جستجوی مقالات مرتبط با کلیدواژه « Spatial pattern » در نشریات گروه « جنگلداری »

The structure of forest stands changes over time and under the influence of local disturbances, these changes are referred as the dynamics of forest stands. Changes in the structure of forest stands result in the formation of development phases. The purpose of this study was to identify the structural characteristics of natural beech forests during the stage of growing up volume in the Kheyroud forest. For this purpose, three one-hectare sample plots with structural features of growing up volume stage were selected and the location, diameter and height of all trees within each sample plot with DBH N 7.5 cm were measured. The structural properties of this stage were investigated using a set of indices based on the nearest neighbors. Based on the results, the mean values of uniform angles and Clark and Evans indices were 0.49 and 0.96, respectively, which indicated a random clumped spatial pattern of trees at this stage. The results of the mingling index showed that the tendency of beech trees to mix with other species was low. The results of diameter differentiation index indicated a clear difference and height differentiation index showed a moderate difference in dimensions of trees with each other. In general, using the nearest neighbor indices showed that these indices have a high ability to detect the differentiation of forest stands in the growing up volume stage and thus are useful tools for forest management.

The tree species regeneration is a critical process in the population dynamics of forests and significantly influences the composition of forest communities. Quantitative analysis of tree regeneration may provide baseline information for conservation and management strategies. Zagros oak forests have been subjected to dramatic changes in forest regeneration, cover and structure in recent decades. Zagros forests have critical national importance. These forests capture over one third of the country’s annual precipitation, and are the headwaters for 40% of the country’s rivers and streams which provide water to the dry central plateau of Iran. Given the national and regional importance of Zagros forests, it is extremely useful for restoration management to evaluate spatial distribution of tree regeneration. Disturbing of ecosystems, changes the dynamic of species and ecosystem processes. Ecosystems are therefore moving in a self-organizing way towards a more efficient use of energy/nutrients to the total energy input. This self-organizing of the ecosystem is an inherent feature of non-linear interacting systems. Techniques used to study non-linear systems could be able to quantify the structure of complex objects and spatial dynamic of plants.

The mathematical features of spatially complex systems are often fractal. Fractal has the potential to exposure a new way to understand and analyze such natural spatial phenomena, which are not smooth, but rough and fragmented to self-similarity. We investigated the spatial patterns of tree regeneration density and diversity in 126 plots (100 m2). The study was conducted at a preserved area (12 years) in Zagros forest of western Iran. We applied autocorelation methods to examine the spatial structure in distribution of regeneration. Fractal analysis was also used to characterize the complexity of the spatial patterns.

We found that preservation favored density and diversity of tree regeneration in this area. On the whole the variables have weak autocorrelation but regeneration density of C.microcarpa, total regeneration density, regeneration height and Shannon index are the variables which have the most autocorrelation. On the other hand, fractal dimension, representing the unpredictability of spatial patterns, is high for trees and regeneration. This implies that although spatial dependence exists, it is generally fairly weak.

These results revealed the scattered and homogeneous spatial distribution of trees and their regeneration. Indeed, our results showed a recovery of regeneration but not the spatial structure of it. It seems that conservation efforts must be continue to complete the recovery of regeneration and their spatial structure.

The importance of study on the structure of mixed stands is not less than that of studies on beech stands. For this purpose, nine sample plots, each one ha, were established in the control compartment of district four in Loveh forest. After recording the general characteristics of the stand, 100% inventory was done in the plots. Coordination and diameter at breast height (dbh) of all woody species with dbh larger than 7.5cm were measured. Spatial pattern of species was mapped using PAST software. Moreover, the locations of the stands were determined in the structure triangle. Results showed that the studied stands were three-storied uneven-aged and composed of 12 woody species with the highest abundance of hornbeam. Mean stem number was 384ha-1, height of trees varied between 3.6 and 34.7 m and large and extra-large trees of Lime and Chestnut-leaved oak with a total height of more than 25m appeared in the upper story. Mean basal area, total volume and dead wood volume accounted to 36.1 m2ha-1, 420.6 m3ha-1 and 17 m3ha-1, respectively. Spatial pattern of the trees was generally cluster. All nine plots were located on the upper part of the structure triangle indicating abundance of old and large trees which were far from the theoretical irregular structure. Considering this structure, immediate application of group selection method is too early in such stands; we suggest starting with silvicultural interventions and moving towards irregular structure, and later establishment of young generation keeping tree diversity and sustainability in mind.

Hyrcanian forests are rare and unique ecosystems and their sustainability is essential. Gaps, as part of a general process, help to establish and stabilize the structure of the Hyrcanian forests and the dynamism of its society. This study seeks to identify possible differences in the gap characteristics in the two managed and intact compartments. For this purpose, compartments No. 114 (intact) and No. 115 (managed) from district one of Livan-Banafshtapeh forestry plan in Golestan province of Iran were selected to compare some gap characteristics (gap fraction, distribution of gap sizes, number of gaps per hectare and status of gapmaker trees). In these compartments, all gaps>100 m2 caused by mortality of at least one tree with remnants of the gapmaker or detectable tree stumps, were identified and recorded. The results showed that the gap fraction in the intact and managed compartments was 10.7% and 6.3%, respectively. The average number of gaps varied from 1.4 ha-1 in the managed to 2.9 ha-1 in the intact compartment. The spatial pattern of gaps was randomly spaced up to a distance of 30 (managed) and 40 (intact) meters and then reached the cluster pattern. The differences between the characteristics in the two compartments were not statistically significant and management did not have a significant effect on these variables. However, no significant differences between the two compartments were due to the low harvest intensity in the managed compartment. The biodiversity of Hyrcanian forests must always be taken into account so that it is not endangered by mismanagement; otherwise irreparable effects on the ecosystem of the managed compartment may occur.

This study aimed to evaluate the structural characteristics of Quercus macranthera forests in the Arasbaran region, Hatam Mashe Si, Meshgin-Shahr. To achieve this, all trees and shrubs were full calipered in three one-hectare plots. Additionally, the structural characteristics were measured using the nearest neighbor’s method. To measure intensity of trees, several indices like nearest neighbor distance index (density of trees), uniform angle index and Clark and Evans index (variety of location), Mingling index and Shannon-Wiener index (tree diversity in diameter classes), diameter and height differentiation indices (dimensional differences of trees), and complex structural diversity index (tree diversity) were used. The results showed that Q. macranthera represented a relatively homogeneous structure in its main site, and the mean of distance to the neighbors was 2.59 m. The results of uniform angle and Clark and Evans indices showed that the spatial pattern of trees was regular. Mingling and Shannon-Wiener indices showed a low tendency of Q. macranthera to mix with other tree species so that the majority of trees were Q. macranthera. The height and diameter differentiation indices illustrated that the dimensions of the trees had a slight difference. According to complex structural diversity index, tree diversity was at the medium level. It can be concluded that the Q. macranthera communities have a homogeneous structure in a study region with a low mixture and single canopy layer. The information can provide the opportunity to monitor future changes in Q. macranthera communities in this region. To promote ecosystem stability, it is suggested to create heterogeneity of stand structure and support other tree species in this area.

Understanding the underlying mechanisms for tree species regeneration, as well as the positive and negative interaction between tree species and regeneration can improve the effectiveness of forest management and restoration activities. English yew, as one of the rare and valuable native species in Hyrcanian forests, Iran, has declined over the past several decades for many reasons such as lack of regeneration in existing populations. This research aims at studying the spatial pattern of English yew regeneration and its interaction with adult trees. For this purpose, the location of all English yew trees and its regeneration was recorded using TP360 device and distance-azimuth method in the Afratakhteh Forest Reserve, Golestan province. Totally, 417 English yew trees and 59 regenerations were recorded in the research area. The minimum and maximum diameter of the English yew trees was 6 and 124 cm, respectively. The results of the univariate analysis O-ring function showed that the spatial pattern of English yew trees is completely random and spatial pattern of regeneration were clustered in < 5 m, and then it is random. The results of the bivariate O-ring function showed that there is strong competition and negative interaction between the yew tree and its regeneration. It seems the density of the mother trees in the forest and a large shadow over the length of the year by yew trees is linked directly to the absence of regeneration in this forest reserve. Also allelopathic influence of parent yew trees could negatively impact on seedling density beneath a conspecific canopy. The areas out of existing English yew canopies are most likely to represent optimal sites for regeneration. Therefore, in order to protect the existing English yew stands, management activities on regeneration should focus on these areas.

One of the important features of plant communities is the spatial pattern of trees. The spatial pattern of the stands determined by measuring and positioning of trees in the stands and inserting them in analytical frameworks. This is because spatial information allows natural resource managers to make and perform better-informed decisions, -. The aim of this study was to assess the spatial pattern of Acer velutinum in two stands, above and below 800 m from see level in Asalem Nav forests, Guilan province. The sampling distance- method was used. In order to gather the required data, characteristics of 88 tress in 30 sample plots (1000 m2) were recorded in two elevation classes in an area of 30  ha (15  ha in each elevation class) with a grid  network of 100 × 100. The number of trees, diameter, height, distance from the nearest tree to the sample plot and distance of the nearest tree to the first tree of maple was measured in each sample plot. To analyze the spatial pattern, the Hopkins index, the variance/average ratio, Morisita dispersion,  Morisita, Johnson, and Zimmer standards were used, which randomized, uniform, maximum uniform (for both Morisita and Morisita standard indexes) and uniform patterns dispersion was observed, respectively. In general, the ability of these indices makes it possible to compare the stands and they can be used as a suitable tool for sustainable management of the northern forests of Iran.

The spatial heterogeneity of throughfall (TF) is a critical component of the hydrological cycle. The aim of this study was to identify TF spatial pattern variability for leaf-out seasons in a natural beech (Fagus orientalis L.) stand located in the Caspian forests using geostatistical method. The rain-collectors used for measuring TF (n= 122) were distributed in a stratified simple random sampling design under the canopy. Measurements were carried out in 2016, and 2017; spring, summer, and autumn. Variograms indicated strong structure of spatial continuous TF pattern beneath the canopy for all seasons when the trees are in leaf. The spherical model was the best fitted model to empirical variograms for summer and fall and exponential model for spring season. The effective range of variogram for spring, summer, and fall were 2, 8, and 7 m, respectively. The leaf area index (LAI) of summer (6 m2/m2) was significantly higher than spring (4.5 m2/m2) and fall (5 m2/m2) seasons. The number of hotspot points was estimated to be the highest in summer (10) and lowest in spring (6). TF spatial variability was attributed to the climate variability and changeability of LAI characteristics, in particular. The LAI increasing may be a claim to increase the spatial continuity of TF and hotspot points observed in summer. This research properly displays the spatial pattern of TF for different seasons by geoestatistical method that could be successfully applied for predicting and mapping the changes in the behavior of rainfall affected by LAI under the canopy of a natural beech stand. Fully understanding the spatial distribution of rainfall within forests will definitely help the managers to optimize the management of these stands in terms of soil water and nutrition availability. The outcomes of this study would help future investigators for providing the appropriate sampling strategies in the beech stand under similar climate conditions.

This study was carried out to investigate the ability of template matching algorithm in wild pistachio tree position and their spatial pattern determination using GeoEye-1 images in Tage-Ahmadshahi protected area of Southern Khorasan. After geometric correction and fusion of multi-spectral bands with panchromatic band, three templates were generated for each band and NDVI index. For accuracy assessment of template matching a 100 by 100 meter network (1 ha) used and 60 samples selected randomly and the location of wild pistachio as ground truth registered using a precise DGPS device. For spatial pattern analyzing two useful functions D(r) and g(r) were used. The result of cross correlation showed that the generated templates based on NDVI have the highest correlation between samples The result of template algorithm on satellite image showed that this method with 95.57 percent overall accuracy have the ability to determine tree position by suitable precision on high resolution satellite images. The result of D(r) function showed that wild pistachio trees have nearest neighbor maximum to 45 meter distance. Also the result of g(r) function showed that the trees have a significant uniform dispersion up to 11 meter while between 11.5 and 17 meter have a clumped dispersion which were statistically significant (p

Maintaining the structure and biodiversity of ecosystems is considered to be one of the most important goals of modern forestry. For this purpose, the tools are needed for forest management, to have the lowest cost and time to check the current status, as well as the changes caused by development of forest management activities. Indicators of nearest neighbor have advantages that their application gives priority to direct measurements of biological diversity. Because in addition to the study of species diversity, it investigates the locations of trees. Also nearest neighbor indices provide valuable information about ecological interactions of trees in forests. Therefore, this study was aimed to introduce and apply important indices based on nearest neighbor analysis to study ecological relationships of trees in beech-hornbeam stands in Nave Asalem- Gilan forests.
In order to do this research, seven 1-ha plots with homogeneous environmental conditions were inventoried in a Fageto-Carpinetum association in Nave Asalem- Gilan. In each plot, distance and azimuth of all trees on the plot with more than 7.5 cm diameter at breast height from the center of sampling area and species, and diameter at breast height were recorded. The spatial pattern and species diversity were then investigated using the uniform angle, mean directional, species mingling and segregation indices. The amounts of each of the mentioned indices were calculated for each sample individually. The average of the values obtained for each sample were calculated for the Fageto-Carpinetum.
The results showed in seven 1-ha plots of Fageto-Carpinetum, Fagus orientalis, Carpinus betulus, Acer cappadocicum, Acer velutinum and Alnus subcordata had the maximum density per hectare. The values of uniform angle and mean directional indices were 0.53 and 2.02, respectively, showing a spatial distribution between random and clustered. In terms of species diversity, the Fageto-Carpinetum association with an average of 0.47 and 0.25 for species mingling and segregation indices, respectively, presenting a medium level of species mixing. The amount of species mingling indices indicated low level of mixing of beech species and high level of mixing of other species. The segregation index showed a pair of trees or nearest neighbor reference trees belonged to different species.
In general, the results of this study indicated the efficiency of nearest neighbor indices to study the structure of Fageto-Carpinetum associations and the results can be used for planning to revitalize the structure and status of biodiversity in degraded Fageto-Carpinetum associations.

Spatial pattern of trees in a stand is the outcome of different processes such as their interactions, seed dispersal, and environmental heterogeneity. In consequence, knowledge of spatial pattern of plant species is important for deeper understanding of different hypotheses in ecology. Considering the importance, unbiased recognition of spatial pattern of plant species using reliable techniques is essential in ecology. Summary statistics used in point pattern analysis to explore spatial pattern of plants are based on the null model of homogeneous Poisson process (Complete spatial randomness: CSR). So it seems necessary to investigate homogeneity of tree spatial distribution before analyzing their spatial pattern. Considering this issue, this study was aimed to evaluate the homogeneity of tree spatial distribution in a mixed mesquite stand in Khalij-Omanian vegetation zone using two methods. Moreover, it was also aimed to investigate the impact of ignoring the CSR null model on spatial pattern analysis of trees in the plot.
A 49-ha study plot (700 m × 700 m) was selected in a mixed mesquite stand in Barchah protected area in Hormozgand province. The spatial location of all tree and shrubs with height > 0.5 m was registered and their height and crown area were measured. Furthermore, another plot with similar number of plants and environmental conditions was simulated with homogeneous spatial distribution and clustered spatial pattern of plants. Two methods of Chi-squared test based on quadrat accompanied with Pearson residuals and Kolmogorov-Smirnov test were applied to explore homogeneity of tree spatial distribution. Moreover, homogeneous and inhomogeneous pair correlation functions were used to analyze spatial patterns in two plots.
The study plot was covered by 498 trees and shrubs including 149 mesquites, 248 umbrella thorns (Acacia tortilis), and 101 desert thorns (Lycium shawii). The results showed that Chi-squared test only with 4 × 4 quadrats could recognize homogeneity of the simulated plot. Mean of Pearson residuals also did not characterize the homogeneity difference of two plots. While Kolmogorov-Smirnov test explored the difference between tree spatial distribution of the real plot (p-value
In general, it was concluded that Kolmogorov-Smirnov test is a reliable method to assess homogeneity of plant spatial distribution in the study area. Moreover, it was revealed that efficiency of g(r) in spatial pattern recognition of plants was influenced by homogeneity of their spatial distribution and application of inappropriate form of g(r) resulted in biased spatial pattern analysis in the study site.

Appropriate management of forest requires indices that can provide adequate information about forest structure condition and its changes with the least cost and time. In this research, the effect of tree marking on natural stand structure was evaluated in Gorazbon district of Kheirud forest using indices ofspatial and non-spatial distribution. For this purpose, 682 structural groups (trees) were studied from the lower up to the upper boundary of compartment in two rectangular plots. The results showed that the changes of some indices, including mingling, Uniform Angle Index, DBH dominance, DBH differentiation, Pielou segregation, Clark and Evans aggregation, stem per hectare, basal area and diameter at breast height were not significant. Also, the paired t-test results showed non-significant differences for Uniform Angle Index and DBH dominance, whereas the Mingling and DBH differentiation indices showed significant differences, in the two studied sample plot before and after the tree marking. According to the results of this research, one can conclude that the applied indices are able to show the changes in the stand structure over different time studies and they are suitable for comparison of stands. These indices could be useful tools for forest management in close to nature silviculture.

The spatial pattern of trees is one of the structural characteristics of forest stands that affects the efficiency of sampling methods. This study aimed at investigating the effect of spatial distribution of trees on the efficiency of distance and plot sampling methods. For this purpose, a dispersed Persian oak stand in Kohgilouye-Boyerahmad province (47 ha) and a clumped wild pistachio stand in Fars province (45 ha) were selected. Six distance and six plot sampling methods were applied on a 100 m × 100 m grid in the stands to estimate the density and canopy cover. The efficiency of methods was evaluated by statistical comparison of the results with true values, accuracy criterion, and root mean square error percent. The true density and canopy cover percent of wild pistachio and Persian oak stands were 19.4 trees ha-1 and 5.1% and 22.3 trees ha-1 and 17.1%, respectively. The results showed that between distance sampling methods, nearest individual (density: 19.5 trees ha-1, canopy cover: 5.2%) and nearest neighbour (density: 20.1 trees ha-1, canopy cover: 4.9%) methods in wild pistachio stand and line intersect method (density: 21.0 trees ha-1, canopy cover: 17.3%) in Persian oak stand were efficient. Moreover, all plot sampling methods were efficient in both stands (except square method). In general, the results showed that in contrast to plot sampling methods, the spatial distribution of trees influences significantly the accuracy and precision of distance sampling methods.

One of the main problems in Zagros forests is oak trees dieback. What is certain and important is that the tree dieback crisis caused the declining of oak in oak forest of Zagros. Oak decline is characterised by crown thinning, foliar necrosis and progressive death of primary leaf-bearing branches and the emergence and subsequent decline of foliage. A range of biotic and abiotic factors has been shown to contribute to the decline. However, no satisfactory investigation has been established to explain the distribution.
The aim of this study was to investigate the spatial variability of Oak decline and it’s relation to tree properties in Zagros Forest of Kermanshah (Gahvareh). In this order, 150 hectares of Gahvareh forest was selected and then 67 sample plots (400 m2) were used in a 100 × 100 m sampling grid. In each of the plots the the number of healthy trees and their canopy cover, the dieback and trees with dieback features including diameter, height, crown diameter, average canopy cover, the number Search trees were recorded. Then the spatial continuity, using geostatistics (variogram) were described.
The results of the Pearson correlation coefficient indicates that dieback has a significant positive relationship with the feature tree dieback including diameter ¡height, crown diameter, canopy cover is a significant and positive relationship between the number of sprouts. As well as between the dieback and features healthy tree such as the number of trees and average canopy cover and there is a significant negative relationship variograms of variables revealed the presence of spatial autocorrelation except for the number of shoots have the spatial structure.
Overall analysis of the spatial structure of healthy and dead tree dieback and features show that the structural component of the variance components of random variance prevails. The variables studied occurred in a relatively large area, indicating the spatial structure of large, uniform distribution and continuity in the desired location in variable amounts. The similarity in the effect of dieback and features trees with dieback (collar diameter, height, crown diameter, average level of cover and canopy cover) and also a significant positive correlation between them, represents the close spatial relationship between the dieback and trees have been dieback features. Given the significant negative correlation between the dieback and characteristics of healthy trees (number of trees and average level of cover), it can be stated that the spatial variability characteristics of healthy trees, the dieback affects as photos.

Since N-tree sampling methods produce biased estimate, bias evaluation should be applied to N-tree estimator. The purpose of this study is to assess the N tree distance sampling method bias with modified estimator Kleinn and Vilcko in estimating number per hectare and canopy cover in Zagros forests. For this purpose, 6-10 trees from real forest map were tested with full inventories. For comparing the results of characteristics in different trees in N-tree method with full inventories, ANOVA was used. Evaluation of N tree distance sampling method was done by using accuracy criterion and standard error of mean. Bias was also evaluated via one-sample t-test and relative bias. Results showed that in estimating number per hectare and canopy cover, there is no significant difference between tree numbers with full inventory. Bias test for six and seven trees per hectare was significant, but it was not significant for eight, nine and 10 trees. Canopy cover for all tree numbers showed no significant difference. So, in order to achieve a maximum accuracy (minimum bias), at least eight trees within sample plot should be measured. Finally, this study implies that in forests with lower density and cluster pattern, bias change in N tree distance method does not follow a predictable decreasing pattern.

According to the few basic and applied research related to the structure characteristics of Juniper (Juniperus excelsa)stands in the Irano-Turanian forests and the need for early recognition and proper management of these forests, the present study was carried out to evaluate the structural characteristics of J. excelsa forests located on south facing slope of Alborz mountain chain, Atashgah area, Karaj. For this purpose, systematic network with dimensions of 50×50 m was laid out and coordinates of all trees were determined by distance-azimuth techniques. Canopy diameter was measured in an area about 15.9 hectare in this stand. In order to study the structural characteristics of the stand, nearest neighbors distance index (density of trees), Clark and Evans index and uniform angle index (a variety of location), Mingling index (species diversity), size differentiation index (variety of trees), crown competition factor (competition of canopy trees) between J. excelsa and S index were used in this stand. The results showed that spatial pattern and arrangement of trees were regularly together and variety of trees, was found to be pure without any mixture. The crown competition index was 0.48 (non-unit) representing low crown competition in this stand. Three different aspects of the S index (diversity of spatial pattern, species diversity, and size variety) were 0.227 indicating low levels of tree diversity. The results of this study can be usefully employed for management, preservation, restoration, and development of sensitive and fragile J. excelsa forest ecosystems.

One of the main components of forest stand structure is spatial pattern and positioning of trees next to each other. Stand’s spatial patterns are measured and mapped by measuring tree locations in the stand and entering each coordinates into analytical frameworks. The aim of this study was to compare K-Ripley and distance indices in order to determine spatial pattern of Quercus Brantii in Choghasabz forests of Ilam. Using systematic-random sampling with 100×100m dimensions, 53 samples were selected. K-Ripley index and Hopkins, Hinez, Eberhart and C distance indices were used to analyze the spatial pattern in the area. Results of K-Ripley index showed that spatial pattern of oak trees in the study area are random pattern. But the results of Hopkins, Hinez, Eberhart and C distance indices showed a clumped pattern for Quercus brantii in the study area.

In order to study the competition and spatial association of trees in mixed Hornbeam stands, two 1-ha sample plots (100m×100m) were selected in the reserve area of Asalem forests in Guilan. In each plot, species and diameter at breast height (DBH) of all trees with a diameter > 7.5 cm were recorded and mapped using slope-corrected distance and azimuth from southwest corner of each plot. Distances and azimuths were later transformed to Cartesian coordinates, and all of the measured trees were assigned to one of four diameter size classes: ST (Small Timber, (DBH ≤ 32.5 cm), MT (Medium Timber, 32.5 < DBH ≤ 52.5 cm), LT (Large Timber, 52.5 < DBH ≤ 72.5 cm) and ELT (Extra-Large Timber, DBH > 72.5). Spatial patterns of the entire trees as well as the spatial associations among tree size classes (Intra-specific) and among species (Inter-specific) were analyzed by univariate and bivariate Ripley’s K-function. Results showed that the two stands exhibited a clustered distribution. Furthermore, the interaction between the ST class and other classes was significant (P<0.05). Although we found a positive correlation between the ST and other tree classes, spatial distribution of trees showed different patterns at different spatial scales. The starting point of the attraction in LT and ELT classes was observed at a small scale, whereas it tended towards independent associations in MT class at scale of 10 meter (P>0.05). The inter-specific investigation revealed that Fagus orientalis and Carpinus betulus trees tend towards an independent association at 1-20 meter scales. At higher scales they showed yet a negative correlation. Moreover, F. orientalis was significantly and negatively correlated to Alnus subcordata at small scales. However, their mutual intra-specific and inter-specific effects were different due to the fact that different natural stands have variety of demands during their life cycle. Therefore, it may not necessarily conform to their response to natural processes. This study concludes a founded understanding of spatial pattern of stands to be a helpful indicator for managing forests based on the currently operational close- to- nature silvicultural system.

Understanding the distribution of plant spatial pattern is useful for explaining the ecosystems stability, designing proper management plans, and preservative and reforestation operations. Considering the importance of the northern Zagros forests in terms of socio - economic, protection and reforestation, and given that most research which has been done on the spatial patterns in the Western forests of the country focused on the even-aged coppice forests, the woody species spatial pattern in Havare–Khol forests of Baneh city, governed by a combination of both even-age (on the tree) and uneven-aged forests (on the ground), was studied. In this research, using the randomized-systematic method and 200×300 m inventory network, sixty sampling points were measured by the nearest individual, T-square and compound methods. Data analyses were accomplished by the distance methods of Johnson and Zimmer, Eberhart, Hopkins, Hinez and C index, using of Ecological Methodology software. Results showed the clumped pattern for Johnson and Zimmer, Eberhart and Hinez, the clumped pattern towards the random patterns for C index, and the uniform pattern for Hopkins indices. The clumped tree spatial pattern in Havare-Khol forest was totally determined. The results generally illustrated that based on some indices, taking distance the tree spatial pattern in Havare-Khol forest from natural condition was mainly related to the major jobs of forest dwellers, animal husbandry, and their activities (pruning and cattle grazing etc.)

To design an optimal plantation map for reforestation، a convenient and accurate method is required to analyze plant communities as well as to simulate the plantation map using the spatial pattern of natural trees. In this study، a new algorithm was designed to simulate a plantation map in Zagros forests. To accomplish this، ten hectares of intact stands located in 45 km south of Khorramabad city in Lorestan province was selected. A set of previously-developed algorithms were evaluated to design a new algorithm. The map extracted from the algorithm showed that the required conditions in drawing the map were met. In addition، an appropriate pattern of plantation in different areas can be reached by using the results of this algorithm. Since this study is the first study of its own in Iran، further investigations are required to remove the weak points. Therefore، it is suggested that the presumably existing weak points may be best removed by applying this algorithm in various regions، as well as by integrating effective indexes such as soil type، height from the sea level and physiographic factors. Being based on computer simulations، the results obtained here should be further experimented in different study sites within Zagros region، followed by a thorough evaluation of their plausibility under natural forest conditions.