فصلنامه پژوهشهای علوم و فناوری چوب و جنگل
سال بیست و هشتم شماره 4 (زمستان 1400)

Community forestry has been introduced with a new concept in forest management with the participation of rural people as an optimal method for sustainable management of forest lands, which has forced governments and forestry officials to revise their role. In this regard, the present study was purposed to exposure social forestry approaches and its role in managing forestry plans in Golestan province.

The present study is an applied research in a survey manner. The population of the study consisted of 606 households with approximately 2250 inhabitants from six villages in three forestry plans including Loveh (East of Province), Vatana (West of Province) and Rezaian (middle of Province) forestry plans. Sampling size was determined through the Kerejcie-Morgan’s table including 241 households. In this research, sampling was done randomly and proportionally according to sampling size and proportion of each village population to total statistical population. . Data gathering was done by a researcher-made questionnaire to determine social forestry approaches through 21 individual interview and 9 group interview including natural resources experts and managers and also rural societies based on intensive grouped and mind-storm method. Respondents were asked to express their opinion on the social forestry approaches based on five-choice Likert spectrum (from very low to very high, numerically 1 to 5). In this research, determinthe validity of the questionnaire’s contents was distinguished by expert opinions from natural resources and social sciences. Reliability of the measuring instrument was also assessed by calculating the Cronbach's alpha coefficient. After collecting information, eleven questionnaires were removed due to incomplete information and 230 questionnaires were used for analysis. After collecting and categorizing data, analysis was performed using SPSS20 in the form of descriptive and presumption statistics.

Results showed that among 230 respondents household, 53.5 percent was men, 80.9 percent was married, with characteristics of 4.61 people household dimension, 43.13 year mean age, 37.9 percent with primary and without education. Also, 45.2 percent of respondents were farmer and animal keeper and 35.7 percent were workers. Results showed there was no meaningful relationship between age and number of household members of respondents with their view about the operation of social forestry approaches in forestry plans. Meanwhile, there is a negative correlation between the levels of education of respondents with their views on social forestry approaches. Rural societies believe that being as a community member and participating to Education workshop can increase the effect of social forestry approaches on managing forestry plans. On the basis of the results of this research, people participation and economical approaches were the most important (priorities 1 and 2) according to rural society’s view while servicing and educational approaches were the lowest important (priorities 5 and 6) in affecting on forest management performance.

In attention to importance and situation of social forestry approaches, it is necessary to apply participating approach for forest conservation and forestry implementation and economical approach for increasing income resources and welfare of rural society for reducing their dependency to forest. Also, educational approaches are important to enhance rural society’s knowledge to access to social forestry goals in managing forest.

Reforestation stands can effect on diversity of plant species and soil characteristics of an area. In this study, the effects of 25-year-old reforestation stands with Acer velutinum Bioss., Alnus subcordata C. A. M. and Cupressus sempervirens species on plant biodiversity, understory vegetation and some physico-chemical of soil properties were studied compared with natural forest (Carpinus betulus and Fagus orientalis) in the Kolet forests of Mazandaran province.

In each reforested stands and natural forest, ten plots (2020 meters) were selectively sampled in transects which were 100-m stretches systematically. Then, the list of all herbaceous species and their abundance (cover percentage) was recorded. Also, in each sample plot, a soil sample was taken from the four corners and its center at a depth of 0-15 cm, then these samples were mixed together and a composite sample were taken to study the physic-chemical characteristics of the soil (bulk density, soil texture, acidity, electrical conductivity, organic carbon, total nitrogen, absorbable phosphorus and potassium). The indices of richness (Margalf and Menhenic), evenness (Shannon-Wiener) and diversity (Simpson and Shannon-Wiener) were also studied.

The results showed that reforested stands were significantly different from natural forest (control) in terms of soil reaction rate (P <0.05), potassium, clay and relative soil moisture (P <0.01). Also, the amount of acidity and absorbable potassium reaction in Acer velutinum Bioss mass (6.99, 904.51 mg kg-1) was the highest and lowest in natural mass (6.18, 557.57 mg / kg). It was observed that the highest percentage of clay in natural mass (43.57%) and the lowest percentage in Alnus subcordata mass (39.32%) and the relative moisture in Acer velutinum Bioss mass (40.78%) was the highest and It has the lowest value in Cupressus sempervirens mass (20.12%). But other soil variables did not show significant differences with natural forest. Margalf and Manhenic richness in the four reforestation stands was significantly different (P <0.05). The diversity indices (Simpson, 0.58 and Shannon-Wiener, 1.26) and the richness (Margalf, 2.00 and Mannick, 1.57) were higher in the natural forest than four reforestation stands and the evenness index (Shannon-Wiener, 0.82) showed the highest value in the Cupressus sempervirens stand. Multiple regression of soil variables with the first and second axes of DCA analysis indicates that only potassium has been effective in the separation and differentiation of vegetation in the area and the four studied stands can be distinguished in terms of understory vegetation.

In general, the results of the present study showed that the richness indices of understory vegetation species as well as the characteristics of moisture, soil reaction and adsorbable potassium changed under the influence of reforestation and according to DCA analysis is the most important component in mass segregation. Potassium is an absorbable plant. Also, the study of biodiversity indices showed that the diversity and richness indices were higher due to the fusion of species in the natural massif (Carpinus betulus and Fagus orientalis) compared to the reforested massifs of conifers (Cupressus sempervirens). In other words, the results show a greater protective role of broadleaf stands (Acer velutinum Bioss and Alnus subcordata C.A.M) and natural stands (Carpinus betulus and Fagus orientalis) than needle stands (Cupressus sempervirens) for richness and diversity of understory vegetation species and sustainable maintenance of communities the underside is in the Kolet area.

Determining and estimating the tree diameter growth and basal area growth of beech are very important in forest management and planning. Due to, the beech trees is one of the most valuable species in Hyrcanian forests, so the aim of this study is determine and modeling the tree diameter growth and basal area growth of the beech tree in forestry plans in Golestan province.

This study was conducted in four forestry plans Vatana, Kordkoy, Shamoshak and Shast-Kalate located in Golestan province. In the study area, 19 beech trees were selected from healthy trees with criteria such as no twisting of the trunk and no wounding of the trunk at a similar altitude from among the healthy stands. A disk (10 cm-thick) at breast height was selected. The maximum, minimum and mean age of the trees in the study area are 243 years (2016-1773), 99 and 142 years, respectively. After preparing the samples, the width of the annual rings of trees was measured using a LINTAB with 0.01 mm accuracy. Then, the average diameter growth and annual basal area growth of trees were determined and the relationship between diameter at breast height and growth diameter and basal area growth was evaluated using four models: Hyperbolic, Heat capacity, Modified power and Richard.

The results showed that with increasing age of beech trees, the diameter growth increased and reached its peak in 1955, then it started a downward trend. The results also showed that with increasing tree age, annual basal area growth of the tree also increases, in compare to diameter growth, annual basal area growth reaches a maximum in 1990 and then takes a downward trend. The results showed that The diameter growth and annual basal area were 3.93 mm and 17.52 cm2, respectively. The results of modeling also showed that the heat capacity model, compared to other models, could better explain the diameter and basal area with a coefficient of determination of R2 = 0.37 and R2 = 0.69, respectively. The results of uncertainty analysis also showed that the real average of diameter growth and basal area growth characteristics is in the range of 95% confidence intervals, which shows the appropriate and reliable performance of the model.

According to the results, it can be concluded that diameter growth and annual basal area were 3.93 mm and 17.52 cm2, respectively and DBH as an dependent variable explains 37% and 69% of changes in diameter growth and annual basal area.

Golestan province located in the eastern part of northern forests of Iran has a wide geographical distribution of Quercus castaneifolia in terms of rainfall, temperature and soil type. Climatic gradients from the west to the east of Golestan province have different impacts on the genetic and the ecotype diversity of tree populations in time that knowing the amount of this diversity helps us to manage/maintain the genetic structure of these species. The genetic diversity of trees is so important for adaptation of forests to climate change and for sustaining other species and entire forest ecosystems. The aim of this research is exploring the ecotypic diversity changes of Quercus castaneifolia populations in drought gradient (western-eastern) of Golestan province.

To do the study, four different populations of Quercus castaneifolia from West to East of Golestan province in habitat areas of Tuskestan, Aliabadekatul, Loveh and Golidagh were selected. First, about 100 bases of Quercus castaneifolia with similar diameter and healthy and with approximately 50 to 100 meters distance from each other to avoid the possible affinity in each population were considered and then 20 bases of Quercus castaneifolia among them were randomly selected. After sampling qualitative study of marker peroxidase of the organ of biennial branch in four different populations was done by the use of vertical electrophoresis and by the method of Poly Acrylamide Gel Electrophoresis (PAGE). To analyze the data, scoring of bands into zero and one respectively for the absence and presence of bands was done based on the prepared gels. Then respective software packages were used to cluster analysis, Principle Coordinate Analysis as well as data analysis regarding the allelic characteristics of studied marker including the number of observed alleles, effective alleles, Shanon,s information index, hetrozygosity and polymorphic percentage and ecotype diversity within and among populations.

The results of this research based on total, observed, effective alleles and hetrozygosity of the peroxidase marker showed that ecotype diversity and genetic diversity parameters examined in the western-eastern gradient of the different habitats of Golestan province is different and in the distant past, the genetic flow has been established through adjacent populations so that ecotypes are not separable.

To manage the maintenance and development of the genetic diversity of these stands, at first it is necessary to stabilize the present condition with respect to the diversity through emphasizing and maintaining the index bases inside the populations and helping their regeneration and secondly, developing the present diversity to combat the climate change threats through gene flow with the help of seed and seedling transition from the adjacent populations.

The present study evaluates the morphological characteristics of leaves and seeds to more easily identify the species of Carpinus betulus, C. schuschaensis and C. orientalis. Morphological and physiological characteristics are always influenced by climatic and ecological factors; hornbeam trees also change in their appearance due to their wide distribution, which makes it a little difficult to quickly identify the species. For the conservation and basic management of habitats of this species, accurate identification of species, recognition of ecological needs, and study of its genetic diversity seems useful.

Sampling of hornbeam leaves and seedlings from two regions of Kordkoy, Derazno and Neka, Hezar Jarib was done randomly from 5 individuals of Carpinus betulus, C. schuschaensis and C. orientalis species that were at least 100 meters apart. Morphological traits studied in leaf was as follows: leaf length (AL), leaf width (WL), distance from the widest part of the leaf to the base (WPL), number of teeth (NT), beak length (DB), beak width (WB), number of teeth in 2 cm (NT 2cm), maximum leaf width (MWL), petiole length (PL), number of veins (VN), width in 0.1 leaf length (W0.1), width at 0.9 leaf length (W0.9), leaf area (LA), the ratio of leaf length to leaf width -leaf shape(LS), the ratio of leaf length to the widest part of the leaf to the base (AL/WPL), the ratio of the widest part of the leaf to the base to the length of the petiole (WPL/PL). Also, the morphological traits in seeds were including total weight of seeds (TW), outer shell weight (WS), seed kernel weight (BW), seed length (A), and seed width (W). Traits were measured on a case-by-case basis using calipers and rulers, as well as seed weight using a digital scale with an accuracy of 0.001. Nest statistical design, Duncan test, and principal component analysis (PCA) were used. The distribution of tree trunks in the coordinate axis space, Discriminant analysis, and cluster analysis were also evaluated.

The results of analysis of variance indicated that among the populations, all studied parameters except NT, MWL, TW and BW traits were significantly different from each other. The results of PCA indicate that in seeds 66.7% of the variances in the first component and in leaves 96.69% of the variances in the first four components are justified. The results of cluster analysis showed that the three populations were divided into three separate groups (clusters). The results of diagnostic analysis showed that NT 2cm, PL, LS, AL / WPL, TW, WS and BW are the distinguishing traits of the three species.

In terms of simple identification, hornbeam seeds do not differ significantly in terms of dimensions, but in terms of leaves, Carpinus betulus are the largest, C. orientalis is the smallest and C. schuschaensis species is intermediate species. Morphological studies of this study confirm the independence of Carpinus betulus, C. schuschaensis and C. orientalis species due to complete separation of traits. However, it may be possible that C. schuschaensis to be a hybrid.

Early warning systems in natural areas are one of the ways to prevent and manage fires. Many factors that affect fire occurrence can be divided into two categories climatic factors and human factors. Among the most important climatic factors; increasing the temperature, decreasing the rainfall, decreasing the humidity and increasing the wind speed can be mentioned. Thus,forest fire risk assessment and early warning systems have become an important component of land management in recent decades. The Canadian Forest Fire Danger Rating System is one of the most important early forest fire warning systems in the world. The Fire Weather Index subsystem provides relative numerical ratings of various aspects of wildfire potential based on four weather observations. The purpose of this study is to identify the most effective input variables of the system in predicting the probability of forest fire in Golestan Province.

In order to estimate the Canadian Forest Fire Weather Index System, the input variables to the system include four climatic variables: daily observations of maximum temperature, relative humidity, wind speed, and 24-hour precipitation for a period of 21 years (1997-2018) during the fire seasons (April to December). Were collected daily from synoptic and evaporative stations in the province. First, the Canadian Forest Fire Weather Index modeling system was calculated daily during the study period at each station. Then, the correlation test and Multi-Dimensional Scaling analysis between input Weather variables and system output index were performed using Spearman, Pearson, and Kendall correlation coefficients.

The results showed that the variable of maximum daily temperature with a correlation coefficient of 0.911 in the study period has the highest effect on the weather index of Canadian Forest Fires compared to other variables. After temperature, daily relative humidity, daily rainfall and daily wind speed with correlation coefficients -0.89, -0.79, 0.29 have the greatest impact on the output of the system of forest fires in predicting the probability of forest fires in this province. Also, in this study, it was found that Spearman’s correlation coefficient is better than other correlation coefficients.

Forest managers can use this system to predict the likelihood of fire if other variables are not available, using the order of importance of each of the climatic variables and rate the risk in different parts of the province.

Mangrove forests of Iran; like anywhere else; are ecologically sensitive areas and exposed to a wide range of anthropogenic threats. Considering the ecological importance of Khor-e-Azini wetland as the only Rizophora mucronata (Lam) habitat in Iran and also due to the lack of information on heavy metals pollution in this habitat, relevant investigation is of utmost importance for their better management. Hence, the aim of this study were to investigate the concentration of heavy metals in sediments and vegetative organs of Avicennia marina (Forssk) Vierh and R. mucronata and compare their concentrations with international standards to reveal the contamination status of this habitat. The ultimate goal was to provide information for pollution control at the source and more efficiently protect these sensitive ecosystems.

After a reconnaissance visit to the mangrove habitat, a six-hectare stand composed of A. marina and R. mucronata was selected and sampling was conducted using line sampling method. In the selected stand, three 300-meter transects, 100 meters apart from each other, were formed. Also six plots (20×20 m2) were selected along transects at equal distances. To collect samples, 10 plots from among the 18 plots were selected in a complete random manner. Then, 5 to 10 trees higher than three meters were selected randomly for sampling of sediment, root and leaf of mangrove trees. Heavy metals concentrations were measured using an atomic absorption spectrophotometer. Also, the mean concentrations of heavy metals in sediments, roots and leaf of A. marina and R. mucronata were analyzed using Independent Sample T-test.

The mean concentrations of heavy metals in sediments and organs of A. marina and R. mucronata showed no significant differences for Ni and Zn in sediments, roots and leaves of the two species, but the concentration of Cu in sediments (66.60; 39.91 µg/g), roots (70.99; 33.70 µg/g) and leaf (72.51; 20.85 µg/g) in the two species was significantly different at confidence level 95%. Also, comparison of concentration of Zn, Cu and Ni in sediment samples of A.marina and R. mucronata with international and national standards showed that of Zn was lower than the international standard, but higher than that the standard set for the Persian Gulf sediments. In addition, the concentration of Cu in sediments for the two species was higher than that of the international standard. Compared with the standard of Persian Gulf sediments, Cu concentration in A. marina habitat was much higher and in R. mucronata habitat, somewhat higher than the standard. The concentration of Ni was much higher than the international and national standards.

Our results indicated that the concentration of Ni in the sediments of A.marina and R. mucronata were critically high and that of Cu was in a warning status based on the standard of Persian Gulf sediments. Although no significant differences were detected for Zn and Ni concentrations in sediments and plant organs of A.marina and R. mucronata, Cu concentration in sediments, roots and leaf for the two species was significantly different with values for A.marina being higher than that in R. mucronata.

Today, the phenomenon of fires as one of the natural disasters threatens a large part of the world's forests. The purpose of this study is to investigation of wood resistance of different tree species of Zagros forests against fire.

To conduct this research, wood species Quercus persica, Pistacia atlantica, Amygdalus scoparia, Crataegus azarolus, Acer monspessulanum and Ficus carica were prepared in two forms: dry and wet wood (with natural moisture) with similar length and dimensions (length 60 cm, diameter 15 cm). For each tree, wood with skin and without skin was selected in order to investigate the effect of stem skin on the burning rate of wood species and the difference in wood burning time was measured using a stopwatch. LPG capsule was used to create a suitable temperature for complete burning of wood. For each wood 4 treatments (wet with skin, wet without skin, dry with skin and dry without skin) and also for each treatment 10 replications were considered. Statistical analysis was performed using GLM and Independent Samels T test.

Comparison of the complete burning time of wet wood of the studied species shows that Quercus Persica wood with a time of 50 minutes until complete burning has the highest fire resistance and after that, the Pistachia had the highest resistance with 42 minutes until it burned completel. Acer and ficus varieties had the lowest fire resistance with 35 and 30 minutes to complete burning, respectively. The results also showed that fire resistance between species Crataegus and Amygdalus was not significant at 5% probability level. Comparison of the complete burning time of dry wood of the species shows that the highest fire resistance was in Quercus species with 40 minutes until complete burning. After that, Pistacia, Amygdalus, Acer, Crataegus and Ficus had 34, 30, 26, 21 and 20 minutes to burn completely in the fire, respectively. The results of comparing the means showed that in wet woods, the biggest difference in the time of complete burning of wood with and without skin in Pictacia species with 13 minutes, followed by Amygdalus and Crataegus with 12 minutes, then Quercus, Acer and ficus with 11, 9 and 6 minutes, respectively. In dry wood, the biggest difference in the time of complete burning of wood with skin and without skin in Quercus species and Pistacia with 15 minutes and then Amygdalus, Acer, Crataegus and ficus with 13, 8, 4 and 3 minutes, respectively.

The results show that the thickness of the skin and moisture of the wood cause significantly increases the resistance of the wood against fire.