Showing 2 results for Bonyad
A.e. Bonyad, T. Hajyghaderi,
Volume 11, Issue 42 (winter 2008)
Abstract
The natural forest and range stands of Zanjan province are located in mountainous areas. Inventorying and mapping of natural forest and range stands in mountainous areas are difficult and costly. Satellite data are suitable for this purpose. The Landsat ETM+ image data of 2002 are used for classification and mapping of natural forest stands in Zanjan province. For the purpose of data reduction and principal components extraction, the principal components analysis (PCA) was used. Just the scores of the first three PCs (PCA1، PCA2 and PCA3 (that accounted for 76.67 percent of the total variance were considered as new images for future analysis. A raster geographic information system (RGIS) database file was prepared and involved 7 ETM+ bands, 3 principle component analysis, 9 factor analysis and 8 vegetation indexes of image data. The correlation coefficients of 27 image layers and optimum index factors (OIF) of selected images were computed and 12 groups were found suitable for natural forest and range stands. Maximum liklelihood classification (MLC) method was used in this study. In order to test the accuracy of map, kappa index of agreement was calculated. The highest KIP belonged to three λ3, λ4, λ5 Landsat image bands with KIP = 0.86. The highest OIF belonged to three PCA3, FA2 and MIR with value of 233.44 and lower OIF belonged to three λ4, λ5, λ7 with value of 83.63. The overall, user’s and producer’s accuracy rates were 88.45, 73.69 and 70.23 percent respectively. The results of the study show that the Landsat ETM+ image data were appropriate for classification and mapping of natural forest and range stands in Zanjan province.
F Tavnkar, B Mjnonian, A Eslam Bonyad,
Volume 13, Issue 48 (7-2009)
Abstract
Forest future depends on forest stands regeneration. Soil is one of the principal capitals in the forest area. It is important to minimize damages to the forest ecosystem during logging operation. In forestry and forest management, it is significant to know the effect of forest logging damages on regeneration, sapling and soil compaction. This study was carried out in Asalem Beech forest area, in the north of Iran. The forest was harvested by selective cutting method. A systematic and randomized sampling method was used for data collection. Analysis of variance (ANOVA) techniques and binomial distribution were used for data analysis. The results showed 14.5 ± 0.99 percent of regeneration and saplings of forest stands were destroyed and damaged by logging operations with 20 m3/ha intensity per year. 9.12 ± 0.83 percent of saplings were totally destroyed and 5.3 ± 0.63 percent were damaged. These damages were caused due to felling, accumulating, skidding and landing. Soil bulk density in range of 0-10 cm depth, logging and skid trails areas were increased 17.54 and 35.61 percent, respectively. To reduce logging damages and soil compaction in forestry, and manage the forest, we need a suitable organization of timber extraction operation, careful designing and standard construction of skid trails on the basis of logging maps before felling the trees down.
