FOREST RESEARCH AND DEVELOPMENT
Year:2018 | Volume:3 | Issue:4 |Papers Count:7

This study was carried out to investigate the ability of template matching algorithm in wild pistachio tree position and their spatial pattern determination using GeoEye-1 images in Tage-Ahmadshahi protected area of Southern Khorasan. After geometric correction and fusion of multi-spectral bands with panchromatic band, three templates were generated for each band and NDVI index. For accuracy assessment of template matching a 100 by 100 meter network (1 ha) used and 60 samples selected randomly and the location of wild pistachio as ground truth registered using a precise DGPS device. For spatial pattern analyzing two useful functions D(r) and g(r) were used. The result of cross correlation showed that the generated templates based on NDVI have the highest correlation between samples The result of template algorithm on satellite image showed that this method with 95.57 percent overall accuracy have the ability to determine tree position by suitable precision on high resolution satellite images. The result of D(r) function showed that wild pistachio trees have nearest neighbor maximum to 45 meter distance. Also the result of g(r) function showed that the trees have a significant uniform dispersion up to 11 meter while between 11.5 and 17 meter have a clumped dispersion which were statistically significant (p<0.05).

Tree mortality and turn it to the snag or logs is one of the most important processes in forest ecosystems. Dead trees are an important characteristic of natural forests structure, especially in the old-growth developmental phases which play a wide range of ecological functions. This study aimed to investigate the mortality of trees in the Afratakhteh forest reserve in the Aliabad region. After the preliminary filed observation, three one-hectare study areas were selected and the quantitative and qualitative characteristics (diameter, height, type, and decay stage) of all dead trees were assessed. Results showed that the average volume of dead trees in the study area was 50.44 cubic meter per hectare.  The yew encompassed the high amount of dead volume (37.40 m3) and the most of dead trees were in the second stage of decay. Tree mortality rate in diameter classes showed the greatest amount of dead volume observed in 25-50 cm diameter classes and the highest mortality of yew trees occurred in 10 cm diameter class that are equal to around 38% of total dead volume. Due to the fact that the Yew species are in the red list of threatened species, and on the other hand, the highest mortality rate of this species is observed in low diameter classes, it is necessary to identify the factors that affect its mortality to provide restoration and conservation of yew.

This study was performed in order to investigate the effect of deleting rare species and common species in compartment No.317 (managed forest) and No.318 (control forest) of Jamand district of Golband forest in Mazandaran (Noshahr). For this purpose, random-systematic sampling method with regular grid of 100×200 m was used to locate samples. The plot size was 400 m2 considering to tree and shrub species and in the center of each main plot, one 100 m2 subplot was set up for herb species. Estimate of percent cover of each plant species recorded using of Braun-Blanquet scale. DCA and NMDS ordination used and the results were compared by Procrust analysis.The results illustrated that deleting  the rare species data had a little effect on output of ordination, although excluding of common species can change significantly output of ordination, and correlation between the raw data and removed common species is low. Generally, it can be concluded that the removal of rare species without losing too much information is a way to prevent probable errors but common species which have so much information should be retained.

The aim of this study was to evaluate the effectiveness of litterfall production, decomposition, accumulation, temperature, moisture, soil texture and stability on soil organic carbon pool (Socp) and exhibition a model for prediction of it, at three mixed beech-hornbeam stands located in district one of Shastkolate forest, Golestan province from 2/11/2014 to 2/11/2015. In order to perform of this study, 20 points were chosen at each treatment and collected soil samples at the depth of 20 cm, to determine soil organic carbon pool and soil moisture. In order to determine decomposition and litter production, 14 litter bags and 1 litter trap were installed in each point and collected within a year. In 60 samples, bulk density, % volume of coarse fragments, soil texture, weather and soil temperature and weather moisture were determined. To display the relationship between socp and litterfall production, decomposition, accumulation, temperature, moisture, soil texture and stability, path analysis at the level of 99% was used and a network model was exhibited which showed the influence of obvious and unobvious factors on socp. The Chi-square and Root mean square error approximation of corresponding model were 9.089 (P>0.05) and 0.013. So the network model had a good fit. In the relevant model, clay, soil moisture, soil temperature and soil stability were direct influential factors with path coefficients 0.62, -0.27, -0.25 and 0.201 respectively which had the highest contribution in socp estimation. So a formula was exhibited by use of direct factors to predict socp.

In this research, sampling was conducted quite randomly from the Ghorogh forest park located in Golestan province. After isolation and purification of the fungi, charcoal pathogen was detected in Caucasian oak based on the information contained in Biscogniauxia key species identification. The effect of three fungal species including Trichoderma viride, T. atroviride and T. koningii on growth rate of charcoal pathogen in vitro evaluated using two dual culture test assay and the impact of volatile substances. All three species of Trichoderma used in dual culture tests and the impact of volatile substances, have a positive impact on the growth of the fungus. Also effect of different concentrations of fungicides including Copper oxychloride, Propiconazole, Carbendazim and Metalaxyl - Mancozeb upon the causal agent of charcoal disease were investigated in vitro culture conditions. Results showed that Propiconazol at concentrations of 50-100 ppm, and Carbendazim at concentrations of 100 ppm have the highest percentage of inhibition among the concentrations of all fungicides. Metalaxyl – Mancozeb and Copper oxychloride showed no significant difference with the control means.

The aim of this study is to assess the effect of climatic parameters on diameter growth of Persian oak trees in Sarab-Karzan forests of Ilam. Climatic data of a 29-year period (1987-2014) was obtained from synoptic weather station of Ilam to extract some mean monthly parameters. For investigation of tree diameter growth, 15 individuals with diameter 20 to 25 cm were chosen and core samples were taken from north side of trees using increment borer. They were polishd with corse and soft sandpapers and dimater growth was measured using microscope model 1001. Pearson correlation was used to investigate the correlation between diameter growth and climate parameters. Independent sample t-test was conducted to evaluate the significance of the correlations. The results showed that mean diameter growth of trees was 2.44 mm over the 29-year period. The highest correlation was observed between diameter growth and relative humidity in July (Pearson coefficient of 0.501) and September (0.558) (P≤ 0.01). In general, higher correlations were observed between diameter growth with rainfall in May (0.273) and temperature in July (0.354).

This study aimed to determine the efficiency of numerical and parametrical indices to evaluate biodiversity of soil and litter mesofauna in different physiographic positions. Sampling was conducted in three height classes above sea level (low land, middele land and high land) and two aspects (north and south). Also, in each altitude class, three different slope classes (less than 25%, 50-25% and more than 50%) were determined. Three transects of about 100 m were established in each of the slope classes. Three sample points were located along each transect. Around the center of each sample point, a litter layer and a soil sample to a depth of 10 cm speratly were taken. In the laboratory, soil and litter samples were placed inside a Berlese funnel to bring out arthropods mesofauna. The results showed that soil mesufauna Shannon–Wiener's diversity, Pielou's evenness and Margalef's richness indices, were significantly affected by aspect, elevation, sampling depth and their interactions. Along the northern aspect and in the litter layer, the highest Shannon-Wiener's diversity index was observed in middle land and slpoe < 25 percentage. In both slope-faces, soil mesufauna Margalef's and Shannon–Wiener's indices were higher in the litter layer and decreased significantly at a depth of 10 cm.