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چکیده
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The biomass of trees generally is measured by cutting them and separating the parts, such as the main stem, branches, small branches and leaves. The destructive nature of the measurement of tree biomass has led to the frequent use of the biomass of a particular part of trees, such as leaves because of their higher photosynthesis and organic matter production. In the study area the locals owners of forest stands (locally called Galajar) divide stands into three or four parts (with the same yield amount), each part locally referred to as Shanegala. Each year, they pollard oak trees in a one part of stands to provide a part of the forage required for cattle in cold seasons. This study aims to investigate pollarding-induced changes in the total height, crown height and crown area, estimate oak leaves biomass, and compare the amount of forages in the main aspects. Before (early September) and after (mid-September) the onset of pollarding, a full inventory was conducted for all species with a diameter at breast height equal to or more than 5 cm. The inventory included the measurement of diameter at breast height, total height, trunk height, and the large and small diameters of the crown at perpendicular directions. In the pollarding season in the selected Shanegala (i.e., Khert) at each geographical aspect, the total number of stacks of all pollarded trees were counted and 10% of the stacks for each tree was weighed using a digital scale (10 g accuracy). Results showed that changes during pollarding process in biometric indices of crown height to total height ratio, crown area, crown height and total height were significant in the studied shanegalas (P <0.01). The amount of forage production in the northern, eastern, western and southern aspects was 955.2, 844.2, 623.26 and 568.4 kg/ha, respectively. There was a significant difference among the main aspects and crown diameter classes in terms of forage production (p <0.01). The interaction of crown diameter and aspect was also significant at the level of P ≤ 0.05 among the main aspects.
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