نتایج جستجو برای: reduction of forest canopy
تعداد نتایج: 21203187 فیلتر نتایج به سال:
Large-scale and long-term habitat management plans are needed to maintain the diversity of habitat classes required by wildlife species. Planning efforts would benefit from assessments of potential climate and land-use change effects on habitats. We assessed climate and land-use driven changes in areas of closedand open-canopy forest across the Northeast and Midwest by 2060. Our assessments wer...
Tropical pastures present multiple barriers to tree regeneration and restoration. Relict trees serve as "regeneration foci" because they ameliorate the soil microclimate and serve as safe spots for dispersers. Here, we describe another mechanism by which remnant trees may facilitate pasture regeneration: the presence of seed banks in the canopy soil that accumulates from decomposing epiphytes w...
Leaf respiration is an important component of carbon exchange in terrestrial ecosystems, and estimates of leaf respiration directly affect the accuracy of ecosystem carbon budgets. Leaf respiration is inhibited by light; therefore, gross primary production (GPP) will be overestimated if the reduction in leaf respiration by light is ignored. However, few studies have quantified GPP overestimatio...
This study attempts to find a new and better approach to estimate forest LAI in fully closed canopy condition. Although there have been many previous studies to estimate LAI using optical remote sensor data, there are not enough evidences whether the red and near-IR reflectance are still effective to estimate forest LAI in closed canopy situation. In this study, we have conducted a simple corre...
1. We evaluated the potential for three species of deciduous-forest herbs to exploit seasonal periods of direct irradiance. In particular, we investigated the importance of photosynthetic acclimation as a mechanism for shade-tolerant herbs to utilize direct light reaching the forest floor before canopy expansion in the spring and after canopy leaf drop in the autumn. 2. We measured the photosyn...
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 ...
Access to the Upper Forest Canopy with a Large Tower Crane Sampling the treetops in three dimensions
Figure 1. Sketch of the canopy crane operating in a forest showing the tower (a), jib (b), counterjib and counterweight (c), the operator's cab (d), and the gondola (e) attached to the hook. The radius and height of the jib are 82 and 52 m, respectively. T he uppermost forest canopy is a frontier ofscientific research (Erwin 1983). It is the primary interface between the atmosphere and the fore...
Estimation of forest carbon storage is a critical challenge for understanding the global carbon cycle because it dominates the dynamics of the terrestrial carbon cycle. Light Detection and Ranging (LiDAR) system has a unique capability for estimating accurately forest canopy height, which has a direct relationship and can provide better understood to the aboveground carbon storage. To test the ...
1- in a search directed to the reaction of compound)23(the cycloaddition reaction of 1,3- diphenylisobenzofurane)14(with p-benzoquinone)19(,followed by addition of cyclopentadiene was carried out.the specific spacial stracture of its ir,nmr,mass spectra. 2- in another attempt the kinetic stability and behavior of compounds)20(and)23(was studied.the main subject of this study was the highly reve...
Oak decline as one of the most important environmental problems of Zagros forests, requires proper management to decrease trees dieback and mitigate its effects. This study aimed to find the best sampling method for estimating density and crown canopy of declined oak trees in Zagros Forests. All declined trees in an area of 100 ha of Dinarkooh protected forest were surveyed and trees density, g...
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