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چکیده
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The objectives of this study were (1) to assess the changes in biometric indices of oak trees in pollarding process, and (2) to estimate leaf biomass and coefficient of leaf biomass. Data were collected from two selected pollarded stands in 2015. Forest inventory was conducted in two stages. In the first stage, before pollarding (August 2015), the locations and boundaries of the selected stands and sections of each stand were separately determined using a GPS device. Then, full callipering of all trees (diameter at breast height (DBH) ≥ 5 cm) was conducted in pollarded section of each stand: DBH, total and trunk heights and crown diameters in two perpendicular directions were measured. In the second stage of data collection (early September 2015), at the time of pollarding by land managers, in addition to biometric indices of trees, position of each store tree (i.e., trees that are used for storing foliage stacks) (using GPS), the numbers and weights of harvested leafy branches from each tree was recorded. The total numbers of leafy branches were counted and 10% of the leafy branches of each pollarded tree were randomly selected and weighed using a digital scale (20 g accuracy). The leaves collected from sample trees were transported to the laboratory to determine their dry weights. Leaves were dried in an oven at 70°C for 72 hours. The evaluation of changes in biometric indices in pollarding process and comparison of dry weight of leaf biomass was performed using Wilcoxon test and independent-samples t test, respectively. Results indicated that in pollarding process, the most changes was observed in crown area in koorpeh (i.e., a section of pollarded stand having oak trees with one-year-old branches) to kor (i.e., a section of pollarded stand having oak trees with two-year-old branches) stage due to increasing the number of branches in the second year after pollarding. Average fresh weight of branch and leaf biomass in pollarding process was 650.6 kg/ha (76.8% fres
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