جستجوی مقالات مرتبط با کلیدواژه « خاک » در نشریات گروه « جنگلداری »

Fire is a destructive phenomenon in natural areas, affecting large parts of forests and rangelands annually with both quantitative and qualitative impacts. One of the most significant consequences is its negative impact on soil conservation, at least in the short term. The average annual area affected by fire in the world’s forests is estimated at four million square kilometers, leading to the destruction of vegetation, global warming, air pollution, loss of biodiversity, and intensified desertification.

Given the importance of this issue, the effects of fire on soil surface cover were studied in the Farakash shrubland habitat in Lorestan province in 2017, 2018, and 2019. This site is located at geographical coordinates 33° 29’ 33” to 33° 30’ 12” N latitude and 48° 38’ 57” to 48° 40’ 56” E longitude, covering an area of 500 hectares, with an average elevation of 2050 meters above sea level. The statistical population consisted of 4 transects of 200 meters, each with 10 plots of 1 square meter spaced every 20 meters, totaling 40 plots in the treatment area. This was repeated exactly in the control field, resulting in a total of 240 plots studied. In these plots, the canopy cover was assessed using vertical images of species on the ground, along with amounts of bare soil, litter, and stones. The range condition was determined using Parker’s four-factor method, suitable for rangelands in semi-arid areas, and the condition trend was assessed by scoring the condition of the soil and vegetation. Pairwise comparisons and multivariate data averages were analyzed using a T-test, one-way ANOVA, and Duncan’s comparison method.

The results showed a significant difference at the one percent level (P≤0.01) between the average values of the canopy, litter, and soil in the two areas over the statistical years. The percentage of vegetation and litter in the burnt field decreased significantly, while bare soil increased. This effect was so strong that it reduced the total plant canopy from 52.54% to 41.44%, causing a negative slope in the burned area compared to the control up to nine years after the fire. It was also found that fire led to the reduction of woody plants and the increase of grasses, changing the vegetation type from Astragalus adscendens-Daphne mucronata-Agropyron trichophorum to Agropyron trichophorum-Annual grasses. The results indicate that fire increases bare soil and erosion. This destruction is caused by quantitative changes such as the reduction of canopy, litter, and natural mulch, and qualitative changes such as alterations in plant composition, vegetative form, structure, age classes, soil seed bank, phenology, and moisture levels. Overall, fire influences the stages of soil erosion by changing vegetation type.

Given the current conditions in fire-affected areas, management programs such as implementing short and medium-term enclosures, determining appropriate stocking rates, seeding, and mulching with fire-resistant species compatible with the climatic and edaphic conditions of these areas can help preserve and restore vegetation and prevent erosion. Finally, due to the common ownership of Iran’s natural areas and the lack of a coherent reclamation plan for burnt areas, controlled fires are not recommended in these regions.

The implementation of the forest restoration plan in the northern region of Iran has led to an increase in efforts to enhance wood production through the cultivation of poplar seedling. Particularly, poplar trees hold a significant position among wood producers due to their distinctive features. The key consideration revolves around identifying suitable and cost-effective lands for planting fast-growing species. Purpose of this study focuses on assessing the land suitability for poplar (Populus nigra L.), a prevalent forest species in the country, through a quantitative land evaluation method based on the FAO approach.
The research gathered and classified the edaphic and climatic requirements of poplar tree by utilizing various library resources, data from the soil laboratory of the Research Institute of Forests and Ranglands, and field survey (Soil Profiles). The climatic and soil characteristics were quantitatively classified into five categories: highly suitable (S1), moderately suitable (S2), low/critically suitable (S3), The Quantitative Classification of soil and climate properties was done in five classes: suitable (S1), moderate suitability (S2), low or critical suitability (S3), currently not suitable (N1) and permanent not suitable (N2). For validation, a quantitative assessment of land suitability for poplar cultivation was performed across six soil types, including Nowshahr forest brown, Nowshahr gray brown pedzolic rich in organic matter, Chamestan alluvial regosol, Chamestan Rendezina, Chalous  Pseudogley , and Karaj alluvial cambisol, using a parametric method (second root).
Results indicate that spruce thrives in wet and semi-humid regions in a dry-type manner, with ideal conditions found in areas receiving 1500-1800 mm of rainfall. In drier, semi-arid zones, irrigation is essential for meeting water requirements. Optimal growth temperatures for spruce range from 11-16 degrees Celsius in moderate climates. Poplar flourishes in soils with a light to medium texture, granular or cubic structure, good to fast drainage, and low underground water levels with adequate calcium and magnesium cations.
The study showed that the most suitable soils for poplars have a light to medium texture with a granular or crumb structure, with adequate drainage, the absence of high groundwater and the sufficient amount of calcium and magnesium cations in the soil. Soils with incomplete drainage and heavy texture do not provide suitable conditions for poplar plantations. In terms of quantitative evaluation, Mollic Udifluvents soils with medium texture had the highest score for poplar plantations.

This research was conducted in 2020 in order to investigating the species diversity and abundance of oribatid mites in the oak and hornbeam forests of Arasbaran (Ahar and Kaleibar) in East Azerbaijan Province. Soil sampling was carried out in May and June. Oribatid mites present in soil samples were separated using Berlese funnels and clarified in relative solution, followed by preparation of microscope slides. After identification, counting, diversity and evenness indices (Shannon and Simpson), as well as species richness were calculated using Ecological Methodology 6.0 software. In general, 29 species of Oribatid mites from 27 genera and 23 families were identified in this study: Cosmochthonius lanatus Michael, Sphaerochthonius splendidus Berlese, Steganacarus (Tropacarus) carinatus Koch, Papillacarus pseudoaciculatus Mahunka, Rhysotritia ardua Koch, Nothrus biciliatus Koch, Hermanniella septentrionalis Berlese, Plesiodamaeus ornatus Pérez-Íñígo, Belba sp., Xenillus setosus Grobler, Ozman & Cobanoglu, Fosseremus quadripertitus Grandjean, Rhinoppia obsoleta Paoli, Ramusella (Ramusella) puertomonttensis Hammer, Ramusella (R.) sengbuschi Tokyoensis, Ramusella (R.) sengbuschi Str., Graptoppia (G.) sundensis acuta Ayyildiz, Rectoppia sp., Suctobelella sp., Austrocarabodes (Austrocarabodes) foliaceisetus Murvanidze & Weigmann, Tectocepheus velaus Michael, Eupelops acromios Haman, Berlesezetes aegypticus Balogh & Mahunka, Oribatula (O.) tibialis allifera Subías, Protoribates (P.) paracapucinus Mahunka, Scheloribates fimbriatus Thor., Ceratozetes conjunctus Mihelčič, Punctoribates angulatus Bayartogtokh, Grobler & Cobanoglu, Galumna sp., Pilogalumna sp. The highest abundance of mites in Ahar and Kaleibar belonged to Scheloribtes fimbriatus and Oribaiula tibilis, respectively. The calculated species diversity indices in the Kaleibar region during June were higher than those in May. The diversity and species richness of oribatid mites were higher in Kaleibar with oak vegetation, which could be due to the higher humidity and acidity of the soil compared to Ahar.

Tree species have different effects on soil properties and nutrients. Plantation as a management strategy for soil productivity retention and the prevention of destruction can be effective in the continuity of forest productivity. One of the most important goals of planting coniferous species is to increase wood production, create forest parks and conservation forests. The objective of this study was to investigate the seasonal variations in nutrient concentrations in plant organs and soil of pinus brutia Ten.  stands.

For this purpose, the ​​Makhmalkuh forest park in Lorestan province was selected and in 1396, random sampling was performed using 5 (400 m2) sample plots. In each sample plot, an indicator tree pinus brutia Ten. was selected and its young and perennial leaves and twigs were sampled in the upper third of the crown in four seasons, as well as from two depths of 0-5 and 5-15 cm a mixed soil sample was taken in each sample plot. Soil texture, pH, organic carbon (C), total nitrogen (N), available phosphorus (P), and potassium (K), for all samples were measured in the laboratory. The soil parameters, nutrients of soil and plants organs were analyzed by using one-way analysis (ANOVA) and Duncan test procedures among different seasons.

According to the results, the lowest amount of dry weight and percentage of moisture in all four organs was observed in summer and the highest amount was observed in winter. Based on the results, there was a significant difference between the nutrient concentrations of plant organs in different seasons (sig<0.01). In all four organs, the highest amount of nitrogen was recorded in spring, potassium in winter and phosphorus in summer. The results of correlation studies also showed a significant relationship between nutrient concentrations of different organs and different soil characteristics.

High amounts of nitrogen and phosphorus in the spring can be argued that increasing the temperature in most cases increases the metabolic activity in the soil, evaporation and transpiration and absorption of nutrients. Different climatic conditions in different seasons, lack of soil moisture, retranslocation of nutrients from perennial needles and branches to young parts and seasonal and monthly changes in the chemical composition of the throughfall can be the most important reasons for these changes.

Forests as one of the important ecosystems plays a noticeable role in reducing the carbon dioxide by the  annual atmospheric carbon sequestration into the biomass of woody plants and soil. The three determining factors for estimating the carbon storage in a forest ecosystem are soil, vegetation, and litters. This study was carried out to investigate the carbon storage and its sequestration in four 1 ha square sample plots in forests of Boyer-Ahmad and Dena counties, Kohgiluyeh and Boyer-Ahmad province. Relevant allometric equations were used to estimate the biomass and carbon storage of the tree species in two vegetative form of coppice and high forests. For the measurement of soil carbon storage, five soil samples were taken from depths of 0- 30 cm, and percentage of organic matter and bulk density were measured in the laboratory. Analysis of variance showed that the total carbon storage in the trees, soil and litter had no significant difference amongst different sites, but the total carbon storage among the trees showed a significant difference (Parikadon site with 31 and Vezg site with 17 tons/ha, respectively). According to the results, the enclosed area (Vezg) had the highest carbon storage and the Sarabtaveh (northern aspect) had the lowest carbon storage. The average carbon storage of the studied areas was more than 159 tons/ha. The average of carbon storage in litters was about 730 kg/ha and the mean economic value of total carbon storage per ha was estimated 188 million Tomans.

This study aimed at evaluating the box tree habitat after the occurrence of box blight disease in Buxo-Fagtum orientalis (B) and reference pure Fagetum (S) stands in the district 3, Lesakoty catchment No. 36, southeast of Tonekabon in the Mazandaran Province. In each stand, 60 micro-plots with 25 m2 were established, in which the frequency of herbaceous species was recorded. For sampling lichens, 60 × 40 cm quadrats were used. Raw data obtained from the field were compared and analyzed using an independent t-test and CCA analysis. Results revealed that the Simpson species diversity (B = 0.813 ± 0.07, S = 0.649 ± 0.07) and Shannon-Wiener (B = 0.830 ± 0.05, S =0.577 ± 0.05) of herbaceous species were significantly higher in Buxo-Fagetum orientalis stand (p <0.05). In addition, the independent t-test for lichen species showed that Simpson species diversity (B = 0.477±0 0.03, S = 0.629 ± 0.03) and Shannon-Weiner (B=0.738 ± 0.06, S= 1.067± 0/06) inboxwood-beech stand was significantly lower than those in pure beech site (p <0.05). CCA results showed that the environmental conditions, as well as the variability of the presence and diversity of different species of lichens as forest ecosystem bio-indicators were changed, mainly due to the boxwood blight disease in boxwood-beech stand. Further, stand opening caused by disturbances and increase of light reaching the forest floor was identified as a key factor in changing the composition of herbaceous and lichen communities in Buxo-Fagetum orientalis stands.

Heavy metals are important environmental pollutants which cause risks for humans, plants and microorganisms by entering to the food chains. This study was done to determine the adsorption of heavy metals in soil and leaves of Persian oak trees in Aleshtar - Khorramabad highway. For this purpose, on the five transects at intervals of 0, 500 and 1000 meters on each side of the road, plots whith 10 × 10 meters were selected. In each plot, 30 soil samples and 30 leaf samples from all directions of crown were collected. After preparation of samples, concentration of heavy metals of lead, copper and zinc on soil and leaves were measured using atomic absorption device. The results showed that the concentration of soil heavy metals decreased with increasing distance from the road. The amount of heavy metal concentration in soil was obtauid respectively in distances 0, 500 and 1000 meters 4.6, 2.65 and 3 for lead, 56.13, 55.38 and 55.32 for zinc and 44.81, 45.34 and 38.00 mg/kg for copper. Also the amount of heavy metal concentration in leaves was obtauid respectively in distances 0, 500 and 1000 meters 0.5, 0.4 and 0.2 for lead, 34.6, 57.3 and 38.00 for zinc and 8.5, 7.3 and 8.6 mg/kg for copper. The results also showed that there is a significant negative correlation between organic matter and soil copper at the 5% level. The concentrations of heavy metals in Persian Oak leaves are lower than the standard values of the world and so this tree species can accumulate heavy metals.

The aim of the present study was selection of adaptable species with proper growth and wood production and resistant to cold with the aim of wood production and cultivation in the urban green space and infertile lands of Saveh. Seedlings of Eucalyptus suggrandis ssp. Suggrandis, E. microcarpa, E. suggrandis ssp. Alipe, E. camaldulensis 41-sh, E. camaldulensis var. camaldulensis, E. rubida 166-sh, E. viminalis 168-sh, E. sargentii and E. camaldulensis 41-ch were planted in 3×3m spacing on late March 2010 in three replications with 25 seedlings based on Randomized Complete Block design (RCB). Also, some physic-chemical properties of soilwere examined. Results of the data analysis showed that the maximum total height, crown diameter and trees quality were observed in E. camaldulensis 41-sh. While E. viminalis 168-sh showed maximum diameter at breast height and E. camaldulensis 41-ch the heigheststanding stock volume, volume increment and quality in compare to other species. Eucalyptus suggrandis ssp. Suggrandis, E. camaldulensis 41-sh and E. microcarpa were most resistant to cold. The maximum rate of survival was measured in E. sargentii and the lowest in E. rubida 166-sh. Total height was found to be the most important factor in extraction data variance. E. camaldulensis is recommended for wood production and E. sargentii is suggested for soil and water conservation in infertile lands of Saveh.

Aim and Beech is one of the most valuable industrial species in the Iran's Hyrcanian forests that has varieties of crown compositions with different species and soil fertility. Several studies have examined the role of canopy composition on biogeochemical cycles, and different results have been addressed. Different combinations of canopy covres create heterogeneity in different scales. Regarding to quantity and quality of input and output for flow of water and nutrients, the biogeochemical cycles will be so different. The aim of this study is to determine the revenue of pure and mixed crown of Hyrcanian beech in changes of biogeochemical cycles. In the above stratum of Experimental Forest Station of TMU, four crown compositions of beech spcies (i.e. beech-hornbeam, beech-maple, mixed beech including beech-hornbeam-maple and pure beech) were considered. Five replicates were selected for each composition and a total of twenty sample plots were set up in the forest. In the growth season (summer), litter and soil samples (50×50×10 cm) were collected from the neasrest location to main stem of beech trees. The samples were taken from four sides of trees and a composite sample was transferred to the laboratory. Litter’s (C and N) and soil (bulk density, texture, water content, pH, organic C, total N, microbial biomass C, microbial biomass N, earthworm density/biomass, emission of carbon dioxide, methane and nitrous oxide) features were measured.
Findings: Litter quality differed among the crown compositions, with the highest total N concentration and lowest organic C under mixed crown cover. Soil bulk density and water contents were respectively lower and higher under pure beech when compared with the other crown compositions. Soil texture was not significantly different among studied treatements, whereas greater amounts of pH and total N were detected under mixed crown covers. Soil organic C and C/N ratio were found to be significantly higher under pure beech than in the others. Pure beech showed the highest values of microbial biomass C (707.80 mg kg-1), microbial biomass N (50.79 mg kg-1), emission of carbon dioxide (0.54 mg CO2 m-2 d-1), nitrous oxide (0.38 mg N2O m-2 d-1) and the mixed composition showed the greater amounts of earthworm density (2.60 n m-2) and biomass (11.29 mg m-2). Methane emissions did not differ for the studied sites. Our findings showed that pure beech has more effects on C and N cycles in compred to the other crown compositions. Among different litter and soil characters, the water contens and organic C had more highlights roles in changes of these cycles.

Soil compaction, as one of the causes of stress, has a negative impact on plant growth. The aim of this study was to evaluate the effect of soil compaction on root system of Caucasian alder (Aluns subcotdata C. A. Mey.) seedlings in controlled condition. After sowing of alder seeds in plastic pots in loamy or clay-loamy soils with constant moisture regimes, the reaction of seeds were evaluated under six levels of soil compaction. Collar diameter, length, biomass, and allocation ratio of root system were measured and calculated. According to the results, the studied parameters decreased significantly by increasing soil bulk density and their trend were downward quadratic, except ratio of lateral root length to main root length. Thirty six percent decrease in the mean of lateral root length, 31% decrease in the mean of main root length, 37% reduction in the mean diameter of main root and 27% fell down in the mean value of root dry biomass was recorded in treatments with different levels of soil compaction in compare to the control treatment. In general, results indicate that compaction tension has negative effect on the characteristics in the root system of Caucasian alder seedlings.

Soil physicochemicalproperties are important factors in plant establishment. Therefore, knowing its properties can improve the forest management practice for having more forest production. The objective of the present study is to determine the soil physicochemicalproperties of Tecomella undulata stands in Bushehr province. For this purpose, two sites including Shahnia (2 ha) and Ali-Abad (10 ha) in Bushehr province were selected. 20 and 30 soil samples were systematically taken from two depths (0-5 and 5-25 cm) using 25 × 25 and 50 × 100 meter grids in Shahnia and Ali-Abad, respectively. Soil physicochemicalproperties results revealed that T. undulata prefers sandy and loam- sandy soils with neutral pH. Also, this species can tolerate more than 535 ds/m soil electrical conductivity in the studied sites. Soil phosphorus, bulk density and clay are the most important factors effecting the T. undulata distribution. Results of quantitative parameters showed that diameters at breast height in Shahnia are significantly more than Ali-Abad. While no significant difference was observed among tree heights in the studied sites.

This study aimed to investigate the role of soil mesofauna for quick and low cost detection of well and poorly seed-origin oak regenerated sample plots in Zagros oak forest ecosystem. The main question of this study is why some areas have a suitable number of natural seedlings while some others do not, despite the presence of mature oak trees? In this study, we sampled 30 100-m2 plots with regeneration and 30 100-m2 plots without or with only few seedlings in the same physiographic conditions. Soil samples for mesofauna investigation were randomly collected within each sample plot to a depth of 0-20 cm. Soil mesofauna was extracted with a Berlese-Tullgren funnel apparatus.According to CCA ordination, plots with and without natural regeneration have shown, respectively, clumped and uniform patterns of mature oak trees based on Johnson and Zimmer index. In this regard, plots with a clumped pattern were characterized by higher saturation percentage, total phosphorus, total potassium, clay, organic matter, total nitrogen and cation exchange capacity than uniform to random patterns of oak trees. Seed-origin oak regeneration patterns around mature oak trees in plots with and without natural regeneration were clumped and uniform, respectively. The results showed that the number of soil mesofauna in clumped pattern (with higher regeneration) was higher than those in the uniform pattern (with lower regeneration).

Nematodes are one of the most abundant and effective soil organisms in natural ecosystems such as forests, and have been used as bioindicators in studying the effect of disturbing factors on environment. In this study, effects of fire on soil-inhabiting nematode populations in superficial soil layers (depth of 10, 20, 30 and 40 cm) of Abr forest, city of Shahroud was studied. To compare nematode populations in the soils of burned and unburned areas, a total number of 100 soil samples were taken from the above mentioned depths in two times (one and 13 months after the fire) based on a randomized complete block design. After exteraction by centrifugation or flotation method in a solution of sugar and identification and counting of nematodes, their groupings were performed using a stereo microscope based on morphological characteristics of stoma and pharynx. The results showed that the populations of nematodes were decreased in burned soil at depths of 10, 20 and 30 cm, compared to unburned soil, one month after burning. The highest population decrease was observed at the depths of 20, 10, 30 and 40, respectively in burned soil and in the first sampling date,while the highest population increase was observed at depths of 30, 40, 20 and 10 cm, respectively for burned soil and the second sampling time (P≤0.05).

The aim of the present study is to assess the effect of pure and mixed plantations of Eastern Cottonwood (Populus deltoides) and Alder (Alnus subcordata) on quantitative stand characteristics and soil properties. The experiment was established in 1994 using randomized block design with five treatments (1- P100%, 2- P67%-A33%, 3- P50%-A50%, 4- P33%-A67%, and 5- A100%) and four replicates in Chamestan Forest Research Center, Mazandaran province. All trees were measured and mixed soil samples were taken from 0-20 cm depth in all treatments in 2014. Result of ANOVA showed that after 20 years, there are significant differences in tree attributes including diameter at breast height, height, crown width, and leaf area index as well as stand attributes including basal area, volume and leaf area per hectare. The maximum growths of poplar were recorded in P33%:A67% treatments with an average of 35.0 cm DBH, and the maximum growth of Alder were recorded in 100%A treatment with an average of 25 cm. No significant difference was observed in soil properties between different treatments. Based on the results, P33%:A67% treatment is the best treatment for future plantations.

Forest ecosystems and their optimal management can play effective roles in mitigating the carbon emission as well as absorbing the atmospheric carbon. The present research was carried out to determine the effects of 21 year old stands of Cryptomeria japonica, Cupressus sempervirens, Pinus taeda, Acer pseudo-platanu and mixed plantation and natural forest stands on sequestration of carbon in the soil of Chamestan plantation area. The results showed that the difference of carbon in pure, mixed and natural stands, in different layers are statistically significant. Moreover, there are not any significant correlations between the acidity of the soil, nitrogen, salinity and phosphorus and carbon sequestration. For the total layers of the soil (0-45 cm), the rate of carbon sequestration in natural stands (108 ton/ha) was significantly higher than other stands) P

This research investigated the effect of canopy gaps created by single-tree selection method on humus layer depth within a managed oriental beech (Fagus orientalis Lipsky) stand in Hyrcanian region. To accomplish this, 16 gaps were selected in 4 classes (small, medium, large and very large) with 4 replications for each sample in a beech stand in Alandan district, Sari (Mazandaran province). Humus layer depth was measured in center and cardinal points of the gaps. In addition, humus was sampled based on composite samples for chemical experiments. The results showed a significant difference of humus thickness among gaps. The correlation coefficients indicated that the total N, P, K, organic carbon and C/N ratio were decreased with increasing humus depth. Humus layer depth in gap center was lower than that in the edge of gap, and the highest humus thickness was observed in the northern geographical aspect. In general, the result of study revealed that canopy gaps created by single-tree selection method affect the humus layer depth after 8 years, which in turn indicates the important role of gaps within forest ecosystems.

Landuse change is one of the most important influential factors on the protection of natural ecosystems, since it greatly contributes to, for example, stabilizing soil and avoiding its erosion. This study aimed to evaluate the effect of different landuses on soil carbon sequestration potential in Chahartagh-e Ardal area of Chaharmahal and Bakhtiari province. To this aim, six different landuse types including natural forest, disturbed forest, enclosure forest, garden, grassland and agriculture were selected, followed by randomly drawing ten samples in each landuse type. In addition, quantitative parameters of existing vegetation, and 60 soil samples were also taken from the 0-60 cm soil depth in each plot. Soil analysis was performed to determine the texture, bulk density and soil organic carbon. The results showed that enclosure forest has the highest rate of carbon sequestration in soil among the different land uses (47.466 Mg C ha-1) and the lowest rate related to disturbed forest (13.689 Mg C ha-1), which was attributed to its appropriate vegetation and ecosystem dynamics. Moreover, a significant difference (p

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

Moringa pregerina (Forssk.) Fiori.، Capparis decidua (Forssk.) Edgew. and Salvadora oleides Decne. are important indegenious shrub or tree species of Sahara-Sindian region which distributed and formed scattered woodlands in south east of Iran. The current research was carried out to find most effective soil characteristics intheir distribiution. For this purpose، a study was conducted in the Balochestan province of southeast Iran in 2008 for four years. Based on a vegetation map and field surveys، indicator sites were identified. Within each site، 1-3 profiles were dug. Soil sample was taken from 0-60 cm. Measured soil properties included: pH، EC، K، P، N، sand، silt، clay، T. N. V، gypsum، T. D. S. and texture. To determine the most soil effective factors on plants، multivariate techniques، including Canonical Correspondence Analysis (CCA) was applied. The results indicated that between three species habitates، only there are significant differences in nitrogen percent، gypsium and electrical conductivity. The CCA results indicated that the main edaphically factors affecting the distribution of Moringa pregerina are total neutralizing value (T. N. V) and clay percentage، and for Salvadora oleides، total neutralizing value (T. N. V)، total dissolved solid (T. D. S.) and sand percentage are effective factors and total neutralizing value (T. N. V) and total dissolved solid (T. D. S) characters play important roles in Capparis decidua presence

In order to investigate some silvicultural and soil physico-chemical characteristics of Christ's thorn (Ziziphus spina christi L. Desf.) natural stands, ten natural stands of the tree species which have similar climate and aspects were selected and altitude from sea level (ASL), the thickest sprout collar diameter (TSCD) and total tree height (TH) of the tree species were measured in 1000 m2 circular main plots. Seedling regenerations of the species were counted in 100 m2 circular microplots. We sampled soil from three depths of 0-30, 31-50 and 51-70 cm for studying on soil physico-chemical properties in each main plot. To compare means of tree quantitative characteristics, t-student, ANOVA and Duncan and for soil studying, CA and PCA were used. The results showed that TSCD and TH hadnt significant differences in two levels of ASL. Although there were an exclusive correlation between presence of the species and sand percent of all three layers of soil in around 60% of Christ's thorn sites, the minimum TSCD were recorded in the sites too. Christ's thorn had the maximum TSCD in sites correlated with N, OC and EC in shallow and percent of silt and clay in deep layers of soil. So for increasing success of Christ's thorn plantations we suggest such sites are selected.