Iranian journal of Forest
Year:2009 | Volume:1 | Issue:3|Papers Count:11

Harvesting system in any form can cause damages to residual stands, but this is clear that decreasing damages to residual stands helps to increase sustainability in forestry. This study was carried out in compartment 3 of district 2 in Galandroud forests in southern Royan which is managed by Shelter - wood method. Logging method in the study area was traditional logging system. Results showed that in damaged trees with respect to the depth of scar, 10.5% of scars have discoloured, 29.8% were skin - damaged but without skin removal, and 59.7% with skin and cambium removal. 6/2% of injuries were more than 500cm2 , 17.5% between 100-500cm2, and 28.9% between 25-100cm2, and 47.4% were less than 25cm2. According to the results, 60.5%, 32.6% and 6.9% of injuries were created by skidding activity, felling activity and human activity, respectively. Also results showed that approximately 82% of damages occurred in the first 2m of the tree bole.

The present research studies factors affecting the amount of citizens' willingness to participate in operational activities in Tehran’s forest parks. This study was a correlational research adopting such a design. The statistical population consisted of users of Tehran forest parks (Chitgar, Lavizan, Taleghani and Sorkhehesar) out of which 202 users were selected using simple random sampling method. A questionnaire was used to collect the data. The findings revealed that understanding of forest park`s functions and citizen`s attitude toward participation are quite effective in people participation`s willingness to participate. The results show that there is significant relationship between the willingness to participate in operational and managerial activities.

In this research, regeneration diversity of species in protected and non-protected areas of Arasbaran forests were compared in species richness, evenness and diversity indices. First, two forest stands with similar floristic and physiognomic characteristics were selected using aerial photographs acquired in 1986 (1:20000 scale). Regeneration of tree species were recorded in 77 0.01 ha circle plots using 250×250 m grid size in the both protected and non protected areas. The mean of diversity indices were computed in both areas and t-test was used to show significant differences. The results indicated that the computed species diversity indices are as follows: mean species richness index: 6.69 and 5.39, Shannon evenness index: 0.87 and 0.76, Shannon diversity index: 1.64 and 1.23, simpson index: 0.76 and 0.61 in protected and non protected areas, respectively. So the protection increase regeneration diversity in Arasbaran forest stands. Therefore, prevention of livestock grazing and irregular tree cutting in the degraded  forest stands can be suggested as a suitable approach for natural restoration and increasing plant diversity.

Leaf beetles of the genus Chrysomela are among the most important leaf feeders of poplar plantations. Chrysomela populi has thrived in many parts of the country and been studied more than other species of the genus Chrysomela. Overwintered adults of C. saliceti were subjected to a biological study under laboratory conditions [T = 25±1oC; R.H. =60-70 %; photoperiod (L:D) 16:8 h]. They were provided by fresh leaves of Populus nigra as food. Mean number of eggs per batch was 48.5±1.53 (n=20). Developmental times of egg, three larval instars and pupa were 5.49±0.03, 3.86±0.04, 4.64±0.10, 13.28±0.47 and 5.71±0.0 days, respectively. The survival of these immature stages were 0.43, 0.38, 0.60, 0.31 and 0.36, respectively. Field observations in Kaka - Reza valley (Lorestan province, west of Iran) revealed that at least a portion of C. saliceti population had more than one generation per year in the region where they fed mostly on poplar trees than on willow. Generally, adults of C. saliceti were smaller (body length: 8.4±0.09 mm) in size than those of C. populi (10.3±0.1 mm) (n=30). Further studies are required to detail the autecology of C. saliceti in the region.

Collection of appropriate qualitative and quantitative data is necessary for proper management and planning. In this research, a region with 457 ha area was selected in northwest of Khoram Abad. An inventory grid with 200×400 m size was designed and established in the study area. Then, 40 control plots with 1 hectare area were laid out. Samplings carried out by diagonal transects with 50, 75, 100, 125 and 140m length on square control plots. Finally, the results of sampling by different lengths of transects were compared with control plots using analysis of variance and (E %) ^2×T criterion. The results of ANOVA showed that different lengths of transects had no significant differences (at confidence level of 95%) with control plots for estimation of species number per hectare and crown cover parameters. Transects with 140m length had the most precision for estimating the above-mentioned parameters. Also, comparison of results for different lengths of transects with (E %) ^2×T criterion showed that transects with 75 and 140m lengths are more appropriate for estimating the crown cover and species number per hectare.

In order to determine the effect of climatic factors on the distribution of forest types in one of the western provinces of Iran, Charmahal, among 71 climatic elements effective in ecological conditions of forest species, 3 factors were selected using factor analysis method.The factors covering 91.82 percent of total variance included thermal temperature, rainfall and radiation. Finally, the effect of each factor as well as the primary climatic varieties on distribution of these species and the mean elevation of the plant types in each distribution class was determined. The results of factor analysis indicate that thermal temperature and rainfall are the most important factors in relation to distribution of forest species. Moreover it can be concluded that semi humid and moderate climatic zones are the best habitats for distribution of Quercus brantii and its associated species, which are the dominant forest types in Charmahal province. This study also suggests that the distribution of Quercus brantii and the appearance of Lonicera nummularrifolia and Amygdalus spp. have been controlled by increasing altitude and decreasing temperature. On the other hand, these two types are found in cold and dry mountainous regions. In conclusion, the selection of climatic variables related to ecological condition of species is important in determining the effects of climatic factors on the distribution of forest types in Charmahal province.

Today, rehabilitation of degraded mixed beech - hornbeam forest stands is one of the most important priorities of forest management in Caspian forests. The rehabilitation in these areas managed by Shelter wood System in mixed and uneven - aged beech stands has not been successful and led to dispersed bare patches with dense cover of ferns and berries. On this basis, 5000 m2 of a degraded mixed beech stand in Shoorab forest was fenced, cleaned and different artificial and natural regeneration methods (treatments) such as: seeding and nurse planting of maple (Acer velutinum), alder (Alnus subcordata), beech (Fagus orientalis) and control under Completely Randomized Design in 4 replications were studied. Weeding was carried out during 5 years (2003-2007) in the last week of September. All re - established saplings were measured in total regeneration areas. Results show that 10 different tree species regenerated in the study area with a number of 19 to 132 saplings and a height ranging 10 to 470 cm in different treatments. Regenerations were observed in all treatments but was best in maple seeding with a mean number of 132 per 25 m2. Results were statistically significant (p<0.05). Previously there were no seedlings in Shoorab degraded study area for many years. Now, by using site preparation methods in the protected area, the number of re - established samplings was increased.

The optimal harvesting can be a function of the stocking volume, stumpage price, harvesting cost, and rate of interest in the capital market. This research was done to determine the optimal harvest decision. First, a growth function was estimated for Kheyrud Forest, North of Iran, then the stumpage price was estimated via an autoregressive model. The optimal harvest was computed based on annual growth and stumpage price functions. The optimal adaptive harvesting which maximizes the expected present value of all profits over time are made conditional on the latest available price and stock level information. In order to determine the optimal harvest level, the optimal harvest decisions were made via stochastic dynamic programming,as well as with deterministic optimization method. The results show that if the stochastic dynamic programming technique is used instead of deterministic optimization method, the expected present value will increase by more than 26% via optimal adaptive decisions.