جستجوی مقالات مرتبط با کلیدواژه « فصل رویش » در نشریات گروه « جنگلداری »

The aim of this study was to compare the richness, diversity, and evenness of soil macrofauna and the factors affecting it during the growing and dormant seasons in Amygdlus scoparia Spach stand in the protected area of Geno located in Hormozgan province, Iran. After the selection of a half-hectare stand of Amygdalus scoparia in the Geno protected area, 10 soil samples were randomly collected in the depth of 15 cm, under the crown of trees in growing and dormant seasons in order to measure physiochemical characteristics and identify soil macrofauna and their relations. After macrofauna separation, samples were transferred to the laboratory for physiochemical analysis. All variables were compared across two seasons using T-Test analysis (p <0.05) and the correlation of variables was analyzed using Pearson correlation (p <0.01). The results showed that all soil properties (nitrogen, carbon, phosphorus, and temperature) except electrical conduction and soil acidity in the growing season were significantly higher than those in dormant season. The frequency and biomass of macrofauna in the growing season were 1060 in m2 and 5.9 mg.m-2, respectively, comapred to 90 in m2 and 0.7 mg.m-2 obtained for dormant seasons. Further, the indices of Margalef, Menhinick, Simpson, Shannon and Waever, and evenness Pielou and Hill in growing season (2.55, 2.15, 0.79, 1.77, 0.89, and 0.93) were significantly higher than those in dormant season (0.23, 0.53, 0.09, 0.13, 0.49, and 0.19, respectively). Soil macrofauna frequency along with biodiversity, richness, and Pielou evenness indices showed positive and significant correlations with organic carbon, phosphorus, nitrogen and soil temperature.

The objectives of this study were determining growing season as well as the relationship between width of growth rings of the Iranian oak and temperature and precipitation. In this study, 12 healthy oak trees (Quercus brantti) were selected and disk samples were taken at the diameter of breast height. High quality image were taken from all of the disks, after preparation. Cross dating was performed among samples and the chronology provided by ARSTAN. Relationship between annual growth rings and climate factors determined by Pearson correlation coefficient. Our result indicated highly significant positive correlation between annual growth ring and average monthly temperature February and July. Also the results revealed that there was non-significant negative correlation between growth and precipitation in studied months. Existence of positive correlation between growth and climate factors (temperature and precipitation) in March, represented that these two factors could help tree growth in early growth season.

Changes in rainfall interception and consequently in water balance cause essential effects on reforestation by indigenous and exotic tree species in the degraded areas of the Caspian forests. The aim of the present study was to compare the interception of Quercus castaneifolia, Acer velutium, and Pinus brutia plantations during the growing season in Darabkola Forest in eastern part of Mazandaran province in northern Iran. The amount of rainfall (GR) and throughfall (TF) were measured from May to November 2012 by 6 and 20 polyethylene manual gauges with 8 cm diameter each. The rainfall interception was estimated as the difference between TF and GR. During the measurement period 20 rainfall events were recorded. The amount of cumulative GR depth was 346.5 mm. Moreover, the cumulative rainfall interception of Q. castaneifolia, A. velutium, and P. brutia were 86.2 mm, 107.9 mm and 178.3 mm, respectively. The results showed that the rainfall interception was higher during the dry season, from April to September. In addition, significant correlations were observed between rainfall interception and the relative interception for the three plantations (r2 =0.781, 0.716 and 0.618 for Q. castaneifolia, A. velutium and P. brutia, respectively). It is concluded that estimating the amount of rainfall interception is crucial for selecting adapted species for reforestation in the Caspian forests. It is also a prerequisite for calculation of the water balance within reforestations.