فصلنامه تحقیقات جنگل و صنوبر ایران
سال بیست و ششم شماره 1 (پیاپی 71، بهار 1397)

Following the Pistacia sp., the Juniper (Juniperus spp.) is associated with the second largest spatial distribution in Iran. However, the historical Juniper habitats have been largely decreased as a result of the low rate of natural regeneration, which calls for an increased effort on rehabilitation of Juniper habitats. The aim of this study was to evaluate the effects caused by maternal stand morphology and irrigation on survival and growth parameters of Greek juniper (J. excelsa M. B.) during a 4 four-year period in Sirachal research station in Alborz province. Twenty seedlings with three different maternal stand morphologies including A (cylindrical), B (non-cylindrical) and C (high seed production) were planted within complete randomized blocks in split plots. Seedlings were irrigated every fifteen, thirty and forty days in the first year (2010), while those in the control treatment were not irrigated. Statistical analysis showed that in the first year, the effect of irrigation was significant on growth parameters including current diameter growth, current height growth and crown. The effect of maternal stand morphology was significant only on current diameter growth in the first year. In the second year, the effect of maternal stand morphology was the only significant effect on crown. After four years of measurement, the effect of irrigation was significant on crown. Our findings showed that one irrigation during the entire planting time is an important necessity in of Juniper establishment, and should be concerned in the rehabilitation of its habitats. Furthermore, Juniper establishment and growth using trees with C morphology will be effective in habitat rehabilitation due to the effects of maternal stand morphology on seedlings survival.

As one of the most important understory evergreen species in Hyrcanian forests of Iran, information on the distribution of Box (Buxus Hyrcana Pojark.) are essential for both forest research and practice. Here, the capability of very high spatial resolution IKONOS satellite imagery acquired in leaf-off condition was tested for mapping Box distribution in a part of Khiboos-Anjili forest reserve in Mazandaran province. The IKONOS imagery was geometrically corrected with a georefrenced panchromatic Pleaides scene, which was orthorectified using 3D ground control points obtained using differential GPS (RMSE less than one pixel). Reference data samples from three classes of non-forested area, deciduous stands without Box understory and deciduous stands with Box understory were recorded using DGPS-supported field survey. By means of a number of vegetation indices, classes seperabilities were evaluated on main and synthetic image channels by partitioning 75% training area and transformed divergence. IKONOS image was classified using both main and best-selected bands and a number of nonparametric (Maximum Likelihood, Mahalonobis distance, Minimum distance to mean and Paralell piped) and parametric (Suport Vector Machine) classifiers. Then the classified images were assessed using 25 percent of unused sample points. Results of validation using the 25% left-out test data showed the highest performance by SVM algorithm compared to other algorithms, with overall accuracy and Kappa coefficient of 97.87% and 0.96, respectively. The results also showed the potential of IKONOS imagery from leaf-off season has to map Box trees in understory layer.

Canopy gaps are amongst the most important small-scale phenomena in many temperate, old growth forests, and play a fundamental role in composition and structure of stands. Their occurrence in Hyrcanian forests is associated with numerous effects, including the establishment of species regeneration and increasing forest biodiversity. Due to the importance of in-depth information on canopy gaps, a number of their characteristics were studied in an intact mixed broad-leaved stand in Shast-Kalateh experimental forest Golestan province. We investigated 82 canopy gaps (with a size larger than 40m2) in the compartments 3, 4, 5 and 7 of the forest. For each canopy gap, two parameters of length (L, as the longest distance within the gap) and the width (W, as the largest distance perpendicular to the length) were measured. In addition, data on natural regeneration was sampled within all gaps by species-specific measurement of individuals with DBH 2, with average and median gap size of 470 and 278.6 m2, respectively. The most frequent canopy gaps were those 1000 m2. Most gaps were formed by tree mortality, where hornbeam trees were responsible for 51.45% of gaps. In this study, the increase of gap size to 400 m2 led to increasing the regeneration of tree species. In contrast, the regeneration of main species decreased when gap area increased by more than 500 m2. Hornbeams were the most frequent regenerations in canopy gaps. Finally, the results showed that canopy gaps are crucial factors for regeneration and restoration of forest trees. Therefore, this study calls for increased attention to the different aspects of canopy gaps in order to achieve sustainable management objectives in forestry plans.

Vitex pseudo-negundo (Hausskn.) Hand-Mzt. is a shrub that is height of about 1-2 meters. To study vegetative propagation of Vitex pseudo-negundo experimental was conducted using a 6 × 3 × 2 factorial design based on completely randomized design with 4 replications and 30 cuttings per treatment in Behbahan municipalitie's greenhouse. The experiment factors included: Cutting time at 6 levels (22 December and 5 January, 21 January and 4 February, 20 February and 6 March), Cutting length at 3 levels (15, 20 and 25 cm) and NAA hormone at 2 levels (with hormones and hormone-free). Results showed that the cuttings taken in 21 January, 20 February and 6 March have the highest rooting and germination percent and root number. The highest (rooting and germination percent) and (root number and root dry and fresh weight) were observed in length cuttings of 15, 20 cm and 25 cm respectively. The interaction effect of hormone and cutting time and cutting length, indicator being more dry weight, fresh weight and root diameter in cuttings with hormone taken in 20 February with a length of 25 cm. The use of hormone has the negative effect on rooting and germination percent and root length. In this study, the best result was achieved for cuttings taken in 20 February, with a length of 25 cm and without the use of hormones.

Characterization of biological attributes of poplars is of essential values for planning afforestation and wood farming projects. Therefore, this study focused on the assessment of their phenology and vegetative potential in Safrabasteh region of Gilan province. The studied trees were planted at 4×4 m intervals in each experimental plot. Each plot was assigned to one poplar clone. Recording the phenology began in the second half of March and ended in December each year. Measuring the growth factors of diameter and height was performed following the annual growth period. The earliest bud opening was observed in P. euramericana 45.51 and P. e. Pacher clones, whereas the latest was observed in P. e. Blanc clone. The seeds distribution of the studied clones started within the first 10 days of June. The biological periods of the clones were different and ranged from the minimum 203 days in P. e. 87m119 clone to a maximum of 240 days in P. e. Pacher clone. Significant differences were observed amongst the growth factors. The highest diameter, height and volume growths with average production of 22.4 and 21 m3 ha-1 y-1 were observed in two clones of P. deltoides Marquette and P. interamericana, respectively, While wood production in the control clone (P. d. 69.55) was 15.5 m3 ha-1 y-1. The results of this research could be used to guide the future planning on the phenology and growth of poplar clones in Iran.

Pilu (Salvadora oleoides Decne.) is a shrub or a small tree indigenous to southeast of Iran and is known as a multipurpose species for forage production, soil protection and medicinal value, which altogether reveal its importance in forestry and reforestation projects in warm and arid areas. The purpose of this study was to investigate the effects of runoff and moisture storage methods in the soil (Bankette arches, pan (control), plastic sheets, straw in the bottom of the pit, superabsorbent polymers and canopy) on the establishment, survival and growth of the pilu species in Southeast of Jazmurian in Sistan and Baluchestan province. The factors studied in this experiment included seedlings survival, seedling height, seedling crowns, seedling collar diameter and seedling vigor, which were measured in the middle of March, 2017. The results showed that the development of plastic layer improved the survival rate and seedlings cover. Creating a shadow increases the height growth and slenderness coefficient of seedlings and decreases the diameter growth of seedlings. In general, it can be concluded that planting plastic surfaces on the surface of the pit and planting canopies on seedlings are the most suitable treatments with respect to the percentage of seedling's survival and seedling growth characteristics. It seems that combination of these two treatments could help to improve seedling establishment across similar areas.

Vegetation in riparian areas, including trees with various hydrological and mechanical effects has an essential role in soil reinforcement. This is accomplished by increasing soil shear strength and inhibiting the higher layer of soil into the lower layers and reducing erosion by roots. The aim of this study was to evaluate the tensile strength changes of Salix purpurea L. trees in different trunk distances and soil depths. Therefore, five trees were randomly selected for root system sampling, which was done by using the soil core technique. Sampling was taken in three different depths, tree horizontal distances and in four directions of the trees. Finally, 97 successful tensile tests were performed on root samples. The relations between tensile force- diameter and tensile strength-diameter were analyzed and compered. The results showed the average of tensile strength of 57.91, 46.96 and 46.27 Mpa for depths 0-10, 10-20 and 20-30 cm, respectively. Furthermore, the average of tensile strength was 29.18, 76.81 and 28.78 Mpa for 0.5, 0.75 and 1 m distances, respectively. Root diameter and tensile force fallowed positive power and exponential trends. However, the association between root diameter and tensile strength followed a negative power trend. Results of Wald test showed no significant difference between tensile strength of three soil depths and three horizontal distances, though root diameter as a covariate parameter with a significant effect on tensile strength.

Tree to tree variation in growth results from compositional complexity, stand structure and competition. Therefore, it is essential to know how trees respond to competitive interactions. This study aims to evaluate of competition indices in order to assessment of management interventions effects in pure beech (Fagus orientalis Lipsky) stands (with 36 hectares) in Lavij- Noor region of Mazandaran province. For this purpose, the positions of all 58 marked trees were recorded as cored trees. Competition plots centered on the cored tree with radius of 3.5 × the cored tree crowns were established. The following attributes were measured for each tree (≥ 7.5 cm diameter at breast height (DBH)) within the plots: X and Y coordinates (m), total height, DBH, crown diameter at the base of the living crown in different directions and crown length. In order to quantify the competition level by each of the cored trees, 4 different distance-independent indices including Gerrard, Bella, Hegyi and Braathe were used. The results showed that the studied stands were middle-aged, the major interventions were in the middle DBH classes, and there was no significant change in the amount of competition indices following the interventions. Accordingly, the management interventions (marking) were not targeted and the process of individual tree competition changes was not measured. Therefore, the process of competition changes is necessary to be considered in stand management due to the high importance of the competition factor and its relation to the stand parameters.

The canopy architecture of different forest trees results in different species interception, quantity and quality of litterfall. Litterfall characteristics affect thickness of organic layer, water storage potential and runoff due to different decomposition rate in habitat conditions. Furthermore, throughfall content and water infiltration of litter are different through time as a result of differences in the evapotranspiration potential, leaf area index (LAI), canopy coverage, tree diameter, stand stages and other geographic factors. This paper was aimed to examine throughfall and water infiltrated of litter changes amongst three important species of Hyrcanian forest over a year. For this purpose, individual hornbeam (Carpinus betulus L.), velvet maple (Acer velutinum Boiss.) and chestnut-leaved oak (Quercus castaneifolia C. A. Mey.) species were selected in a mixed stand in Shast-Kalateh Forest, and quantity of water passing through the canopy of individual tree and organic litter layer beneath them were investigated with 9 throughfall collectors and 18 forest floor infiltration collectors after each rainfall event over a year. The results showed that species and times are two important factors in changing water balance. The hornbeam and maple species have the most throughfall and litter water contents, respectively (hornbeam with 71.1 % of throughfall and maple with 40.5 % of water infiltration of litter). The litter water infiltration of hornbeam and velvet maple in non-growing season were higher compared to the growing season, while throughfall showed no significant difference. The results of this study are concluded to be helpful for managers to regulate the stand composition as a reaction to the increasing water crisis.

In order to evaluate the applied management function on forest habitats, soil properties will provide useful information. In the present study, the effect of conservation based management on soil properties of Arasbaran forest habitats has been investigated. At first, the protected (Dizmar) and non-protected area of Arasbaran is divided into two altitude classes of 1000-1500 and 1500-2000 m.a.s.l. In each region, 22 soil samples (11 soil samples per elevation class) and totally 44 soil samples were taken at 0-30 cm depths of Northern aspect of these forests in the summer of 2016. Two-way ANOVA tests were carried out to evaluate the effects of 46-year conservation management treatment on the soil properties. The results showed that conservation management has significant effect on acidity (6.5%), Electrical Conductivity (EC) (1.45 ds/m), saturation moisture (77.5%), organic carbon (8.31%), clay (31.77%), sand (40%), N (0.84%), K (2475.86 ppm) and soil water content (17.42%). The mean of all these parameters except the sand are higher in protected region than the non-protected region. Also, the results indicate that in the Arasbaran area, the treatment of altitude from the sea level had significant effect on the bulk density and soil water content of the area, so that the mean bulk density in the low altitude is higher, whereas the mean soil water content is higher in upon altitude. The results of this research confirm the significant effect of conservation management approach on the soil quality indices of forest stands in the Arasbaran area.

Understanding of biodiversity status can be applied as a guide to better ecosystem management. The ecosystem ecological sustainability is ensured by high species diversity and better conservation. Therefore, the purpose of this research is to identify the species diversity of trees and shrubs in the Guijeh-bel region of Ahar and to determine species diversity using related indicators, as well as the relationship between biodiversity and physiographic factors. Sampling was done in 48 circular sample plots, each 314m2, by a random-systematic method within a 150×200m network. In each sample plot, a list of all of tree and shrub species with abundant-overcome values was recorded based on the Brown Blanche scale. The results showed that there were 13 woody species. Smilax excelsa L. and Rhamnus sp. had the highest (39%) and the lowest (0.04%) presence in the sample plots, respectively. The number of stems varied from 10 to 110 stems of different species in the sample plots. Two index species of Arasbaran region, Acer campestre L. and Viburnum lantana L., were observed in this area. Viburnum lantana and Acer campestre were often found on the western and the eastern aspects, respectively. The main effects of slope on the Taxa, Simpson, Shannon-Weiner and Margaleff indicators were not significant. The main effect of aspect was significant on the taxa index at 1% level and on other indicators at 5% level. The average of all indicators of diversity in the western aspect was higher than those of other aspects. The results of clustering of vegetation composition confirmed the results of the comparison of the site diversity indices. According to the results of the coefficient of variation, the taxa and Margalaf indices had the highest coefficient of variation. Therefore, in other studies, as well as assessment of the effects of management and monitoring of vegetation changes, it is recommended to use the indicators. Based on the results of this study, the high values of slope steepness and biodiversity, provides the protection of the area.

Knowledge about geographic variation within the native range of forest tree species is the logical first step in genetic studies. Wild almond (Amygdalus scoparia Spach.) is a multi-purpose species with a widespread geographic distribution in most of the vegetation regions of Iran. In order to study the geographic variation of wild almond, nineteen biometric features of seed, leaf and seedling from seven natural population of this species in Fras province were measured. Significant differences were observed among the populations for all of the studied characteristics. Hundred seed weight, leaf area and number of stems showed maximum variation among the studied traits. Seed traits presented a significant positive correlation in terms of mean annual rainfall. Correlation analyses between biometric traits and geoclimatic factors indicated the existence of clinal variation in some seed, leaf and seedling traits. Seedling leaf morphometric (dimension) traits decreased gradually from north to south populations; while seedling height declines from east to west populations. That means the geographic variation of the plant at the seedling stages reveals a two- way variation with the latitude and longitude. Principal component analysis (PCA) and cluster analysis of data revealed four distinct groups of populations, and separated populations of high rainfall area form that of lower rainfall area. Results also revealed that A. scoparia uses adaptive strategies in response to water deficit.