Iranian Journal of Forest and Poplar Research
Year:2016 | Volume:24 | Issue:2|Papers Count:22

Earthwork operation is a complicated part in forest road construction that accounts for ca.25% of the associated costs. Thus, accurate forest road profile planning is an important factor of determining earthwork volume. Planning a profile design with the aim of minimizing earthwork volumes entails a computer program that is capable to calculate earthwork area in different intervals of every cross section. The aim of this study was to incorporate ground shape at cross sections as a first step of determining an optimal vertical alignment of forest roads. First, AutoCAD was used to calculate the exact extensions of cut and fill areas in 1m intervals at every 275 cross sections as a witness sample. Then cross sections with different slopes were investigated by means of MATLAB heuristic programming. The accuracy of results was validated by AutoCAD.Paired sample T-Test was used for comparing the results of the suggested method against the commonly used method. The results revealed a good performance of the suggested method, which not only reduced computational burden but also keep the design's rectitude constantly by R2=0.99. The flexibility of the MATLAB heuristic programming makes it a powerful tool in rapid redesigning of new road standards.

Sequestration of atmospheric carbon in plant and the underlying soil is a mechanism to encounter the global warming. This study investigated carbon sequestration in biomass and soils of Chaharmahal and Bakhtiari’s poplar plantations. To this aim four one-ha regions were initially selected, in which Populus alba seedlings were planted. The 10- year individuals were planted at four different planting spaces (0.5×0.5, 1×1, 2×2 and 4×4 m). From each of the areas 10 trees (total number of 40 trees) were selected and felled. They were immediately weighted, and the wet weights for different tree parts were recorded separately. Biomass was derived after sampling carbon stocks, which revealed that the highest sequestration rates in tree organs is accumulated in trunk, branches, twigs and leaves, respectively. The sequestrated carbon in the biomass was derived by burning in electrical kiln. In addition, 10 soil samples were randomly drawn from two different depths (0 to 15 and 15 to 30 cm) across each region. The Walkley- Black method was applied to obtain the amount of carbon sequestration in the soil. The highest amount of sequestrated carbon (226.465 ton per ha) was recorded for 0.5×0.5 m planting space. The results indicated a 50% decrease in carbon sequestration along with increasing the planting space, with 79.6 and 76.3 tons per ha in 0.5 m and 1 m space, whereas 37.6 tons per ha was sequestrated in low-density plantation.

Knowledge on stand’s quantitative and qualitative characteristics (tree volume and growth) are fundamental requirements for monitoring close-to-nature forest management plans. In addition, future planning is based on statistics and information obtained from the forest. Thus, structural information such as standing stock, growth and diameter distribution are highly required. Volume increment provides the amount of allowable annual cut. In this study 768.4 ha of virgin forests located in Gorazbon district in Kheyroud educational- experimental Forest was inventoried by 258 permanent sample plots measured in 2012. Following elimination of statistical deficiency and exclusion of deviated points, the data were divided into 80% training and 20% test data to examine the applied neural network. The data was initially standardized by using training data. Neural network with back propagation error algorithm was developed. Furthermore, volume was regressed against diameter, height, slope and aspect using the allocated training data. Model diagnostics including R2, MAE and RMSE were applied for evaluating those two methods. The analysis resulted in R2=0.98, MAE=0.69 and RMSE=1.006, respectively. For the regression method the diagnostics amounted in R2=0.85, MAE=0.95 and RMSE=2.5. The results have suggest the higher accuracy of neural network for growing stock estimation compared to regression approach. However, care must be taken during data preparation, network design and network training to reach an optimum final model. It is concluded that this model should be further considered and applied for the estimation of volume across the study area.

This study aimed to determine the relationship between vegetation properties of Cerasus microcarpa C. A. Mey. and physiographic and soil conditions in forests of Kermanshah province. After identifying the main habitats of C. microcarpa habitats, min and max range of altitude were determined. Concerning geographic expositions and terrain condition, 17 circular sample plots of 500 m2 each were established, in which C. microcarpa individuals could be grouped, with at least three of the total 122 shrubs in a plot. Furthermore, 17 soil profiles were dug, in which the parameters including pH, EC, C%, CaCo3 and soil texture were determined. The PC-ORD software was used for Canonical Correspondence Analysis on the data. The results suggested that the geographical aspect plays an important role in selecting land form for C. microcarpa establishment, so that the shrubs are more distributed at the edges and valleys in northern slopes, while they are more presented in foothills and plains in southern slopes. The total height of shrubs in northern slopes and edges was higher than those in both southern slopes and plains. Both trunk and crown length reduce by increasing clay, CaCo3, EC and decreasing slope%. A direct relationship was observed between total height of shrubs and altitude and sand. Finally, the environmental conditions in southern slopes and plains which are accompanied by increasing the acidity and silt, which in turn contribute to increase the crown area and diameter at breast height of C. microcarpa shrubs.

The development of forest parks not only entails the governmental and public support in multiple (political, economic, social and cultural) aspects, but it also requires an indepth expert knowledge on forest management. The purpose of this study was to control the conducted management plans and review the recreational needs of tourists across Mirza Kouchak Khan forest park in Amol. A total number of 100 questionnaires were distributed among park visitors using the Clawson method. The analysis was performed using Cronbach's alpha coefficient. Results showed that the Cronbach's alpha=0.251, turning out that the questionnaires were not valid. By excluding the outliers (i.e. highest numbers) the value of Cronbach's alpha was improved up to 0.55. The relationship amongst the parameters was surveyed by a chi-square test. Except two cases, namely the relationships between the type of park equipment and the right to use parking space as well as between the knowledge and understanding the forest with the other variables, no other significant differences were found. In fact, the public willingness to violate the regulations significantly decreases if the park would be associated with a proper design and planning, which in turns results in reduced damage to a given park. Therefore, this study revealed that the public culture of the park visitors is currently lacking an intuitive understanding and awareness about the biological and ecological values of the studies forest park.

The purpose of this study was to investigate flora and plant species diversity in a mixed plantation in western Iran. Therefore, a 20-year mixed coniferous and deciduous plantation (Pinus brutia Ten., Cupressus arizonica Green. and Amygdalus scoparia Spach) was selected in Remela region, Lorestan province. In each of the three stands, 10 plots of 100 m2 (10 ×10m) each were randomly established, in each of which 5 subplots (2.5×2.5 m) were positioned in center and corner points. Plant species cover (%) and diversity indices were calculated for each site. Totally, 93 plants from 24 families and 8 genera were identified. The results showed that the main families included Asteraceae (18 species), Leguminosae (17 species), Labiatae (13 species), Graminae (12 species), and Apiaceae / Caryophyllaceae (6 species). The most frequent life form was therophytes (64.51%). From the chorotypical perspective, the highest frequency belonged to Irano-Turanian region (36.55 %). The result also indicated that Shanonweaver’s diversity index and species richness (SR) were higher in coniferous plantation compared to the deciduous one, yet no significant difference was observed among the Hill's evenness indices of the three test sites. All in all it can be concluded that the habitats are associated with a high diversity due to the presence of 93 species, which is presumably driven by the climate and geomorphologic conditions of the region.

A permanent sample plot with an area of 6 ha is located on mid elevation of the Neka- Zalemrood forest, south of Sari in northern Iran. After fencing the plot, a metal tag indicating tree number was installed on each tree. A full calipering was conducted, which was followed by measuring the diameter at breast height (DBH) and height of selected trees. Forest structure, proportion of dead wood, and proportion of tree species were studied for a period between 2006 and 2012. Results of the inventory of the total 2375 trees in 2012 showed three storeys and an uneven-aged structure in Fagus orientalis-Carpinus betulus forest type. Further results included mean tree number of 389 ha-1, mean basal area of 43 m2ha-1, mean stand volume of 538 m3ha-1, and De' Liocourt factor of 1.38. Dead trees accounted for 3.1% of the total tree number and 5.7% of the stand volume. Comparison between the two inventories (2006 and 2012) showed that beech trees gained a higher proportion among the tree species in almost all diameter classes, while hornbeam lost more of its presence in the diameter classes.Amongst the DBH classes<30cm, the proportional difference between beech and hornbeam was more obvious. Compared to hornbeam, Parrotia persica and Diospyrus lotus showed more presence in the DBH classes of 30 to 50cm. Volume of damaged trees (broken, hollow, snag and log) was accounted for 97 m3ha-1, while for dead wood was 30.6 m3ha-1. Within the six-year study period, hollow large trees have been fallen down. Mortality of trees in DBH classes<50cm provided a lot of scattered small gaps within the stand and supported the establishment of younger individuals and cohorts. In addition, almost 9.6 m3ha-1, comprising 1.6% of the total volume, 28% of dead trees and 8.9% of damaged trees was decomposed. All in all the studies forest was concluded to be tending from the senility to juvenility in forest succession.

A study on the impacts of soil humidity and artificial shading on growth, biomass production and its allocation to different organs of wild pistachio (Pistacia atlantica Desf.) saplings was carried out in Alborz research station complex (Karaj, Iran). One year seedlings were treated by soil humidity (20, 50 and 100 percent of field capacity) and shading (100, 70 and 50 percent of full sunlight) factors in a split plot experiment based on a randomized complete block design from June to December 2014. Results showed significant impact of oil humidity on height, collar diameter, fresh and dry biomass of leaves and stem as well as on total fresh biomass. Shade significantly decreased height, root and total dry biomass and root to shoot fresh biomass ratio.Moreover, wild pistachio saplings with different soil humidity treatments show different responses to shade. In particular, shade significantly decreases height, fresh leaves biomass and R/S fresh biomass ratio for well-irrigated saplings and increases these parameters for saplings under drought stress. Response trends of different parameters under humidity × shade treatments showed that shade can reduce undesirable effects of drought stress on wild pistachio saplings.

Dareh Si is a forested valley located 3 km from southwest of Kalaybar county within the Arasbaran forests in the north of East Azerbayijan Province. High Biodiversity and ecological conditions that generally govern Arasbaran area had turned those forests to a unique biogeographic area of Iran. In this study, the recreational value of the Dareh Si Castle Park (as the minimum recreational value of Arasbaran forests) was estimated using Contingent Valuation Method (CVM). Questionnaires were used to collect the required information. Descriptive statistics of variables were introduced, followed by providing results of LOGIT models and expected WTP values. Analytical results indicated that for each visit to the park the visitors would like to pay 3908 IRR.Annually, 275000 individuals visit the park, which results in the estimated recreational value of 1.074 billion IRR when multiplied by the WTP (The base year was 2007). This was updated based on Consumer Price Indexes (CPI) announced by Central Bank of Islamic Republic of Iran in 2014, accounting for 4.14 billion IRR.

Concerning the importance of tree and shrub regeneration and its effect on the feature of forests, the present study was designed to evaluate the regeneration of forest species and its relationship with environmental factors in Dena protected area. To this aim, 50 plots of 450 m2 each were selected in a randomly- systematic design based on a 500 × 250 m grid. Then the regeneration of species in three different height classes (<30 cm, 130-30 cm, and>130 cm) was counted. The results showed that the regeneration of different species was affected by various environmental factors. Among the physiographic factors, height had the greatest impact on regeneration, i.e. increasing the height from sea level leads to reducing the regeneration of Quercus brantii, Cerasus microcarpa, and Daphne mucronata, Whereas Amygdalus reuteri and Lonicera nummulariifolia showed increase of regeneration. However, the regeneration of Q. brantii and C. microcarpawas was higher in medium slopes on northern aspects. The results of soil elements also showed positive correlation between that soil nitrogen levels were with C.microcarpa regeneration and negatively correlated between L. nummulariifolia and soil nitrogen levels. On the other hand the correlation results revealed that the association of Q. brantii and C. microcarpa occurs jointly in low altitudes, while association of A. reuteri and L. nummulariifolia jointly occurs across high altitudes. Also regenerations of Pistacia atlantica and A. scoparia were observed to be jointly, similar to those of A. orientalis and L. nummulariifolia. Finally, the anthropogenic and environmental factors as well as the competition between species are concluded to affect the regeneration of variety of forest species.

Environmental Impact Assessment (EIA) is well-known as a basic tool for environmental management and sustainable development. However, modelling approaches are generally preferred when quantitative entities are required for decisionmaking.The purpose of this study was to test artificial neural network incorporating ecosystem components, forest management activities and the forest canopy density confusion. The study area embraced three districts of Patom, Namkhaneh and Gorazbon within Khyroud research and educational forest of University of Tehran. Land Management Units were formed using available ecological databases and GIS. Based on qualitative and quantitative measures of ecological condition and human activities, the forest canopy density was simulated using artificial neural networks in Neuro Solutions ver.5 software. Multilayer Perceptron network with one hidden layer and four neurons created the best function for optimizing topology with highest coefficient of determination ~ 0.9864. The results of sensitivity analysis revealed that human activities like the cattle density in land unit (ha), ecological and natural factors such as the average diameter of forest type trees and soil depth are associated with the highest effects on forest canopy density. As a conclusion, the impact assessment of implemented projects could offer an improved solution in decision making for similar projects across similar locations.

This study evaluated soil and nutrient concentration in different phases of developmental cycle in untouched habitat of oriental beech (Fagus orientalis Lipsky) in Guilan province. Three sampling plots (one ha in each site) were selected, with each plot divided into four sub-plots of 10 ×10 m each. Soil samples were taken from the corner and center of each sub-plot. After air drying, soil properties were measured. At each plot, 10 trees were randomly selected and leaves were sampled from different expositions. The samples were transferred to the laboratory, dried at 40oC, ground and further used for the analysis. Nitrogen, phosphorus, calcium, magnesium, potassium, zinc, manganese and iron were measured. Analysis of variance (ANOVA) was conducted on the data. Mean comparisons were carried out by Duncan’s multiple range tests (P£0.05). Percentage of organic carbon and soil organic matters in decay stage were greater than the other stages. Furthermore, the exchangeable content of K and available P in initial stage was greater in both depths. Mineral nutrition and organic matter in soil surface was greater than soil depth. In addition, leaves analysis showed that the nitrogen in the decay stage was greater than in other stages, whereas the other elements do not notably change. Nutrient uptake was independent of the amount of nutrients in the soil. The results showed that despite differences in the amount of nutrients leaves of beech trees in various stages of evolution the range of nutrients show the health of this ecosystem.

western Iran, forest stands containing multi-purpose species such as Sumac (Rhus coriaria), Barberry (Berberis sp.) and Pistachio (Pistacia sp.) in pure or mixed form mainly occur in the Northern Zone of Oak forests. The present paper aimed to study the site demands as well as the most important quantitative and qualitative characteristics of sumac in Urmia, West-Azerbaijan province. Therefore, two regional stands in Kachale and Khan Valley regions were selected. Total number of 30 circular plots, each 100m2 were established, in which attributes including collar diameter, diameter at breast height (DBH), height of main stem, crown height, mean crown diameter, the origin and vigor (health) of the trees were measured. Physicochemical properties of the soil were studied within 10 soil samples in Kachale and three samples in Khan Valley. Results indicated that collar diameter of main stem, DBH, height and mean crown diameter in Kachale were significantly higher than in Khan Valley stand. Surveying soil samples in Khan Valley and Kachale also showed that lime (51.8%) and potassium (276 p.p.m) in Khan Valley stand were significantly higher than in Kachale (1.25% and 224.5 p.p.m, respectively). Moreover, stand organic matter (1.6%) and potassium (210.75 p.p.m) under the canopy were more than in open space (%0.9 and 146.60 p.p.m respectively) across Kachale test site. This test site also revealed a significant correlation was observed between fruit weight and crown diameter.

This study was carried out to determine appropriate methods for rooting and seedling production of Crataegus pseudohetrophylla Pojark. from hardwood cuttings by IBA, bacterial and mycorrhizal treatments and two different sources of sprout and seedling.For this purpose, cuttings were sown in two separate experiments in a Complete Randomized Design (CRD) with 11 treatments and 3 replications of 10 cuttings in greenhouse benches. Treatments contained dipping the basal end of cuttings in H2O2 (3.5% w/v) followed by the application of IBA at concentrations (0, 1, 2, 3, 5, 8, and 10 g l-1) or dipping in 4 g l-1 IBA and then application of bacterial suspension of Agrobacterium rhizogenes A13, Pseudomonas fluorescens 169, Bacillus subtilis FzB24, and mycorrhizal inoculums of Glomus intraradices. In the first experiment, cuttings from sprout source were sown in greenhouse benches. The seedlings were transplanted to the open field condition after three months, and were assessed for rooting characteristics after a season of growth. In the second experiment, cuttings were prepared from seedlings produced from the first experiment, and the experiment was conducted in greenhouse and open field conditions and with similar treatments to those applied in the first experiments. Results showed that in the first experiment the highest rooting percentage was obtained in the combination of H2O2 with 3 g l-1IBA, and the highest root area, specific leaf area, total seedling dry weight, height, and total chlorophyll contents were obtained when a combination of IBA with bacterial suspension of A. rhizogenes was applied. In the second experiment, the highest rooting percentage was observed for the combination of H2O2 with 3 and 5g l-1IBA, as well as for the combination of IBA with bacterial suspension of A. rhizogenes.

As the first phase of a 16-year project, this research was carried out in a section of coppice Brant`s oak (Quercus brantii Lindl.) trees in Chegeni, Khorramabad, Lorestan province. We assessed the effect of different thinning treatments on growth of Brant`s oaks during a 4-year period. Three treatments with 3 replications were used including heavy (decreasing 30 percent of basal area), medium (decreasing 20 percent of basal area) and light (decreasing 10 percent of basal area) thinnings. One treatment was considered as control with no intervention. Quantitative characteristics of sample trees were measured prior to thinning. The measurements were repeated during 4 years to calculate the growth values. Based on results, heavy thinning had considerably positive impact on growth of diameter, height and basal area of sprouts as well as on growth of sprout-clumps crown area. It is concluded that thinning operations can improve the unsustainable structural characteristics of young coppice stands within Zagros forests.

Site productivity is a key indicator of forest ecosystem, and is therefore an important criterion for forest managers to estimate the yield, annual exploitation and site growth.In this study, dominant height index was used as the most reliable criterion for evaluating site productivity of even-aged stands. A selective sampling method was used to locate 52 square sample plots of 0.04 ha each in poplar stands. The height and diameter of Populus deltoides Marsh. trees and altitude of each plot was recorded. Also, in each plot, soil samples from 0-20 cm and 20-40 cm depths were taken for analyzing several soil properties. Evaluation of stands productivity by using generalized additive models and AIC showed that altitude, P, saturation, organic carbon, gravel, N from 20- 40 cm depth as well as Ca, bulk density and pH from depth 0-20 cm were the significant variables explaining the 90% of variability in productivity of P. deltoides. Using the relative importance criterion showed that altitude, P from 20-40 cm depth and bulk density from 0-20 cm depth were associated with dominant roles, yet the overall contribution of altitude, organic carbon from 20-40 cm depth, bulk density from 0-20 cm depth, together with other variables, were the most significant drivers of poplar site productivity.