this research aimed to evaluate the effect of planting seasons (autumn and spring) on 10 accessions of two species of astragalus effusus and astragalus brachyodontus in the field condition (homand absard station, damavand). after preparing the seedbed, the plant species were planted on two lines in 2 m, where the spacing between the lines of each accession was 0.5 m, and the spacing between the...

The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require informatio...

soil erosion is undoubtedly one of the most important problems in natural areas and has a devastating impact on grassland ecosystems. the present study was conducted to assess the ability of rangeland hydrology and erosion model for estimating sediment yield on rangeland’s hill slopes in dry regions at shahid noori paired watershed of kakhk. rhem is a mathematical, distribution and physical mod...

We used a predictive model to map canopy cover of vegetation over seven feet in height (“tall woody vegetation”) at 30-meter resolution over nearly 29 million acres within and adjacent to the range of the greater sage-grouse in Oregon (Figure 1). Texture measures computed at various resolutions from colorinfrared aerial photography provided the main source of predictor data used to produce the ...

[1] We quantified canopy transpiration (EC) using sap flux measurements representing the four major forest types (northern hardwoods, conifer, aspen/fir, and forested wetland) around the WLEF-TV tall tower in northern Wisconsin. In order to scale individual sap flux measurements to EC, we quantified the amount of sapwood area per unit ground area and the spatial distribution of sap flux within ...

the relationship between some habitat factors and fish assemblage was analyzed in the taleghan river, alborz province, iran. fish specimens from thirty-three sites were sampled by electrofishing device in october 2014. the habitat parameters, including elevation (m), water depth (cm), river width (m), river slope (%), current velocity (m.s-1), number of large stone (> 15 cm), average stone diam...

T h e effect of variable tree canopy cover, shadows, and topography on Thematic Mapper (TM) data was examined for blue oak (Quercus douglasii) woodland and wooded grassland on rugged terrain in central California. Thematic Mapper data were analyzed from September 1986 (trees in leaf, grass understory senescent) and December 1984 (trees leafless, grasses emerging. Tree cover measured in 84 60 m ...