مجله پژوهش و توسعه جنگل
سال دوم شماره 4 (زمستان 1395)

In this study, for evaluation of ecological capability in the study area, the maps of slope, aspect, elevation, soil type, vegetation type and forest density were provided. At the first step, land unit maps, basic environmental unit map, and the final environmental unit map were created respectively. Special model of protection regarding to general forestry model of Makhdoum was obtained with overlaying of wildlife map on basic environmental unit map and ecological capability of environmental units were created. Finally, the obtained environmental unit data was compared with special model of protection and ecological zoning of the area in order to protection planning was done, and priority of operations were determined based on zoning map. The results showed that 436 hectares of the entire region (989 ha) have the first conservation potential and priority. In addition, 281 hectares have the potential for the first protection class. 272 hectares of the 436 hectares, which were determined as the conservation zone, had the potential for conservation planning and were proper for operating the plans.

This study aimed to evaluate the effect of destroying the understory species diversity using frequency distribution model has been discussed. Three forest patches with similar physiographic conditions of each region were selected and in each patch, 3 plots of 400 square meters (on transects and at a distance of 100 meters) were taken to record the floristic information. Type and abundance of understory species in 5 micro plots with 1.5 × 1.5 m dimensions were recorded in each sample. Broken stick model of distribution, lognormal, geometric series and logarithmic series were fitted for each treatment and the best distribution model based on the p˃0.5 was selected. The three treatments using diversity ordering curves (Renyi), and k-dominance were compared. Based on all models both less disturbed and middle disturb forest had high diversity compare to severe disturb forest.

The aim of this study is to evaluate the effect of decline on the structure of central Zagros forests. For this purpose, an area of about 32 hectares located in Khoramabad forest was inventoried using full calipering method. The values of Clark and Evans index were calculated 0.62 and 0.95 for before and after the decline respectively. These values showed a change from cluster positioning to random pattern with effect of decline in spatial distribution of trees. Also, the result of uniform angle index were calculated 0.51 and 0.48 for before and after the decline respectively that showed the random arrangement of nearest neighbors in both situation. The mean value of mingling index was calculated 0.06 and 0.09 for before and after degradation respectively which represents a slight increase in mixture. Also, the results of the Shannon-Wiener index, was 0.21 for before decline and 0.30 after decline that showed a slight increase in species diversity. The canopy area size index was calculated 0.71 and 0.50 respectively before and after the decline indicating that being dominant of the reference trees (Trees of center structure groups) than their neighbors. This dominance has been decreased by decline effect. Size difference of canopy area index calculated 0.48 and 0.56 respectively before and after the decline that the area difference between s reference trees and neighbor trees has been increased with influence of decline. The results of these indices can reveal forest figure to managers and planners which could be used to determine of created changes caused by natural processes in optimized management of forest.

In this study we assessed the role of plantation spacing on the quantitative and qualitative characteristics of black poplar (Populous nigra L.) in three stands at 1/5×1, 1/5×irregular (0.44-1) and 3×1-meter planting intervals in the campus of Urmia University. The diameter at breast height (dbh) along with qualitative characteristics, including tree forking and vitality, crown and/or stem breakage and tree leaning of all individuals, were assessed in an area of 2500 m2 in each stand. To calculate form factor (F), 30 stems were chosen randomly in each stand (90 in total) and felled at 10-15 cm above ground. The diameter of all cut trees was measured at intervals of 0.1, 0.3, 0.5, 0.7 and 0.9 of tree length. A growth-ring disk (cross-section) was obtained from the stump of each tree to study the relationships between annual rings and plantation spacing. Furthermore, the standing volume of each stand was calculated using Huber, Hohenadel and simple (F=0.5) formulas. Results showed that the maximum dbh and height growth occurred in 1x3 m and 1x1/5 m planting intervals, respectively (α=5%). Also, the minimum mean volume was recorded for 1/5×irregular spacing. No significant differences were obtained for the amount of standing volume/ha using the three methods. Based on our results, the highest incidence of stem breakage and nearly 50% of tilted trees were observed in 1/5×1 m spacing.

Regarding to extensive forest land use change in Iran and especially central Zagros region, this study paid to the effects of land use changes on the statical distribution of tree’s canopy in this region. For this purpose three 10 ha mass located in the city of Ilam was considered that there are including contains mass of the northern edge of the Goljar village with a background of long-term agriculture, the southern edge of the Goljar village with a background of destruction (extracting of stones, sand and Agriculture), and the area is located about a mile from the east Goljar village as witness stand. For this purpose statistical functions beta, gamma, Johnson, Weibull, normal and lognormal, were used which they are frequently used in biological studies. Then ranking functions and significant tests were performed with Anderson-Darling goodness of fit test. The results showed that in the Long-term land use change to agriculture, various long-term damage and witness area are the most appropriate function to model the distribution of trees were including lognormal, weibull and beta respectively. The results of this study indicate that in effect of land uses based on statistical distributions (Beta, Gamma, Johnson, Weibull, Normal and lognormal) in the different canopy classes has been created dispute, and these changes demand a variety of management for Protection and development of these masses.

In this study, the amount of carbon stored in plant biomass and soil of four land uses (virgin forest, protected, exploited and orchard) in the forests of Mirabad, Sardasht was estimated and valued. First, in the each land uses, and in each same units, 30 samples with 25*25 m dimension were determined. Diameter at breast height of those trees >10 cm class were measured in each sample. Sampling of litter were done based on direct collecting method in sub samples with 0.5*0.5 m dimension from four corners and center of each main sample. Also, height of the thickest and the nearest tree to the center of each sample were measured. To estimate of the amount of organic carbon stored in soil, samples from two depth of soil 0 - 15 and 15 - 50 cm were collected. In order to valuation of this ecosystem service, an alternative costs method was used. The results of statistical analysis showed significant differences in the amount of carbon stored in plant biomass and soil horizons of four land Uses. The results showed that each uses of Virgin, protected, exploited and orchard had economic value 890, 466, 380, 190 million Rials (hectare/year) respectively from carbon storage approach. Obviously, this research data, would reveal the environmental values of Zagros forests more than before.

This study aimed to extract effective spatial criteria in construction of forest fire fighting stations. In this study for extraction and prioritization of effective criteria, Delphi and AHP methods were used. To determine effective criteria, the opinions of experts and specialists in a Delphi approach were asked to clarify the influencing factors to allocation of land to forest fire fighting stations. In the first stage after sending and collecting questionnaires, mentioned criteria by experts were examined and using expert perspective the criteria that have less importance was omitted. Finally the following criteria were selected: Proximity to residential areas, Proximity to river, Proximity to post fires, Proximity to road, and Proximity to forest edge. Then with using Analytical Hierarchy Process (AHP), weight or relative importance of each selected factors were obtained. Based on results the highest important factor was the proximity to road with 0.25 weight among other factors. Then Proximity to river (0.23), Proximity to post fires (0.22), Proximity to forest edge (0.19) and Proximity to residential areas, were next in rank, respectively. Also pairwise comparisons of sub-criteria for each factor showed that areas close to roads, river and areas with a history of prior fires in forest regions and also areas close to residential areas have highest importance in allocating land to the forest fire fighting station.