نتایج جستجو برای: 30 dead trees were selected

تعداد نتایج: 3924983  

2017
Michele Colangelo Jesús J. Camarero Marco Borghetti Antonio Gazol Tiziana Gentilesca Francesco Ripullone

Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده ادبیات و زبانهای خارجی 1393

abstract this quasi-experimental study was aimed at examining the impact of storyline complexity on the grammatical accuracy and complexity of advanced and intermediate efl learners. a total of 65 advanced and intermediate efl learners were selected from iran language institute (ili). an intact group including 35 intermediate participants and another intact group with 30 advanced participants ...

Journal: :جنگل و فرآورده های چوب 0
جلیل کرمی دانشگاه علوم کشاورزی و منابع طبیعی گرگان محمد رضا کاوسی دانشگاه علوم کشاورزی و منابع طبیعی گرگان منوچهر بابانژاد دانشگاه گلستان

evaluating the population density and spatial pattern of infected trees are one of the important criteria for selecting the management method and epidemiology of forest diseases. this study aimed at assessing the damage intensity and spatial-temporal mortality patterns of oak in qoroq forest park, golestan province. the health of oak trees was evaluated in seven transects by using quarter-point...

2007
Desheng Liu Maggi Kelly Peng Gong Qinghua Guo

A new forest disease called Sudden Oak Death, caused by the pathogen Phytophthora ramorum, occurs in coastal hardwood forests in California and Oregon. In this paper, we analyzed the spatial–temporal patterns of overstory oak tree mortality in China Camp State Park, CA over 4 years using the point patterns mapped from high spatial resolution remotely sensed imagery. Both univariate and multivar...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1393

this thesis attempts to measure learning styles, self efficacy and intrinsic motivation as predictors of iranian ielts reading comprehension. in order to address this issue, a quantitative study was conducted on some randomly selected intact students at ferdowsi university. these two groups were assigned as they were undergraduate (ba=91) and graduate (ma =74) students; they were all aged betwe...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1387

this study was designed to investigate the impacts of teachers self-disclosure on students foreign language classroom anxiety, attitude to english language learning and their achievement scores at the end of the term. there were 48 female learners of intermediate level. they were not randomly selected. there were one experimental group with 21 students and one control group with 27 students.the...

Journal: :Annals of botany 2008
Aki Sinkkonen

BACKGROUND AND AIMS Physiological data suggest that autumn leaf colours of deciduous trees are adaptations to environmental stress. Recently, the evolution of autumn colouration has been linked to tree condition and defence. Most current hypotheses presume that autumn colours vary between tree individuals. This study was designed to test if within-tree variation should be taken into account in ...

امیراحمدی, بهمن, ذوالفقاری, رقبه, میرزایی قره لر, محمدرضا,

In recent years, fundamental changes in the ecosystems of Zagros forest structure have occurred, including the decline of brant’s oak (Quercus bratii Lindl.) that is main species in this region. So this research intends to study trees decline in relation to sylviculture, topography, and soil characteristics. For this purpose, first, parts of forest that showed oak decline were identified by fie...

2017
Sarah Yoga Jean Bégin Benoît St-Onge Demetrios Gatziolis

Recent increases in forest diseases have produced significant mortality in boreal forests. These disturbances influence merchantable volume predictions as they affect the distribution of live and dead trees. In this study, we assessed the use of lidar, alone or combined with multispectral imagery, to classify trees and predict the merchantable volumes of 61 balsam fir plots in a boreal forest i...

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