فصلنامه تحقیقات جنگل و صنوبر ایران
سال بیست و یکم شماره 2 (پیاپی 52، تابستان 1392)

The aim of the study was to predict future fires at District Three of Neka-Zalemroud Forests، using fire risk modeling. Fuzzy Analytical Hierarchy (AHP) method was used to weight the effective fire factors، then map of each factor was developed for modeling sites with fire risk. The fire factors consisted of four major criteria and 17 sub-criteria. The major criteria consisted of topographical، biological، climatical and human factors. The maps of these factors were developed، using DEM and existing data in Neka Corporation Company. In addition، the past fires map was generated، using existing data in the Company and mapping fire patches perimeter by GPS. Verbal scales and results of distributed questionnaires among forest fire experts were used to weight the effective fire factors، using fuzzy AHP. Then relation consistency of each criterion was calculated، in order to investigate accuracy of criteria weight. Results showed that final weight of human، biological، climatical and topographical factors in forest fire risk potential were 0. 301، 0. 2595، 0. 2315 and 0. 208، respectively. Local fire risk model was presented، using weight of each criterion and sub-criterion، based on fuzzy AHP. Then map of effective fire factors (17 sub-criteria) was standardized، using fuzzy membership command in GIS and the pixel values of each map were scaled between 0 and 1. Finally، at first major criteria map (using weighted overlay of sub-criteria maps of each criterion) then fire risk map (using weighted overlay of four major criteria maps) was developed، using fire risk model equation. Overall، fire risk map was presented at five classes. Results showed that the sites with high fire risk on the developed map of fire risk potential are highly in accordance with the sites with past fire records which shows the high validation and accuracy of the developed model.

Fire in forests and rangelands degrades vast part of natural resources. Although predicting the exact time and location of fire occurrence is a difficult task due to various parameters affecting wildfires، but application of Geographical Information System enables us to identify and control areas with high fire potential. The purpose of this study was to achieve a fire hazard map، developed by integrating several data layers such as topography، climate، vegetation cover and socio- economical factors. Some forest sites of Guilan province of I. R. Iran were selected for the study project due to their high cover density and their frequent fire occurrence history. Because the fire influencing parameters do not affect fie occurrence and distribution equally، a multi criteria method was used to grade them. The Fuzzy Analytical Hierarchy Process (FAHP) was used to consider uncertainties and to weight the criteria within 0 and 1 values. After calculating the Fuzzy weights and allocating them to the raster maps of the influencing parameters، finally the weighted informational layers were integrated and overlaid in the GIS. To assess accuracy of the applied method، the final fire hazard map was compared to further layer consisting of areas with high fire frequency during the last five years. Results showed that 66% of the hazard fire points were completely overlaid on sites with high and vey high fire risk، which reveals the capability of the study method in predicting forest fire potential. Furthermore، short distance between forests، roads and residential areas، identified as the main factors affecting fire occurrence and forest degradation more than the topographical parameters.

uantification of wild fire characteristics is believed to be the main purpose of spotting fire spatial distribution. In the current study، we detected distribution pattern of all main fire events in the natural areas of Lorestan province over past six years. To do that، physiographic factors as well as applied features were come into consideration. Quadrat Analysis، Nearest Neighbor Analysis and Ripley''s K function were applied for distribution allocation of fire spots and Kernel Estimation was used to outline areas with high fire risk. The highest fire frequencies were detected on the southern and south-western aspects with 1300-1700 meter above sea level elevation، and on 10-20% slopes. Forests with average coverage (36%) and rangelands with average coverage (25%) were affected most by the wild fires. All three distribution analysis methods (best elucidated by Ripley''s K function at different map scales)، showed a clumped pattern for fire spreading behavior in the province. Finally، based on Kernel Estimation function، a fire hazard map was produced، which would be a proper guide in natural area management.

In order to identify the diversity of tree species in relation to physiographic factors (elevation، aspect and slope)، the Kandelat Forest Park with an area of 614. 85 hectare was surveyed، where is located southeast of Rasht city. For this reason، maps of slope، aspect، elevation and dominant vegetation types were provided، using GIS technology. As a result، 18 homogeneous units were obtained by layering the mentioned maps. In each homogeneous unit، five sample plots، and totally 90 plots were randomly located. The trees at each plot were found and their diameter at breast height (dbh) was measured. Overall، 17 tree species belonging to 16 genera and 12 families were identified. Result revealed that aspect had significant effect on diversity and evenness of the tree species. Species diversity and evenness on south aspect were significantly more than the other aspects. In addition، elevation had significant effect on diversity and species diversity and richness were greater at high elevations. There was not significant effect of slope aspect on tree''s species diversity، richness and evenness.

The present trial was carried out in Yonesi Experimental Station at Khosbijan local area of Markazi Province of Iran in 1997 in order to select and introduce the most adaptable and productive poplar clones. For this reason، 14 clones of four open crown Populus species، including: P. deltoides، P. alba، P. euramericana and P. nigra which have been selected from a previous selection nursery trial as most promising clones، were planted under the randomized complete blocks statistical design with three replications at 4 x 4 m. spacing for eight year period. Poplar characteristics، including diameter at breast height (dbh)، total height، volume per hectare، mean of diameter، height and volume increment، resistance to pests and stem-crown quality were measured annually، end of growth period. Variance analysis results demonstrated that there were significant differences between the poplar clones in respect to their characteristics، except diameter and height increment. Duncan test results indicated that P. e. vernirubensis achieved the highest mean dbh، total height، volume per hectare and volume increment، P. e. vernirubensis and P. a. 45. 77 achieved the highest resistance to pests، the best stem quality belonged to P. a. 45. 77 and the greatest crown quality belonged to P. e. triplo. The lowest variables of total height، volume per hectare، volume increment، resistance to pests and stem-crown quality were observed in P. n. 72. 8. P. e. vernirubensis، P. d. 69. 55، P. e. 214، P. e. 455 and P. e. triplo were distinguished as the most promising clones due to their vital wood production)19. 45، 18. 5، 18. 23، 17. 13 and 16. 46 m3/ha/year، respectively) whereas P. n. 72. 6، P. n. 72. 10، P. d. missouriensis، P. d. 73. 51 and P. n. 72. 8 were introduced as the lowest adaptable and productive clones.

Kermanshah is one of the most important provinces of I. R. Iran for poplar plantation and wood production. Ten natural hybrid clones (half-sib) of P. deltoids 69/55 x P. euramericana were selected in 1994 from different poplar plantations at Caspian region of the country and were planted in Mehregan Research Station، in order to identify the most productive and adaptable clones to local climate and introduce them to people for mass wood production. The clones were numbered as follows: Populus deltoides 63/1 to Populus deltoides 63/10. The trial wad conducted under the randomized complete blocks design with three replications and at 44 m. spacing. During the experimental period، weeding was done manually and irrigation was performed with the weather and stack method. At the end of each growing season، diameter at breast height (dbh) and stem total height were measured. Furthermore، annual diameter and height growth increment، volume per hectare and average volume per hectare were calculated. ANOVA was performed for height، diameter and volume per hectare and Combined analysis of variance was made for height، diameter، volume per hectare and annual growth increment. The clones were grouped according to their average growth characteristics. Results showed that the clones: Populus deltoides 63/10، P. deltoides 63/8، P. deltoides 63/9 and P. deltoides 63/7 (18. 4، 16. 4، 16. 38 and 14. 33 m3/ha، respectively) were the most productive ones and are recommended for high extent plantation at Kermanshah province.

The aim of the study was to investigate the effects of different species and clones of poplar on beneath soil properties and their differences in amount of nutrient elements in their litters. Soil (0-20 cm depth) and litter sampling was made under the randomized complete blocks design with three replicates and five treatments of 18 year old poplar species and clones، including four exotics; Populus euramericana triplo، Populus deltoides 69/55، Populus deltoides 63/51، Populus euramericana 45/51 and one native: Populus caspica (control) planted at 4 x 4 m. spacing. The measured soil and litter chemical properties consisted of: Organic carbon، total nitrogen، phosphorus and potassium. The measured poplar characteristics consisted of: total height، stem diameter at breast height (dbh) and crown diameter. Results showed that there were significant differences (ρ<0. 05) between the poplar species and clones in respect to the soil and litter chemical properties، except potassium in soil. Furthermore، the highest and the lowest amount of nutrient elements in the litter belonged to P. d. 63. 51 and P. caspica، respectively and Populus deltoides 63/51 achieved the greatest stem and crown diameter and total height. It can be concluded that Populus deltoides 63/51 in addition to its proper growth، has a positive effects on soil nutrients due to its better litter quantity and quality production in comparison to the other species and clones.

Since plantation has a major impact on carbon sequestration and soil quality، two sites with alder and poplar covers at three-replications in Safrabasteh Research Poplar Station at Guilan province of Iran were selected in order to investigate these effects. At each site، morphological، physical and chemical soil properties were studied upon standard laboratory methods. The results showed that bulk density، dispersible clay، wet aggregate stability measured as mean weight diameter، carbohydrates and amount of phosphor were significantly different among sites (p<0. 01). While in the second depth (7-15cm) of both cover aggregates with 2-4 cm and 6-8 cm size have the maximum amount of carbon respectively، in third depth (15-45cm) there was no differences among alder cover but maximum amount in 6-8 cm aggregates in poplar cover. The amount of sequestered carbon in organic layer in poplar and alder covers were 1277. 23 and 1477. 70 ton/ha respectively which had significant different (p<0. 01). Microbial respiration in both cover had significant different in 0-15 cm depth (p<0. 05) too. The findings of this research indicate that plantation has major impact on carbon sequestration and thereby controls quality indicators of soils. Alder plantation is more effective in accumulation of organic carbon in soil compared with a poplar plantation.

Forest plantation with Prosopis juliflora at southern coastal provinces of Islamic Republic of Iran for sandy dune stabilization، transferred the region to green forests with relatively high stand and crown cover density. Conservation and development of such wide extant area، requires advanced knowledge and information of this species، particularly its water requirement. In this study، water requirement of P. juliflora at eight sites of the region، started from Ahwaz and ended in Chabahar cities، was determined، using together Cropwat 8- FAO Penman-Monteith and WUCOLS III methods. Two important parameters for calculating water requirement for each plant species are: the reference evapotranspiration and crop coefficient. The reference evapotranspiration and crop coefficient were calculated using the mentioned methods، respectively. In recent method، instead of using crop coefficient، landscape coefficient was applied which is usually calculated by considering three factors، including plant species، plant density and micro-climate. The required climatical data for calculating the reference evapotranspiration were obtained from the nearest stations to the P. juliflora plantations. Soil profiles were applied at the forest plantations sites in order to study soil texture and root depth of one or two year old seedlings. The species phenology was defined، using the available references and information. After collecting the required data and calculating the reference evapotranspiration (ETO) and the landscape coefficient، water requirements for P. juliflora at the eight sites were calculated. Results showed that the highest and the lowest required supplement irrigation belonged to the sites Dasht-e Azadegan (255 mm for seven months of a year) and Chahbahar (174 mm for nine months of a year)، respectively. The maximum and the minimum required monthly supplement irrigations for Dasht-e- Azadegan were 52 and 9 mm at July and April، respectively، whereas for Chahbahar were 29 and 5 mm at May and March، respectively and for Bandar Abbas site were 33 and 12 mm in June and November، respectively. It might be concluded that the required supplement irrigation for P. juliflora differs due to variation in site characteristics and variation in months of the year، but unfortunately there was less attention and consideration to that fact by the executive organizations of the country.

Distance sampling methods are extensively used for forests management of Zagros region of Iran. In the present study، estimation of quantitative characteristics of sampling methods، including individual، nearest neighbor، second nearest neighbor، compound and joint point، were studied and compared. The individual sampling method was examined، using the estimators of Morisita، Byth & Ripley and Cottam et al. and the nearest neighbor method was assessed، using the estimators of Byth & Ripley and two predictors of Cottam & Curtis1 and Cottam & Curtis2. Location of total trees and shrubs of a 53 hectare forest stand at Ardal city of Chaharmahal and Bakhtiari Province was recorded. Having the actual trees density and canopy cover percentage، as well as their estimated values، the bias of each replication was obtained. Difference between the bias and the actual values (for bias test) by one-sample t-test method and analysis of variance by Games Howell test، were studied. The results showed that the differences between the distance sampling methods in respect to mean trees density per hectare were significant، except for the nearest neighbor method، using the Cottam & Curtis1 estimator، which was not significant، whereas in respect to mean canopy cover percentage، the differences were significant، except for the second-nearest neighbor and the combined methods. According to the results of this study، it is suggested to use the Cottam & Curtis1 method for estimating the density and to use the compound sampling and the second nearest neighbor methods for estimating the canopy cover percentage.

Identify and explore the changes caused by various methods of management and degradation on natural resources might help managers to identify the influence of land use change، degradation and management and be ready to deal with them. Three Oak forest sites were selected، including five and 20 year conservative managed and non-managed or highly disturbed sites in Ilam city، at west of I. R. Iran. Systematic-random sampling method (100  200 m.) was applied to collect data from 50 plots of 100 m2 area within each site. Three soil samples were made at 0–30 cm depth from center of each sampling plot، using soil auger. The samples were mixed to obtain one composite sample for laboratory analysis. Two-step cluster method was used to identify the most effective factors related to each cluster of sample plots، based on their importance and direction of effects. In other words، to identify effects of the short and long term conservation management methods in comparison to the degraded sites on chemical and physical soil properties. Results showed that lower amount of organic matter and ammonium nitrogen and higher amount of bulk density and EC are the most important and common indicators of the unmanaged or degraded sites. The most common and important indicators of the 5-year protected sites were lower amount of organic matter and total nitrogen and higher level of ammonium nitrogen، Whereas in the 20-year protected site were higher amounts of ammonium nitrogen، clay، available phosphorus، total nitrogen and organic matter and lower amount of lime. Overall، the results of this study showed that organic matter، bulk density and nitrogen are the appropriate indicators for assessment of effects of management on west oak forest ecosystems of Iran.

This research was done in forests under the Shafaroud Forest Company in Guilan province of I. R. Iran during 2006 to 2010، using questionnaires and incident report forms. Results showed that incidence of accidents increased from 2006 to 2008 (45. 29 cases per thousand) and decreased from 2009 to 2010 (25. 71 cases per thousand). The Lowest and the highest values of the accident coefficient were 11 (2010) and 20 (2008) cases per million، respectively. The percentage of accident incident locations at central، Shafaroud، Shanderman، lowlands and Asalem sites were 46، 27، 13، 7 and 7، respectively. The greatest job accidents at forest logging units، related to drivers، chainsaw worker، and chokeman، at support service units related to welder and mechanic، and at restoration and development units related to forest guard. Results showed that main causes of the events are due to striking different things (43%)، accidents (22%)، falling (12%)، falling from high object (10%)، high extent stress and action (9%) and other factors (4%). Some of the organs are subject to more risks than the others، including hand، eye، face، back، spinal column and leg (41، 21، 19، 18 and 15 cases، respectively). Application of personal protective equipments as main safety effort and standard machinery and working equipments in order to prevent accidents، can reduce injuries and provide safe conditions for workers.

Trees as alive components of an ecosystem are able to convert some of the environment contaminants to unharmful substances and store some of them in their tissues and reduce their density and intensity in the air and soil by breath، root absorption and photosynthesis and other biotic functions. Trees function in such condition is completely related to environmental and habitat circumstances and their physiological potential. At beginning، five research sites at Khuzestan and Bushehr provinces were selected among the contaminated area by the Gulf War. At each site، soil sampling was made from three levels of depth (0-20، 20-40 and 40-60 cm). Soil physical and chemical characteristics test was made to measure nine metal elements and 12 other soil properties. The eucalypt species consisted of: E. camaldulensis، E. camaldulensis 9616، E. microtheca and E. sargentii which were planted under the Randomized Complete Blocks statistical design with three replicates. Before sampling the trees for determining the contaminant elements. Three individual trees were selected at each plot per one replicate to make sampling for leaf (four specimens per tree at four mean geographical directions). The data were analyzed under the variance analysis and Duncan test programs، using Excel and SAS computer soft wares. Overall، amount of the contaminants in different sites and at three levels of depth was not significantly different. The best eucalypt species and the best sites for absorbing the contaminants in their leaves are respectively as follows: 1- E. camaldulensis، E. microtheca، E. sargentii and E. camaldulensis 96162- Dezful، Isvand، Shooshtar، Karkheh and Kaki. The species which made the best performance in relation to their site interaction are respectively as follows: 1- E. microtheca firstly at Karkheh and shooshtar sites and secondly at Dezful and Isvand sites. 2- E. camaldulensis 96163- E. camaldulensis and E. sargentii.

Almond is one of the major shrub species with high ecological extent in Iran. Impact of climate change and drought stress on forest ecosystems، as well as the unsuitable conditions of Zagros forest ecosystem and importance of planting shrub species at such ecosystems، have brought the attentions to use the wild almond species in forest plantation programs. Awareness of the impact of habitat factors on tolerance to environmental stresses will guarantee success of most of the forest rehabilitation programs. For this reason، seeds of four wild almonds، including Amygdalus arabica، A. scoparia، A. haussknechtii and A. eleagnifolia، were collected from three altitude levels، including: 1600-1800، 1800-2000 and more than 2000 m. above sea level at Karebas site; (Chaharmahal and Bakhtiari province)، west of Iran. After cold stratification، the seeds were sown in nylon bags. Two months later، the seedlings were treated by four levels of drought stress (control، -0. 4، -0. 8 and -1. 2 MPa) induced by application of Polyethylene Glycol 6000 in irrigation water، using the factorial experiment under the completely randomized design with three replications (five seedlings per each replicate). Results showed that drought stress significantly reduced seedlings growth characteristics، including total height، shoot height and shoot wet and dry weight، except root wet weight which was increased. Furthermore it increased seedling''s nitrogen and calcium content، while the minimum levels belonged to control treatment. In addition، the seedlings from the lowest (1600-1800 m. a. s. l.) and the highest (above 2000 m a. s. l.) altitude origin، provided the highest and the lowest growth values، respectively. Overall، Amygdalus arabica showed the highest resistance to drought levels among the other species، due to its greatest growth values at these hard circumstances.