Iranian Journal of Forest and Poplar Research
Year:2016 | Volume:24 | Issue:1|Papers Count:20

Each skid trail construction affects the trees located on the road margins in various extents. The present study was conducted with the aim to assess the changes in annual ring widths of Beech and Alder trees compared to the control trees inside the Nav District in Asalem forests. To this aim, 40 samples from previously felled Alder and Beech even-age trees were randomly drawn alongside and inside the forest stands.Disks were acquired from the trees and were perfectly polished with sanding machine.They were finally used to measure annual ring widths with an accuracy of 0.01 mm.Effect of species (Alder and Beech) and location (along the skid trail and inside of stand) on the average width of annual ring were analysed using a two-way ANOVA test in a complete randomized design. Results indicated larger average annual ring width of marginal trees (0.20mm and 0.38mm for Beech and Alder trees, respectively) compared to those located inside the stand. Moreover, ANOVA results indicated highly significant main effect of species and location on the average of annual ring width, while their interaction was shown to be insignificant. It can be concluded that this increase of trees growth in marginal trees may compensate the loss of volume caused by skid trails construction.

The forest management plan of Sangdeh (Mazandaran province) was first implemented in in1969 under a Shelterwood system, which led to final cuttings conducted between 1991 and 1995. This study was planned to compare some of the major quantitative characteristics of compartments managed under a unique block method to a selected control compartment. The forest inventory was carried out in a systematic random sampling with a 100×150 m grid size. The results showed the average growing stock of 464.27 and 240.95 silve per hectare in control and unique block, respectively. In addition, the average number of trees per ha were 232 and 599 trees, the average basal areas per ha were 22.74 and 31.69 m2, the average tree diameters were 39.90 and 21.00 cm and the average heights were 28, 30 and 21, 27 m, respectively. Furthermore, the vertical forest structure consisted of three and two stories in control stand, while it consisted of one and maximum two layers in the unique block. The average rates for total regeneration accounted for 1487 and 715 tree per ha in control and unique block, respectively. Furthermore, regeneration frequency in unique block showed a reduction compared to the control for all of class except in 7.5-12.5 cm class. Significant differences were observed for the average stock density, basal area, tree height and diameter between the control and unique block stands. All in all, although the unique block was evaluated relatively successful in the light of the majority of measured characteristics, the achieved results are assessed to be still sup-optimal when considering the mother trees and the expected advanced regeneration mixture.

The increasing amount of air pollutants in large cities has turned into a crucial factor that affects morphological and physiological tree characteristics, particularly on leaf level. In order to study those effects, 5 areas ranging from least to most polluted areas were initially selected in Urmia, the capital of West Azerbaijan province, using fixed and mobile air pollution recording stations of the Environment Office in August 2013.From each three species in each area 5 individuals were randomly selected and the leaves were measured in terms of their length of petiole, length of blade, maximum width of blade and leaf area. The above-mentioned parameters were repeatedly measured in May 2014. The ANOVA, Duncan and paired-t tests were performed analyze the data. The results revealed that the morphological properties of all species are affected by air pollutions (a=0.05), with the greater effects occurred in August 2013 compared to May 2014.

The vegetative potential of stump is divided among various sprouts in coppice stands.The main objectives of this research were to 1) identify the growth respond of Brant`s oak (Quercus brantii Lindl.) sprout clumps to thinning and 2) to choose the best intensity of thinning. This study was done based on completely randomized design with four treatments and three replications in Kermanshah province (Darbadam forests).We assessed the effect of different thinning intensities on growth of oaks in Darbadam region, Kermanshah, during a 5-year period. Four treatments including heavy (decreasing 30 percent of basal area), medium (decreasing 20 percent of basal area) and light (decreasing 10 percent of basal area) thinning, each with 3 replications was used.One treatment was considered as control with no intervention. Prior to thinning quantitative characteristics of sample trees were measured. In the last year of research, the measurements were repeated to calculate the growth values. Based on results, heavy thinning had considerably positive impact on growth of sprout-clumps crown area and basal area of sprouts. However, no significant difference was observed between treatments regarding to height of sprout-clumps and diameter of sprouts. We concluded that the heavy thinning with removing 30% of basal area was the most influential on sprout clumps growth that is applicable in thinning projects in Zagros oak coppice stands

Plant residue of forest nurseries is among the best available raw materials for producing compost to amend and strengthen forest nurseries soil. The size of raw materials has a major effect on shortening the time of composting as well as on increasing its quality.The mechanism, availability and working convenience with the threshers in different site conditions to convert plant residue into small pieces that are suitable for composting shows the suitability of threshers for such tasks. In this research, two kinds of knives with flat and sharp edges applicable to threshers were designed and applied to study the crushing quality of common plant residues. Treatments included pine cones, branches of deciduous, pine branches, coarse plants, herbs and pine needles. The performance of both flat and sharp edge knives were evaluated in a design with three repetitions. For most samples, the results showed that performance of the sharp knife exceeded that of flat knife. The crushing quality of different materials in different dimensions were significantly different at the a=0.01 level. The time performance of sharp knife with an average mean 0.069290 kg per second was far better than flat knife with an average mean of 0.035661 kg per second. Sharp knife performed best for grinding pine cones with an average 0.01321 kg per second. Generally, more uniform and brittle plant residue can be crushed in a shorter time. Finally, the efficiency of threshers system with the designed knife is acceptable and suitable for the crushing of plant residue.

A forest stand of 25 ha in Tol-e Gah region nearby Yasuj (Kohgiluyeh and Boyer Ahmad province) was selected to assess the spatial distribution pattern of its dead trees of Brant`s oak (Quercus brantii Lindl). The fixed area plot samples and adaptive cluster sampling method were employed to collect qualitative and quantitative information of the forest stand. Using sixty-five, 10-Ar sample plots, quantitative characteristics of all dead trunks together with those for the healthy trees in the sample plots were recorded in a way that each dead trunk found in each of the plots was considered as the center of another sample plot. In addition to determining the geographical coordinates of the dead trunks, diameter at breast height, tree height, and crown diameter of trees were measured. The Johnson-Zimmer, Eberhart, and Pielou indices (based on the distance of the sampling spot to the individual trees) and the variance to mean ratio, Morisita index, and standardized Morisita indices (efficient in using plot samples) were applied to quantify the distribution pattern of dead trees. All sample plot-related indices indicated a clumping distribution pattern for the dead trees. Among the distance indices, the Johnson-Zimmer and Eberhart indices also showed a clumping and a uniform pattern of dead tree distribution, respectively.

The study presents models of error estimation in trees’ directional felling according to several effective factors using the subtractive clustering in the Adaptive Neuro-Fuzzy Inference System. A total number of 95 trees in the compartment 207 of 2nd district of Nav watershed in Guilan province were felled by felling group and regardless to the group’s skill, using manual chainsaw. The difference between predicted and real falling direction of trees was measured as felling error. To generate models, twelve independent variables were assumed to be the effective factors, and the two types of learning algorithm (LA), two inference types (IT) and five types of membership function (MF) for input variables were applied through the subtractive clustering method in the ANFIS. Results indicated that the trapezoidal type of MF in combination with the first-order type of Sugeno IT and the back propagation LA had the best performance among all combinations of setting parameters. The sensitivity analysis of the optimal model showed that the model was very sensitive to the changes in terrain slope, the angles of backcut and undercut surfaces and DBH, respectively. Results also revealed that felling group properly predicted the fall direction and performed the directional felling in the steeper terrain. In addition, the increase of DBH and opening too much the undercut notch have accompanied with the increase of felling error.

Spatial pattern and interspecific association between plant species are two important measures for understanding relation between species and their surrounding environment. Regarding the importance of Zagros forests as well as the role of spatial patterns in forest management, this study aimed to investigate spatial patterns of two important species “Quercus infectoria Oliv. and Q. libani Oliv.” in northern Zagros forest. Two forest stands of 5 ha each located in Khedr Abad of West Azerbaijan province were fully calipered. Cartesian coordinates for all trees location were computed and the trees locations were mapped for both stands. Riply’s K function and L (r) and O (r) statistics were used to analyze spatial patterns and interspecific association between plant species. Results showed a clumped pattern for Q. infectoria in less degraded stand using L (r) statistics, while Q. libani tended to random pattern. Using O (r) statistics, the spatial pattern for both species in less degraded stand were clumped that tended to random. However, both species showed a clumped pattern in degraded stand using both statistics. Bivariate statistical analysis showed a positive association between the two species at small scales in less degraded stand, whereas at larger scales the species were independent. Furthermore, the two species were positively correlated at all scales as shown by both statistics. Based on the results, mixed tree plantation is recommended to restore degraded stands via reforestation programs.

Non-wood forest products (NWFPs) and environmental values are preferred to woody products in Zagros forests. This study aimed to plan a utilization policy for NWFPs including Gazu, Mazouj and acorns. Therefore, three villages (Gandoman, Mirhesam and Kokh-e Mamo) in the Armardeh municipality in southwest of the city of Baneh in the Kurdistan province of Iran were investigated. The SWOT analysis technique was applied for planning. Field data were collected via an empirical survey based mainly on face-to-face interviews and questionnaires distributed amongst the ecosystem stakeholders. Respondents were selected among stakeholders of local community (12 individuals of local people and 18 individuals of experts). The results of SWOT and Space Matrix analyses revealed that an aggressive, competitive, defensive and conservative strategy is appropriate for NWFP utilization. Results also showed that the most important strength, weakness, opportunity, and threats concerning the utilization of Gazu included social acceptance from local communities, soil erosion, reduction of rural-urban migration, and air pollution due to dust storm, respectively. For Mazouj, utilization those factors included household’s income, collection by non-local people (resulted in conflicts and tree damages), people motivation for participatory management, and lack of marketing and formal supports, respectively. Finally, livestock feeding, damaging to high forest regeneration, creating alternative livelihoods, and jeopardizing the continuity and sustainability of the forest are m to be of major concern when utilizing acorns. By analyzing the opinions of experts, an aggressive management strategy for the utilization of Gazu and Mazouj and a competitive management strategy for acorn are prescribed by this study.

Drought and environmental crisis caused by climate change are amongst the most crucial challenges in Iran. Due to the essential importance of absorbing CO2, the most crucial factor of global warming, in forest ecosystems, accurate estimation of carbon sequestration in different parts of the trees is of high significance for forest planning and management under climate change scenarios. In this study, 20 velvet maple (Acer velutinum Boiss.) individuals distributed in different diameter classes were initially felled and divided into separate parts of bole and crown. The specific wood density and carbon factor of each fraction and their product were directly calculated and used for non-destructive method to estimate above-ground carbon sequestration (AGC).Allometric equations were developed by weighing of harvested tree parts and measuring each section’s drought coefficient. The ANOVA revealed no tree-specific significant difference among carbon factors. However, the specific wood density was significantly different among the each part of tree individuals. Allometric models showed that the highest accuracy of AGC (R2 adj=0.98, RMS=0.101, CF=1.05) was achieved by the exponential model considered re-conversional equation that included DBH and crown diameter. The result of paired t-test showed that the non-destructive estimation method was associated with the highest uncertainty with the low confidence (S%=318.4, t=- 3.5). However, the result of paired t-test between the observations and predictions of the optimal allometric model here showed that the aforementioned model estimation was confident (S%=22.6, t=1.36).

Ribes khorasanicum Saghafi & Assadi is considered as one of the valuable medicinal native species of Razavi Khorasan province that is distributed across high-altitudes of Hezar Masjed Mountains in a small range of Dargaz and Kalat cities as scattered patches. Because of human interference, high ecological requirements and low seeds germination this species is currently endangered and as even considered to be prone to extinction. The aim of this study was to investigate the role of symbiotic microorganisms in the growth and survival of plantlets produced by tissue culture techniques. For this purpose a factorial experiment was conducted in a completely randomized design. Mycorrhiza fungi treatments included treatments without mycorrhiza, those with Rhizophagus interaradics, Glomus mosseae, as well as R.interaradics+G. mosseae and fungus that were separated from the test site. Bacteria treatments included those without bacteria and those with Pseudomonas fluorescens inoculation. The results showed that bacteria inoculation could improve survival, crown area and number of leaves. The results also showed that the inoculation of mycorrhizal fungi separated from the site habitat improved root colonization, survival, height, number of leaves and crown area. Furthermore, the combination of mycorrhizal fungi R.intraradices+G. mosseae improved the survival rate. It was concluded that the inoculation of fungi and bacteria improved plant acclimatization in ex vitro conditions.

To assess the diversity of woody species (as a major task to understand the changes in forest ecosystem), collection of appropriate qualitative and quantitative data is of particular importance. This study attempts to introduce the most appropriate sampling method for estimating woody species diversity in the northern Zagros forests. An area of 40 ha in Blakeh forest was selected, in which 40 quadrangular samples of one ha each in a 100 m × 100 m grid were established. In each plot a set of characteristics such as species, tree position, the number of trees and smallest/largest crown diameter were measured. All inventory data were processed in GIS to produce a dispersion map of trees. Different sampling methods (rectangular samples with 20 × 50 m, transect methods with 50 and 100 m length, quadrangular method with 10 × 10 m, 15 × 15 m, 20 × 20 m, 40 × 40 m sample sizes) were implemented in a 100×100m sampling grid. The %E2 ×T criterion was used to compare the results. In addition, quadrangular methods were analyzed using the Shannon-Wiener and Simpson diversity and the Margaleff and Minhinick enrichment indices. The quadrangular method with 40 × 40 m and 20 × 20 m sample size was shown to be the most appropriate method for estimating stem number per ha and percentage of canopy cover.

Willow (Salix sp.) is one of the main trees occurring within valleys, plains and the river margins in Iran. The aim of study was to evaluate and compare the growth of willow hybrids and parents. Therefore, hybrid seedlings from S. alba (female) x S. alba (male), S. alba x S. excels and S. alba x S. fragilis crosses were planted in the field in April 2012. In first stage, superior hybrids were selected based on growth characteristics. In the second stage hybrid seedlings and parents were tested by planting cuttings (5 cuttings for each hybrid and parents) in the nursery. Growth traits such as survival rate, collar diameter, height, number of branches and stem form were measured at the end of growth season. Measuring growth characteristics of hybrids showed that 7 hybrids from S. alba x S. alba, 7 hybrids form S. alba x S. excelsa and 2 hybrids from S. alba x S.fragilis crosses were associated with straight stem form as well as the highest diameter and height growth. The average diameter and height growth of hybrid seedlings from planted cuttings cuttings showed two hybrid S. alba x S. alba crosses with the highest growth. Moreover, four S. alba x S. excelsa crosses and one seedling from S. alba x S.fragilis hybrid showed the highest height growth compared to the parents. The superior hybrids also showed straight stems. It is concluded that the superior hybrid seedlings from this study can be evaluated in the next phase of compatibility.

Understanding the phenological characteristics of the semi-parasitic continental mistletoe (Loranthus europaeus Jacq.) is an essential step for a timely control management of its expansion. To this aim, a portion of oak stands of the southern slope of the Manesht mountain located in Hyanan region in the North East of Ilam was investigated. Three test sites located in altitudes of 1800-1600, 2000-1800 and 2200- 2000 m above sea level were considered, in each of which five mistletoe-infested Persian oak trees were selected. The phenological traits were monitored over five years.The results showed that phenological traits are affected by elevation, i.e. the phenological events at lower altitudes occur a few days earlier than the higher elevations. In addition, the appearance time of phenological events was different during successive years. According to the results of our phenological analysis at different altitudes and in different years, it is concluded that the optimal time span for removing mistletoe is prior to its fruit ripening until August. In order to avoid the problems of collecting and dispersing of mistletoes seeds, we can remove the mistletoes on the Brant`s oak trees before the ripening of fruits in the proper time of cutting.

This study aimed to evaluate the results of soil seed bank in Tarbiat Modares Lowland Experimental Forest by using the two methods of washing and non-washing. Therefore, four main plots (40×40 m2) with each of them comprising 4 sub quadrats of 400 m2 were considered as representative stands. Aboveground vegetation was sampled by 16 plots of 400 m2 in two time steps of March and June. Seed bank flora was studied using seedling emergence method based on 64 soil samples (2 methods×4 main plots×4 replications×2 depths of 0-5 and 5-10 cm) which had been hammered by a hollow 400 cm2 metal frame. Statistical analysis was performed using split plot in space set within a randomized complete block experimental design. Results showed that both species richness and density of soil seed bank in non-washing method (63 species with 1872 seed density per m2 in upper layer and 46 species with 975 seed density in lower layer) were significantly higher than in washing method (45 species with 1137 seed density per m2 in upper layer and 33 species with 699 seed density in lower layer). Results also showed that similarity between soil seed bank with corresponding extant vegetation decreased with increasing soil depth. However, the two methods were not significantly different. We concluded that seedling emergence method without washing results in better soil seed bank assessment.

Whereas sustainability is a principle in forest management, a mechanism to identify and quantify the sustainability is of great importance, too. Although several indicators and criteria exist at the international level, the main challenge is to define criteria and indicators and implement them at the national, regional and local levels of implement sustainable forest management. The purpose of this paper is to define appropriate criteria and indicators for sustainable forest management through a network of multicriteria decision analysis methods in the Nav-e Asalem forests in Guilan province. The result included a set of 11 criteria and 65 indicators (5 ecological, 2 social and 4 economic criteria). In addition, the results showed that the area of natural forests with healthy regeneration, tree marking of seed stock and balance between growth and harvesting are the most important indicators for sustainable forest management in local scale across the study site. Of least importance were import and localization of appropriate technologies and capacity to implement international instruments.