جستجوی مقالات مرتبط با کلیدواژه « مشخصه های خاک » در نشریات گروه « جنگلداری »

The aim of this study was to investigate some soil properties that were affected by management including logging, tourism and forest reserve in Guilan province, Iran. In each of the studied area, five transects with a length of 200 meters, perpendicular to the road, were selected and soil samples at 10, 50, 100, 150, and 200-meters distances from the road were gathered. In each transect, five samples of 25 m2 were selected. Measured soil properties were consisted of bulk density, porosity, pH, organic carbon, and microbial respiration. The results showed that with increasing distance from the road, the mean of bulk density in the area of logging, tourism and forest reserve decreased from 1.64 to 1.10, 1.33 to 1.07 and 1.11 to 1.08 gr/cm3, respectively, and mean of pH decreased from 6.96 to 5.48, 6.57 to 5.48 and 4.88 to 4.56, respectively. The highest and lowest levels of organic carbon and rate of microbial respiration were observed in the control and logging areas, respectively. The results of analysis of variance showed that there is a significant difference between all soil properties in the sampled areas and different road distances. Mean comparison also showed that there was a significant difference between the mean of soil properties in the control area with the logging and tourism areas. The results of this study showed that the type of management of natural areas may have different destructive effects on soil properties.

Caucasian whortleberry (Vaccinium arctostaphylos) is one of the most valuable medicinal shrubs in beech Forests. This study aimed at determining the relationship between vegetation properties of whortleberry with soil and landform index in Soha forest. Sample plots, each 500 m2, were selectively established in three land forms (ridge, valley and hillside) and in four geographical directions (north, south, east and west) from lower to higher distribution areas. Overall, 24 sample plots were used to measure the vegetative characteristics. Soil characteristics including soil texture (clay, silt and sand), pH, Ec, total nitrogen, soil organic carbon and calcium carbonate were also studied in 12 sample plots. The results showed that Caucasian whortleberry distribution varies from 1570 to 1940 meter above sea level. In general, hillsides and ridge forms with south and west-facing hillsides are suitable sites for this species. The highest mean of height (2.19 m), collar diameter (8.7 cm) and crown diameter (1.92 m) were observed on slope land form.  The soil of whortleberry habitats is deep to semi-shallow with pH (5.32 to 6.01), electrical conductivity (0.481 to 0.809 ds/m) and with soil texture loam to sandy- loam. The PCA analysis showed that the physical properties of soil (sand, clay and silt), pH, and soil organic carbon content have important impacts on the presence of this species. From the results of this study, it can be concluded that habitats of Caucasian whortleberry in land forms valley and hillside, and aspects of north and east with light soil texture have created favorable conditions for the growth of this species in the study area.

Understanding soil carbon fractions in relation to global warming is important for improving soil carbon management in natural forest ecosystems. Therefore, in this study we measured the contents of soil total organic carbon (SOC) in soil upper layers (0–20 cm) along a natural altitudinal transect (100–1400 m a.s.l.) in northern slope of Salaheddinkola forests, Nowshahr. Accordingly, vegetation data based on Braun-Blanquet method with some environmental properties were recorded in totally 77 plot with an area 400 m2 including seven classes of altitudinal gradient. Four ecosystem units were distinguished by using combined results of clustering (based on environmental data) and TWINSPAN (based on floristic data) as numerical classification analysis. Results analysis of variance showed that the amount of soil carbon sequestration had significant difference (0/05> P) in the four ecosystem units and third unit, which represents beech-hornbeam forests, to be allocated the largest amount of carbon sequestration (73/57 ton/ha), Because of the establishment of this unit in higher elevations and then high density of beech. Results of stepwise regression showed that nitrogen percentage, sand percentage and altitude were the most important factors affecting soil organic carbon content. Totally, the results of this study reiterate that the variability of soil carbon sequestration does not show a regular pattern along the altitudinal gradient and ecosystem units by exhibiting a proper distinction of environmental changes in habitat can be priority used in soil carbon stock variations study.