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Carbon sequestration rate of forest trees and their spatial pattern are prominent factors which affect global carbon dynamic and can be basically applied to predict climate change. For this reason, compartments2 and 4 of district3 of Glandrood Forest were selected for this study and few disks (2 cm thick) were sampled from each felled oak tree at 2-5 m. interval of its bole. Further samplings were made from each disk at constant volumes (3x3x3 cm) and intervals (2 cm). The samples were oven dried in lab for 24 hours (105°C) in order to determine their dry density. Carbon factor was obtained directly by exposing the wood samples in the oven and was estimated, based on organic carbon/organic material ratio. Compartment3 of district3 (38 hectares) was selected as a control due to its undisturbed and virgin characteristics, to determine carbon sequestration of the oak trees and their spatial pattern in relation to the physiographical units. After that, 400 m2 sampling plots were allocated in the compartment, using the random systematic method at 100 m. grids, then diameter at breast height and total height of the aimed trees were measured. Carbon sequestration was estimated, using the volume x dry density x carbon ratio equation. The results of one-way Anova analysis showed that although there was significant difference between the dry wood density values at different intervals, with respect to pith to periphery (bark) of cross-section of disks (P 0.05). As the average value of oak wood dry density is 0.81± 0.0083 g.cm-3 and average carbon factor is % 57.37 ± 0.108, so according to the results of Paired-Samples t test, the values of calculated carbon sequestration were significantly more than the estimated values (P 0.05) which indicates that the spatial pattern of carbon sequestration values in the oak bole trees at the aimed study area were not associated with the environmental physical affects.

This study was carried out to evaluate the effects of drought stress on 12 genotypes of vetch (Vicia dasycarpa) at the experimental field of Agriculture and Natural Resources Center of East Azarbaijan Province during 2003. Field trial was conducted as a spilt plot design based on randomized complete blocks with three replications. Drought treatments (normal, medium and severe stress conditions) were included in main plots and the genotypes were allocated in subplots. During the growing season, plant height, pod length, pod width, number of grains per pod, 1000 grain weight, number of pods per plant, number of grains per plant, number of axillary branches, harvest index, biomass and grain yield were measured. Drought stress effected all traits (except number of grains per pod) significantly. Greatest amount of reduction in value due to water stress belonged to grain yield and biomass. Number of pods per plant and number of grains per plant were affected by drought more than other yield components. However, the adverse effect of water stress was not similar for all genotypes and there were significant genotype by environment interaction for important characters such as biomass, grain yield, number of pods per plant, number of grains per plant and plant height. Evaluation of the genotypes based on drought tolerance indices (STI and TOL) indicated that under medium water stress environment the genotypes 9 (from Italy) and 7 (from Turkey) showed better drought tolerance performance in terms of grain yield. Regarding biomass, the genotypes 3 (from Italy) and 6 (from Australia) were recognized as the most appropriate genotypes for hoth medium and severe drought stress conditions.