نتایج جستجو برای: forest stands

تعداد نتایج: 123621  

2005
JOHN J. STRANSKY JOHN H. ROESE

The fruit of woody plants is important as food for wildlife (Martin et al. 1951, Lay 1965). The relation of fruit production to southern forest stand conditions has been explored in only a few studies. Fruit production is greater in forest clearings than in closed forest stands (Lay 1966, Elalls and Alcaniz 1968). In Georgia slash pine (Pinus elliottii) plantations, fruit yields of shrubs are g...

2017
Yanchun Liu Qing Shang Bo Zhang Kesheng Zhang Junwei Luan

Liana constitutes an important structural and functional component in many forest ecosystems and has profound impacts on forest carbon (C) cycling. However, whether and how liana regulates spatial distributions of litterfall and soil organic C are still poorly understood. To address this critical knowledge gap, we investigated litterfall composition and soil physicochemical characteristics in s...

Journal: :Ecology 2008
Mark Andruskiw John M Fryxell Ian D Thompson James A Baker

The probability of prey encounter, attack, capture, and kill are often hypothesized to depend on habitat structure, but field evidence in terrestrial systems is rare. We tested whether predation efficiency by the American marten (Martes americana) and fear of predation by their primary prey, the red-backed vole (Clethrionomys gapperi), differed between 20- to 50-year-old regenerating forest sta...

The aim of this study was to investigate soil respiration in the plantation stands of Acer velutinum, Quercus castaneifolia, Fraxinus excelsior and Pinus brutia and to compare them with the natural stands in Sari educational-research forest of Darabkola. In order to measure physical and chemical properties of soil in each stand, 10 points were selected systematic randomly and samples were taken...

2013
Zhiyong Zhou Chao Guo He Meng

The basal respiration rate at 10°C (R10) and the temperature sensitivity of soil respiration (Q10) are two premier parameters in predicting the instantaneous rate of soil respiration at a given temperature. However, the mechanisms underlying the spatial variations in R10 and Q10 are not quite clear. R10 and Q10 were calculated using an exponential function with measured soil respiration and soi...

Journal: :جنگل و فرآورده های چوب 0
سمیرا ساسانی فر دانشگاه ارومیه منوچهر نمیرانیان دانشگاه تهران نصرت الله ضرغام دانشگاه تهران

knowing and conducting studies on size characters of trees is essential for assessing the tree volumeand/or other statistical parameters and also forest management. the characteristics of 529 treesincluding diameter at breast height (dbh) and total height were measured in an even-aged fraxinusstand for two periods from 2005 to 2012 in chelir district, a part of experimental kheyrud forest.resul...

Journal: :جنگل و فرآورده های چوب 0
مرتضی مریدی دانشجوی کارشناسی ارشد جنگل‏ شناسی و اکولوژی جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران وحید اعتماد استادیار گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران کیومرث سفیدی استادیار دانشکدة فناوری کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی، اردبیل، ایران منوچهر نمیرانیان استاد گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران سید محمد معین صادقی دانشجوی کارشناسی ارشد جنگل‏ شناسی و اکولوژی جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران

knowledge of the stand condition and the gradual replacement of tree species in different development stages and phases provide appropriate information related to the close to nature treatments. stem exclusion phase is one of the important development phases in the forest stands development. the aim of study was to analyze the characteristics of dead trees in the stem exclusion phase in the les...

Journal: :تحقیقات آب و خاک ایران 0
آرش کرمی کارشناسی ارشد، دانشگاه تهران قوام الدین زاهدی دانشیار، دانشگاه تهران جهانگیر فقهی دانشیار، دانشگاه تهران

some soil physical and chemical characteristics were analyzed in order to reveal the relationship between forest soils and regeneration patches. gorazbon district of kheyrud was selected as a case study for the research area. all regeneration patches were recorded using gps device. to assess the spatial structure and to quantify the metrics of regeneration patches, analyzing of landscape metric...

1999
Jennifer C. Jenkins Charles D. Canham Paul K. Barten

The hemlock woolly adelgid (Adelges tsugae Annand.), an introduced pest specializing on eastern hemlock (Tsuga canadensis (L.) Carr.), threatens to cause widespread hemlock mortality in New England forests. In this study, we used a stem-based model of forest dynamics (SORTIE) to predict forest development in a northeastern forest both with and without eastern hemlock. In all simulations, forest...

2004
Tom Santos L. Telleria

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...

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