Iranian journal of Forest
Year:2012 | Volume:3 | Issue:4|Papers Count:10

Sample size is a critical issue for genetic diversity studies and conservation programs. However, sample size evaluation requires previous knowledge of genetic diversity. Here, we evaluated sample size requirements for accurate genetic diversity in adult trees and family arrays in a Fagus orientalis Lipsky population in central Hyrcanian forests of Iran. Data consisted of 350 adult trees and 480 offspring's from 60 mother tree genotyped at four nuclear microsatellites. Results indicated that several adult individuals (about 300) are necessary for accurate measures of allele richness. However, expected heterozygosity requires smaller samples (30). Seeds from 50 trees captured about 90% of adult allelic diversity suggesting that seed sampling is heavily finalized for allele counts, and this should be considered in conservation programs. Nevertheless, gene diversity of seeds was lower than that of the adult population, which emphasizes on conservation of natural stands and in situ conservation programs. Extrapolation of these results to other tree species with similar distribution (widespread), way of propagation (wind-pollinated, dispersion of the fruits by gravity), density (about 200-400 individuals in ha), and genetic structure as oriental beech could be possible.

The aim of this research was to predict tree density and basal area using IRS-P6 satellite data in the northern Zagros forests. A random-systematic sampling grid consists of 312 circular sample plots (each plot, 0.1 ha) were used to collect field data. The images were georeferenced using 29 ground control points. Spectral values related to field plots were extracted from original and synthetic bands composed of vegetation indices, principle component analysis and data fusion. Ancillary data such as slope, aspect and elevation are also extracted. Multiple regression and stepwise method were used to predict tree density and basal area from original and synthetic bands as independent variables. The best models (at first just original bands and then combined of original and synthetic bands) were selected using RMSE, Bias, Correlation and the F values (the best model for tree density: R2adj=0.31 & for basal area: R2adj=0.38). Using slope, aspect, and elevation ancillary data did not improve the results.

The main goal was to measure interception loss (I) and to determine the contribution of the meteorological parameters as well as rainfall size inPinus eldarica Medw. and Cupressus arizonica Green. in the arid climate zone of Iran. The selected trees were located inside a forest plantation in a dry area at Semnan province, where mean annual precipitation, and air temperature are 127 mm and 16°C, respectively. The gross rainfall (GR) was measured by the mean of three hand-made collectors placed in an open area neighboring to the chosen trees. Eight throughfall (TF) collectors were positioned beneath the tree canopies to average into TF mean per species. Measurements were made on a rainfall event basis in a year, from March 2009 to March 2010. We investigated the correlations between intercepted rainfall (I: GR) with rainfall size (GR) and combination of the daily meteorological parameters of wind speed (WS), relative humidity (RH), evaporation (E) and air temperature (Ta). Averaged over all 26 events during a one-year measurement, approximately 44.6% of GR forP.eldarica and 32.6% for C. arizonica did not reach the soil surface beneath the afforestation and lost through evaporation process. The results showed that rainfall size was highly correlated with I: GR. However combinations of the meteorological parameters of Ta, RH and E improved the suggested models for estimation of I: GR. We concluded that the meteorological parameters could be usefully applied for estimation of interception of P. eldarica and C. arizonica planted in arid climate zone and in particular near meteorological stations like urban plantations.

This research was conducted to investigate the spatial structure to estimate the crown cover and density of a coppice oak forest in west of Iran (Loristan province) using Kriging and IDW (Inverse Distance Weighting) interpolation methods. Field sampling was performed based on a 100m×100m systematic grid using 1500 m2 circular samples of. Totally, 54 sample plots were measured at 54 ha. Experimental variograms for forest stem density and crown cover were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of stem density and crown cover showed medium spatial autocorrelation fitted by spherical models. Estimations were made by ordinary block (38m×38m) kriging and IDW (power=2). Crossvalidation results showed that all estimations are unbiased. Therefore, Kriging and IDW are able to accurately estimate and map the crown cover and density of this kind of coppice forests.

Soil properties affected by passing the machines in skid trails and establishment of natural regeneration and herbaceous palnts in these routes after the harvesting operation could be a suitable opportunity to study the reaction of different plant species to soil conditions. This study has been done in district 1 of Nav forest, Guilan/Iran. The skid trails where have been abandoned without traffic for 10 years were chosen among the available skid trail routes. Soil samples were taken and type and the number of natural regeneration in skid trials and adjacent forests (natural forests) were recorded. The results showed that among soil physical properties, soil bulk density, porosity, saturation moisture percentage and soil texture differed significantly between skid trail routes and natural forest. The natural regeneration of cappadocia maple, hornbeam and alder showed significant difference between natural forest and skid trails routs, while natural regeneration of beech and Velvet maple did not show any significant differences. The regeneration of alder was significantly higher in skid trail routes compared to natural forests, but for hornbeam and maple this regeneration was better in natural forest. Among soil physical properties, bulk density, porosity and soil texture showed significant correlation with amount of natural regeneration and among tree species, cappadocia maple showed the higher correlation with soil physical properties. This study showed that the natural regeneration of some species is affected by soil physical properties. In addition to the determination of natural regeneration responses to soil physical properties, the results of this study could be used in silviculture and forest management.

The Sadetarik Forest Park with an area about 614.85 ha is located at south-east of Rasht city. The aim of this research was to study the floristic composition, life forms and chorotype in Sadetarik Forest Park. Floristic composition in the region, and plant species were identified at the levels of species and genus by fieldwork. Floristic study indicated that there are 90 plant species belonging to 81 genera and 46 families. The important families were Asteraceae, Rosaceae and Apiaceae with 11.1%, 8.9% and 6.7%, respectively. According to Raunkiaer’s classification, the life forms were hemicryptophyte and phanerophyte with 36.6% and 30%, respectively. Chorotype of the most species belonged to Euro-Siberian (32 species, 35.6 %) on the basis of Zohary’s criterion.

In order to study the quantitative and qualitative traits of Persian oak (Quercus macranthera F&M.) and oriental hornbeam (Carpinus orientalis Mill.) one of the most important habitats of these two species in Khalkhal was selected. For this purpose, 48 sample plots, each 500 m2, were established in three land forms (ridge, valley and slope) in four aspects (north, south, east and west) from lower to higher distribution areas. Quantitative and qualitative characteristics of individual trees were measured and recorded within the sample plots. The results showed that the distribution range of the two studied species varied from 1940 to 2540 m.a.s.l. In general, slopes and valleys with north-facing slopes are suitable sites to these species. The tallest Persian oak and oriental hornbeam trees were observed on north-facing valleys (3.65 m) and (2.62 m), respectively. The greatest trunk length of oak and hornbeam were measured both in slope land form, with 3.35m and 1.68m, respectively. The highest frequency of vegetative coppice regeneration was in north facing slopes. Trees (Persian oak and oriental hornbeam) with highest quality were located in north-facing slopes.

Anthropogenic sources of cadmium in soils, and in particular in arable soils are of great concerns.Phytoremediation is a simple, cost-effective and environmental friendly technique to clean up the contaminated environment. In this research, the influence of soil amendment on accumulation of cadmium by one-year oldPopulus alba L. seedling was investigated. CdCl2, 2.5 H2O salt were spiked to three prepared substrates and mixed homogenously. The experiment was carried out in a factorial experimental design with complete random design with three replicates. At the end of summer, the amounts of cadmium accumulation in leaves, shoots and roots were measured. The results indicated that higher biomass productions in amended substrates compared to control led to increase of total cadmium uptake two times more than that in control substrate at 150 mg kg-1 cadmium supply, although in some cases, there was no significant difference in cadmium accumulations among substrates (P<0.01). Using synthetic chelating agents in order to enhance phytoremediation leads to increases of the environmental impacts while they are not expected when close-tonature approaches are applied.