مجله پژوهش و توسعه جنگل
سال پنجم شماره 3 (پاییز 1398)

This study aims to identify factors affecting the secondary humus forms differentiation in the East Hyrcanian forests. For this purpose, we select 189 sample points using a nested transect sampling design in the Dr-Bahramnia forest. Humus forms identified based on morpho-functional classification and adjacent trees characteristics were recorded and then forest type were determined. Primary and secondary topographic attributes and land forms were extracted from digital elevation model due to the geographical location of sample points. Random forest classification, boosted tree classification and multiple adaptive regression Spline classification were applied as modelling tools to analyse important variables influencing differentiation humus forms. The seven secondary humus forms were differenced include Dysmull, Eumull, Mezomull, Hemimoder, Dysmoder, Eumoder and Eumacroamphi. The highest accuracy and agreement between the observed and predicted were boosted tree classifier while adjusted rand index and Cohen’s kappa coefficient were 0.76 and 96.3 percent respectively. The results showed that humus forms variability were dependent on the characteristics of the surrounding trees of sample points and topography.

We assessed the urban trees structure in Tabriz city and estimated the isoprene and monoterpenes emission using i-Tree Eco model. The results indicated that the i-Tree Eco model could be used as a successful method in Iran. Estimations of i-Tree Eco model showed that urban trees with 9.4% tree cover emitted 18428.6 and 49757.5 monoterpenes and isoprene during the year 2015. Open spaces and the ten tree species among the existing 48 species accounted for 63.3 and 92.22% of the total emission respectively. In the other hand White poplar and Austrian pin emitted the highest amount of isoprene and monoterpenes. Our results suggest that to plant the trees that emit fewer BVOCs in order to help to reduce the ozone level in cities. The results of this study could be used in proper urban environments and green infrastructure management.

The aim of this study was to investigate the effect of pure and mixed stands of beech and hornbeam on soil properties, soil respiration andlitterfall rate in Sari educational-research forest of Darabkola. Ten circular plots were randomly considered in each of the three stands. Soil samples were taken at a depth of 0 - 10 cm and soil chemical and physical properties were measured. To collect litter, 10 litter traps (50 × 50 cm) were placed in the stands and the litter was collected every two months. Results showed that soil acidity, total nitrogen, sand and silt percentage and soil microbial respiration were significantly different in different stands. The studied stands showed a significant difference between the amounts of litter. According to the results, the highest and lowest amount of litter was observed in October and April, respectively.

It is necessary to evaluate sustainable spatial allocation of afforestation. For this purpose, this study was conducted in the Kan watershed of Tehran province to assess the suitability of land for afforestation. First, suitable tree species were chosen based on land characteristics of study area and purpose of restoration. Then, the ecological demands of tree species were investigated and effective Indicators that affect the evaluation process were identified. After processing, classification and integration of spatial layers in GIS using the system analysis method, a random forest algorithm was trained and suitability map of afforestation was produced. Results show that Random Forest method has high accuracy in predicting suitable areas for afforestation. Also, 2116 ha of the study area is moderately suitable for afforestation. Based on Boruta algorithm Soil depth, growing season precipitation, elevation, soil texture, slope, and aspect are considered as the most important to the least important features, respectively and it is not necessary to carry out weighting methods for evaluation of afforestation capability. Generally, the Random Forest method can be used as a capable way to prepare ecological capability maps.

Seed provenance testing, which is often done to determine the best seed provenance in terms of seedlings' survival and growth, is one of the common methods for seed quality evaluation and seed germination. In this research, healthy seeds of Quercus brantii Lindl. were collected from four altitudinal gradients located in Baneh. After measuring the morphological characteristics of the seeds, they were planted in a mixture of pitted and perlite soil and stored in greenhouse conditions. Then, the germination characteristics, ground and aerial biomass of seedlings were measured. The results of this study showed that the effect of altitude on diameter, length and seed weight was significant. The results of the mean comparison showed that the seeds from 1550 m taller and heavier than the others. Seed size is a trait that results from compliance with ecological conditions. Also, seed size has a significant effect on germination rate. In this research, the origin of altitude of 1550 m was introduced as the best altitude for Q. brantii species in Baneh region.

In recent years, charcoal disease as one of the important causes of oak decline has caused great damages to Zagros forests. Identification of efficient factors in the development of the disease could be helpful in managing strategies. In order to study the effective agents in spreading of charcoal disease in Kakasharaf district forests, which is an infection foci of the disease in Lorestan province, statistically grid in the form of systematic random sampling with dimensions of 200 × 150 m in the GIS software was drawn and applied randomly and trees were assessed on circular plots of 15-are (1500 m2). In the studied area, 9.26 percent of trees were died due to Biscogniauxia mediterranea infection. Result of logistic regression showed that with increase in the values of variables such as soil phosphorus, borer beetles damage, altitude, tree's diameter, percentage of crown dieback and tree's distance from villages, and with decreasing in the amount of crown area, the number of infected trees to charcoal disease were increased. Results of Poisson regression showed that in the final stages of infection to charcoal disease, the values of variables such as borer beetles damage, percentage of crown dieback and tree's distance from villages will be increased.

In this study different concentrations of SiO2 nanoparticles (o, 75, 150, 250, 350, 500 milligram per liter) have been used as a pre-treatment before cold stratification on Sorbus luristanica’s seeds in order to assessment of the nanoparticle potential for simulation of seed germination and growth of the species. For this purpose, the seeds were primed with the nanoparticles for 24 hours and then stratified in sand for 3 months. The experiment was performed as a completely randomized design with 4 replications with 25 seeds in each replication. After 3 month, stratified seeds were transported to germinator and after starting of germination symptoms, germination data were recorded daily for 22 days. The results showed that seed germination under 250 and 350 m/L NSiO2 treatments improved around 100% while seed germination in control seeds was 26%.

Arasbaran has created unique treasures of environmental resources in the northwest geography of the country, irrespective of hunting, economic, social, and cultural attractions due to its rare herbaceous and animal species, pristine and vast landscapes. Therefore, the aim of this study is to estimate the total economic value of Arasbaran forests using choice experiment approach. The required data were collected through field studies and completion of a questionnaire among 334 visitors and citizens of ten cities from three provinces of East Azarbaijan, West Azarbaijan and Ardebil by multi-stage cluster sampling. The results of the study showed that the total value of Arasbaran forests is about 4956 billion rials; the information and refugee functions with the highest 43% and the production functions with 0.2% are the least part of the values of Arasbaran forests. Also, the non-use values with 34% and regulatory functions with 21% of the next rank in the total value of forests. The results showed a positive and significant relationship between the level of education, income, the viewpoints of people about the forest and the annual number of people willing to pay. The high value obtained for forests shows the need for appropriate planning and policy to protect and improve the condition of forests

This study was conducted in Maroon riparian forests in Behbahan, Khuzestan province and aimed at calculating interception loss of a pure natural stand Populus euphratica in leafless and in leaf periods. Fifty plastic collectors (9 cm in diameter and 20 cm in height) were placed in a 10 meter grid layout in the studied stand to collect the throughfall (TF). Stem flow (SF) were measured for nine trees belonged to three DBH classes of 10-15, 15-20, and 20-25 cm. In the present research 20 rainfall events (eight in the leafless period and 12 events in the leaf period) were recorded. The value of accumulative rain depth was 218.3 mm. Our results indicated that the percent of SF, TF and I were two, 53 and 45 total rainfall during the in leaf period and three, 62 and 35 during the leafless periods. We showed that large amount of precipitation cannot reach forest floor and The SF and TF had an increasing trend with increasing rainfall. Against, interception showed a decreasing trend with increasing rainfall. We revealed that larger trees produced higher amount of SF. Also, SF production in P. euphratica stand cannot be ignored in the water balance.

Due to the wide geographical distribution and tolerance range too many environmental variables, the fast growing species of Euphratespoplar (Populus euphratica Oliv) has a great ecological significance. In order to identify the best provenance of Euphratespoplar regarding to establishment characteristics in the region, this study was conducted in Fozveh research station in Isfahan Province on Nineteen Euphrates poplar provenance and acell-cultured clone from all over country. Thirty cuttings from each provenance were planted under a RCBD in February 2010. Growth characteristics including collar diameter ( CD), height (H), survival percentage (SP) of cutting, special leaf area, and dry matter percentage of leaves were studied. In addition, a number of leaf morphological traits including leaf length (LL), maximum width (MLW), LL to MLW ratio, petiole length (PL), PL to LL ratio, thickness and leaf area were also recorded during one year after planting. ANOVA results showed that all investigated traits significantly differed in all parameters. Moreover, provenances of Hamidieh and Ramhormoz showed the highest rates of CD and Tafresh and Hamidieh H growh. Mahneshan provenance was the most unfavorable genotype for establishment in the Isfahan province due to its low SP as well as its leaf incompatible morphology. Consequently, PCA results revaled significant differences of that provenances Ghalakhlar, Sarakhs, Zabol, Kerman, Mahneshan, Sanandaj, Khojir and Manjil to other genotypes.

The purpose of this study was to evaluate the effect of road distance and age on roadside vegetation cover on  Nav district forest roads in the west of Guilan province.Therfore required data in 240 Systematic random plots on linear transect in two road age classes were collected. Percentages of vegetation were calculated using Brown Blanket combination scales. Then, the values ​​of richness, evenness, Shannon-Wiener, and Simpson indices were calculated for each age class of road. Relative importance index was used to determine the distribution of species abundance. The results showed that the relative importance and presence of dominant tree species in the newly constructed roads were higher than the old ones. In both age groups, the relative importance of beech (Fagus orientalis), hornbeam (Carpinus betulus) and alder (Alnus subcordata) saplings was higher than other species. Also, the relative importance of tree species decreased with increasing distance from forest road. Also at different distances of the road, beech and maple regeneration were the most frequent. The highest values of diversity and richness were observed at 0-30 m distance from the road and its value was significantly different from other distances.