فهرست مطالب ایرج پروانه

In order to investigate the decline of oak trees in Zagros forests in relation to forest soil characteristics and topographic conditions, Ghalaje Forests with an area of 500 ha in Kermanshah province were selected. For forest classification, systematic-random sampling was used with a 200×150 m grid by 50 m transects. Work units were specified based on the land form, aspect, altitude, slope degree and rate of oak decline. Soil samples were taken within work unit to analyze soil texture by hydrometer, soil nitrogen by Kjeldahl, bulk density by clod method, organic carbon by Black and Walkey method and lime percentage with Calcimetri method. The results of analysis of variance showed that the number of dieback trees was significant (P

We studied the effect of different slopes and aspects on some qualitative and quantitative characteristics of Quercus persica in BadrAbad region of Lorestan Province. Thirty six circular plots each with the area of 1500m2 were selected in a random-systematic method. We measured crown diameter, diameter at breast height, number of shoots per each stem, quality of stems, and the number of all Q. persica coppice and seed grown stems within the plots. The results showed that higher crown diameter of coppice elements was in western, eastern, southeast aspects and it was lower in south, north, and northwest aspects. Diameter at breast highest was highest in north, and southeast aspects and it was lowest in south and northeast aspects. Q . persica had the highest rate of coppicing per each stem in west and northeast and lowest coppicing rate of this species were found in north and south aspects. The highest and lowest number of healthy stems of Q. persica were in north and southeast respectively. The density of Q. persica in slope range of 16-30% was highest and it was lowest in the range of 10-15%. The slope range of 16-30% had also the highest number of non healthy stems of Q. persica. In general, 90% of all measured stems of Q. persica were healthy. Those trees of Q. persica with crown diameter range of 2-5 meter the highest frequency and those with crown diameter of higher than 6 meters had the lowest frequency in the study area.

In order to investigate the effect of tree forms on characteristics of Quercus brantii, seeds of 60 trees (both tree forms: high and coppice trees) were collected and studied on north-facing slopes ranging from 1040 to 1960 m a.s.l in Gilane Gharb city, Iran. The results of analysis of variance showed that there is significant difference between two forms of trees regarding to number and weight of seed, unsound seed, canopy and height of trees. Analysis of correlation indicated that in high trees, 1000- seed weights had positive and significant correlation with number of seeds, weight of individual seeds, sound seeds, unsound seeds (p≤%1), and with germination (p ≤%5). In coppice trees, 1000-seed weights had positive and significant correlation with individual seed weight, sound seeds(p ≤%1), and unsound seed(p ≤%5), but they had no correlation with seed number and seed germination. The results of ANOVA showed that the difference between two forms was significant other than individual seed weights and 1000-seed weights. Therefore it would be better to collect seeds from high trees, use the seeds of trees grown in the same elevation (considering other affecting conditions) and from different areas to prepare seeds for seedlings and afforestation.