نتایج جستجو برای: average of canopy cover diameter

تعداد نتایج: 21187469  

2007
Tedmund J. Swiecki Elizabeth A. Bernhardt Christiana Drake

We used logistic regression to identify environmental and management history factors associated with blue oak (Quercus douglasii) sapling recruitment. Recent canopy gaps caused by natural mortality or clearing were positively associated with sapling recruitment. Plots with very high or low levels of tree canopy cover were less likely to have saplings than those with intermediate canopy cover le...

Journal: :مرتع و آبخیزداری 0
محمد جنگجو دانشیار، گروه مرتع و آبخیزداری، دانشکدة منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد فریبا نوع دوست مربی گروه زیست شناسی، دانشکدة علوم پایه، دانشگاه صنعتی خاتم الانبیای بهبهان فهیمه رفیعی کارشناس ارشد زیست شناسی، دانشکدة علوم، دانشگاه فردوسی مشهد

this research was conducted to compare plant functional types (pft) and traits in an old-field (abandoned for 28 years) and a control site, in the baharkish rangelands, quchan, iran. in the both sites, 40 randomized quadrates were established. floristic list, frequency, canopy cover and 20 vegetative, phenological and morphological plant traits were measured for all plant species, within each q...

2014
G. P. Asner C. B. Anderson R. E. Martin D. E. Knapp R. Tupayachi F. Sinca

Elevation gradients provide opportunities to explore environmental controls on forest structure and functioning. We used airborne imaging spectroscopy and lidar (light detection and ranging) to quantify changes in threedimensional forest structure and canopy functional traits in twenty 25 ha landscapes distributed along a 3300 m elevation gradient from lowland Amazonia to treeline in the Peruvi...

2009
Conghe Song Gabriel Katul Ram Oren Lawrence E. Band Christina L. Tague Paul C. Stoy Heather R. McCarthy

[1] This study investigates the impacts of canopy structure specification on modeling net radiation (Rn), latent heat flux (LE) and net photosynthesis (An) by coupling two contrasting radiation transfer models with a two-leaf photosynthesis model for a maturing loblolly pine stand near Durham, North Carolina, USA. The first radiation transfer model is based on a uniform canopy representation (U...

2014
Encarna Rodríguez-García Felipe Bravo Thomas A. Spies

Seedling emergence, survival and early growth of the Mediterranean conifer P. pinaster were studied under closed canopy and open canopy (gaps) cover conditions in a Mediterranean forest of central Spain during two consecutive years (March 2008 to January 2010). Our main objective was to understand how overstorey structure, shrubs and soil properties influence recruitment in this species. Natura...

2014
Nian-Feng Wan Xiang-Yun Ji Jie-Xian Jiang

Many studies have supported the enemies hypothesis, which suggests that natural enemies are more efficient at controlling arthropod pests in polyculture than in monoculture agro-ecosystems. However, we do not yet have evidence as to whether this hypothesis holds true in peach orchards over several geographic locations. In the two different geographic areas in eastern China (Xinchang a town in t...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد شاهرود - دانشکده مهندسی شیمی 1389

on this project we try to calculated power of hydrogen on dycarbonil compound in different ways ; the first way is shoster way , for sain power of hydrogen notice the different power between central conforms on it and main conform that’s didn’t have hydrogen joint . or in other way different of energy between open and close form. second way, is average way? this is for way that studied conf...

2010
Mats Dynesius Heloise Gibb Joakim Hjältén

Many species use coarse woody debris (CWD) and are disadvantaged by the forestry-induced loss of this resource. A neglected process affecting CWD is the covering of the surfaces of downed logs caused by sinking into the ground (increasing soil contact, mostly covering the underside of the log), and dense overgrowth by ground vegetation. Such cover is likely to profoundly influence the quality a...

Journal: :journal of rangeland science 2015
mohamad taghi kashki amr ali shahmoradi ehsan zandi esfahan

abstract. rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. accordingly, data collection and measurements for evalu...

Hussein Azarnivand Leila Darvishi Majid Yousefi Valikchali Mohammad Ali Zare Chahouki Mohammad Jafari

Growth and productivity of plants are mainly affected by various environmentalfactors in different ecosystems and natural habitat in the world. This research aims to studythe existing relationships between the phytosociology characteristics of Thymuskotschyanus and environmental factors in order to find the most important factorsgoverning development of the species in middle Taleghan rangelands...

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