نتایج جستجو برای: stands

تعداد نتایج: 21645  

2005
R. FLINT HUGHES JULIE S. DENSLOW

Invasive species pose major threats to the integrity and functioning of ecosystems. When such species alter ecosystem processes, they have the potential to change the environmental context in which other species survive and reproduce and may also facilitate the invasion of additional species. We describe impacts of an invasive N2-fixing tree, Falcataria moluccana, on some of the last intact rem...

Journal: :روش های عددی در مهندسی (استقلال) 0
محمود سلیمی و حمیدرضا ملک m. salimi and h. r. malek

this paper is concerned with investigations into the effect of tension between the stands of the finishing mill on width control in a hot rolling process. an analysis is given to predict satisfactorily the variation in width due to spreading and also due to strip tension between the stands. wusatowskis model which is developed to give an account of spreading is specified and a similar model to ...

   Biomass measurement is important in terms of ecological and economical evaluation of the structure and conditions of habitat and can provide an estimate for carbon sequestration in different organs of tree. In order to assess the amount of biomass in harvested and unmanaged Beech stands, two compartments (511 and 514) of Safaroodchr('39')s forest  were selected. A plot of 6.25 hectare from e...

A. Eslami

Modification of stands’ structure and managing them using silvicultural methods close to nature and single selection system require information on status of structure, determining the target diameter, basal area and suitable volume to result in long-term equilibrium and sustainability. So, this study was conducted using the selection sample statistical method by selecting  five 1-ha sample plot...

S.A. Bonyad, T. Rostami Shahraji

Forests of Iran located on the Southern border of the Caspian Sea cover 1.9 million hectares. The Caspian forests are divided into four separate forestry areas. One of these being Guilan influx area with total area of 565000 hectares. About 30 to 40 percent of Guilan province forests are suitable to short rotation forestry for afforestation. Slash pine (Pinus elliottii) is one of the main exo...

2014
Sunil Dhiman Pronobesh Chattopadhyay

Malaria elimination campaign during the end of the last century relied on insecticides and malaria treatment, but this effort did not succeed in many endemic countries and collapsed after a few decades. India is among the 35 countries, which contribute 96% of total malaria cases and 98% of total malaria deaths in the world (1). Recent studies suggest that the neighboring countries of India are ...

2005
N. Brüggemann P. Rosenkranz H. Papen K. Pilegaard K. Butterbach-Bahl

Pure stands of temperate forest tree species modify soil respiration and N turnover N. Brüggemann, P. Rosenkranz, H. Papen, K. Pilegaard, and K. Butterbach-Bahl Forschungszentrum Karlsruhe, Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, Germany Risø National Laboratory, Plant Biology and Biogeochemistry Department, Roskilde,...

2016
Sofia Bäcklund Mari Jönsson Joachim Strengbom Andreas Frisch Göran Thor RunGuo Zang

With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native ...

2009
Hal O. Liechty James M. Guldin

Streamside management zones (SMZs) in the Ouachita Mountains of Arkansas and Oklahoma are frequently established along headwater ephemeral and intermittent streams to protect water quality, provide wildlife habitat, and increase landscape diversity. To better understand the function of these riparian forest corridors, we characterized the tree density and composition, forest floor mass, and dow...

Journal: :محیط شناسی 0
سعید ورامش دانشجوی دکترای جنگلداری، دانشکدة منابع طبیعی و علوم دریایی دانشگاه تربیت مدرس سید محسن حسینی دانشیار گروه جنگلداری، دانشکدة منابع طبیعی و علوم دریایی دانشگاه تربیت مدرس. نوراله عبدی استادیار گروه مرتع و آبخیزداری، دانشکده کشاورزی و منابع طبیعی، دانشگاه آزاد اسلامی، واحد اراک

co2 is the main greenhouse gas which urban forests have a high potential to absorb and sequestrate it. the air pollution of tehran is one of the most important environmental problems of the iran. to do this research 40 years old stands of robinia pseudoacacia and fraxinus rotundifolia and the surrounding barren land ( as blank) were selected in chitgar forest park of tehran and the amount of ca...

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