نشریه بوم شناسی جنگل های ایران
پیاپی 3 (بهار و تابستان 1393)

This research was conducted to investigate regeneration conditions and evaluate quantitative and qualitative characterestics of pistacia atlantica subsp. mutica on different physiographic conditions of South Alborz Mountains. The role of effective factors on establishment of regeneration was also studied. The forest area map prepared, and then probed by systematic random network of statistical method. Within each plot some quantitative parameters consist of number of stands, total height, average diameter of crown canopy and number and height of saplings were recorded. Vegetative form and nursing type of regeneration of pistacia atlantica subsp. mutica were also determined. Also some parameters such as number, crown diameter and height of Amygdalus lycioides as an important accompany species were recorded. Results showed that the most number of stands, height of regeneration, health of leaf and regeneration of Pistacia atlantica are located in Northern side of 1500-1600 height from the sea level. The most height and diameter of Pistacia atlantica and number of regeneration in 1400-1500 height from the sea level were recorded. This study showed that two factors included Amygdalus lycioides species and rock stone are the best factors for nursery of Pistacia atlantica regeneration, also physiographic factors have significant effect on quantitative and qualitative of saplings and trees of Pistacia atlantica. According to these results, in order to protection and maintenance of Pistacia atlantica, especially in enrichment and afforestation projects, the physiographical factors and nursing effect must be noticed carefully.

The decomposition of leaf litter has important in the ecosystem level through regulating buildup of soil organic matter, regulating of nutrient for plant growth and influencing the flux of Co2 from the soil. Several studies have introduced Home-field advantage (HFA) as an index for indicating more rapidly decomposition process of litter in its own site. In the present study, beech and alder sites and Norway spruce plantation of lajim region were selected for testing the hypothesis that decomposition of litter in its own sites is happening more rapidly. Decomposition process was treated for 400 days using litterbag technique. The findings of this study showed that decomposition process to 180 days, the index significantly was negative (-12.96) for beech and alder in their sites but with passing time and simultaneously enhancement of soil biota activity, it was positively increased (27.36). Whereas this index was initially positive for beech and Norway spruce (54.67) and also for alder and Norway spruce (34.58). Then reached at maximum rate after 180 days. The obtained results confirmed that the decomposition process of litter was more rapidly in its own site. Therefore according to the role and importance of Home-field advantage, we can propose Norway spruce in mixed plantations of beech.

Maple tap spot is one of the fungal diseases which has been infected maple trees. Early deciduous, the disappearance of leaf, reduction of growth, seed and wood production of maple trees are resulted due to this disease. The objective of this research was isolation and identification of the pathogen on leaves of Acer velutinum in Dr. Bahramnia educational and research forest (Shast-Kalateh of Gorgan). After sampling and culture of explants in PDA medium, growing of fungal pathogen was white delete and fluffy shape. Pathogenic fungi were identified after purification and isolation and characterization of spore, color, shape and disease symptoms. In PDA liquid medium, a scus of fungi was white and a clubbing shape with the fiber shape and linear ascospores was observed inside them. Upon the results, the identified fungal pathogen was Rhytisma acerinum on maple trees in this area.

Information about gaps and their sizes distribution is useful for protecting herbaceous diversity. This study was conducted to investigate the effect of gap size on herbaceous species diversity in oriental beech (Fagus orientalis Lipsky.) stand in Asalem, Guilan province. For this study, fifteen gaps in small, medium, and large sizes were randomly selected. Then, herbaceous species were identified in 4 m2 micro plots within the gaps and percent covers of herbaceous species were estimated in the basis of Domin’s criterion. Diversity indices including Shannon-Wiener, Mc Arthur, Hill, species richness and Smith -Wilson, the modified Nee’s, the modified of Hill’s evenness indices were computed. The results revealed that with increasing gap size, the diversity and richness of herbaceous species have been significantly increased, while evenness indices showed no significant differences in different gaps. The highest evenness values were obtained in the small gaps. In small, medium and large gaps 22, 24 and 25 species were found, respectively.

In order to evaluate the effects of forest road on vegetation and some soil properties was selected a road with the length of 400 m. Type and number of regeneration species of trees and shrubs in plot area of 100 m2 and type and cover percentage of herbaceous species using minimal area method were recorded in plot area of 64 m2 and herbaceous species was classified into two groups using Two-Way Indicator Species Analysis (TWINSPAN). Samples of soil were taken in depth of 0-10 cm. Multivariate analysis methods ( PCA and CCA ) and ANOVA were used to recognize the most important soil variables and determine relationship between species composition and soil factors. Results indicated that species composition of plots in near the road has been varied in comparing with plots of inside the forest and it was classified into two separate groups . Percentage of moisture content , saturation moisture , clay , porosity and organic carbon in plots near to road decreased , while the amount of sand , silt, bulk density and pH were increased in this site. Among the regenerations Alnus subcordata abundance had significant difference between the edge of the road and inside the forest. The findings showed that the roads affect to adjacent ecosystem effectively and it is essential to reduce the damage and disturbance in construction of forest roads.

In order to Study the quality of diameter at breast height distribution, height and height till the beginning of the crown of Oak trees in un-even aged stands from the collected data of the forestation plan in Shanderman Siyahkesh Guilan province, 367 trees were randomly selected as samples and the diameter, height and the height till the beginning of the crown were analyzed. According to the land observations the under study area was considered as the witness piece and has trees in all height and diameter classes and it lacks stand interference and health. In order to fit diameter, height and height till the beginning of the crown Beta, wei bull, Power, Gamma, Normal and log- normal statistical distributions were used the results obtained from Kolmogorof- Smirnov (K.S) and Anderson-Darling (A.D) at the level of %95 showed that in sequence Gamma, log normal wiebul and normal statistical distributions have created a suitable fit for Oak tree’s diameter and from among other suitable distribution weibull distribution is the most appropriate model for the trees height goodness, Also all applied distributions except exponential model have the abality to describe the height till the beginning point of Oak trees crowns but Gamma distribution is the most appropriate one.

Seed priming is the most important technique for increasing the germination power. This study was conducted to investigate the effects of halopriming and hydropriming on improvement of seed germination in black locust (Robinia pseudoacacia L.) in a completely randomized design with 4 replications. Halopriming treatments of KNO3 with concentrations including (100, 250, 500, 750 mM) and hydropriming treatments at three time levels (24, 48, 72 h), and also seed soaking treatment in boiling water for 1 hour as well as control treatment were considered. Results indicated that hydropriming 48 hours, halopriming 100 mM-48 and 24 hour and control treatment had the highest germination percentage. The greatest germination speed was observed in hydropriming 48 hours. The hydropriming 100 mM had the least average germination time. The highest amount of stem (fresh and dry) weight was observed in hydropriming 72 h and halopriming 100 mM-48 hours, respectively. Also, halopriming 100 mM-24 h and hydropriming 72 h showed greatest amount of root (fresh and dry) weight. The highest stem length was related to control treatment. The greatest root length was showed in hydropiming-48 hours and control treatment. Generally, the highest seed vigor index was observed in control and then in hydropriming-48 hours. Application of hydropriming (48 hours) as easy and inexpensive technique can be useful to improve some germination characters like germination speed, and dry and fresh weight of root in black locust seedling.