were reviewed, and the information presented in each paper was analyzed and finally summarized. Eighty seven percent of the papers were about Brant’s oak (Quercus brantii Lindl.). Most of the studies were focused on the pest and desease of oak decline. ...

2013
Wen J. Wang Hong S. He Martin A. Spetich Stephen R. Shifley Frank R. Thompson III Jacob S. Fraser

Oak decline is a process induced by complex interactions of predisposing factors, inciting factors, and contributing factors operating at tree, stand, and landscape scales. It has greatly altered species composition and stand structure in affected areas. Thinning, clearcutting, and group selection are widely adopted harvest alternatives for reducing forest vulnerability to oak decline by removi...

امیراحمدی, بهمن, ذوالفقاری, رقبه, میرزایی قره لر, محمدرضا,

In recent years, fundamental changes in the ecosystems of Zagros forest structure have occurred, including the decline of brant’s oak (Quercus bratii Lindl.) that is main species in this region. So this research intends to study trees decline in relation to sylviculture, topography, and soil characteristics. For this purpose, first, parts of forest that showed oak decline were identified by fie...

2008
John M. Kabrick Daniel C. Dey Randy G. Jensen Michael Wallendorf

Oak decline is a chronic problem in Missouri Ozark forests. Red oak group species are most susceptible and decline is reportedly more severe on droughty, nutrient-poor sites. However, it was not clear whether greater decline severity was caused by poor site conditions or is simply due to the greater abundance of red oak group species found on poorer sites. We conducted this study to determine w...

2012
Zhaofei Fan Xiuli Fan Michael K. Crosby W. Keith Moser Martin A. Spetich Stephen R. Shifley

At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and basal area of standing dead oa...

2011
Cathryn H. Greenberg Tara L. Keyser James H. Speer

3 Corresponding author: [email protected]; +1-828-667-5261 ext. 102 ABSTRACT: The sustainability of eastern oak-dominated forests is threatened by high oak mortality rates and widespread oak regeneration failure, and presents a challenge to natural area managers. We tracked the rate and cause of mortality of 287 mature oak trees of five species for 15 years to determine the temporal patterns...

Oak mortality is one of the most important management problems in the Zagros forests and the first signs of oak mortality appear in the canopy of trees. The aim of this study was to investigate the trend of oak mortality in trees with different crown-dimensions in the forests of Baneh County (northwest of Kurdistan province). For this study, four sites in the northern slopes (Saraki and Mirhesa...

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