نتایج جستجو برای: forest harvesting operations for extracting of forest products in these trails

تعداد نتایج: 25583941  

2014
Edgar Pérez-Negrón Patricia Dávila Alejandro Casas

BACKGROUND TEK, ecological and economic aspects of columnar cacti were studied in the Tehuacán Valley, Mexico to design sustainable regimes of fruit harvest. We analysed the amounts of edible fruit, seeds and flowers produced per hectare of cardonal, jiotillal and tetechera forests, their economic value and actual extraction rates, hypothesizing that the economic benefits of these NTFP would po...

Journal: :Journal of environmental management 2015
Chadwick D Rittenhouse Adena R Rissman

Climate change may impact forest management activities with important implications for forest ecosystems. However, most climate change research on forests has focused on climate-driven shifts in species ranges, forest carbon, and hydrology. To examine how climate change may alter timber harvesting and forest operations in north temperate forests, we asked: 1) How have winter conditions changed ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده زبانهای خارجی 1389

the aim of the present study was to investigate the frequency and the type of discourse markers used in the argumentative and expository writings of iranian efl learners and the differences between these text features in the two essay genres. the study also aimed at examining the influence of the use of discourse markers on the participants’ writing quality. to this end the discourse markers us...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم انسانی 1390

one very decisive factor in students’ academic destiny is the result they get at final term examinations. because of its importance, both students and teachers are curiously anxious about them. as normally it is the case, these final term tests are prepared hurriedly in short time by teachers which result in students’ dissatisfaction, complaining on how the test was different from their expecta...

2006
Changyou Sun Daowei Zhang

This study focuses on the logging sector by analyzing timber harvesting margins in the southern United States between 1977 and 2001. The real growth rate of harvesting margins has been negative for pine pulpwood, while positive for pine sawtimber, hardwood pulpwood, and hardwood sawtimber. Harvesting margins for pulpwood are more stable over time and more integrated spatially when compared with...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - پژوهشکده مهندسی فرایند 1395

abstract: mineral scaling in oil and gas production equipment is one of the most important problem that occurs while water injection and it has been recognized to be a major operational problem. the incompatibility between injected and formation waters may result in inorganic scale precipitation in the equipment and reservoir and then reduction of oil production rate and water injection rate. ...

2014
Maria Beatriz N. Ribeiro Adriano Jerozolimski Pascale de Robert Nilson V. Salles Biribiri Kayapó Tania P. Pimentel William E. Magnusson

Brazil nut, the Bertholletia excelsa seed, is one of the most important non-timber forest products in the Amazon Forest and the livelihoods of thousands of traditional Amazonian families depend on its commercialization. B. excelsa has been frequently cited as an indicator of anthropogenic forests and there is strong evidence that past human management has significantly contributed to its presen...

Journal: :آمایش سرزمین 0
علی جهانی دانشجوی دکتری جنگل داری، دانشکده منابع طبیعی، دانشگاه تهران مجید مخدوم فرخنده . استاد گروه جنگل داری، دانشکده منابع طبیعی، دانشگاه تهران ، جهانگیر فقهی دانشیار گروه جنگل داری، دانشکده منابع طبیعی، دانشگاه تهران ، وحید اعتماد . استادیار گروه جنگل داری، دانشکده منابع طبیعی، دانشگاه تهران

nowadays because of various factors, including inappropriate land use, and indiscriminate exploitation of water resources, soil and vegetation, wide areas of the country were exposed to destruction of lands and desertification. therefore dealing with this situation requires a comprehensive land use program (water and land) and appropriate environment potency. the study area is patom district of...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و 1387

we show that when both sources ( lepton flavor violation sources and cp-violating phases) are present, the electric dipole moment of the electron, $d_e$, receives a contribution from the phase of the trilinear $a$-term of staus, $phi_{a_ au}$. for $phi_{a_ au}=pi/2$, the value of $d_e$, depending on the ratios of the lfv mass elements, can range between zero and three orders of magnitude a...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم انسانی 1390

this study attempted to explore if teaching english collocations through two different modes of awareness-raising and input flooding has any possible differential effect on immediate retention as well as retention in a delayed assessment. it also compared the possible differential effect of teaching english collocations implicitly and explicitly on actively using the items in writing. m...

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