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Because there is not enough information on the percentage of seed germination of native broad-leaved species of Caspian Forests of lran, seed sowing is usually done with extra density. For this reason, most of the produced seedlings are thin and have low height and diameter growth rate. In case of sowing seeds with low density, the seedling production is not profitable due to few numbers of seedlings per area unit of nursery. The current trial was conducted, using Randomized Complete Blocks Design with three replicates for each species to obtain an ideal density of seed sowing and increase seedlings quality. Four species were tested including Quercus castaneifolia, Tilia begonifolia, Acer velutinum and Fraxinus excelsior. Four seed mass treatments per squar meter of nursery were applied for each species which differ for different species. The plot area was three squar meters. After measuring weight of 100 seeds of each species, the seed mass of each treatment was sawn inside of the plots along five rows. Only the seedlings grown on the three middle rows were considered and studied, leaving the first and the last rows as bufer lines. Space between the rows and between the plots was 20 and 30 cm, respectively. Two seed sowing seasons were planned: spring and autumn. According to the results achieved, autumn was the best, so all of the measurements and evaluations were made in that season. The differences between the seed density treatments were not significant, for all species. Best seed density for Q. castaneifolia, T. begonifolia, A. velutinum and F. excelsior was 500, 100, 40 and 50 g/cm2, respectively.

Beech (Fagus orientalis) is one of the most valuable species in Hyracanica forest which contain 26% of standing volume. A National project was planned and carried out to assessment of growth and performance of Fagous orientalis in Asalem region. In this study, eight plots were selected in different aspect and elevation from550 up to 2000 m. a. s. l. Each plot covered one hectar and in terms of dbh classification, five trees were selected in each plot. Tree height, dbh, diameter at median height, crown height and crown diameter was assessed. Other characteristics such as crown layer, crown health, crown size warp and branchiness of stem was considered. The obtained results of this study indicated that trees under 80 cm diameter had 170 m3 volume per hectar. The calculated form factor for beech was 0/4075. The value of mean annual increment was 3/47 m3. Correlation analysis showed that there was significautly correlation between height and age, diameter and age as well as dbh class and mean height crown, depth and dbh crown size.

Urbanization and population growth increased the demand for wood, which can be partially supplied via wood culture. Poplar plantation with fast growing clones of poplar is thus required to investigate their compatibility and wood production potential. This study was carried out with 12 treatments (11 new clones and one control clone) and three replications in a Randomized Complete Block designto determine the compatibility and wood production in Lasht-e Nesha agriculture research station in Gilan province. In each experimental plot, 12 one-year-old seedlings were planted at a 4×4 m distance. Then the diameter growth, height, volume and survival percentage of trees were calculated, followed by a statistical analysis. The results showed good compatibility of all clones, yet with different growth quantities. The P. x. Intreramericana, P. d. Marquette, P. d. 92.258, and P. e. Ita199 with diameter of 12.8, 12.35, 10.58 and 9.42 cm and height of 11.08, 12.58, 12.22, and 10.76 m were superior compared to the control clone (diameter = 9.65 cm, height=10.62 m and volume =5.83 m³/ha). In addition, the volume production of the studied as well as the control clones were 9.35, 9.76, 6.84 and 5.11 m³ha-1 year-1 in a five year period, respectively. The survival percentage of the clones were different, with the lowest survival rate =66.6 % for P. e. Blanc de Poitou and the highest rate of 97.2 % for P. e. 45.51, P. e. 92.160, P. d. Marquette and P. e. 87m119. The clones surveyed here can therefore be introduced as competent and successful clones in the comprehensive program of agri-wood development across the study site.

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.

Norway spruce (Picea abies (L.) Karst) trees were planted in Asalem region in 1974 in altitude of 1400 m.a.s.l. In order to study the stand response to thinning practice, 1.4 ha of this area was selected and an experiment was conducted by Complete Randomized Block with four treatments and three replications. The thinning treatments included light removal of basal area (10-15%), moderate (15-20%) and heavy (20-25%) and control (with no intervention). Thinning rotation were 3, 5 and 7 years for the treatments, respectively. Diameter at breast height (DBH) of all trees were measured every year. The study began at the age of 23 years and the study period extended between 1996 to 2006 when the trees were 34-years old. The thinning method was positive and from above (Swiss method). Results showed significant difference of stem numbers and diameters among different treatments after 11 years of study (P> 0.05). The lowest and the highest diameter increment was observed in control and light thinning treatments, 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 this research typology of seedlings composition and density of Fagus orientalis stands in Caspian forests of Iran (Ramsar area), at altitude of 1200-1300 m.a.s.l. within 43 gaps were studied. The gaps were created after marking and cutting the trees. The gaps area varied between 67 and 617 m2. The trial was conducted under the fully randomized design. Based on gap size and homogeneity, 1 to 3 microplots (1m2) were established in each gap. Seedling frequency was counted in each microplot, according to their species and age range (1 and 2-4 years old). The statistical methods of chi-squareand ANOVA (analysis of variance) were used to analyze the data. There was no significant difference of seedling frequency and species diversity among the gap sizes. However, the number of the defined seedlings composition and density types were four and six, respectively. Beech showed the highest frequency among the species. The maximum and average densities of beech seedling were 60 and 15 per m2, respectively. 57% of gaps showed a number of 10/m2 with 1 to 4 years old seedlings.