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In order to rehabilitate the degraded mountainous forests (in particular those located in the vicinity of villages), the appropriate fast-growing tree species can be used. We selected an experimental site in mountainous part of eastern Guilan (Rostam-Abad County) in northern Iran. A number of 75 seedlings from 12 different clones of Poplar and Paulownia species were planted in 5×5 groups in a Randomized Complete Block Design (RCBD) featuring 3 replications. After a 5-years period, the results showed that Populus euramericana triplo, P. euramericana costanzo, P. nigra 62/127 and P. nigra 62/154 were amongst the most promising species in terms of establishment, growth and survival. Therefore, these can be suggested for rehabilitation and wood production across this and similar sites. The study also showed the lack of success for Paulownia clones, especially in the areas featuring higher altitudes. However, this implies further research to enable a more comprehensive conclusion.

Management of mountainous forests implies detailed information on the extent and intensity of snow damages. Furthermore, such information is required for improved conservation of natural stands. In this study, snow damages on six dominant tree species including Beech (Fagus orientalis Lipsky), Hornbeam (Carpinus betulus L.), Velvet Maple (Acer velutinum Boiss.), Cappadocian Maple (Acer cappadocicum Gled.), Caucasian Alder (Alnus subcordata C. A. Mey) and Chestnut-leaved Oak (Quercus castaneifolia C. A. Mey.) were investigated across a portion of the Nav forest in the east of Guilan province. Circular 0.1-ha plots were systematically sampled in a grid with 100m sampling distance. Four types of tree damage were detected including crown damage (8.6%), stem breakage (5.5%), uprooting (3.2%) and bending (1.4%). The six studied tree species have different resistance to snow damage. The highest rates of uprooting and stem breakages were observed in Alder trees. The Oak trees were mostly influenced by crown damages. Furthermore, the Beech trees showed the lowest rate of crown damage and stem breakage. Based on the results, the tree species of Alder, Oak and Cappadocian Maple were categorized as being more vulnerable to snow risk, whereas Beech, Hornbeam and Velvet Maple proved to be less vulnerable. In addition, the slenderness coefficients were calculated for bended trees (76.7), stem broken trees (64.5), uprooted trees (64.0), crown damaged trees (60.1) and intact trees (50.2). This study also showed that trees of higher slenderness coefficient are more vulnerable to the snow risk.

Norway spruce (Piceae abies L. Karst.) has been planted on a wide range of world. It is generally pyramidal in shape and can grow to 40 m in height and to 1-1.5 m in diameter. Norway spruce has apoor reputation for wind firmness. It is a shallow rooting species on sites with a high fluctuating ground water table or on soils where the effective rooting depth is limited. This study was carried out during 2001-2002 in four sites of Guilan Forests. These sites were Aroston, Rec, Picehson and Shenrud. The primary distance between the trees was 2×2 m. The stands age in Shenrud and the other sites was 17 and 27 years, respectively. The investigated growth parameters were; Survival %, mean height, mean D.B.H., density per hectar, basal area per hectar, annual growth rate of diameter, annual growth rate of height, dominant height, number of diameter classes per hectar, annual growth rate of tree volume, stand volume per hectar, volume table (tarif), form factor (f), relationship between quantitative parameters (diameter to height and diameter to volume) and stand qualitative parameters (natural pruning, stem condition and branch angle). The wood mechanical characteristics (density and fibre length) and the stand pests and diseases were investigated as well. In order to study the effects of Picea plantation on soil characteristics, soil samples were tested physicaly and chemicaly and the data of the two sites were compared. The results showed that Aroston site was the best one due to its greatest survival (70%), growth rate (basal area: 37 m2, Volume: 301.25 m3/ha, annual volume growth; 11.1 m3/ha) and wood quality (tracheid length: 2.89 mm and specific gravity: 0.36 g/cm')

Fire is an integral factor in many forest ecosystems and is strongly influenced by human activities. The first visible effect of forest fire is destroying the existing vegetation, which results in the forest stand being host to more resistant species. Different plant species, including trees, show different responses to natural disasters such as fire according to their characteristics. In this study the fire resistant tree species in the Noghlehbar Rostamabad forest of Roudbar in Guilan province was investigated, since the area has been heavily damaged by fire in 2010. The area contained Parrotia-Carpinetum forest community, accompanied by oak, beech, maple and elem. In this study was used a full calipering method to determine the amount of damages to the trunk and crown, and a random sampling was used to determine species regeneration. The statistical tests revealed a significant difference between species in terms of their fire resistance. In addition, Oak was shown to be of highest fire resistance, while the Iron tree was of lowest one. The Elem species was able to produce the highest rate of post-fire regeneration, and the highest growth rate was observed in the Oak tree seedlings.

As a necessary tool, statistical distributions have a wide application in forest. Actual and future condition of stands, description of stand structure and reaction of stands to silvicultural interventions are other applications of these functions in forest management. In order to study the statistical distributions, three sample plots of one hectare, were selected in three development stages of an untouched beech stand in Shafaroud forest. DBH of all trees (larger than 7.5 cm) within the sample plots were assessed. Distribution functions were fitted to the stem number distribution in diameter classes and were compared to the observed data within development stages using Kolmogrove-Smirnov, Anderson-Darling and Chi-Square tests by Easyfit software. Results showed that 1) for initial stage, three-parameter log-normal, 2) for optimal stage, beta and 3) for decay stage, Johnson’s SB have been fitted. In general, three-parameter log-normal function has been fitted well for all three stages.

The aim of this research was to review of relation between tree ring width of Quercus castaneifolia C.A.Mey trees and region climate changes in the Saravan forests of Guilan province. For this purpose, the relation between these two factors was studied using Dendroclimatological study and increment borer sampling method. Weather information was obtained from Rasht meteorological station. In this study, the effect of June, July and May-July’s precipitations on tree ring width of Quercus castaneifolia was positive while, the effect of maximum temperature of July, minimum temperature of November, mean temperature of July and mean temperature of November was negative.

Establishment of germplasm collection project was performed with planting of 64 Populus deltoides, P. euramericana, P. nigra and P. alba clones in Safrabaste Poplar Research Station in 1983. Five seedlings of each clone were planted in 5 m×5 m. This study conducted on seven P. deltoids clones. Phenological characteristics (flushing, flowering, seed bearing and leaf fall) were recorded every year up to the end of the study at 2005. Results showed that P.d. 69/55 and P.d. 73/51 were both the earliest and latest clones in flowering and seed bearing, while P.d. 69/55 was the earliest and P.d. 72/51 was the latest clones in flushing. Results of poplar clones growth showed that P.d. 73/51 and P.d.72.51 clones with 40.7 cm and 26.4 cm had the maximum and minimum DBH, respectively. Also P.d. 73/51 and P.d.72/51 clones with 28.7 m and 25.6 m had the maximum and minimum height growth, respectively. The P.d.73/51 and P.d.72/51 clones had the highest and lowest wood production with 32.07 and 13.01 m3ha-1yr-1, respectively.

Quercus castaneifolia is one the most valuable species of northern forest in Iran. Therefore, study and determination of feasible time of planting is important for this species. This research was conducted in low and middle altitudes of Shafaroud watershed with 3 replications in six treatments including of planting of one year old seedlings in December, January, February, March, April and storing in March and planting in April. The study was carried out for 10 years continuously. In each plot 100 seedlings were planted in a spacing of 1m×1m. Totally, 1800 seedlings were planted in each zone and a sum of 3600 seedlings was used in this study. At the end of growing period, the survival percentage and height of 36 seedlings in the middle of each plot were recorded and ten years results showed that there was no significant difference among treatments (P < 5%).

In order to investigate on the adaptation and performance of exotic trees in northern of Iran, a field experiment was carried out during 1991 to 2006 in Asalem forests. Nine species of different conifers, consisting of Pinus nigra var. austriaca, P. nigra var. pallasiana, P. nigra var. calabrica, Picea abies (prov. Klardasht), P. abies (prov. France), P. glauca (prov. Canada), P. orientalis (prov. Turkey), Pseudotsuga menziesii (prov. America) and P. menziesii (prov. California) were planted using a Random Complete Block design. At the end of each growth period, three parameters of survival, diameter and height were measured and results analyzed finally at the end of 16 years. The results showed that there was a significant difference of growth factors (diameter and height) among species (treatments) at significant level of 1%, whereas no significant difference was found in survival rate. Pseudotsuga menziesii (prov. California)showed the highest height (10.2 m) and Pinus nigra var. calabrica the highest diameter (16.1 cm) after 16 years of study period.

In order to study the effects of logging on plant species diversity, two compartments of logged and unlogged of beech forests in the Shafaroud region in western Guilan were selected. Inventory procedure was systematic- random method. Sampling plot area was 50´50m to survey woody species and for herbaceous species, 8´8m nested plot sampling was obtained. Regeneration (seedlings) was studied at 10´10m subplots. Data analysis was carried out by Shannon – Wiener and Pielou’s evenness indices and Jaccard’s similarity index. Results showed that species richness for trees, shrub and herbaceous were obtained 7, 8 and 28 in the logged forest, whereas they were 6, 4 and 18 in the unlogged forest, respectively. The diversity value in the unlogged forest was found higher than in logged forest in tree layer, while in the seedling, small sapling, large sapling, shrub and herbaceous layers were higher in the logged than unlogged forest. In addition, the evenness values in all vegetation layers were found higher in the logged than unlogged forest. Jaccard’s similarity index for tree, shrub and herbaceous layers were 62.50, 50.00 and 60.71 percent in the studied forests, respectively.

Depletion of natural forest due to different reasons has made the forest plantation important for extending forest area and wood production. Therefore, evaluation of forest plantation can play an important role to establish the plantation for the future. The objective of this study is to evaluate three different reforestation which was planted by Acer velutinum, Alnus subcordata and Fraxinus excelsior species. Each planted area with 49 ha was established in 1985. For data collection, 90 plots of 400 m2 were selected randomly. Different variable such as diameter, total height, trunk length, forked tree and number of trees in different classes of diameter were assessed. The obtained results indicated that Alnus subcordata with 3.2 percent in 5 cm diameter class and 38.5 percent in 20 cm diameter class had the highest values in survival, while Fraxinus excelsior with 31.7 percent in 5 cm diameter class and 19.7 percent in 20 cm. diameter class had the lowest values in survival. Data analysis for stem quality showed that Fraxinus excelsior with 31.6 percent forked trees had the lowest value, while Alnus subcordata with 18.5 percent forked trees had the highest value in stem quality. Therefore, assuring seed quality for seedling production and protection after out planting could be resulted as a good quality of plantation.

In an 18-year-old Pinus taeda plantation in Pylambra region (Guilan province, north of Iran), 1.5 ha of well stocked stand at 3x2 meter spacing in 4 replications and 2 treatments, a: light thinning with 15% removing of basal area at 3 years rotation, b: heavy thinning with 30% removing of basal area at 5 years rotation and c: control, were selected and the effects of thinning operations on remained tree growth were studied during 15years. d.b.h, hieght and stem volume,were annually measured and all data were analyzed with SPSS. The results show that the age of 8-10 is suitable for precommercial thinning. The mean d.b.h., hieght and basal area of trees in thinned plots are greater than unthinned plots. Mean d.b.h. increased of %68 and %72 in light and heavy thinned plots and the stem quality obviously improved. Mean tree volume increased from 0.29 to 1.3 m 3 stem-1, respectively during 15 years. Equations for volume estimation of trees in 10-25 cm and 20-40 cm d.b.h. are presented for the region. It is concluded that the d.b.h, height and volume per stem of Loblolly pine increased with thinning. Heavily and lightly thinned plots produced higher total stem volume compared with the controlled plots and differences were significant at 5%. Mean annual volume increment are estimated up to 18.7 m3ha-1 hectare. Therefore, Loblolly pine is introduced as an adapted and resistante with high volume growth species in the coastal plain of Guilan province.

Genetic variation within population as a result of geographical variation is one of the important factors in forest tree improvement. Therefore investigation of genetic variation rate and its variability is necessary for each species that is used in reforestation. Quercus castaneifolia is one of the valuable forest species in Northern Iran that are exposed to danger because of inclement utilization severely. One of basic studies for improvement of Quercus castaneifolia and using it in reforestation programs is investigation of geographical variation that is performable in provenance experiment. For this study seeds of Quercus castaneifolia from 9 region in west of Guilan province are used and were planted in randomized complete block design in parcel 5 of district 15 of ShafaroodForest. Height, diameter and survival of provenances investigated in this study showed that there were significant differences between provenances in mentioned parameters. Means of annual height growth of 9 studied provenances varied from 24 cm to 43 cm. Provenances 1, 2, 3 and 9 had the best height growth. D.B.H of provenances was between 0.6 cm and 1.9 cm, where and provenances 1, 2 and 9 had the most D.B.H. Survival rate of studied provenances was between 52% and 86%. Result of ANOVA showed that there was a significant difference in survival rate (p