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

In a reserved forest parcel in a virgin eastern Hyrcanian mixed beech forest, 80 ha was surveyed to determine the pit and mound topography, canopy gaps and dead trees. The aim was to investigate the spatial patterns and correlation of pit and mound features with canopy gaps. Seventy-five canopy gaps and 61 pit and mound features were identified. The univariate first order nearest neighbor (RCE) and bivariate second order test (Ripley’s K) statistic were applied. RCE statistics highlighted a general aggregation pattern for canopy gaps and pits and mounds, while pits and mounds alone were more clumped. Distances between canopy gaps were 130 m average, whereas distances between pit and mound features and dead trees were 60 and 78 m, respectively. Spatial positive correlation of canopy gaps with pits and mounds were observed with all distances. The result of spatial correlations between canopy gaps with pits and mounds confirmed that windthrows cause micro successions in fallen tree ecosystem-scale correlated with gap phase dynamics in the forest community-scale.

Earthworm population, as a biotic factor, affects health and productivity of forest ecosystems. Earthworm density and biomass indicates biological activities and quality of soils. In order to get the benefit of earthworm ecological potential in Zagros forest management, the current biological activities as well as environmental factors impacting of this invertebrate have to be understood. This study aims at determining the density and biomass of earthworm and investigating their relationships to environmental factors including seasonal variability, soil depth and the tree canopy in Brant’s oak (Quercus brantii Lindl.) high forest of Darber area (Khoram Abad, Lorestan). Thirty two single-stem trees of Brant’s oak were sampled. Earthworm’s density and biomass were measured in spring and autumn, under and away from the canopy, using soil profile. Soil profiles were 50 cm deep and samples were taken from layers at 0-10, 10-30, and 30-50 cm depth. Means of earthworm’s density and biomass were compared using one way ANOVA and independent t-test at the 95% probability level. The results of this study showed that seasonal variation, soil layers depth and tree canopy had significant impacts on earthworm’s density and biomass. Earthworm’s density and biomass were decreased in autumn and also in spots away from tree canopy. Minimizing topsoil disturbance and expanding canopy coverage in managing Zagros forest resources could optimize the environmental conditions for earthworm biological activity, which would improve soil quality and ecosystem health.

Soil organic carbon (SOC) is a major component of global carbon cycle, hence forest soil as one of the major carbon sinks has a key role in the control of atmospheric Co2 concentrations. Consequently, changes of carbon release or uptake by forest ecosystems due to disturbance or management in an unsuitable period can have a considerable impact on atmospheric Co2 concentrations and global warming. In this study, the effect of selection systems were investigated on seasonal changes of soil organic carbon pool (SOCP) in the mixed beech-hornbeam stand in district one of Shastkolate forest, Golestan province. For this purpose, SOCP was determined in depth of 0-20 cm from February of 2014 to February of 2015 in four stands with one hectare area (one in compartment 32 of virgin forest) and three in compartments 30, 33 and 31 in managed forest, in which the last interventions date back to 10, 7 and 1 years ago). Soil temperature and moisture changes were measured through one year as effective factors on SOCP. One-way ANOVA were used to determine soil moisture and temperature variability in each treatment through one year, and seasonal dynamics of SOCP were comprised using repeated measures design (General linear model). The SOCP relationship with soil moisture and temperature were analyzed using Pearson correlation coefficient. Results showed that the monthly changes of soil moisture and temperature had a significant difference in each treatment. SOCP was also significantly correlated with soil moisture and temperature. SOCP difference in different seasons was also significant, which was more obvious in the managed treatments. SOCP showed severe decrease in the managed stands compared to the unmanaged stand in the summer.

Earthworm biomass is one of the most important quantitative indices of forests soil. Estimating the earthworm biomass in forest soils is often difficult due to changes in soil properties. This study aims at comparing the performance of multiple linear regression and regression tree models in estimating the earthworm biomass in different forest conditions. Earthworm biomass was sampled in 40 forest gaps and adjacent virgin forest. They were then separated from soil using hand-sorting method and weighted in 0.01 gr precision in compartment 32 Shastkolate forest. Physical and chemical soil properties were analyzed by using standard laboratory methods. The best fitted models were specified in multiple linear regression and regression tree models for estimating the earthworm biomass. The fitted models were then validated by using Mean Error (ME), Root Mean Square Error (RMSE) and Relative Error (RE) measures. Soil bulk density and total nitrogen explained 24% of total earthworm biomass variances in virgin forest while canopy area solely explained 66% of total variances in canopy gap. Multiple linear regression models overestimated the earthworm biomass while regression tree model underestimated the biomass in virgin forest but it was precise estimator in canopy gap. According to the results and due to heterogeneity in forest environment, it is recommended the research is done hierarchically for finding the important and effective variables (gap area and soil potassium in the current study) and after the site stratification based on these variables, the relationship between independent and dependent variables is studied.

Gaps within forest canopy cause changes in the received amount (intensity) and quality (PAR) of incoming light on forest ground. This research was performed in natural gaps of a reserve control compartment at Kelardasht region in Mazandaran, northern Iran and aimed to determine the role of gap size and relative light intensity on soil enzyme activity. Hence, 14 gaps at four size class (2- 200-300 m2- 300-400 m2 and >400 m2) and four light classes (25 %) were selected. Soil was sampled at 0-20 cm of top soil in the center of each gap. The results showed significantly different dehydrogenase activity in classes of gap size and light intensity, where its maximum amount was observed in the large gap size (300-400 m2) and at low light intensity (< 8%), respectively. Urease activity did not show significant difference within the classes. In addition, relative soil moisture was significantly different across the gap size and light intensity classes, whereas organic matter and Nitrogen did not show to be significant different.

Changes in chemical properties of throughfall and forest floor leaching in growing (leafed) and non-growing (leafless) periods essentially influence the biogeochemical cycle of forest ecosystems, especially in the broadleaved stands. The aim of this study was to compare the chemical composition. i.e. Calcium, Magnesium, Sodium and Potassium contents of throughfall as well as forest floor leaching in oriental beech trees in the Shastkolateh experimental forest of Golestan province. Throughfall and forest floor samples were taken after each rain within one year (21.08.2008 to 21.12.2009). To investigate leached nutrition of throughfall and forest floor in growing and non-growing periods, we used t-paired at the 95% confidence level. Results showed that Sodium and Potassium leaching in throughfall in the non-growing period (24.3 and 60 kg ha-1, respectively) were significantly higher than those of the growing period (52 and 18.7 kg ha-1, respectively). Furthermore, Sodium, Potassium and Calcium fluxes via forest floor in the non-growing period were 12.6, 42.3 and 8.2 kg ha-1, which showed significantly higher rates than those measured during the growing period (8.6, 23.5 and 6 kg ha-1, respectively). This study concludes that factors e.g. bark, decomposed leaves, and dry deposition play remarkable roles in the cations leaching process in forest floor within the eastern Hyrcanian forests during the non-growing period.

The aim of this study was investigation of Carbon, Nitrogen and Phosphorus dynamics in Carpinus betulus L. leaf litter in organic layer of a broad-leaved mixed forest in Gorgan. Fresh litters were collected from five plots in district one, Shastkalate forest and were placed into some litterbags with 2 mm mesh. Then, they were located in the study site. Over one year (8 sampling), chemical analysis was carried out. Result showed total Nitrogen concentration in fresh litters was 1.5% and after one year increased to 1.9%. Phosphorus concentration in fresh litter was 0.134% and increased to 0.136% after one year. Carbon to Nitrogen ratio in fresh litter was 24.5, but after one year decreased to 17.4. Carbon to Phosphorus ratio in fresh litter was 282 and after one year decreased to 245. Weight of fresh litter was 14.65gr, but decreased to 8.23gr after one year. Nitrogen content, C/N and N/P ratios of Hornbeam leaf litters were correlated with secondary weight of litter. C/N and C/P ratios were appropriated for discriminating of decomposition phases. Hornbeam Leaf litters caused soil fertility and increased site indexes. It is necessary to use Carpinus in reforestation and rehabilitation of destroyed forest, considering climate, elevation and forest degradation density.

Gap formation affects environmental conditions in forest ecosystems. In this study, the effect of forest gap on humus form in amixed Fagus orientalis Lipsky (Oriental Beech) forest was investigated by comparing the humus forms found in gaps with those in parts of the stand with closed canopies in atemperate mixed forest in northern Iran. In total, 32 gaps were selected from which 160 humus profiles were considered within gaps, and afurther 160 within adjacent closed canopies. In each profile, humus forms were determined based on their morphological characteristics. Results indicated that gap significantly affected humus forms. The humus forms in gaps differed significantly from those in ad¬jacent areas of closed stand. Mull order type humus was the most commonly found in the study site (70% of all profiles). The results also showed that forest floor thickness was lower in gaps than in adjacent closed areas. The suborder eumull was the most common in gaps, whereas dysmull was found to be the most common within closed areas. Przemysław Szmit

In order to evaluation relationship between trees and shrubs biodiversity with some soil physical properties in hyrcanian forests, in range of 850-950 altitude from the sea level in 6 sites (in each site 30 plots) with least interfering of human in north aspect and with equal distance from each other were located. In this 20*50 meter frame, the characteristic of trees and shrubs species (Species name & diameter) recorded. The heterogeneity indices of simpson, shannon–wiener, simpson , s reciprocal, and number of equally common used for the quantitative data. In each plot, four soil samples (500g) taken in the depth ranges of 10–20-cm. After mixing its, one sample (200g) was selected for laboratory. Physical properties of used in research are soil texture (percent of sand, silt, and clay), percent of soil saturation and bulk density. Results showed sand percent have positive correlation in all sites except Carpineo-Paroteum type. In addition, results showed clay percent has negative correlation in all sites. Thus, according to special site condition in forest types, appropriate technique should be base on knowledge of qualitative and quantitative condition of communities.

In forest ecosystems, there is an important interaction between hydrological cycle and nutrient contents. Rainfalls not only have an important role for entrance of nutrient contents to forest ecosystem, but also have an important role to transfer elements from canopy to forest floor and soil. This study performed to investigate the effect of throughfall and forest floor leachate on base-cations dynamics in a mixed hyrcanian beech forest in Golestan province. Throughfall and forest floor leachate samples were taken through 6 months (winter and spring 2008). Amount of base-cations (Ca2+, Mg2+, Na+ and K+) were compared by T-Test between rainfalls and throughfall. Results showed that the amount of Ca2+, Mg2+, Na+ and K+ contents in throughfall were higher than rainfall (p

This research was carried out for predicting probability of forest type's presence using topographic attributes in the Educational and Research Forest of Doctor Bahramnia, district 1, with 1714 ha area. Field sampling was performed, based on cluster random sampling and systematic random sampling and 249 plots were sampled with 0.1 hectare area (without plantation area). Diameter of trees larger than 12.5 cm, species information and geographic position were registered in each plot with GPS. Since, thick trees are dominated in the canopy cover, 10 thick trees in each plot were selected to determine the forest type. Using computing of frequency percent of species, forest type in each plot was determined and four types of Fagus-Carpinus, Quercus-Carpinus, Carpinus-Parrotia and Parrotia-Acer (mixed with Carpinus betulus) were determined in the study area. The topographic attribute maps were derived from a digital terrain model and these attributes were extracted in location of plots. Logistic regression was implemented to analysis of forest type’s correlation with attributes and to construct a predictive model. The analysis was performed using 70% of the plots and each forest type map was resulted by extrapolation of model in GIS. Validation of results was performed by 30% of the remained plots and total accuracy computed for each model. Validation result of accuracy showed that spatial prediction models of forest types for Fagus-Carpinus and Quercus-Carpinus have narrow amplitude than Carpinus-Parrotia and Parrotia-Acer (mixed with Carpinus betulus) types that spread in large extent region. This result showed that spatial predictive models of forest types, which have narrow amplitude, are more acceptable. The results also showed that consideration of altitude, solar radiation potential and aspect in the model were the main factors which are controlling forest types in the study area.

In order to identify the effect of shelterwood logging on the species diversity in each stages performance, a study was conducted at the Loveh forest, east of Golestan province. Totally, 117 plots with 60×60m were set down with systematic cluster sampling method at the study area. Diameter at breast height (DBH) of trees and species were assessed in each plot. In this study three managed stands including 20 years practiced stands (shelterwood system), 40 years practiced stands (shelterwood system), and improvement stand as well as one unmanaged stand were compared based on Shannon-Wiener, Smith-Wilson and richness indices. The results of analysis of variances showed that difference among four stands were significant (p

After performing the first and Second 20-years periods of forest projects, even with proper execution of the programs, most of them have many problems yet. One of the most important factors that caused these problems is the method of data preparing and processing. The hypothesis of this research project is “there is a significant difference between the result of random-systematic inventory and full caliper method”. After sampling in plots with 1000 m2 area under a random-systematic grid, correlations between variables were surveyed. Volume, basal area and tree number amount and distributions in diameter classes were compared with the Willcoxon test between the two inventory methods. Conclusions are: data obtained in current random-systematic method in plots with 1000 m2 area have acceptable accuracy just for fuelwood species and hornbeam (Carpinus betulus). For beech (Fagus orientalis) and other species, accuracy decreases with increasing in diameter and heterogen distribution in forest stand.

Mixed beech forests (Fagus orientalis) are the most important forests with the highest degree of naturalness in Hyrcanian forest of Iran. These forests commonly dominate by shade tolerance species with irregular and uneven-aged stand structure. The aim of this study is to analyze the stand structure and spatial pattern in order to identify specific structural patterns. We studied the stand structure and spatial pattern of trees in mixed beech forest in the Shastkolate Educational Forest to examine the coexistence strategies of different species. Data was collected from a 16.9 ha permanent plot on a 406×416m quadrate area. We measured all trees exceeded than 7.5cm in diameter at breast height on permanent plot. The six main species were divided into two groups based on density and stand structure. Group A had higher density than group B, as well as reverse J shaped DBH distribution of live standing trees. Species in group A have clump spatial distribution pattern in all layers. However, clump intensity is more than in understory and size of patch clump was smaller in this group. This situation for group A may explaining by having numerous coppice, sucker and patch regeneration in the understory layer. Middlestory and understory stems of the six major tree species were patchily distributed throughout the plot. However, for Alder (Alnus subcordata) and Maple (Acer velutinum) common pattern in canopy layer was complete spatial randomness. The distributions of beech trees were negatively associated with other species. These results suggest species differences in favorable canopy condition.