Iranian Journal of Forest and Poplar Research
Year:2017 | Volume:24 | Issue:4 (66) |Papers Count:21

The aim of this research is to evaluate current uses of forest (animal husbandry and wood harvesting) in district no.11 of Shafaroud forest with an area of 2200 ha in Gilan province. Factors including stumpage price, annual growth rate and rate of interest were used to determine the net present value of timber harvesting. Furthermore, price, animal husbandry costs and rate of interest were applied to determine the net present value of animal husbandry in forest. Economic analysis revealed the net present value of 30105809 IRR per hectare gained by wood harvesting and animal husbandry in forest, with 92.7% and 7.3%, proportions of forestry and animal husbandry, respectively. In other words, net present value of animal husbandry is about 12.7% lower than forestry. The results of this study showed that the present forestry practice in the study area enables the timber production management. In order to manage the forest based on sustainability and meet the forest dwellers needs, forest management is suggested to be planned toward the social forestry.

Identifying regeneration characteristics is a decisive prerequisite in forest stands management. Therefore, the objective of this research was to 1) present the most appropriate tree species for reforestation within stand gaps and 2) study the effect of relative light intensity on regeneration characteristics. Quantitative characteristics were measured in 10 gaps at district one of Loveh forest in Golestan province. Results showed differing frequencies of species depending on gap positions and relative light intensities. Except checker (Sorbus torminalis (L.) Crantz) regenerations, no significant difference was observed between mean of spring shoot length within gap positions. Annual height growth of checker was maximum for 40% relative light intensity, while the annual diameter growth of hornbeam (Carpinus betulus L.) and wild cherry (Prunus aviumL.) were maximum for relative light intensity ranging between 30 and 40%, respectively. No significant difference for relative light intensities was observed between other spices characteristics. Therefore, the study concludes that the highest attention should be paid to species mixtures and their ecological requirements for reforestation within the gaps.

Assessment of forest road pavement condition and its optimal cost management is backbone of a forest road network. In addition, an optimum budget allocation is a challenge during road life cycle. The precise assessment requires special equipment that is often neglected due to its absence or the associated high expenses. Therefore, it is recommended to use techniques that can provide cheap and fast linear and nonlinear modeling of pavement deterioration. The aim of this study was to investigate the performance of Genetic Algorithm (GA) to detect the warning level of forest road pavement as well as to plan the pavement maintenance. The GA was evaluated to identify the warning level of pavement and provide a plan for the maintenance of the road network over a period of five years based on annual plans across a test site of 5 series located 50 km west of Haraz forest road network. The results showed the optimum protrusions warning level for five centimeters damage and rutting 10 cm. Moreover, it was shown that an optimum planning combined with regular repair and maintenance work enables reducing the associated costs from 25 to 73 percent during the first years. It showed the importance of regular maintenance activities at the network level of pavement and application of novel techniques to allocate budgets for pavement maintenance.

One of the most important principles of clean development management (CDM) is to maintain or increase organic carbon pool in the natural ecosystems. As keeping the biodiversity is one of the prominent criteria of sustainable development, this study was conducted to study the relationship between the amount of carbon sequestration and plant biodiversity in the natural stands of Alder-Ironwood (AI), Maple- Ironwood (MI) and Elm-Hornbeam (EH) in the Noor Forest Park, Mazandaran province. The main purpose was to see if variation of plant biodiversity represents the optimal monitoring of soil carbon stock in the studied forest. The common diversity indices related to the different plant storeys were calculated in the random distributed plots with 400 m2 and five repetitions in each stand. Furthermore, the 0-20 and 20-40 cm soil depths were sampled in each stand to measure carbon factor. The results showed significant differences amongst the plant biodiversity indices of the studied stands. Only the index of species richness and species dominance of tree storey was not significantly different among the stands. As such, the findings showed that the AI stand had significantly less soil carbon stock in different soil layers compared to other stands; however, the soil organic carbon was significantly higher in the different soil depths in the MI stand. The results of Pearson’s correlation test showed a significant relationship between tree species dominance and mineral layer of soil carbon stock, implying that density and dispersion of dominant tree species in the stands prominently affect the carbon stock of the soil mineral layer. As such, the following results indicated that potential level of carbon pool of soil organic and mineral layers are significantly correlated with the abundance and evenness of herbal storey. Therefore, coverage and distribution of herbal species in the studied forest can be considered to represent the carbon pool weight in the different soil horizons.

In this paper the financial maturity and optimal rotation age of poplar (Popolus deltoids Marsh.) was studied in a study site in in Kurdistan province. First, the growth information of poplar was obtained from poplar plantation plans of Agricultural and Natural Resources Research Center in Sanandaj. Then data concerning stumpage price, fix and variable cost per hectare were collected by using questionnaires and conducting interviews with local people and poplar farmers. Finally, the age in which farmers achieve the maximum net present value was determined using the expected value of land model, i.e. Faustmann model. The findings showed that optimal rotation period occurs at the age of 12 years, where the marginal revenue and marginal cost curves intersect. However, the local farmers cut poplar trees at the premature ages of 6-7 years, thereby ignoring higher profits associated with the further growth. The obtained results can be attributed to the risks in regional poplar market, which is attempted to be avoided by the farmers.

Deadwood is widely recognized as an extremely important structural and functional component of forest communities. Therefore, understanding its role and dynamics are important to improve forest management strategies in both managed and unmanaged forests. The aim of this study was to analyze the qualitative and quantitative characteristics of dead trees in the mid-succession stage in intact mixed oriental beech (Fagus orientalis Lipsky) forests of Kheyrood, Mazandaran province. Three one-ha sample plots were laid out in compartment 310 of Gorazbon district, in which a number of quantitative (diameter at breast height³7.5cm and height) and qualitative (species, type of deadwood (log or snag) and decay class) characteristics were recorded. Our results indicated the mean volume of deadwood of 37.8 m3 ha-1. In addition, common hornbeam (Carpinus betulus L.) possessed the highest frequency (64%) of the deadwood among the species. The frequency and volume proportions of logs were 74.7% and 69.3%, respectively, and the maximum amount of deadwood was observed in the large timber size (50-75 cm). As conclusion, forest management planning should pass an adequate attention to succession stage and the amount of deadwood to guarantee the health, long lasting productivity and sustainability of forest ecosystem.

Ecologically and economically sound forest logging is regarded as a biological and practical necessity. However, the logging activities cause damages to forest, in particular to its regeneration. Both traditional and in mechanical wood harvesting and transportation are practiced in Caspian forests. Here, the damages to the regeneration raised by skidding with mule (traditional) and Skidder (mechanized) were assessed and also compared. This study was conducted in Parcel 4 of Lala series of Mazandaran Wood and Paper Company forests. The applied forestry regime is single tree selection. Random systematic sampling was used with circular sample plots to study the regeneration damages for the two methods, measured before and after skidding. The results showed that 2.38 % of the regeneration was damaged during the tree felling and conversion operations, whereas 8.56% was damaged after the skidding operations. In this study, the industrial skidding damages to groups of seedling, small sapling and sapling were assessed to account for 10.67%, 7.46% and 1.78%, respectively. Furthermore, the traditional skidding damages to groups of seedling, small sapling and sapling were 9.2%, 9.11% and 6.58%, respectively. Also the total damages to regeneration in the industrial skidding were assessed to be 7.93%, whereas the rate was 9% in traditional skidding. Finally, the statistical analysis showed that the damages caused by traditional and industrial skidding are not significantly different between the two studied parts of the forest parcel.

This study aimed to investigate the response of gall oak (Quercus infectoria Oliv.) to pollarding. Therefore, a less-disturbed stand (1.4 ha) and a pollarded stand (1.7 ha) were selected. Five rectangular plots (20×30 m) were established in each selected stand by random sampling. In each plot, tree species, diameter at breast height (DBH), total height, trunk height and crown diameter for all trees (DBH³ 5 cm) were recorded. In addition, 18 tree samples were taken in each studied stands to assess the diameter increment of Gall oak. A pair of increment cores per sample tree was taken 50 cm above ground level, in which annual radial increment was measured and further multiplied by 2 to derive the annual diameter increment. Then, the diameter increment distribution of gall oak trees in identical diameter classes was determined for the period of 1984-2010. The mean radial increment of two cores extracted from each sample tree was used in the calculations. The results showed that the average diameters, total height, trunk height, crown height and crown area were significantly lower (P<0.01) in pollarded stands. Moreover, the average diameter increment in less disturbed and pollarded stands was estimated 1.32 and 2.08 mm per year, respectively. The results indicated that average diameter increment of gall oak trees across the identical diameter classes during the studied period was significantly different between the examined stands.

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 design to 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. TheP. 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 % forP. e. Blanc de Poitouand the highest rate of 97.2 % for P. e.45.51, P. e.92.160, P. d. Marquetteand 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.

Arbuscular mycorrhizal fungi (AMF) are soil microorganisms that play an important role in ecosystem processes. They are able to increase the water uptake and mineral nutrients to the plant roots, and thus improve establishment, growth and survival of plants. Here, the effect of mycorrhizal fungi (Glomus intraradices, G. mosseae and G. hoi) on growth parameters of seedlings of mahaleb cherry (Cerasus mahaleb (L.) Mill.) under greenhouse condition were investigated. To produce theCerasus mahaleb seedlings, seeds of native trees were collected in Chahar Tagh-e Ardal, Chaharmahal and Bakhtiari province. After one growth season, mycorrhizal and control seedlings were evaluated. Results of measurements on root colonization showed that fungal can establish well symbiosis with Cerasus mahaleb seedlings. The results also revealed that mycorrhizal fungi significantly influenced all parameters except the length of main root and plant development, while G. hoi did not significantly affect the growth parameters and established a weak symbiosis. Overall, using of G. intraradices and G. mosseae were assessed to be positive here, therefore it can be applied as an appropriate way to increase the seedling growth and establishment in C. mahaleb, particularly in the degraded areas of Zagros forests.

In this study, some forest biometric parameters were studied to evaluate the decline severity in Tang-e Solak forest area in Kohgiluyeh and Boyerahmad province. Hundred plots of one hectare each were used. The Fierke method was used to evaluate the decline severity. In this method, crown condition classes (CCC) and Basal Emergence hole Classes (BEC) are divided into 6 groups. Finally Rapid Estimation Index (REI) was calculated by aggregating CCC and BEC. REI was then classified into tree classes for determining the dieback severity. The result of this study showed that 86% of broadleaved trees are in weak severity, while only 14% include medium severity of decline.

In this study, numerous crosses were initially performed between male and female parents of two poplar species, P. euphratica Oliv. and P. alba L.. Aseptic immature hybrid embryos were cultured on MS medium to produce hybrid seedlings. Several morphologic and micro-morphologic characteristics of a great number of three year-old seedlings of new genotypes based on six half-sib families were recorded with three replications, with the aim to assess possible potentials of the hybrids between the two species. An additional goal was to compare the hybrids of P. alba as either male or female parents. Analysis of variance revealed significant differences between the families. Two crossings, P. alba × P.euphratica and P. euphratica × P. alba, formed two distinct groups for some of the characteristics which partially implied maternal effects of inheritance on the traits. Range of the attributes was significantly wide, as for example the progenies varied between 24 and 424 cm of height. The most noticeable difference was observed on stomata characters. The hybrids with the two species as their female parent showed significantly different behaviors on several traits. The total average of leaf upper side stomata number was 123 for the crosses with P. euphratica as female parent, whereas the value was 4.8 in the crosses with P. alba as female parent. The variation might be beneficial is selecting superior genotypes to introduce new poplar varieties.

This study was performed to survey the site and silvicultural characteristics of Juniperus foetidissima Willd. in its exclusive habitat in the Arasbaran Biosphere Reserve. Measurements of height, canopy diameter, diameter of breast height, number of trees with single trunks, age, annual ring diameter, seedling density, health of canopy and quality of trunk were performed in 36 plots of 300 m2 each distributed in three height, four aspect and three slope classes. In addition, soil profiles were excavated in 12 plots, in which samples were taken from surface and lower horizons. The measured samples were applied to determine the values of pH, EC, OC, N, P, K, Ca, Mg and Na, lime and soil texture. Except for annual ring diameter, abundance of trees with medium and low health of canopy and bad quality of trunk, the results showed significant differences of other vegetative characteristics among the three height classes. These attributes were significantly different in four aspect classes, while other differences in tree characteristics were not significant. Furthermore, all vegetative traits except the number of trees, abundance of trees with single trunks, abundance of trees with good health of canopy and excellent quality of trunk were not significantly different among the three slope classes. The results also showed that in different geographic aspects all the physical and chemical properties in surface and lower layers were significantly different. Finally, the J. foetidissima populations were associated with an old age structure and low regeneration. Full enclosure and planting seeds and seedlings of J. foetidissimawill therefore ensure the sustainability of these populations in the future.

Projection of stand development over time relies on accurate height-diameter functions. In this study, we evaluated the capability of 18 nonlinear models to estimate hornbeam heights in a portion Shastkalateh experimental forest in Gorgan, Golestan province. We applied a systematic random sampling method to collect field data within a 150×200 meter network (3.33% intensity). It resulted in 308 circular plots with 17.84 m (0.1 ha) radius. In each plot tree species, height and diameter at breast height (DBH) of all trees with DBH>12.5 cm were measured, resulting in 2177 pairs of measured heightdiameter. From the available dataset, we included 75% in the model development and the remaining 25% to validate the models. The relationship between height (dependent variable) and DBH (independent variable) was analyzed using 18 non-linear regression models. The results showed no significant difference between the applied model diagnostics, and the applied t-test showed non-significant mean stand height estimation using all models and actual height at 99% confidence level, with the exception of the Prodan model. In addition, the results of Hyperbolic, Ratkofsky, Richard-chapman and Weibull models with RMSE% of 12.91%, 12.92%, 13.01% and 13.01% and Bias% of 0.21%, 0.21%, 0.22% and 0.22%, respectively were almost similar in that they were better predictors of hornbeam height. Based on the results, we conclude that these models can be used for predicting hornbeam height in similar broadleaved stands of northern Iran, provided that comparative studies are conducted elsewhere to approve the results obtained here.

To assess the changes in qualitative and quantitative attributes at the end of a period of forestry plan implementation, a portion of the Jojadeh zone with an area of 1270 ha was selected. Data were collected from 265 permanent plots in a systematic random design (1000 m2 plots and150 × 200 m grid size) in 2004 and 2014 to facilitate a comparison. In each plot diameter, species, quality grade, height of control tress and quality of regeneration (in 100 m2 microplots) were measured. During the ten-year period, approximately 14000 silve of growing stock was marked within a single tree selection cutting system. The results showed following figures for 2004: the average number of trees per ha=173, volume per ha=318.36 silve, basal area per ha=25.87 m2, diameter of basal area=43.93 cm and Lorey’s mean height=25.31 m. The values in 2014 were 175, 360.24 silve, 28.31 m2, 43.39 cm and 26.40 m, respectively. Apart from number of trees per ha, significant differences were observed between the two measurement times for the other attributes. Furthermore, the species specific regeneration frequency was affected by a significant reduction in seedling and saplings in 2014. However, tree percentages increased in 1st and 3rd quality grade classes, whereas it decreased 2nd class and remained unchanged in 4th class. All in all, the results showed that the average values of quantitative and partly qualitative characteristics were not far from favorable conditions during the period of forestry plan, which indicated the conducted silvicultural practices served the defined goals of the close to nature forestry method.

Quality and quantity of forest utilization belong to the most debated issues in managing the Hyrcanian forests. There are two conflicting views of 1) sustainable forest utilization and 2) forest rest. The present study aimed to apply these two approaches. Therefore, Shafarood forests located in Guilan province were selected. Strengths, weaknesses, opportunities, and threats (SWOT) were applied to prescribe the policy and planning of forest utilization and rest by forest sector stakeholders, referred to as participants here. The statistical population i.e. participants group includes local communities and experts at regional, provincial and national levels (in total 11 people from local communities and 48 experts). The management strategy (aggressive, competitive, defensive or conservative) was selected based on the results of SWOT and the Space Matrix. Subsequently, Results showed that 73% of participants agreed with sustainable utilization, while 27% accepted the rest of forest. In addition, the most important opportunity and strength associated with forest rest were increase of sustainability and employment in the forestry and wood industry sectors on national level. Furthermore, the most eminent opportunity and strength included reduction of soil erosion and soil conservation. Based on participant’s views, the conservative strategy for sustainable utilization and the defensive strategy for the forest rest were suggested. Based on the latter, the current plan should be either ceased or revised by taking the suitable planning should in all factors contributing to forest degradation, including the presence of livestock, forest dwellers, timber smuggling, landuse conversion to orchard and villa, and inappropriate utilization.