جستجوی مقالات مرتبط با کلیدواژه « broad-leaved » در نشریات گروه « جنگلداری »

After 28 years, the effects of Alnus subcordata (AS), Acer insigne (AI), Cupressus sempervirens (CS) plantations and also bare land on soil aggregate stability and particulate organic matter (POM) were studied in Darabkola forest located in Sari, Iran. In each stand, six soil profiles were sampled at depths of 0-10 and 10-20, resulting in 12 soil samples for each stand. The samples were transferred to laboratory for analysis. The soil properties were analyzed by using two-way analysis (ANOVA) procedure, treating forest stands and soil depths as factors with interaction. Results are indicating that the variability of soil physico-chemical and biological properties, i.e., bulk density, texture, moisture, pH, EC, lime, carbon (C), nitrogen (N), available nutrient, earthworms density/biomass, in different studied areas. According to our data, the plantation increased aggregate stability, POM-C and POM-N in both of depths. The upper and lower layers of soil had the highest amounts of soil aggregate stability (79.3 and 82.4 %), POM-C (4.24 and 3.56 g/kg) and POM-N (0.45 and 0.4 g/kg) under the AS forest stand. The least values of these characters were found under bare lands (50.54 and 52.76 %, 1.98 and 1.48 g/kg, 0.22 and 0.16 g/kg, respectively). Results showed that the planting of AS trees improved aggregate stability and POM and it is recommended for rehabilitation of degraded forest areas.

In order to identify and sustainable management of afforested tree stands, the effects of Alnus subcordata, Acer insigne, Sequoia sempervirens and Acer insigne - Sequoia sempervirens stands on quality of litter and soil were investigated in Salmanshahr areas of Mazandaran Province. Samplings were done from the litter and 0-10cm depth of topsoil using randomly systematic method with 15 replicates for each stand. Organic carbon (C) and total nitrogen (N) content of litter, soil water content, pH, organic C, total N, nitrate and ammonium concentration, microbial respiration, microbial biomass of C and N were measured. Results showed that the highest values of soil water content, litter and soil N, nitrate and ammonium concentration, microbial respiration, microbial biomass of C and N belonged to Alnus subcordata compared with Acer insigne > Acer insigne - Sequoia sempervirens > Sequoia sempervirens pure and mixed stands. Whereas greater amounts of C/N of litter and soil organic C were found under Sequoia sempervirens stand. Generally, Acer insigne - Sequoia sempervirens mixed stand presented intermediate mode viewpoint of litter quality and soil fertility. According to our data, afforestation with broad-leaved species, especially N-fixing trees of Alnus subcordata, improved the litter and soil quality, whereas the Sequoia sempervirens species created the inappropriate condition.

This study aims at analyzing the understory plant species composition in relation to soil characteristics in forest plantations. For this purpose, two plantations with coniferous (Cupressus arizonica and Biota orientalis) and broad-leaved species (Fraxinus rotundifolia and Robinia pseudoacacia) along with a nearby non-forested control area were selected in Gerizeh of Sanandaj, Kurdistan province, western Iran. Random systematic method with a network dimension of 75×50 m was used for collecting soil samples and vegetation data. Canonical Correspondence Analysis (CCA) differentiated the three sites in terms of soil and vegetation parameters. Results show that the majority of samples belonging to the hardwood plantation contained high values of OC, N, Mg, sand, silt and Ca which had a positive correlation with pH. The control area, showed significant correlation with clay and bulk density. Most samples of conifer plantation, however, had the lowest OC, P, N, Mg and pH. The most abundant understory species in the broadleaf plantation were Geranium tuberosum and Vicia michuuxii, in conifer plantation Erysium billardieri and Galium vernum, and in the control area Bromus tectorum and Euphorbia denticulata.