FOREST RESEARCH AND DEVELOPMENT
Year:2021 | Volume:6 | Issue:4|Papers Count:10

The aim of this study was to investigate characteristics and amount of biomass chages of gap makers in beech forests of Sourdar-Anarestan Forestry Plan, Noor. For this purpose, an area of 100 hectares was selected and physiographic characteristics, area and age of the gaps, also the diameter and height of the gap maker trees were measured by a full inventory whithin the gaps. The results showed that there is not a significant difference between the gap maker aboveground biomass changes in the studied area with physiographic characteristics and the canopy area of the stand, but there is a significant difference between gap maker species, gap age and the type of disturbance (α =0. 01). The mean rank of gap maker trees biomass in the wind created gaps was the lowest value, and in the forest harvesting created gaps was the highest rank. The result of this study have shown, most type of disturbances only remove a small amount of biomass on the aboveground biomass in forests. The effect of disturbance on regeneration seems small at first, but then it has a significant effect on it and forest continuity. Therefore, by better understanding the existing disturbances, the most important factors of which in the region were wind, longevity and exploitation, it is possible to help the continuation of forest production and sustainability.

In this study, to evaluate the performance of anti dust material DS-300 and calcium chloride in road dust control, each with concentrations of 10, 20. 30% by amount as two liters per square meter in parts of Takht series roads of Minoodasht city were sprayed by the solution spray system. Dust concentration was recorded when passing the vehicle at a speed of 40 km / h after 3, 9 and 27 days after the treatments using the electronic dust meter HAZ-DUST EPAM-5000. Roadside soil sampling was performed to examine soil calcium and magnesium changes and chlorine contamination. The results showed that the concentration of dust on the treated roads increased over time. Also, in each time period, with increasing the concentration of treatments, the dust concentration decreased. After 27 days, only 30% calcium chloride, 20% DS-300 and 30% DS-300 were able to maintain the road dust emission concentration in the allowable range of 0-50 μ g / m3. Since 30% of calcium chloride and DS-300 concentrations altered the concentrations of calcium and magnesium and contaminated the roadside soil with chlorine, only 20% of DS-300 was identified as a low-risk concentration for road dust control.

This research was carried out with the aim of optimizing in vitro proliferation of J. foetidissima under various proliferations and rooting treatments. For this purpose, the plant samples were collected of healthy and young annual branches of this species without symptoms of disease and deficiency from Arasbaran forests. This experiment was conducted as a factorial experiment in a completely randomized design and data were analyzed using two-way GLM. In order to test micro propagation, well established explants were treated with BAP, KIN and TDZ growth regulators at 4 levels (0, 1, 3, 5 mg / l) individually or in combination with IAA at three levels (0, 0. 1 and 0. 5 mg / l). Various parameters such as survival percentages, regeneration percentage, number of shoots and shoot length were considered. Also in order to survey rooting in J. foetidissima, shoots over 1 cm height were cultured in OM, MS, DKW, WPM, 1/2 MS and 1/4 MS media containing IBA (0. 5 mg/l) and rooting percentage was recorded. Results revealed that, there was a significant difference at 5% level between different experimental treatments. In BAP and IAA experiments, the highest shoot proliferation (3. 82, 2. 78 and 1. 67 shoots per explant) were obtained in MS medium supplemented with BAP (1 mg/l) and IAA (0. 1 mg/l), KIN (3 mg/l) and TDZ (3 mg/l) respectively.

In this study, the effect of climate variables (temperature and precipitation) on diameter growth, basal area and volume of trees on the surface of Permanent sample plots in North of Iran were investigated. In this research, 313 permanent sample plots were used for correlation modeling. These sample units are located in the Jojadeh district, farim Forest. Using growth data obtained during 2003 and 2013 in this section, the growth model was obtained during a ten-year period in permanent sample plots, Also, the mean diameter, basal area and volume were used as variables related to the model. The results of this research showed that the model of growth, diameter basal area and volume with 83%, 94% and 90% correlation, respectively, have good accuracy. In addition, diameter at breast height, basal area at breast height, basal area of the thickest trees, volume and climatic factors were the most important characteristics in the variation of growth in the plot area of the specimen. Finally, the results showed that by using growth models, we could determine tree growth and its effective factors with proper accuracy.

This study was carried out in Asalem Watershed basin NO. 7 In order to determine relationship between the percentages of herbaceous cover with environmental factors. 17 linear transects with about 1600 m elevational gradient and 3000 m horizontal distance were selected. For this purpose, 46 plots of 400 m2 were selected by field survey within 200 m intervals along the elevational gradient. Within each plot, three quadrates (5 × 5 m) on the diagonal line were chosen and internal (1 × 1 m) quadrates were used for investigation herbaceous cover. Independent variables including aspect, slope and dependent variables including abundance and percentage of cover were recorded by using Domin’ s criterion in each plot. In addition, soil samples were taken from three soil cores at each plot. The most effective factors on herbaceous cover percentage were obtained using Canonical Correspondence Analysis and multiple regression method. Results indicated that Soil characteristics showed the highest impact on percentage of herbaceous cover and the most important factors were soil organic matter, phosphorus and Potachium content. The cover percentage in the species belonging to the Poaceae increased with increasing percentage of silt.

The aim of this study was to investigate morphological diversity and canonical correlation analysis between four environmental variables (altitude, slope, latitude, longitude) and 10 plant characteristics (collar diameter, number of sprouts, diameter at breast height, main stem height, large crown diameter, small crown diameter, leaf length, leaf width, leaflet length) in sumac (Rhus coriaria L. ). Plant samples were selected from five geographical locations with unique features in two provinces of East and West Azarbaijan. According to the results of descriptive statistics, the highest coefficients of variations were observed for diameter at breast height (61%), number of sprouts (52%), collar diameter (40%) and the lowest one was observed for leaf width (21%). The highest sprout was found in the plants sampled from Nizhdarreh that can be due to its bad growth conditions. Canonical correlation analysis revealed that with increasing the amounts of latitude and reducing the amounts of slope and longitude, the length of leaves increases.

Retranslocation of nutrients from senescing leaves to young and permanent parts of tree bodies is one of the main strategies to confront with nutrient loss from the soil especially in sites with nutrient poor soils. The aim of this study is to investigate retranslocation of nitrogen, phosphorous and potassium in pinus brutia. For this purpose we selected Makhmalkooh afforested forest at Lorestan province and sampling was carried out at 5 times. In each plot, young and senescent needles and twigs were sampled and nutrient retranslocation were measured. Within each plot, we also collected a composed sample of soil and soil physico-chemical properties were measured. Our results showed that net retranslocation was done at two growing seasons (spring and fall) and September to November. Results also highlighted correlations between nutrients concentration in plant tissues and some of the soil properties like electrical conductivity, organic carbon and pH. This emphasis on close relationship between nutrient's soils concentration and plant retranslocation. In conclusion, based on the results of this study, soil properties such as soil fertility, nutrient concentration in the senescent needles, annual precipitation and drought periods at summer are key factors that influence on nutrients retranslocation. The retranslocation results in Makhmalkooh forest reinforced the hypothesis that forest adapted to climate and edaphic condition and can be used as a guide for management plans to assist in nutritional decisions making of forest trees.

The purpose of this study was to compare the quantitative regeneration status of gaps with different areas in managed and unmanaged forests at different elevations. 72 gaps in three size classes and 18 control plots under canopy cover were randomly selected. The results showed that up to an elevation of 1400 m, there was no significant differences between the average relative abundance of seedlings among the gaps and also between gaps and under canopy cover in both managed and unmanaged stands. However, with increasing elevation, the relative abundance of Fagus orientalis Lipsky increased in unmanaged stands in small gaps. Also, the relative abundance of Fagus orientalis Lipsky at elevation of 1000-1200 and 1400-1600 m in small gaps showed a significant difference between unmanaged and managed stands. While the relative abundance of Fagus orientalis Lipsky at an elevation of 1200-1400 m in medium size gaps showed none-significant difference between the two stands. The results of this study showed that the elevation is one of the most important and influential factor on the establishment of regeneration and growth of seedlings in canopy gaps.

In this study, the leaf area index was estimated using Sentinel-2 satellite imagery over a small part of the Baneh forests. A digital camera with a fish eye lens was used to collect the hemispherical photographs in 58 field reference plots with a size of 20m × 20m. The requiered digital image processing procedures were applied on the remote sensing data, and various vegetation indices were also calculated. Elevation, slope, and aspect maps were also used as an ancillary data. Spectral and non-spectral values were extracted from satellite imageries and ancillary data in each sample plot. Our results showed that the Red band and TNDVI (Transformed Normalized Difference Vegetation Index) have the highest correlation with LAI. The results of the regression analysis showed that considering only original spectral band as independent variable, a model based on the red and the near-infrared bands achieved the highest accuracy (R 2 = 0. 753, RMSE= 22%). Considering a combination of original spectral bands, vegetation indices and non-spectral variables, a model based on TNDVI and DEM produced the highest accuracy (R 2 = 0. 781, RMSE= 20%).

Forest management plan are prepared for desirable use of forest products, ensuring the survival and continuous production. In forest management plan, designing appropriate roads play an important role. In this study, Delphi technique and statistical parameters such as mode, median, mean, and binomial test were used to select the criteria. Afterwards, the criteria were weighted using TOPSIS method based on pairwise comparison and a road construction utility map was prepared by combining the criteria map and the weight of each by linear weighting method. Based on the suitability map, nine road network variants were designated and evaluated using PEGGER in ArcView software and the best option was selected. The weight of factors such as slope, forest stock and natural terrace were calculated 0. 42, 0. 24 and 0. 10, respectively. Among all, the three variants including 3, 5, and 7 with 5725. 01, 5668. 88, and 5573. 85 unit value per km revealed the best road networks. The study results showed that considering the environmental and technical criteria in the forest road designing mitigate environmental impact and reducing maintenance costs. Therefore, it is possible to design more suitable forest roads by combining GIS and Pegger software.