نتایج جستجو برای: canopy decreasing

تعداد نتایج: 103479  

2003
NALlNl M. NADKARNI

Many processes that are fundamental to tropical rainforest maintenance and regeneration take place in the forest canopy. Recently developed access techniques afford biologists nondestructive means to document and quantify canopy biota and their accompanying activities and interactions. Results from studies involving within-canopy observations and measurements of nutrient cycling, epiphyte distr...

2003
Yujie Wang Wolfgang Buermann Pauline Stenberg Heikki Smolander Tuomas Häme Yuhong Tian Jiannan Hu Yuri Knyazikhin Ranga B. Myneni

A small set of independent variables generally seems to suffice when attempting to describe the spectral response of a vegetation canopy to incident solar radiation. This set includes the soil reflectance, the single-scattering albedo, canopy transmittance, reflectance and interception, the portion of uncollided radiation in the total incident radiation, and portions of collided canopy transmit...

2010
Yuhong He Amy Mui

Remote sensing imagery is being used intensively to estimate the biochemical content of vegetation (e.g., chlorophyll, nitrogen, and lignin) at the leaf level. As a result of our need for vegetation biochemical information and our increasing ability to obtain canopy spectral data, a few techniques have been explored to scale leaf-level biochemical content to the canopy level for forests and cro...

2006
Maina Kariuki Margaret Rolfe Robert M. Kooyman

We examined tree diameter growth in 20 plots subjected to various disturbance intensities (natural, low, moderate and intensive logging) in a bid to understand the general tree growth responses in relation to habitat characteristics in subtropical rainforests of north-eastern NSW, Australia. Species-specific regeneration strategy, maximum size and level of shade tolerance were used to classify ...

Journal: :مرتع و آبخیزداری 0
ملوک رویان فارغ التحصیل کارشناسی ارشد رشته مرتعداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران عادل سپهری دانشیار دانشکده مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران عبدالرسول سلمان ماهینی دانشیار دانشکده شیلات و محیط زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

remote sensing and aerial photographs are used to produce medium to small scale images. however, for detailed information especially to estimate rangeland vegetation canopy cover there is a need to larger scale images. it is therefore necessary to study the technical applicability of different devices such as short range light airplanes, kites, gliders and balloons. in this research, we focused...

Journal: :international journal of advanced biological and biomedical research 2013
seyed mostafa moslemi seyed mahalleh mehrnosh shabanipour nilofar mostafa soltani maziar haidari

to detection of suitable sampling method to study tree canopy cover in the northern zagros forest, baneeh region forest, kurdistan province, and west of iran was selected. 40 square sample plots one hectare (100×100 m) were selected and perfect inventoried. in every sample plot the position of tree, kind of species and two diameter of crown (m) were recorded. to study of canopy cover different ...

2016

A multi-layer ozone (O3) dry deposition model has been implemented into SOSAA (a model to Simulate the concen-trations of Organic vapours, Sulphuric Acid and Aerosols) to improve the representation of O3 concentration and flux withinand above the forest canopy in the planetary boundary layer. We aim to predict the O3 uptake by a boreal forest canopy undervarying environmental condit...

Journal: :Sociological Methods & Research 1979

Journal: :IEEE Trans. Geoscience and Remote Sensing 2001
H. Peter White John R. Miller Jing M. Chen

As optical remote sensing techniques provide increasingly detailed canopy reflectance data at a variety of illumination/view geometries, direct quantitative comparisons between data sets require a flexible model of the bidirectional reflectance distribution function (BRDF) suitable for inversion. Typically, such derivations rely on:1) complex and computationally expensive empirical canopy descr...

Journal: :Tree physiology 2000
M Kazda J Salzer I Reiter

We measured gas exchange and various leaf parameters of ash (Fraxinus angustifolia Vahl.) and oak (Quercus robur L.) in the high canopy and of lime (Tilia cordata Mill.) in the lower canopy of a planted, 120-year-old floodplain forest in southern Moravia, Czech Republic. The high-canopy leaves of F. angustifolia and Q. robur had nitrogen concentrations on a leaf area basis (N(area)) that were t...

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