مجله جنگل ایران
سال نهم شماره 3 (پاییز 1396)

Nowadays, one of the most popular tools to cut and process the trees in northern forests of Iran is chainsaw. One of its most important defects is constant vibration during operation. The aim of this study was to investigate the hand-arm vibration in beech tree cutting and bucking in Kheyrud forest, Nowshahr, Mazandaran Province. Three beech trees and bucks were selected and hand-arm vibration was measured by using vibrometer Bruel & Kjear 2237 in the back and front handles of chainsaw in three directions x, y, and z. The index of vibration equal value (aeq), vibration total value (ahv), transmitted vibration coefficient (Tr) and daily exposure duration (A(8)) were used to explain the chainsaw vibration. In cutting stage, the value of aeq on the x-axis was significantly higher than the two others in front and back handles (P= 0.010) and in bucking stage, the value of aeq on x-axis is significantly more than z-axis, (P= 0.008). The value of ahv during logging (P= 0.017) and bucking (P=0.013) in the back handle is significantly higher than front handle. Tr coefficient in the back handle of chainsaw while cutting (2.78) was significantly higher than the same handle in bucking (2.75) mode (P= 0.011). The results showed that the values of Tr, aeq and ahv in the back handle is more than front one, hence it needs immediate operation to improve it ergonomically.

Forest roads are the most important infrastructure to access and apply the forest management activities, which they can impose a significant impact on adjacent stands. The objective of this study was to investigate the effect of the forest road geometric plan (switchback, curve, and straight road) on some chemical and biochemical indicators of soil in adjacent stands for forest road planning. Considering three different road geometric plans, from the edge of the road up to 100 meters toward the forest interior, the rate of organic carbon, nitrogen, and dehydrogenase and urease enzymes activity in forest soil at the depth of 0-10 and 10-20 cm in two forest types was measured. Data were analyzed by using t-test, ANOVA, and broken-line regression model. The results of ANOVA showed significant effect of forest type and geometric plans of the road on measured variables. In addition, results indicated that by increasing the depth of soil, the impact of the road on some measured indicators was not significant. The results of broken line regression model showed that the lowest range of road effect was related to the straight road (13 m) and its highest range was related to switchback road (42 m). Results of this study can provide guidelines for forest road planners and evaluators to design the road effect buffer at the stage of forest roads network planning and to minimize the effect of forest road on its adjacent stands.

Combating wind erosion is one of the functions of vegetation in environments prone to this type of erosion. But vegetation establishment in such places is limited. In such a situation, the use of physical protection methods like plastic pipe is required to plant trees. The aim of research is to find out the scientific method to re-establish the vegetation cover and desert prevention with low-water-using in dry land regions. In order to conduct the research, 20 holes, 80 cm in diameter and 120 cm in depth were drilled and Eucalyptus seedlings were planted inside them. Inside plastic tubes with a diameter of 15 and a length of 80 cm, 10 seedlings were placed, so that they were 50 cm high and 30 cm inside the soil. The irrigation time was determined using the Time-domain reflectometry, TDR, and the seedlings were irrigated. Seedling height, crown cover and water were measured monthly. 18 soil samples were taken from three plots and six depths, and some of their characteristics were measured. Dates were analyzed using SPSS software. The statistical analysis showed that there is no significant difference between the canopy cover of the two treatments, but there are significant differences between the height, biomass and water consumption of seedlings at the level of 0.01. In addition, biomass index for seedlings of these treatments was estimated to be 1.5 and 6.3, respectively. In order to grow a square meter of canopy and one meter height seedling in treatment with tube, 505 and 132.7 liters of water are required, while for tubeless treatment, they are 1422.22 and 471.2 liters, respectively.

The aim of this descriptive and survey research was to determine the factors affecting the knowledge needs of Eucalyptus growers in Golestan Province. The data were collected using descriptive-correlation research and survey techniques. The study population consisted all of 300 Eucalyptus growers in Golestan province, out of which, 170 growers were randomly selected. Data was collected through a questionnaire which its content validity and reliability were confirmed by a pilot study using experts comments. The correlation test showed that there is a significant relationship between variables age, literacy level, history of agricultural activity, Eucalyptus cultivation background, wood crop cultivation area, visiting experts and people with experience in the field of wood growing, attendance in extension classes and programs, presence in collective visit programs from typical and model fields, number of hours listening to the radio during the day and knowledge needs of Eucalyptus growers in planting, growing and harvesting. Regression analysis results showed that Eucalyptus cultivation background, attendance in extension classes and programs, visiting experts and people with experience in the field of wood and wood crop cultivation area are the most important predictors for knowledge needs of Eucalyptus growers in the fields of planting, growing, and harvesting. This study recommended continuous use of practices such as extension classes and programs, collective visit programs from typical and model fields, visiting experts and people with experience in the field of wood growing, preparing and production the radio programs in wood grower training with the aim of response to their knowledge needs.

The idea of this research is to select the appropriate model for the rapid estimation of volume in even-aged Persian oak coppice stands. For this purpose, 19 widely used univariate and bivariate models were used in volume estimation. Initially, actual volume data from 73 cut trees in different diameter classes in 12 forests of Ardal and Kiar cities were divided into two sets of 70% for modeling and 30% for validation. Then, the coefficients of the selected models were calculated using the weighted least squares method. Models with significant coefficients were ranked by the root mean square error and R-squared. Of the 19 models, nine models were selected. The fitting results of the selected models showed that the least amount of root mean square error (0.035) was related to the five-parameter model and the highest amount of R2 (0.979) was related to the four and five-parameter models. The results of validation showed that among the bivariate models, the four and five parameter models and among the univariate models, the power model were the most efficient. The obtained results can be used in growth and yield models, preparation of Tarif and standard volume tables.

Proper Seed germination and establishment is one of the most important issues in pre-planting treatments. Seed osmopriming is proposed as a pre-emergence treatment to increase the characteristics germination and seedling establishment, especially in unfavorable conditions. The effects of osmopriming on germination (germination percentage, maximum daily average germination, germination rate, mean germination time, germination value) of Scots pine, black pine and Turkish pine under controlled conditions in order to determine the best treatment were investigated in this research. A factorial experiment was conducted as a completely randomized design with three replicates. Main factors included the time (0, 1, 2 and 3 days) and osmotic potential (0.8, 1.2 and 1.5 MPa) using polyethylene glycol 6000. The results indicated that there were significant differences between treatments on germination characteristics in all three species, and all studied traits were improved by osmopriming. The highest germination factors were recorded for Scots pine and black pine treated with 1day in concentrations of 0.8 MPa (polyethylene glycol 6000) and for Turkish pine were obtained with 2 days in the concentration of 1.2 MPa in compared with control treatment. So it can be suggested that in order to increase the quantity and quality of production in seedlings nursery of these species, the pre-planting treatments should be considered further.

Rainfall partitioning into throughfall, stemflow, and interception is an important component of the water cycle in tree’s ecosystems in forest ecohydrological research. The aim of this research was to compute the throughfall, stemflow, and interception of a natural stand (Fagus orientalis) and exotic plantation (Picea abies) in Siahkal forest (Gilan province). In order to measure the gross rainfall and throughfall, 10 and 50 manual rain-gauges were used, respectively, and stemflow was measured using average of nine individual trees equaled to the stemflow amount of trees. The cumulative percentage of throughfall, stemflow, and interception of F. orientalis stand were 78.2, 10.1, and 11.7%, respectively. For P. abies stand, the corresponding values were 72.1, 4.6, and 23.3%. Paired T-test suggested that rational stemflow (%) of F. orientalis was significantly greater than P. abies (P

The bacteria species that have positive effects on plant growth and performance, which is called plant growth promoting rhizobacteria (PGPRs), can help or play a crucial role in reforestation programs. For this purpose, phosphate solubilizing bacteria were isolated from soil of Yasuj forests, Iran in this study. Ten isolates of phosphate solubilizing were extracted from five soil samples. Two out of ten bacteria strains with highest phosphate solubilizing activity were selected. The results of gram staining and other biochemical tests illustrated that those bacteria were identified as Microbacterium aurantiacum and Streptomyces cinereorectus. In order to study the effect of PGPR bacteria on growth performance of Brant’s oak seedlings, an experiment as completely randomized block design was done in greenhouse conditions. Treatments consist of four seedlings groups of non-inoculated (control), inoculated by M. aurantiacum, inoculated by S. cinereorectus and inoculated by a mixture of both strains. The results of analysis of variance of the effect of PGPR bacteria strains on growth performance of oak seedlings revealed that all studied traits with exception of stem length and shoot to root ratio were significantly affected by bacterial treatment. So that, inoculated plants showed better growth performance compared to the control treatment, but plants treated with both strains had lower stem and leaf fresh weights in comparison with pure inoculated plants. It can be concluded that the application of biofertilizers especially M. aurantiacum might be conducted to increase the growth and subsequent establishment of seedlings in the first year resulted in successful reforestation.

Nowadays, importance of non-wood forest products (NWFPs) has been increased. However, there is no comprehensive information about these products. The purpose of this study was to list and prioritize NWFPs of Arasbaran forests economically. To do so, all information related to the harvest, consumption, sales, and processing of NWFPs and other economic activities were collected by surveying at the household and village levels. For better distribution of samples within the study area, all the villages were grouped into three categories using factor analysis in SPSS software. The grouping was based on six effective indicators related to forest activities (area percentage of village forests), livestock (number of livestock per household) and agriculture (irrigation-fed land surface of household), natural conditions (altitude from sea level), literacy and employment (total employment rate and the female literacy rate). After estimating the sample size with Cochran formula, household samples was randomly selected within all groups covering all altitudes ranges. The collected species were ranked using mean annual economic benefits of harvest at household level. The results showed that fruit of 13 species was harvested by local people. In terms of economical prioritization, cornelian cherry, walnut, and sumac are the most important species with 6370, 6317, and 1270 thousand Rials, respectively. Further researches are required to rank the NWFPs in terms of production potential and to reveal their role in local economic development.

By comparing the pattern of rings among the trees in each region, it is possible to determine the exact year of ring formation. In this study, the data were collected from two different sites, Basht and Dehdez. In each site, 18 Quercus brantii individuals from two growth forms were selected and cut within each plot and the felled trees were then partitioned and the fresh weight was measured in the field. Also, a complete cross-sectional disk was sampled from each sampled tree at stump height (0.3 m aboveground). Moisture and carbon content of samples were measured in the laboratory and dry weights and carbon stock were also calculated. The proportion of annual diameter and average annual biomass quantity in the scale of individual tree and the growing forms including coppice and high-forest were studied in the current research. Average annual radial increment for Quercus brantii from two plantations, high forest, and coppice, were 1.73 and 1.95 in central Zagros forest and 2.04 and 1.98 (mm/year-1) in south Zagros forest, respectively. Also, average annual biomass increment for high forest and coppice were 6.34 and 6.52 in central Zagros forest and 7.20 and 6.84 (kg/year-1) in south Zagros forest, respectively. The carbon allocation was 48% of the biomass production. The results showed that there are no statistically significant differences between annual diameter increment and average annual biomass amounts in two different sites (p