Search

Extended Abstract Introduction and Objective: Measuring rainfall and its components is essential in forest areas to manage the land's water resources. Throughfall is one of the most important components of the water cycle in forest ecosystems, which has many spatial variations due to the heterogeneous structure of canopy and variable rainfall patterns. However, few studies conducted to determine the optimum samples size for estimating this variable. This study aimed to estimate the number of collectors needed to estimate the average cumulative throughfall of Persian oak (Quercus brantii), pine (Pinus eldarica) and silver cedar (Cupressus arizonica) stands within certain error limit percentage in the semi-arid Zagros forests (Chaoghasabz Forest Park, Ilam County). By determining the appropriate number of collectors, it is possible to have a proper measurement of rainfall and its components in forest areas with acceptable accuracy and saving time and cost. Material and Methods: This research was conducted from October 2017 to February 2018, in natural stands of Persian oak, 30-year eldar pine and silver cedar plantations. The amount of rainfall was measured by five rain gauges located in the open space (outside the canopy), adjacent to the studied stands. The measurement of throughfall was carried out by 27 collectors in Persian oak underneath the canopy and 36 collectors in each eldar pine and silver cedar stands. The average stemflow of five trees in each stand was considered as the average stemflow of the stand. The amount of rainfall interception was estimated from the difference between the amount of gross rainfall and the sum of throughfall and stemflow. Results: During the study period, 20 rainfall events (in total, 258.2 mm) were measured, and on average, 80, 50 and 59% of it has passed through the canopy in the form of throughfall in each oak, pine and cedar stands, respectively. The mean values for rainfall interception were computed as 46.23 mm for Persian oak, 113.17 mm for eldar pine and 92.17 mm for silver cedar stands. The average number of required collectors estimated with 5, 10 and 15% error percentage of the cumulative average of throughfall at a confidence limit of 95% are 102, 25, and 11 for oak, 5, 10, and 15 for pine and 30, 8 and 3 for cedar, respectively. Conclusion: According to the results of this study, a positive and strong relationship was observed between the amount of rainfall and throughfall for Persian oak (R2=0.9155), eldar pine (R2=0.8831) and silver cedar (R2=0.8967). On this basis, it can be said that with the increase of rainfall size, throughfall increases. Considering the rainfall regime and the importance of water in these areas, in forestry and modeling of ecohydrological processes in forest ecosystems, priority should be given to planting species with higher throughfall and less interception loss. The estimated number of 27 collectors is enough to measure average cumulative throughfall of Persian oak with an error of 10%. In the eldar pine and silver cedar stands, where 36 collectors used, this number found to be optimum for measuring the cumulative average of throughfall with an error of 5%. Thus, in the Persian oak stand, the number of collectors should be increased in order to estimate the cumulative average of throughfall with a lower percentage of error, and in the other two stands, the number of collectors was found to be suitable.

Background and Objectives: Numerous models, ranging from simple to multidimensional, have been developed to estimate tree competition within forest stands. These models serve to measure and illustrate the interactions between trees, intending to evaluate the intensity of competition based on these interactions. Typically, these indices rely on the morphological characteristics of trees or the distance between neighboring trees. The assessment of individual tree competition, through the use of competition indices, is based on mathematical techniques that quantify the level of competition experienced by a tree from its neighboring trees. This outcome is commonly interpreted as the detrimental impact of neighboring trees on the growth of individual trees, as they compete for limited resources. Materials and Methods: Distance-independent competition indices are commonly employed to assess the competitiveness of tree species by utilizing tree size ratios, such as dbh, height, basal area, or canopy cover. In contrast, distance-dependent indices take into account the dimensions of neighboring trees and their spatial proximity. To calculate the competitive indices, namely the distance-independent competition index (IDI), distance-dependent competition index by diameter (DDIdbh), and distancedependent competition index by height (DDIh), measurements of diameter and total height were conducted for all trees within sample plots covering a one-hectare area. This investigation was carried out in four stands of poplar plantations located in Gilan province. The distance between the trees was also measured. Subsequently, to determine the wood density and incorporate its value into the distance-independent competition index, 15 trees from various diameter classes were randomly selected within each plot and felled for wood density analysis. The density calculation process was then conducted. Results: The obtained results indicated significant competitive conditions in both types of indices across all stands. In terms of the distanceindependent index, all stands exhibited a significant difference (P≥0.05). However, when comparing the distance-dependent index for tree diameter, stand 3 displayed a significant difference compared to the other stands. Additionally, stands 1, 3, and 4 also exhibited significant differences (P≥0.05). Furthermore, the comparison of the distance competition index for tree height revealed no difference between stands 1 and 2, but a significant difference was observed between stands 3 and 4 (P≥0.05).Conclusion: The calculating of various competition indices holds value in silvicultural programs such as thinning. Such studies yield a clear comprehension of the spatial structure of trees. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the socio-economic and environmental effectiveness of rangeland restoration projects using Atriplex canescens plantation in Mallard county, Tehran province, Iran. The research methodology employed a descriptive-analytical approach, utilizing a questionnaire administered to 65 experts, 132 pastoralists, and 29 members of the local communities. The sample sizes were determined using Cochran's formula, and random selection was utilized. The validity of the questionnaire was assessed through expert consultation, and Cronbach's alpha coefficient was used to estimate reliability. Two-way analysis of variance, Friedman's test, and the Kruskal-Wallis test were employed for data analysis. The findings revealed that Atriplex canescens plantation had a significant social impact, while no significant effects were observed on the economic and environmental indicators. Consequently, the social index was determined to be the most important, followed by the environmental and economic indices. Experts highlighted that the economic, social, and environmental benefits of the plantation primarily manifested through increased livestock products, improved ranching conditions, enhanced motivation, and community participation in rangeland restoration activities, as well as the prevention of fine dust and soil erosion. Similarly, pastoralists identified increased livestock products, improved ranching conditions, heightened awareness about pastures, and prevention of land use changes and fine dust as the most significant economic, social, and environmental benefits of Atriplex canescens plantation. Local communities emphasized economic benefits in terms of improved employment and income, enhanced public health and hygiene, and increased vegetation and fodder production. Overall, the study demonstrated a convergence of opinions among all three groups, highlighting the effectiveness of Atriplex canescens plantation. This alignment of perspectives indicates the potential for successful project implementation, goal attainment, and ultimately, satisfaction among pastoralists and local communities. The positive economic and social outcomes of rangeland restoration projects contribute to sustainable development, facilitating the prosperity of local communities. [ABSTRACT FROM AUTHOR]

The number of trees in each diameter at the breast height (DBH) class is considered the diameter distribution model and it is one of the most critical parameters in describing the structure of the stands. The diameter distribution of trees is one of the most important aspects that should be considered by forest managers when deciding on forest management strategies. This study aimed to investigate the diameter distribution functions of poplar (Populus deltoides) trees in the plantation in the Guilan province under the influence of different planting distances. To use models of diameter distribution functions as a tool to obtain reliable information about the structure, growth, and performance of plantations, and to manage silvicultural treatments in these stands. For this purpose, the measurement of all trees' DBH in the one hectare plots was used in five pure poplar plantations with 5×5 m, 3×5 m, 3×3 m, 3.5× 5 m, and 3×4 m planting distance. Kolmogorov-Smirnov fitting test showed a specific distribution function in each stand. The diameter distribution of the trees followed the Beta function in the stand with a planting distance of 5×5 m. The diameter distribution function has of Log-Normal (3P) distribution at a planting distance of 3× 5 m. The diameter distribution of trees was a Normal function at a planting distance of 3×3 m, at a planting distance of 3.5×5 m in the fourth stand, the diameter distribution of the trees was fitted as a Weibull function and Normal distribution was shown in 3×4 m planting distance in the last stand. The present study showed that planting distance on the plantation is a factor in changing the diameter distribution functions. At less planting distance, the diameter distribution of trees was normal, and by increasing the planting distance, various diameter distributions were obtained in the stands. Therefore, the present research can be used as a reference study by introducing the diameter distribution model for a mono-culture homogeneous pure stand regarding planting distance. This is practical for stand management to reach a desired distribution or management to transform from a pure stand to a mixed species stand by combining several species with appropriate distribution. In addition, transitioning from a single species structure to a diverse structure using growth performance models is required to simulate this stand's dynamics, the initial step is the determination of the tree's diameter distribution models as a basic study. [ABSTRACT FROM AUTHOR]

In arid areas, increasing irrigation periods is necessary to providing the water needed for the development of green space and plantation. This study was conducted in forest park of Saveh based on a randomized complete block design in split-split plot arrangement with irrigation period as main plot and coniferous species of Juniperus excelsa M.B., Cupressus arizonica Green., Platycladus orientalis (L.) Franco., Cupressus sempervirens Var. fastigiata., Cupressus sempervirens Var. horizontalis., Pinus eldarica Medw., Pinus brutia Ten., Pinus mugo Turra., Pinus pinea L., Taxodium distichum L. Rich., as sub plot with different origin in three blocks for 5 years. In each block from each species, 24 seedlings as a group were planted at 2.5 × 2 m. spacing that from these numbers, 12 seedlings were considered for 7 days irrigation and 12 seedlings for 14 days irrigation using of TerraCottem hydrophilic polymer. The results showed that height and collar diameter showed a significant statistical difference.in the interaction between irrigation periods and species. The main effect of irrigation period was significant on characteristics of collar diameter and vitality. P. brutia obtained the highest height (2.76 m), survival percentage (90.67 %), and vitality (90 %) and P. mugo obtained the highest collar diameter (6.42 cm), canopy cover diameter (1.27 m) and area of canopy cover (5.12 m2). Cluster analysis showed that species of P. orientalis, P. brutia and C. sempervirens Var. fastigiata with Koloudeh origin are in the most suitable conditions in terms of each of the variables studied and along with 14 days irrigation period using of TerraCottem hydrophilic polymer introduced for planting in Saveh.

In plant ecohydrology studies, stemflow considered as point input of rainfall into plant ecosystems. To date, due to field measurement, time-consuming and high cost of stemflow measurements, models are used to estimate the stemflow amounts. The aims of this study were to test the performance of three physically-based model of Gash and revised versions (Gash-1 and Gash-2) to estimate the stemflow in an elder pine (Pinus eldarica Medw.) stand in the Chitgar Forest Park for three-years study period. Rainfall magnitude and throughfall was measured with 10 and 60 rain-gauges, respectively. Stemflow was measured for 9 trees in each stand that were considered representative of the stand. According to the validation step, Gash and Gash-2 models were found to be the best models to estimate the stemflow, respectively, however the performance of each model was different at each rainfall magnitude class. For the very small rainfall class (lower than 2.50 mm), estimation of all models was incorrect. For the small (2.51-5.00 mm) and medium (5.01-7.50 mm) rainfall classes, Gash-2 was the best model, while Gash model estimated very well for the large (7.51-10 mm) and very large (more than 10.00 mm) rainfall classes. In conclusion, Gash model requires few input variables, hence would be more applicable than to other models. Due to the climate change, which is affected by the frequency of rainstorms in different rainfall magnitude classes, it is necessary to use appropriate models to estimate the amount of stemflow.

Earthworms are considered as the most important characteristics in assessing the quality and soil health of forest ecosystems. Earthworms were identified according to their shape and appearance, and their biomass was measured at the laboratory. In order to study the earthworm's biodiversity, Simpson diversity and Margalef richness indices and Camargo evenness were employed. A total of 5 different types of earthworms were identified in the studied habitats. According to the results, all of the earthworms identified were belonged to a family (Lumbricidae), four genera (Lumbricus, Dendrobaena, Aporrectodea and Octolasion) and three ecological groups (Epigeic, Anecic and Endogeic). The Dredrobaena octaedra earthworms from the Epigeic ecological group in all studied habitats were observed in this study and have the highest frequency. The earthworm species belonging to the Anecic and Endogeic ecological groups were not found in the oak, cypresses and degraded areas. In general, ecological groups of earthworms under less degraded natural forest and alder habitats were the most frequent and they had positively significant relation with litter and soil nitrogen and also soil pH, whereas they were negatively related to litter and soil carbon and carbon to nitrogen ratio. As a conclusion, the degradation of forest habitats has reduced the frequency and diversity of earthworms, while the reforestation of degraded forests, especially alder plantation, has increased diversity and abundance of earthworms.

The aim of this research was to estimate the ecohydological parameters of the canopy covers including estimated canopy saturation point (P´G Estimated), canopy storage capacity (S), the ratio of mean evaporation rate from the wet canopy to the mean rainfall intensity ( ), free throughfall coefficient (p), computed canopy saturation point (P´G), and stemflow funneling ratio (F) of a Picea abies plantation in Lajim, Mazanderan province, north of Iran. To measure throuhgfall (TF), 45 rain-gauges were installed beneath the crown of the stand. Stemflow (SF) was measured using the average of 12 individual trees equaled to the SF amount. Over the measurement period, the cumulative percentage of TF, SF, and rainfall interception (I) were 41.0%, 5.1%, and 53.9%, respectively. The abovementioned ecohydrological parameters were found to be 4.2 mm, 3.54 mm, 0.38, 0.18, 5.90 mm, and 4.6, respectively. The ecohydrological parameters should be considered while converting natural stands to plantations of exotic tree species as this altering would be alter soil humidity, soil pedogenesis, and forest floor composition.

The aim of this research was to measure rainfall components (throughfall, interception, and stemflow) in needle-leaved (Pinus brutia, Cupressus arizonica) and broadleaved (Fraxinus rotundifolia and Platanus orientalis) plantations located in Broujerd Forest Park. The total amount of gross rainfall was measured using three rainfall collectors fixed on an open area neighboring to the chosen trees. In order to measure throughfall, five trees of each species were selected and four collectors were fixed underneath each tree. The amount of interception was calculated based on the difference between throughfall and gross rainfall. In a time-span of six months running from November 2012 to May 2013, 24 rainfall events with total amount of 131.8 mm was measured. The amount of interception was measured as follow: Pinus brutia 46.1%, Cupressus arizonica 50.7%, Fraxinus rotundifolia 49.6% and Platanus orientalis 38.1% of total gross rainfall. Strong positive correlations were observed between total rainfall and throughfall for each kind of species. It was found that throughfall in hardwoods species was more than conifer species and the amount of throughfall in aforesaid masses increased as total rainfall increased. The amount of stemflow for all species was less than one percent of total precipitation. Regarding to importance of rainfall regime in this area, interception and throughfall of each species should be considered with priority of broadleaved in plantation and hydrological modeling process in forest ecosystem.

One of the most important factors in determining the volume of trees is selection of appropriate form factor. In the present study, four different methods of form factor calculation were evaluated for two rapid growth species including Populus deltoides and Taxodium distichum. For this purpose, in each stand, 12 trees per 4 diameter class ranging from 10 to 45 cm in DBH were randomly selected and diameter at breast height of all trees was measured. Then, using sectional measurement (cylindrical volume formula and Esmalyan) method, the actual volume of each tree was calculated. Also, Real (Fr), Normal (F0.1), Artificial (F1.3) and Hohenadl (Fh) form factors were measured. Analyses of variances were used to investigate any significant differences between the calculated coefficients. Dunnett's test was used to explore significant differences between various methods of coefficient calculation and the real form factor coefficients. Results showed that for Populus deltoides, artificial form factor (0.50) was closer to the real form factor (0.51) while for Taxodium distichum, hohenadl form factor (0.52) was closest to the real form factor (0.50). In addition, natural and artificial form factors were related to DBH, but real and hohenadl form factors were not related to DBH. Artificial form factor can be used for both species in this study as a suitable and useful form factor.

In this study, Pinus nigra forest plantation with an area about 10 hectares, located in Urmia airport was investigated. Sixteen 300 m2 circular sample plots were set up with systematic random method in 50×50 m grids network. One 100 m2 subplots, within the same plot, were established to record plant species and its cover. Soil samples in two depths (0-10 and 10-30cm) were taken in every other samples and soil factors including pH, soil organic carbon, total nitrogen, absorbable phosphorous were measured. Also a rangeland adjacent to plantation area was selected and three plots with 50 m distance spacing were laid out along a transect. Herbaceous species and soil factors were assessed in each plot similar to plantation area. The mean of diameter and height annual increment was calculated via dividing the diameter and height means by stand age till study time (40 years). Species richness and diversity indices were calculated in each plot. T-student test was used to test for significant differences between the means of indices and soil factors of two areas. Non-metric multidimensional scaling was applied to assess the rate of changes on the vegetation and soil chemical properties due to the plantation. Results showed that the mean diameter and height increment were 0.46 cm and 0.29 m, respectively.Species richness and Shannon diversity indices considerably decreased in the plantation area. The average of soil organic carbon, total nitrogen in the control area were more than those of the plantation area. Light, soil organic carbon, total nitrogen and absorbable phosphorous were the most important factors influencing the distribution of plant species. Generally, it is suggested that this species would not be planted in the wide regions and in the region in which it’s necessary to conserve plant composition and diversity.

Direct measurement of aboveground biomass of trees is considered as one of the labor-intensive, expensive, time consuming and destructive tasks. The objective of this study was to estimate the biomass of four coniferous and deciduous trees species (Pinus eldarica, Cupressus arizonica, Robinia pseudoacacia and Morus alba) by means of high resolution Quickbird remotely-sensed data of over a plantation are established around the industrial domain of Isfahan’s Mobarakeh Steel Company. To this aim, three approaches based on vegetation indices, texture analysis and Principal Component Analysis (PCA) were applied to extract required information from satellite imagery. The correlation analysis between field-assessed biomass and the image-based information and regression models were built. The results using vegetation indices (DVI and NDVI) for coniferous species as well as athose from texture analysis and PCA for deciduous species showed significant corelations. As depicted by the species-specific regression of biomass revealed the amount of RMSE ​​ for P. eldarica, C. arizonica, R. pseudoacacia and M. alba to be 53, 20, 30 and 50, respectively. Moreover, species-specific biases for P. eldarica, C. arizonica, R. pseudoacacia and M. alba was shown to be 30, 10, -30 and 44 respectively. The results of this study supports the use of the applied Quickbird data for model-based estimation of aboveground biomass across the study site.

The potential for carbon sequestration was evaluated for two coniferous species (Cupressus arizonica Green var. arizonica and Pinus eldarica Medw) in 17-18 year old plantations of Zob-e-Ahan industrial company near Isfahan. Transect sampling was conducted in each section, and five trees in each of the available 5 diameter classes were randomly selected and cut. Moreover, soil samples from 0 to 30 and 30 to 60 cm depth were collected in each part. Shoots and roots of the trees were separately collected and weighted. In addition, carbon sequestration of organs and soil was determined with an in-situ combustion method. Results showed that the rate of carbon sequestration was significantly different between two species (p

Biomass factor is one of the efficient methods for non-destructive estimation of biomass and carbon storage in forest stands. To fulfill the existing lack of biomass data in plantations of Northern Iran, this study derived biomass factor (BF), crown biomass to aboveground biomass ratio (R) and biomass expansion factor (BEF) coefficients for three tree species of Eastern Poplar (Populus deltoides), Caucasian Alder (Alnus subcordata)and Bald cypress (Taxodium distichum) across a 20-years old plantation. For each species, 12 individual trees were felled down. Then the dry weigh of stem, branches, twigs and leaves were separately measured for each tree. The BF values for Eastern Poplar, Caucasian Alderand Bald Cypress were 0.036, 0.007, 0.006 Mg m-3 for branch, 0.055, 0.017, 0.024 Mg m-3 for twigs and 0.041, 0.006, 0.031 Mg m-3 for leaves, respectively. Compared to the other two species, the R value forEastern Poplarwas significantly lower. The BEF values were 0.499, 0.554 and 0.621 Mg m-3 for Eastern Poplar, Caucasian Alder and Bald Cypress, respectively. Although these coefficients are easy to apply and efficient for use, but using them for other plantations must be done with caution, because applying them for other plantations with different stand structure may result in a biased estimation.

Oak (Quercus castaneifolia C.A.M.) is one of the most important forest tree species in the Caspian region of Iran and every year huge lands are purely planted by it. The aim of the research was to study characteristics of an even-aged planted stand (25 years old, 1.2 ha) of the species and proper management which lead to suitable tree form in future. For this purpose, diameter at breast height (dbh) and total height of all the trees and volume of 30 sample trees were measured. Results showed that although tree plantation was made only by oak species, but the stand today consists of 10 species as follows: oak (85.2%), horn beam (7.9%), iron wood (0.7%) and other species, including velvet, Cappadocian maple, elm, alder, and lime tree (6.2%). Most of the trees were classified at three diameter classes, including 10, 15 and 20 cm. diameter and height increment for trees with average dbh and total height of 15.3 m. and 16.4 m, were 6 and 66 mm. respectively. Mean dbh and height increment rates were 0.6 and 66 cm per year, respectively. Mean volume increment was 5.13 silve per year per ha. It can be concluded that according to our findings and other similar research results that diameter growth of oak in Iran is faster than its growth in Europe and might be utilized at lower age stage for veneer industry. Furthermore, stand structure in respect to trees form and mixture rate was studied and its trend process into mixed stand was silviculturally discussed and analyzed.

In order to determine the most suitable spacing of ash, (Fraxinus excelsior L.), the effect of three levels of planting spaces ( 1.5×1.5, 2×2 and 2.5×2.5 meters) on quantitative and qualitative characteristics of ash were examined. Statistical design used was random completely block design with three replicates. The site is located in north- west aspect, 250 m a.s.l and 5 percent slope in south of Sari in Mazandaran province. After termination of ten years period, survival, height, diameters and some quality traits of trees were measured and recorded. The results showed that the effect of planting space on tree survival (p

The effects of different irrigation regime on survival and growth of holm oak (Quercus ilex L.) plantation was studied in a semi-arid Mediterranean climate condition located in Marzanabad region (Mazindaran province). This study was done as Randomized Complete Block design with three replicates and four treatments, including no-irrigation and irrigation with 10, 20 and 30 day periods during dry months in growing seasons (spring and summer). Climate data analysis showed that a severe frost and three to six dry months annually occurred in growing season during study years (2006-2010). Height growth and survival of saplings were measured every year and at the end of 5th year. Analysis of data showed that irrigation treatment with 10-day intervals with a 65% survival is preferred and differences are significant (p

Decline in natural forests area due to various factors has caused the importance of plantation which is carried out with the aim of developing forest surface and wood production. Therefore, assessing the nature of plantations can play an important role in creating forests with better quality and quantity in the future. Nutritional status of habitat is an important qualitative factor in forest stand. The primary sources of nutrient elements in soil and leaf are nutrient retranslocation of old leaves. Retranslocation, movement and transfer of nutrient elements from aging leaves to tissue reservoirs occur each year, which is a key process in most ecosystems. In this study, the amount of nutrient elements (Ca, K, P, N, Mg) in summer and autumn leaves and amount of retranslocation of these elements in three plantation species (Acer, Zelkova and Pinus) of Darabkla-Mazindaran were measured. Sampling was conducted in two stages, one in mid-summer during ascending period of nutritional dynamism of trees, and the second stage in mid-autumn simultaneously with the beginning time of leaf fall in the same trees previously sampled. Results showed that there is difference between nutrient elements in summer and autumn leaves in the studied species. The magnitude of nutrient retranslocation was obtained in order of: P>Ca>N>Mg>K. Among the studied species, the highest retranslocation of Ca and Mg were determined in Acer, N and K in Zelkova and P in Pinus. The results of this study showed that the studied species had different nutritional elements and also different amounts of element retranslocation. Since the studied species had been raised under similar conditions, therefore it could be concluded that these differences are due to genetic variation of species.

Forest canopy rainfall interception loss (I) and canopy water storage capacity (S) are important components of the water balance in arid and semi-arid climate zones. The goal of this research was to quantify S and free throughfall (p) in a mature Pinus eldarica Medw. afforestation planted in the Chitgar Forest plantation near Tehran, Iran. Measurements of gross precipitation (GR (n=6)) and throughfall (TF (n=45)) were recorded on an event basis from September 2009 to April 2010. I was calculated as the difference between GR and TF. For the measurement period, GR totaled 164.8 mm and rainfall interception loss (I) was 61.2 mm. In this study S was estimated as 1.7 mm, 1.4 mm and 1.8 mm by methods of Leyton, Gash and Morton, and Pypker- Jackson, respectively. Free throughfall (p) was estimated 0.1422. I was estimated 44% and 91.3% of total GR for rainfall events sufficient to saturate the canopy (GR>1.6 mm) and insufficient to saturate the canopy (GR>1.6 mm), respectively. The results demonstrate that canopy storage capacity represents a considerable portion of intercepted rainfall from GR in P. eldarica plantation regions of the semi-arid climate zone of Iran where soil moisture is a limiting factor on plant growth and productivity.

This research was carried out in parcel 15 of the first district of Arabdagh afforestation plan to study the growth performance of 17- year old Turkish pine (Pinus brutia Ten.) plantations (ca. 63 ha and 2×3 m spacing). Sixty three sample plots were selected as random-systematic design. Within each plots, DBH, Total Height (TH), form factor, natural regeneration, stem form, crown vitality, stem health, mode of branching, stem straightness and crown symmetry were recorded. Computation of Dominant Height (DH), mean height and DBH, Basal Area (BA), height/DBH ratio, Total Volume (TV) and Mean Annual Increment of Volume (MAIV) and analysis of variable correlations were performed. Results showed that Arabdagh plantation had greater DBH and BA (14 vs. 13.7 cm and 27/983 vs. 24 m2/ha respectively) and less DH, mean height, TV and MIAV than the good sites of Turkish pine plantations in the country of origin with same age and plantation density which generally located between good and medium site conditions for Turkish pine plantation. Therefore regions with same ecological conditions can be considered as suitable sites for Turkish pine plantation.

In order to study the effect of thinning operation on growth and wood production, an alder plantation (Alnus subcordata) on deep and moist soil with medium fertility was selected and thinned during 10 years. All standing and fallen trees were measured in terms of diameter at breast height (d.b.h), total height and standing volume. By thinning, the number of standing trees were decreased from 1700 to 400 stem per hectare. Results show that after thinning, the percentage of mortality decreased from 35% to less than 1% during 10 years. D.B.H growth, total height and standing volume increased 76%, 40% and 17%, respectively. The mean annual increment of standing volume was greater than 20 m3 for alder plantation grown on heavy and moist soil. Thus, Caucasian alder is proposed for intensive wood culture program in such areas (which are not suitable for poplars) in Caspian coastal plains.

The significance of biodiversity maintenance in sustainable forest management has been indicated at many scientific studies. The present study was conducted to investigate the impact of Pine (Pinus nigra Arnold.) and Ash (Fraxinus excelsior L.) plantations on diversity of herbaceous vegetation cover and soil properties in Alandan site of Sari Forest area of the Iranian Caspian Forests. herbaceous vegetation cover percentage and natural regeneration number of woody species were measured, using six plots (20×20 m.) at each stand, which have been selected by random systemic statistical method. Soil sampling was made at center of each plot up to 30 cm depth at 10 cm intervals, using coring method (8 cm diameter). Soil tested propertirs consisted of: C, N, pH, EC, particle density and bulk density. Biodiversity indices (Shannon, Simpson), richness indices (Menhinick, Margalef) and uniformity indices (Equitability, Evenness) were estimated, using PAST software. The results showed that the biodiversity richness and evenness indices for herbaceous species cover and woody species regeneration at pine stand were greater than at the ash stand (p

Plantation forests can influence both plant diversity and soil properties. This study mainly aims to determine and compare the status of plant diversity of ground flora andsome physico-chemical properties of soil under influencing of plantation with conifer and broad leaved species. Three sites (conifer, broad leaved and non-planted site as control) were selected in Sanandaj (Dushan region). These sites were physiographically and climatically similar. Systematic random sampling was used as a method for data collection. To study quantitative characteristics of stands, 20 quadrate sample plots with 400m2 area were selected in each site (60 plots totally). In order to determine the herbal species and their coverage percent, each plot was divided into 4 sections and a microplot (1.5m×1.5m) was selected in each section. To study the physico-chemical properties of soil influenced by planted species, 3 soil samples were selected in the center of each plot in depth of 0 to 20cm and the soils were mixed with each other to obtain mixed soil samples. The data was analyzed using complete randomized design. Results showed that the plant diversity and frequency on ground flora under influence of plantation with broad leaved species was maximum, while the evenness index was minimum. There was significant difference among all sites regarding to porosity, however there was no difference among the sites from view point of other physical parameters. Moreover, there were significantly differences between most chemical parameters of soil in three studied sites.

This research has been carried out in twenty-years-old plantations with species of Cupressus sempervirens, Acer velutinum, Populus deltoides and Alnus glutinosa, located in Sourdar- Vatashan forestry plan which have been damaged due to the heavy snowfall in February 2008. The study aimed at evaluating and comparing of the damage intensity in studied species and determining the correlation between effective factors with damage rate. Damage rate was evaluated using 30 circle sample plots with an area of 314m² in a systematic-random grid (125m×125m) in 48 ha area. Results showed that damage rate was 84% in Cypress stand, 6/18% in Poplar and 18.28% in Alder, while Maple stand remained intact. There is significant relationship between damage percentage and diameter at breast height (P

The objective of this study was a comparative evaluation of 20-year old plantations of Alder (Alnus subcordata C.A. Mey.), Chestnut leaved Oak (Quercus castaneifolia C.A. Mey.), Maple (Acer velutinum Bioss.) and Cypress (Cupressus sempervirens var. horizontalis) with the adjacent mixed broad leaved stand from qualitative and quantitative point of view. The study area is located in Darabkola, east of Mazandaran province in the Caspian region. One sample plot, each 1 hectare was selected in every plantation as well as in the natural stand. A total of 5692 trees were measured by full callipering; the studied factores were diameter at breast height (dbh), height and qualitative characteristics of trees. Also the physico-chemical properties of soil were studied in all treatments. The differences of the studied factors between the treatments were significant, statistically (p>0.01). Analysis of quantitative characteristics showed that natural forest and plantation of Alder were the most promising followed by Maple and Chestnut leaved Oak. From the qualitative point of view, alder and maple plantations were the most promising stands, while the Cypress plantation showed the worst results.

This study was conducted to determine the increment and wood production of 22-year-old cypress plantation in Kordkuy region in the north of Iran. Thirty sample plots, each 200m2 area were selected at 101 ha of Cypress man-made forest which was planted in 2mÍ2m spacing. The samples were taken by systematic random method. In each sample plot, diameter at breast height (DBH) of whole trees and height of witness trees were measured. Moreover, 53 trees were selected as sample trees based on classified diameter in sample plots and felled trees. The data were analyzed with SPSS and Excel softwares. Results showed that the survival rate was 58.72%. The quantitative parameters were calculated and revealed that mean DBH, mean height, basal area, volume and annual volume increment were 15.2cm, 14.02m, 24.35cm2 ha-1, 157.31 silve and 7.15 silve ha-1 y-1, respectively. Results showed the studied plantation compare to Cypress plantations in other parts of the country is promising

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%).

This research was conducted to investigate on spatial structure and estimationof tree attributes in a forest plantation in the Caspian region of Iran. Field sampling was performed based on a 50m×125m systematic grid in a maple stand (Acer velutinum Boiss.) at age of 18 years using circular samples of 200m2 area. Overall, 96 sample plots were measured in 63 hectare and 14.25 hectare was inventoried as full census area, as well. Experimental variograms for forest stem basal area, stem density and tree height attributes were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of basal area and height showed a high spatial autocorrelation, which fitted by spherical models. However, stem density showed a large amount of nugget effect. Based on variography results, optimal sampling distance for stem basal area and density obtained 165m and 350m, respectively. Estimations for basal area and height were made by ordinary block (15m×15m) kriging and cross-validation results showed that all the estimations are accurate. Furthermore, the estimated kriged mean of basal area showed no significant difference to the real mean in the full census area, while kriging in term of statistical precision was two times better than sampling. Therefore, geostatistics is able to capture and describe the spatial variability as well as estimates tree attributes (not stem density) in this kind of forest plantation, accurately.

The determination of survival and vigority effective parameters on old saxaul (Haloxylon aphyllum) shrub is essential for sustainable development of planted forests in desert area. In fact, the objective of this study was to determine the effects of different density and pruning levels on survival and the vigority of saxaul. The study was carried out in obviously wilted planted saxaul forest that is located in Ashkezar desert region of Yazd province. Experiment was conducted in split plot design with main-plots that had 250 and 125 trees per ha and sub-plots were 3 types of pruning at height of 10, 35 and 70 cm above ground surface, plus control (no pruning) sub-plot. Pruning was done on autumn 1994. After one year from shrubs pruning, analysis of plant mortality percentages was started and continued on the same pruning time to 2000. The determination of vigority carried out only in 2000. Results showed that the differences of survival among all treatments were not significant. The effect of density on vigority was also not significant, whereas the pruning height had significant effect (p

In order to compare adaptability and growth of Pinus elliottii and P. radiata, the trial was conducted in 1995 at Chamestan-Noor Forest and Rangeland Experimental station (Caspian Sea of Iran). The seedlings oftwo species were planted in separate groups. Each stand area was 7500m2. In addition, determination of survival and measurements of quantity accomplished (for five years). After 10 years, parameters such as survival, quantity and quality are determined. Finally, data with T-test method in SPSS are analyzed. Species comparisons showed that P. elliottii survival (75%) is more than P. radiata survival (57%) in the studied area. The mean diameter at breast height (D.B.H) of Slash pine and Monterey pine were 15/4 and 15.5 centimeters, respectively. Also mean height of Slash pine and Monterey pine were 11.1 and 9.5 meters, respectively. Analysis of mean height and diameter demonstrated that there were no significant difference for diameter growth between P. elliottii and P. radiata. However, there was significant difference for height growth between two species. Furthermore, volume per ha for P. elliottii 190 sylve and for P. radiata 91 sylve were determined. Comparison of two pines revealed that Slash pine (P. elliottii) grows faster and is more resistant than Monterey pine (P. radiata) in theChamestan region. Thus, Slash pine for plantation with aim of wood production and using of fast growing species is proposed.

Depletion of natural forest due to different reasons has made the forest plantation important for extending forest area and wood production. Therefore, evaluation of forest plantation can play an important role to establish the plantation for the future. The objective of this study is to evaluate three different reforestation which was planted by Acer velutinum, Alnus subcordata and Fraxinus excelsior species. Each planted area with 49 ha was established in 1985. For data collection, 90 plots of 400 m2 were selected randomly. Different variable such as diameter, total height, trunk length, forked tree and number of trees in different classes of diameter were assessed. The obtained results indicated that Alnus subcordata with 3.2 percent in 5 cm diameter class and 38.5 percent in 20 cm diameter class had the highest values in survival, while Fraxinus excelsior with 31.7 percent in 5 cm diameter class and 19.7 percent in 20 cm. diameter class had the lowest values in survival. Data analysis for stem quality showed that Fraxinus excelsior with 31.6 percent forked trees had the lowest value, while Alnus subcordata with 18.5 percent forked trees had the highest value in stem quality. Therefore, assuring seed quality for seedling production and protection after out planting could be resulted as a good quality of plantation.

In this research, the qualitative and quantitative characteristics of Oak (Quercus castaneifolia), Nettle tree (Celtis australis) and Walnut (Juglans regia) were investigated in experimental plantation. Two-years old seedlings of species were planted in separated groups in 4×4 meter spacing as a part of a research project “Group plantation of industrial fast growing trees” at 1983. Diameter at breast height (dbh), total height, crown and trunk height were measured in 2005. The results indicated that survival in 23-years old trees of oak was 73.2% and for nettle tree and walnut were 97.1, 85.7 percent, respectively. Mean height of oak, nettle tree and walnut were 19.67, 11.48 and 15.96 m, repectively. The annual height increment of oak, nettle tree and walnut were 81.9, 47.9 and 66.5 cm, respectively. The mean dbh were 26.7, 11.2 and 17.9 cm for oak, nettle tree and walnut. The volume was 287.9 m3ha-1 for oak, 39.4 m3ha-1 for nettle and 128.6 m3ha-1 for walnut. Volume increment was calculated 12.5 m3ha-1y-1 for oak, 1.6 m3ha-1y-1 for nettle tree and 5.36 m3ha-1y-1 for walnut.

This research was conducted on north and south aspects in plantation site of Wild Almond (Amygdalus scoparia Spach) in Mishan region at Chaharmahal and Bakhtiari province. At the first step, 50 shrubs of A. scoparia were selected randomly in each aspect. After that, quantitative charactereistics such as height, collar diameter, crown diameter and number of coppice sprouts were measured. The results indicated that the mean height, collar diameter, crown diameter and number of coppice sprouts in north aspect was significantly more than those in south aspect. The results of this research might help the foresters to establish a more desirable plantation with wild almond on the degraded forests.