فصلنامه تحقیقات جنگل و صنوبر ایران
سال بیست و دوم شماره 4 (پیاپی 58، زمستان 1393)

This research aimed at mapping the risk of wildfire based on a number of influential factors including Elevation، slope، aspect، average annual precipitation، average maximum monthly temperature، land use/land cover، distance from road، distance from river، distance from agricultural lands and population density. The study was conducted in a study site encompassing 273. 3 km2 near Sardasht in northwest Iran. The burned areas were initially mapped by field visits. Then، using Analytical Hierarchy Process (AHP) method، influence of each factor on occurrence of fire was compared pairwise and weights were assigned to them. The frequency ratio method was used to derive a weight for individual classes of each factor. This was followed by mapping fire risk zones based on weighted combination of digital maps of the influential factors. The zonation map was later divided in five risk classes (ranging from very high to very low) by Jenks method. Validation of the risk map indicated the 98. 44 percent of the observed fires to be located in the mapped high risk zones. This represents the high accuracy of the applied technique for wildfire risk mapping across the study site.

Throughfall (TF) has a large spatial variability due to the heterogeneous canopy structure and variable rainfall patterns. In this study، the aim was to estimate the optimum number of collectors needed to obtain a mean cumulative TF value within certain error limits for five individual Brant’s oak trees (Quercus brantii) in the Zagros forests of Ilam in western Iran. Sixteen TF manual gauges were placed beneath the five selected tree canopies in eight geographic directions and the gross rainfall (GR) was measured by the mean of six homemade gauges for a period of 14 months in leaf-on condition. During this period، 23 rainfall events with cumulative depth of 257. 4 mm were collected، of which an average TF rate of 68. 9% reached the forest floor. An average of 70 (range between 41-138)، 18 (range between 10-35)، and 8 (range between 5-15) gauges would be required to estimate mean cumulative TF to within ±5، ±10، and ±15% percent errors at the 95% confidence level، respectively. Based on the results of this study، 16 gauges are sufficient to estimate mean cumulative TF with an error of 15% and a confidence interval of 95%. However، the number of gauges should be increased if a lower error rate for the mean cumulative TF estimations is required.

Model-based prediction of potential land use patterns can support environmental planners and natural resource managers for more effective planning decisions. This research aimed at modeling land use change across kouhmare Sorkhi plain of Fars province by means of logistic regression. To do this، land use maps were first retrieved from multi-date Landsat imagery of 1987، 2000 and 2012. A change detection analysis was performed following the validation of classified imagery. Results of change detection between 1987 and 2000 returned a Kappa coefficient of 0. 83 showed the highest increment for rangeland class (4224. 24 ha). In contrast، the highest rate of decrease was observed on forest area (3953. 75). Having this in mind، 10 explanatory variables were selected to model potential land use changes in 2012 by LCM logistic regression. The land use map of 2012 was modelled using a Markov chain. This resulted in a 0. 74 Kappa coefficient for an error matric between the modeled and the 2000 Landsat-based land use maps. In addition، the revealed changes for the 2000-2012 period with 0. 88 Kappa coefficient show a highest increment rate for rangeland class (1807. 02 ha)، whereas the greatest decrease was observed for forest (2132. 82 ha). In accordance to this، the land use map of 2024 was predicted، for which the irrigated agriculture would be associated with the highest rate of change.

This paper aims to study the spatial pattern of marked trees in compartments 513 and 514 of district five of Safarood Ramsar which is located between 1200 and 1300 m. a. s. l. in the watershed management unit 30. For this purpose، twenty، 1ha sample plots were selected based on two independent communities، 16 plots in managed and 4 plots in unmanaged (control) stands، and the data on 2000 and 2012 were compared. Results showed that the structure of the 20 plots on 2000 was irregular and the selection cuttings within 12 years have made ​​some effects on the structure in 2012 which is now a bit far from irregular form. The number of trees in small، large and extra large diameter classes is reduced. The spatial pattern of marked trees in the compartment 512 showed cluster pattern (located around large and extra large timber)، whereas in the compartment 513 was random (located around small and medium timber) which is directly related to the typology of the stands. Moreover، the results indicated that the mean area of gaps in the managed and control stands was 414m2 and 284m2، respectively. Mean total height of seedlings was 1. 4m and 1. 2m in the managed and control stands، respectively. Mean seedlings number in the managed and control stands was 603 and 512 in 100 m2، respectively. None of the differences of above mentioned data were statistical significant.

Study of Cypress (C. sempervirens) trees in Zagros region of Iran is of vital importance due to its rare occurrence in the region as well as its functional، socioeconomic and ecological values. In this study، quantitative and qualitative characteristics of this species have been studied across on of its native habitats in Khuzistan province. To accomplish the study، a portion of Cypress – dominated area of 100 ha near Baghmalek was inventoried by full callipering. One-way ANOVA and Duncan test were used to compare the means of Diameter at Breast Height (DBH)، height and percentage of canopy. Similar ANOVA was used to quantify the effect of humidity and aspect on seedlings height. The tests indicated a significant difference between means of DBH، height and percentage of canopy in all geographical aspects. The Duncan tests also showed a significant difference between Western slopes and a range of others (South، South-West، South-East and North-West) for DBH. It also indicated the South-East aspect to be significantly different that all other aspects for height. For the percentage of canopy، South-Eastern and Western aspects were different than South ern and North-Western aspects. Furthermore، the qualitative analysis showed that 53. 1%، 34. 6%، and 12. 21% of C. sempervirens trees were of 4، 3، 2 quality degree، respectively. The Univariate test for the effect of humidity and aspect on the height of seedlings showed a significant effect. However، aspect as well as their interactions did not indicate any significance. As a conclusion، this study suggests a biological enhancement of soil moisture which in turn improves the natural regeneration of Cypress trees in this and similar areas.

Due to their significance for carbon sequestration and ecosystem management، information on decay dynamic of deadwood and its total decay time are of great importance to ecologists and forest managers. This study was conducted in Kheirud forest of Nowshahr to study the decay process of beech and hornbeam deadwood. Therefore، 72 beech and hornbeam dead trees were randomly selected. For each sample tree، information on species، diameter، decay classes and slope gradient were recorded. The cubic cut samples with 5 cm length، width and height in two perpendicular aspects were taken from each decaying stump. 30 and 16 years of decaying time were shown to be needed for 95% dry mass of dead beech and hornbeam logs، respectively. In addition، the required periods for passing through all stages of decay for beech and hornbeam dead trees were 27 and 21 years، respectively. A strong relation (R2=0. 8) between density and decay stage of dead trees was indicated. Therefore، the density of dead wood was concluded to significantly decline with increased decay stage in both species.

In this survey، we investigated the flora and habitat conditions of wild Fig (Ficus johannis Boiss.) in a part of its natural habitat in Yazd province. To obtain climatic information، the required data were obtained from the closest climatologic stations. With average precipitation of 177. 4 mm/year and the average annual temperature of 14. 4 °C، the study area is a dry temperate region. Physiochemical analyses were conducted on previously-taken soil samples. Floristic investigation was conducted in two subdistricts (Sadegh-Abad and Mazrae-Ghebleh). Moreover، qualitative and quantitative characteristics of trees were recorded via transect sampling. Results of soil analysis indicated that F. johannis grows in the soils featuring a pH ranging between 7. 74 and 8. 39 with sand-silt texture. Results also showed that there were 27 families، 64 genera and 73 species in the study area. The family of Compositae with 22% (16 species) and Labiatae with 14% (10 species) presented the highest richness among all families. In terms of biological forms، the following composition was indicated: Chaemoephytes with 34% (25 species)، Throphytes with 12% (7 species)، Hemicryptophytes with 40% (27 species)، Microphanerophytes and Nanophanerophytes with 5% (4 species)، Geophytes with 6% (5 species) and Mezophanerophytes with 1 % (one species). Among the total 90 species، 15 species were found to be endemic to Iran. F. johannis was evaluated as a hydrophyte species according to its frequent growth in valley margins which is due to higher moisture content. The transect sampling resulted in calculating the population density and cover in Mazrae-Ghebleh (46 ha-1 and 3. 51 %. ha-1) as well as in Sadegh-Abad district (49 ha-1 and 7. 76 %. ha-1)، respectively. Overall qualitative features of trees were moderate. Partial withering of branches was observed in majority of trees but no damage was observed on stems.

Sustainable forest management in Zagros Mountains entails accurate information on tree crown density، which could be possibly derived from remote sensing data. Moreover، those remote sensing products need to be objectively evaluated. In this study، the results of three pixel-based classifiers of UltraCam-D aerial imagery were evaluated for classifying Brant`s oak (Quercus brantii Lindl.) crowns in Zagros forests in western Iran. This was carried out by means of receiver operating characteristic (ROC) curve. Therefore، a 30 ha plot was selected in pure Brant`s oak stand، in which the location and crown area of all trees were mapped. The UltraCam-D aerial imagery was classified by maximum likelihood (ML)، artificial neural networks (ANNs) and support vector machines (SVMs) classifiers. The classification results were then evaluated by ROC curve and were presented by overall accuracy and Kappa coefficient. Results showed that the ML classified returned the largest area under ROC curve of «tree crowns» (0. 894)، whereas the lowest rate was found for SVM classifier (0. 819). Sensitivity and specificity of «tree crowns» in ML classifier (0. 999 and 0. 999، respectively) were higher than those in two other classifiers. Although the precision of SVM classifier was the highest in discriminating «tree crowns» (1. 000)، the achieved accuracy of tree “crown class” was higher for ML classifier (0. 999). This study concluded that using ROC curve enables an evaluation accuracy and precision of common pixel-based classifiers of such aerial imagery to discriminate tree crowns.

To design an optimal plantation map for reforestation، a convenient and accurate method is required to analyze plant communities as well as to simulate the plantation map using the spatial pattern of natural trees. In this study، a new algorithm was designed to simulate a plantation map in Zagros forests. To accomplish this، ten hectares of intact stands located in 45 km south of Khorramabad city in Lorestan province was selected. A set of previously-developed algorithms were evaluated to design a new algorithm. The map extracted from the algorithm showed that the required conditions in drawing the map were met. In addition، an appropriate pattern of plantation in different areas can be reached by using the results of this algorithm. Since this study is the first study of its own in Iran، further investigations are required to remove the weak points. Therefore، it is suggested that the presumably existing weak points may be best removed by applying this algorithm in various regions، as well as by integrating effective indexes such as soil type، height from the sea level and physiographic factors. Being based on computer simulations، the results obtained here should be further experimented in different study sites within Zagros region، followed by a thorough evaluation of their plausibility under natural forest conditions.

In this study، the main objective was to assess the spatial variation of chemical and physical soil and water properties. Using this information، the studies also aimed at establishing a pasture rehabilitation experiment in the mangroves of Qeshm Island. To this aim، soil and water samples were analyzed for a set of factors including pH، EC، Oc، Na، Ca، Mg، K، SP، ESP، SAR، Clay، Sand، Silt، water pH and water EC. The kriging method was applied to derive the spatial variation of chemical and physical soil and water properties. Experimental variograms were calculated for soil and water properties. The variograms of EC، pH، Clay، sand، Na، Oc، SAR، water EC and water pH indicated a high amount of spatial autocorrelation fitted by spherical models. However، SP and K showed large nugget effects. In addition، diagnostic measures of RMSE، MAE and R suggested kriging to feature appropriate accuracy to estimate the spatial variability. Results of cross-validation for EC، pH، Clay، sand، Na، Oc، SAR، water EC and water pH also showed high accuracy of the estimates. Therefore، geostatistics is concluded to enable capturing the spatial variability and estimating the majority of soil and water attributes across such Mangroves.

Litter biomass and leaf area index (LAI) are two important attributes which play crucial roles on the biological processes which impact forest productivity، including photosynthesis، water and nutrient cycles. Litter biomass of a Beech-Hornbeam stand located at the mid-elevation of the Hyrcanian region (Forest management plan of Neka-Zalemroud، district five) was measured using 27 litter traps in a one-year period. In addition، LAI was determined by means of gravimetric method، applying a leaf area meter as well as a metal pipe cutter. A regression model was parameterized to predict the values of litter biomass and LAI using a set of allometric parameters including density، basal surface area، trunk volume، and crown area / volume. Total litter biomass and leaf biomass were determined to be 5. 472 and 3. 707 ton per hectare per year، respectively. Mean LAI was measured to be 7. 5، and 7. 7 using leaf area meter، and metal pipe cutter، respectively. The analysis shows that area and volume of crown presents a greater coefficient of determination and smaller root mean squared error than other allometric parameters، indicating the best predictors regarding litter biomass and LAI. Stand-specific models of Beech-Hornbeam were detected more robust than species-specific models of Beech and Hornbeam. Furthermore، species-specific models of Hornbeam were significantly less robust than those specified for Beech.

In greenhouses used for reproduction of tree species، several methods can be used for controlling seeds and rhizomes of weeds in soil. A number of these methods are used in situ، whereas some are applicable in fields when mass reproduction is pursued. The methods embrace a range from heat-based methods to those using chemicals. However، the chemical method is associated with a number of restrictions including harmful environmental effects and high costs. Therefore، we designed and constructed a steam-based instrument which additionally contributes to a disinfection of soil by water steam. The system was tested at different treatments as three temperature levels of 70، 90 and 110 degrees، as well as at three soil types containing various portions of clay. The study site was conducted in a botanical garden، in which garden soil was mixed with compost and weed species seeds of Dactylis glomerata، Festoca arundinacea and Medicago sativa. The 110 degrees temperature and a mixture of garden soil with compost were shown to be associated with the best performance of soil sterilization in eliminating all three weed plants. Due to the fact that the designed system is a small industrial steam instrument which is domestically manufactured، it can be suggested as an appropriate cost-effecting means for easing the mass reproduction of forest species within greenhouses and botanical gardens.

In this study، socioeconomic factors affecting poplar plantation development in North Khorasan Province in 2013-14 was analyzed using cross sectional data from 54 poplar plantation in 30 villages and was estimated by a linear regression analysis. The results obtained from correlation coefficient showed a positive relationship between poplar plantation and a number of factors including educational level، provision of free seedlings by the state، using low-interest bank loans، guaranteed purchase of wood by the government and attending in poplar cultivation courses offered by the state. In addition، the results of linear regression indicated significant differences amongst three qualitatively variables (including free seedlings by the government، low-interest loans and guaranteed purchase of wood) which also positively affect the amount poplar plantation.

Northern Zagros Forests has remarkable diversity of oaks (Quercus sp.) as one of the most important tree species in Iran. Based on the modern taxonomy of this genus، five species of Q. libani، Q. carduchorum، Q. ophiosquamata، Q. magnosquamata and Q. apiculata were recognized form Q. libani complex. In order to complete the previous studies، here we evaluated the vegetative characteristics of acorns for those five species. Acorns of studied species were gathered from native forest stands of Baneh Forests in Kurdistan province. The acorns were then planted in a fully-identical condition in greenhouse. A completely randomized statistical design with three replications and 50 acorns per replication was used for statistical analysis. The results showed that the acorn length، acorn width and germination rate were significantly different (p < 0. 01) amongst the five species. Furthermore، seedling height، wet and dry mass of stem، dry mass of root and total biomass of seedlings showed significant differences (p < 0. 05) amongst the five species. Based on cluster analysis، Q. carduchorum was separated from other species and categorized in different category.

In order to rehabilitate the degraded mountainous forests (in particular those located in the vicinity of villages)، the appropriate fast-growing tree species can be used. We selected an experimental site in mountainous part of eastern Guilan (Rostam-Abad County) in northern Iran. A number of 75 seedlings from 12 different clones of Poplar and Paulownia species were planted in 5×5 groups in a Randomized Complete Block Design (RCBD) featuring 3 replications. After a 5-years period، the results showed that Populus euramericana triplo، P. euramericana costanzo، P. nigra 62/127 and P. nigra 62/154 were amongst the most promising species in terms of establishment، growth and survival. Therefore، these can be suggested for rehabilitation and wood production across this and similar sites. The study also showed the lack of success for Paulownia clones، especially in the areas featuring higher altitudes. However، this implies further research to enable a more comprehensive conclusion.

Estimates of tree biomass are useful in assessing forest structure and evaluating ecological and economic processes such as nutrient cycle، forest productivity and fuel inventories. The information on tree biomass is required to assess the amount of carbon held in trees. This research was conducted in order to measure biomass and Carbon stocks of two vegetation forms of Brant''s oak (Quercus brantii) in Chaharmahal & Bakhtiari Forests in west of Iran. Therefore، sample trees were selected to be felled using 30 randomized systematic plots. Thirty trees including 16 individuals with single stem and 14 sprout-clumps were randomly selected. Quantitative and qualitative traits were measured before felling. The felled trees were separated into six different components and weighed on a portable hanging scale in the field in order to obtain the fresh weight. Samples were taken from each tree component. The samples were weighed on a scale with 0. 01 gr accuracy and transported to a laboratory. According to results، biomass of single stem trees was 2. 5 times more than coppice forms. Moreover، biomass allocation of single stem trees and coppice trees were identified.