نتایج جستجو برای: oak forest

تعداد نتایج: 113572  

2016
Erik Charles Mottl Brian Palik Kirk Moloney

Oak forests throughout the world are in a state of decline due to lack of oak seedling recruitment to larger size classes. Much of this recruitment decline has been attributed to changes in ecosystem disturbance regimes that have led to increased competition from other species. The Midwest Driftless Area forests in the United States are currently dominated by large oak trees of three species: Q...

Journal: :Molecular plant pathology 2008
Niklaus J Grünwald Erica M Goss Caroline M Press

UNLABELLED Phytophthora ramorum is an oomycete plant pathogen classified in the kingdom Stramenopila. P. ramorum is the causal agent of sudden oak death on coast live oak and tanoak as well as ramorum blight on woody ornamental and forest understorey plants. It causes stem cankers on trees, and leaf blight or stem dieback on ornamentals and understorey forest species. This pathogen is managed i...

2011
Felix Ponder

—Nine-year old artifi cially regenerated red oak (Quercus rubra L.), white oak (Q. alba L.), and shortleaf pine (Pinus echinata Mill.) trees were excavated from plot borders of a U.S. Forest Service long-term soil productivity study in the Carr Creek State Forest near Ellington, MO, to quantify treatment eff ects on aboveand belowground tree biomass. Th e study consists of factorial combination...

Abstract Understanding in variation in tree leaf related to altitude and climate change define the plant adaptation. These variations will predict their respond to the future changes. According to the vast distribution of Persian oak (Quercus brantii) trees in Zagros forest, the study of structural changes and the recognition the Persian oak ecological needs is crucial for their conservation a...

2015
William T. Flatley Charles W. Lafon Henri D. Grissino-Mayer Lisa B. LaForest

Patterns of past fire disturbance may be an important contributor to contemporary vegetation composition and structure in old-growth forests of the southern Appalachian Mountains. However, due to a lack of information on pre-suppression fire regimes, vegetation pattern in the region has been primarily attributed to variability in soils and climate. To assess the pre-suppression fire regime’s ro...

2015
Jinsong Wang Wensheng Bu Bo Zhao Xiuhai Zhao Chunyu Zhang Juan Fan Klaus V. Gadow Eric J. Jokela

The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N) deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture de...

2016
Yifeng Zhang Yuhua Shi Alfred M Sichilima Meilin Zhu Jiqi Lu Eric J. Jokela

In drought temperate forest, seedling recruitment is highly dependent on seed burial by native animal dispersers. To prolong seed storage, animals often take measures to impede seed germination. Aiming to understand the strategic balance between the natural seed germination and the role played by animals in the constraint germination procedures, we investigated the stages on the germinated acor...

Journal: :محیط شناسی 0
علی جعفری استادیار گروه علوم جنگل دانشکدۀ منابع طبیعی دانشگاه شهرکرد زهرا آرمان دانشجوی کارشناسی ارشد جنگل داری، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی سلطانی استادیار گروه علوم جنگل، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی لطفی هیات علمی دانشگاه صنعتی اصفهان

introduction forest ecosystems have continuously downgraded due to every environmental pressure including climate change, aerosols deposits, industrial pollutions and other degradation factors. the output soon or late would be a different forest. forest monitoring is a well-regulated and usually long running procedure, which has the ability to detect these phenomena and reactions based on aims ...

2009
J OHN

Oak-hickory forests of the Arkansas Ozarks recently incurred extensive tree mortality due in part to a native wood-boring beetle, the red oak borer Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae). Historically, red oak borer has existed throughout southeastern U.S. forests at relatively low population levels, but Arkansas infestation estimates in 2001 and 2003 reported much higher pop...

Journal: :Tree physiology 1996
T D Sharkey E L Singsaas P J Vanderveer C Geron

The atmospheric hydrocarbon budget is important for predicting ozone episodes and the effects of pollution mitigation strategies. Isoprene emission from plants is an important part of the atmospheric hydrocarbon budget. We measured isoprene emission capacity at the bottom, middle, and top of the canopies of a white oak (Quercus alba L.) tree and a red oak (Quercus rubra L.) tree growing adjacen...

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