Iranian journal of Forest
Year:2010 | Volume:2 | Issue:3|Papers Count:10

Forests are one of the most valuable terrestrial ecosystems that provide variable goods and services. One of the most important functions of forest ecosystems is conservation of water resources and volume of surface runoff water in watershed. In order to determine the value of this function, forest contribution in surface water runoff control and increases of saved water, should be valued by using economic valuation methods of ecosystem services. In this study in part of Caspian forests, height and volume of surface runoff in the current status of the study area (natural forest) was computed with using Justin experimental methods, then by definition of two scenarios including converting the forest area into degraded forest, and converting area to eroded pasture, amount of saved water were computed in each area of defined scenario. Volume of this function was calculated by using substitute cost method. Research results indicate that converting the study area into degraded forest will double the amount of runoff water, and into eroded pasture this volume of surface water will increase more than six times, which means reduction in amount of water stored in underground water table. The value of this forest ecosystem function has been estimated by using substitute costs method. The results show that each hectare of the study area has a value as 102 Thousand Rials ($ 100) by the conservation of water resources, compared with a degraded forest, and 464 thousand Rials ($ 450) compared with an eroded pasture.

The object of this research is biodiversity study of woody plant species in White Georgian Oak tree sites, Choobe Daragh and Darana, Arasbaran. By using randomize block sampling statistical method, samples plot were determined and in samples plot type of tree species and their diameter at breast height (DBH³ 10 cm) were measured. Also bush species identified and their numbers were recorded. Regeneration of seedling and stem-sprouts of White Gorjestanian oak trees and related species were calculated in 1R microplots.  In addition, number of tree seedlings were recorded. Data analysis caerried out using diversity indices of Simpson, Hill’s N2, Shannon- Wiener, Mc Arthur’s N1 and Wilson and Smith’s evenness index  and Species Importance Value (SIV) was calculated in both tree and bush sites. Results showed that tree and bush species richness in Choobedaragh were 11 and 18, and in Darana were 13 and 10, respectively. In the tree species layer, mean of richness and the mentioned diversity and evenness indices at Choobedaragh were 0.495, 2.144, 1.256, 2.489 and 0.657, and also in the bush layer the mentioned parameters were 0.683, 3.723, 1.937, 4.234 and 0.693. . these parameters were obtained in Darana were 0.651, 3.462, 2.002, 4.092 and 0.639 respectively in tree layer, and 0.287, 1.142, 0.655, 1.284 and 0.289 in bush layer, respectively. In the tree species layer, the highest value of SIV belonged to Quercus petraea in Choobedaragh and Darana sites (203.064 and 166.710 percent) in that order and the lowest value belonged to Sorbus torminalis (indorder 3.203 and 3.908 percent), respectively.

The west oak forests have special importance in terms of their positions, functions and diversities. Restoring and developing of these forests depend on qualitative and quantitative characteristics of forest’s stands regeneration. In this study, qualitative and quantitative properties of regeneration have been studied in a part of west Azerbaijan’s forest (Piranshahr).In this order, 460 ha of perdane’s forest was selected primarily and then 61 circle plots (each one had 100m2) were used in 250×300 m grid. In each plot all annual and perennial seedlings with genus segregation which had diameter less than 7.5 cm at breast height were recorded, as well as, site factors inside plots. According to this study, the mean number of regeneration in studied forest stands was estimated 4130 tree per ha which gall oak (Quercus infectoria oliv.) and Lebanon oak (Q. libani oliv.) had highest percentage of mixture among species. The regeneration structure was coppice-with-standards. Also between the mean number of seedlings and stem-sprouts regeneration of gall oak, Lebanon oak and pear-tree (Pyrus sp.) significant difference was around 95%. But there were no significant differences about azarole (Crataegus sp.) and the other species (a=5%). There were significant difference between mean number per plot of dominant species like gall oak and Lebanon oak (a=5%) in different levels of site factors such as aspects and canopy cover of main stand.

Log extraction with draught animals continues to be a suitable choice in many areas, even in industrialized countries. As compared with ground-skidding equipment, the use of animals has been shown to reduce soil disturbance, soil compaction and damage to residual trees significantly. This research was carried out in compartment No. 220 & 225 of Namkhaneh district, in Kheyrud Forest. In order to evaluate damage to stand and regeneration following mule hauling, before and after operations, hundred percentage inventory of regeneration in mule trails were conducted. Compacted soil sampling in mule trails was measured. Results of this study showed that following traditional wood hauling by mule, twenty two percent of regeneration in mule trails was damaged and no damage was observed to trees by this wood hauling method. As a whole, 4.3% of total area were disturbed and compacted by applying tradition hauling. The ANOVA effect f mule passes an slope, and soil bulk density showed that mule passes and slopes, as well as, their interaction effect had no significant effect on soil bulk density (P<0.05). Also paired sample t-test showed that traditional hauling has no significant effect on soil bulk density in trails befor and after mule hauling statistically.

Capability of ETM+ Data in canopy cover and tree diversity mapping were investigated in Ghalajeh Forests in the Kirmanshah province. land information were provided in 114 plots with 0.36 ha trough systematic sampling method. The images were georeferenced using ground control points. Synthetic bands were generated using rationing, Vegetation indices, principal component analysis, Tasseled Cap transformation and fusion. For supervised classification, some training areas were selected and selection of the appropriate bands was performed using divergence separability index. Classification of images was done using maximum likelihood classifier and map obtained was assessed by sampling ground truth map. The results showed that the classified map had an overall accuracy of 52% and Kappa coefficient 0.25 for four density classes and for two merged classes of sparse and semi dense classes with an overall accuracy and Kappa coefficient of 71% and 0.39, respectively. Results generally showed a moderate capability ETM+ data to provide canopy cover map in Zagros forest. For diversity mapping, the Shannon-Weiner index was calculated for each plot. After the extraction of spectral values of plots in the original and processing bands and the Kolmogorov-Smirnov normalization test, the Pierson correlation coefficient was used for selection of the best bands in regression model. Among 40 original and synthetic bands, the 3 band of ETM4, NDVI and MSAVI2 had better linear combination for modeling by using the best subset regression method. Results showed that the linear combination ETM4, NDVI and MSAVI2 could better be estimated (Radj2=0.327) for the scrubs and trees diversity in comparison with other combinations and bands. Obtained results are expressing moderate low capability of ETM+ data in scrub and trees species diversity estimation in study region.

Knowledge of forest extent during past decades is necessary for future planning. This research was done in order to determinate the distribution and rate of deforestation from 1987 to 2006 and possibility of modelling the changes extent and its relation to physiographic and some human factors by using logistic regression in the Chehl-Chay catchment, Golestan province. After geometric correction on TM image, the forest extent map of 1987 was generated using maximum likelihood classification. In addition, forest extent map in 2006 was generated using merged Liss III images with panchromatic image of SPOT-HRG and maximum likelihood classification. Deforestation map was produced through crossing the two maps. Spatial relation of deforestation was investigated by logistic regression using slope, aspect and elevation physiographic factors along with distance from road and village's population. The results showed that about 2400 ha from forest areas were deforested in the 19 years. The results of deforestation modeling by logistic regression showed a relative agreement of the predicted model and occurred forest extent changes map with a Pseudo R2 of 0.114 and ROC coefficient equal to 0.72 in the region. According to results slope and distance from road and village variables were in contrary of deforestation expanding. This factor was increased with increasing in elevation and around populated villages.

Populus euphratica Oliv. Distribute naturally in vast regions of Iran and is native species in arid and semi arid areas. Geographical and climatical diversity of this species in distributed area in different sites results in the morphological and genetic variation between trees. In order to study genetic diversity between male and female trees, protein evalution )SDS-PAGE( was conducted on 44 leaf extracts samples of 11 natural provenances that were different in environmental factors like elevation, longitude and latitude. Leaf protein bands for male and female in studied provenences was shown on gel and each band position was located by related mobility. In total 22 separated bands were appeared on gel with different mobility. The results of protein bands showed that male and female trees contain different patterns at different distances, whereas male trees had more bands than female trees. Also result of principal components analysis (PCA) showed differences between male and female trees. Grouping of P. euphratica provenances showed that, provenances of east and south classified in different groups. Also provenences of Golfa in North west classified in different group. In spite of the correlation between geographical distance and genetic distance among all provenances (P=0.07) this correlation statistically was not significant.

The spectral reflectance of tree crown can be different from spectral reflectance of its leaves because of diverse leaf and branch angles as well as internal space of tree crown. For these reasons it is necessary to study spectral reflectance of both adaxial and abaxial surfaces of the leaves. Such information is necessity for modeling the reflectance of tree crown and forest stands. The main objective of this study was to obtain and study the spectral reflectance of both adaxial and abaxial leaves of beech and hornbeam in natural condition and to investigate their spectral differences using indices sensitive to chlorophyll, chlorophyll to carotenoid ratio and photosynthetic pigments. Field spectroradiometric measurements were performed using a portable spectroradiometer (ASD FieldSpec) in Kheyrud forest. A total of 52 trees were sampled and 312 spectra were recorded and analyzed. Spectral measurements cover the wavelength range between 350 – 2500 nm. The results of the spectral reflectance analysis of these two species showed that the abaxial spectral reflectance from 350 to 2500 nm was higher than the adaxial one for hornbeam species. However, for beech species in the visible region and far infrared region, the abaxial spectral reflectance was higher whereas in the near infrared it was lower than the adaxial one. For more detailed investigation of spectral reflectance difference for these two species, spectral indices sensitive to chlorophyll and carotenoid were calculated and statistically analyzed for both surfaces. The value of adaxial NDI index was found to be higher than abaxial for both species. In contrast, the values of adaxial SIPI and PRI indices were lower than abaxial. The differences significant (α= 0.01, p< 0.0001) for both species.