Iranian Journal of Forest and Poplar Research
Year:2009 | Volume:17 | Issue:1 (35)|Papers Count:19

Elimination trials of exotic species are important for afforestation and reforestation projects. For this purpose, Cedrus atlantica and Cedrus deodara seedlings were planted in 1983 and 1992 in Chamestan region and adaptation of them were studied in 2005. Results showed that the survival of Cedrus deodara (97%) is more than that of Cedrus atlantica (67%). The mean diameter and mean annual diameter increment of Atlas cedar were 28.8cm and 1.1cm, respectively, while those of Deodar cedar were 16.8cm and 1.2cm, respectively. The mean height and mean annual height increment of Deodar cedar were 13.8m and 0.9m, respectively, while those of Atlas cedar were 14.8m and 0.6m, respectively. The volume of Deodar cedar and Atlas cedar were 208 silve ha-1 and 80 silve ha-1, respectively. Besides, the qualitative characteristics of Deodar cedar were better than Atlas cedar. Therefore, this research indicated that Cedrus deodara is more adaptable than Cedrus atlantica in Chamestan region.

In this research, 44 clones of different Poplar species including Populus alba, P. nigra, P. candican, P. deltoides, P. euramericana, P. suaveolens, P. ciliata and P. trichocarpa were studied within three years at Ghaleh –Sefid Experimental Station in Esfahan Province. The studied growth parameters consists of survival, height, diameter and effect of seedling basal cutting on shoots height and diameter growth. Height and diameter were measured annually. After measuring the one-year old seedlings, they were cut off from stem base. At the second year, the seedlings 1/2 (with one-year old shoots and two-years old roots) and at the third year the seedlings 2/3 (with two-years shoots and three-years roots) were measured. Results showed that the highest and lowest survival rate belonged to Populus simonii, P. nigra and P. alba, respectively; whereas the highest and lowest height growth belonged to P. nigra and P. suaveolens, respectively. The highest and lowest height and diameter growth of the one and two-years old shoots belonged to P. deltoides and P. suaveolens, respectively. The basal cutting affected the height growth of P. deltoides, significantly.

This experiment was conducted in Rikhalan Experimental Station in Marivan city of Kurdistan province of Iran in 1999 and ended in 2006. In first phase, (nursery selection) 29 genotypes of walnut (Juglans regia L.) were studied, under Randomized Complete Blocks Design (RCBD) with four replications in three years. The measured tree characteristics were: height, collar diameter and survival. Based on the results of first phase, for the second phase, five genotypes of walnut (J–2, J–10, J–17, J–18 and J–19) were selected and planted under Split Plots Design with three replications during seven years (1998–2006). The main plots were: Control and soil surface with mulch cover and the secondary plots contained five walnut genotypes. Results showed that there were only significant differences between the main treatments in respect to the growth characteristics (p < 0.01). Survival, crown diameter, height and collar diameter of the walnuts at plots applied with plant material mulch (oak chipped branches) were significantly greater (96.7 %, 72.6 cm, 135.9 cm and 37.4 mm, respectively) than the walnuts at control plots (77.9 %, 50.1 cm, 95.6 and 28.4 mm, respectively).

In order to study the effective factors influencing distribution of wild pistachio species in Zanjan province, the first step was to inquire and review all the related documents and information. The next step was to make excursion in the natural habitat of the species located in the study area. Finally, the distribution of the species was overlayed on topographic maps. The total area of this species estimated to be 23208 ha. Considering the main factors including: elevation, aspect and geological formation; working units were specified and 40x40 m sampling plots were located on the units to determine different forest types. Three forest types were distinguished, including: pistachio-juniperus (5002 ha), pure pistachia (3401 ha) and degradaded open pistachio (14805 ha). The last one was the vastest forest type which demonstrates the degradaded extent of this forest type. Most of trees at the forest types were coppice and only few seed originated seedlings were found. The highest distribution (44%) was found on 45 percent and higher slops. About 65 percent of the forests located on northwest and southwest aspects. The lowest distribution was found on the main aspects (north, south, west and east). Approximatly, the most distribution was found in cold semi-arid climate (61.74%) and the lowest distribution (0.16%) was seen in the cold-humid climate. Most of the forests were located on volcanic, shaill and sandstone geological formations (45.94%).

This study was carried out in order to investigate the capability of digital data of ETM+ sensor in separation of forest types in Gazoo district of Lafoor area in Savadkooh. The bands were controlled according to radiometric and geometric errors, separately. Band 1, was omitted because of the existence of radiometric error and its less importance in vegetation cover study. Geometric correction was performed by 21 ground control points with DEM, up to ortho rectification level with precision of less than half pixel (0.3 pixel). The supervised classification was performed by using basic and synthetic bands to 6 classes, (pure beech type, mixed beech type, mixed hornbeam, road and non covered area, persimmon, mixed broad leaf). Ground truth map prepared through sampling in 24% of whole area. The highest overall accuracy was belong to maximum likelihood classification for 6 classes which was 38.29% and Kappa coefficient was 27.7%. Six vegetation types were merged because of radiometric mixing, therefore classification with 5 classes was performed again. Accuracy assessment of classification results indicated that the highest overall accuracy and Kappa coefficient were 53.22% and 34.71%, respectively. Results showed that the ML classification increases %15 of overall accuracy and %7 in Kappa coefficient. Overall, using ETM+ data is not so appropriate in the studies which the map type is considered as a base map with maximum number of existing type in the area. In order to increase the classification accuracy, using of other classification methods like object-base method and the other information and multitemporal data is suggestible.

In order to investigate on the adaptation and performance of exotic trees in northern of Iran, a field experiment was carried out during 1991 to 2006 in Asalem forests. Nine species of different conifers, consisting of Pinus nigra var. austriaca, P. nigra var. pallasiana, P. nigra var. calabrica, Picea abies (prov. Klardasht), P. abies (prov. France), P. glauca (prov. Canada), P. orientalis (prov. Turkey), Pseudotsuga menziesii (prov. America) and P. menziesii (prov. California) were planted using a Random Complete Block design. At the end of each growth period, three parameters of survival, diameter and height were measured and results analyzed finally at the end of 16 years. The results showed that there was a significant difference of growth factors (diameter and height) among species (treatments) at significant level of 1%, whereas no significant difference was found in survival rate. Pseudotsuga menziesii (prov. California) showed the highest height (10.2 m) and Pinus nigra var. calabrica the highest diameter (16.1 cm) after 16 years of study period.

Regeneration and forest durability guarantee is one of the most important aspects of forest sustainability and it should be placed in forest plans priority. So, due to important role of Zagros forests, comprehensive investigation about regeneration crisis becomes an increasing necessity. In this study we tried to investigate on seedling and coppice regeneration in two categories of higher and lower than 2 meters height classes and in untouched and traditionally pruned stands in three regions with different disturbance regimes. Study sites were located at Armardeh in Baneh city (Northern Zagros, Iran). Results of the study state that seedling and coppice regeneration in lower than 2 meters height classes are significantly more in untouched forest stands, and its density in site number "1" to "3" is 3250 versus 375± 92, 1600 versus 130±18 and 310 versus 81±37 per sample plot (2500 m2), respectively. In untouched stands in site number "1" and "2" saplings in higher than 2 meters height classes are 533 and 66 per sample plot., respectively, but in untouched stand in site number "3", due to livestock grazing, there is no sapling higher than 2 meters like other pruned stands. According to our results the most important factors affecting oak regeneration in this region are livestock grazing, fire, acorn collecting by villagers for domestic fodder, summer drought, pests and diseases on acorns and seedling.

In natural ecosystems, site classification can be used as a model to determine the quality of forest ecosystems based on ecological factors. Therefore, vegetation analysis based on plant communities and soil properties was performed in Kheyroudkenar forest – Nowshahr. Based on Braun - Blanquet method and using ANAPHYTO software vegetation data were analyesed, and associations recognized. Morevere, ecological groups and differential species were determined based on phytosociological data using TWINSPAN. Afterwards, depending on one sample selected in each landform class, the area with differential species was recognized for soil study. Results showed that two communities constitute the major part of the study area, Rusco-Fagetum and Carpineto–Fagetum. Soil variables that played the most important role for expantion of Rusco-Fagetum associaton were depth, silt, P and pH, while in Carpineto–Fagetum important were clay, sand, Sp, N and C.

The National Botanical Garden of Iran (NBGI) with an area of 145 hectares contains various plants with different ecological requirements, including trees, shrubs, herbs and ornamentals. Weakness and decline of some tree species including Elm trees of botanical garden is one of the problems, which considered as the main priorities to be investigated by the garden authorities. Soil productivity and plant nutrient were concerned to be studied. For this reason, soil samples were taken from three layers of each profile (0-10, 10-30 and 30-100 cm) around Elm trees, after studying the soil profile morphology. Leaf sampling was made at appropriate time in order to test N, P, K at first year and N, P, K, Ca, Fe, Mn and Zn at second year. Results showed that the soil texture was sandy, organic mater were low and pH was alkaline. The mineral elements were lower than the optimum range in soil and tree leaves. It can be concluded that increasing soil organic matter, adding adequate amount of manure and chemical fertilizers to soil and applying appropriate irrigation regime might improve the plants health and growth and prevent their decline.

Wild cherry (Prunus avium L.) is one of the most valuable Iranian native broad- leaved species that its seed study is very important due to its rare distribution and valuable wood. In order to determine the effect of Prunus avium's seed origin on germination, survival and growth, seeds of wild cherry were collected from different sites including: Lajim (900 m.a.s.l.), Neka (1000 m.a.s.l.) and Farim (1200 m.a.s.l.). Seeds were sown in nursery of Mazandaran pulp and paper industry at 140 m.a.s.l. Seed germination, survival and height growth of seedlings were measured and recorded after first growth season. Results showed that the effect of seed source on germination was statistically significant. The effect of seed source on seedling survival and the height growth of seedling were significant too. Germination rate, height and diameter growth of seeds which collected from Lajim origin was higher than other origins.

In order to study dbh distribution of trees in uneven- aged stands and fitting tree diameter using statistical distributions, data of Gorazbon district of Khyroudkenar forest were used. 196 trees were selected randomly as sample and their dbh were analyzed. After basic calculation, three distribution: Exponential, Gamma and Lognormal were used to fit on dbh data. Results of Chi-Square and Kolmogorv-Smirnov tests showed that Exponential distribution cannot determine diameter distribution of trees, and between two others, the Gamma is more appropriate.

Using species richness, Shannon-Wiener diversity and Simpson indices, diversity of woody species in protected and non protected areas of Arasbaran forests were studied and compared in this research. Two forest stands with similar floristic and physiognomic situation were selected by using of aerial photographs of 1968 with 1:20000 scale. Then tree species were recorded in 92 transects, each with 30 meter lengths, which was established in 150×300 m grid in the forest stands of the protected area and in a similar way in the non protected area. For data analysis, the means of different diversity indices were calculated and t-test was used to test all indices means differences in the studied areas. Results showed that species richness, evenness and plant diversity indices were significantly increased in the protected area. One can conclude that preservation-based management caused increasing of the woody plant diversity in Arasbaran forests. Therefore, preventing against livestock grazing in the forest stands and uncontrolled tree cutting in the destroyed forest stands could be introduced as a suitable approach for natural restoration and increasing of plant diversity

In order to investigate some of the qualitative and quantitative characteristics of oriental beech (Fagus orientalis Lipsky) at optimal phase, this research was carried out in the Caspian forests of Iran in 1999. The study area consisted of a natural stand which was located at Sangdeh District (Mers-e-se) with three hectare area. It was located at 1900-1950 m.a.s.l. Moreover, six sample plots with 0.36 ha area and 25m buffer zone, were selected and all trees (1244 stems) within the plots were measured and recorded. Results showed that the highest frequency of stem number was recorded between diameter classes of 25 to 40 cm. The mean dbh, stem number, basal area, and volume were 35 cm, 562, 53.59 m2ha-1 and 677.9 m3ha-1, respectively. The mean height and dominant height of the stand was 27.1 and 31.3 m, respectively. Moreover, crown canopy was 77%. The mean crown diameter and mean distance between trees was 5 and 4.5m, respectively. On the other hand, the mean slenderness and Reineke coefficient was 79.74 and 1.05, respectively. The results of qualitative characteristics showed that the healthy and non healthy trees of the stand were 48% and 52%, respectively. Moreover, 70% of the trees (402 stems per hectare) were defective or damaged. Thus, 30% of the trees (160 stems per hectare) were faultless, from which the good elite and fine elite trees were 23% and 7%, respectively. The frequency of forked and unforked trees was 28% and 72%, respectively.

This study was carried out in Melehgavan protected area (app.160 ha) located in northwestern of Ilam city. The main objective of the study was to survey the ecological species groups in relation to some physiographic attributes and soil physico-chemical properties. The field data were obtained using 67 sample plots (20m×20m) in a systematic random grid. The attributes including tree and shrub species type, number of each species and canopy coverage, which were recorded by measuring their small / large crown diameters in each sample plot. In order to record the herbaceous species, the Whitaker’s snail plot method was applied, which resulted in 81 m2 of the minimum plot area. The Canonical Correspondence Analysis (CCA), Principal Components Analysis (PCA) and TWINSPAN methods were used for the site classification, determining of the relationship between species composition and environmental properties and also definition of ecological species groups, respectively. Results indicated that there were three ecological species groups in the study area. The first group had a positive correlation with the soil pH. There was no indicator tree species in this group but Stipa capensis, Fibigia macrocarpa and Medicago rigidula could be detected as indicator herbaceous species. The second group was established in the higher elevation and its site had more moisture and mineral nutrients than the sites of other groups in the area. Quercus brantii and Bromus tectorum were identified as the indicator species for this group. Daphne mucronata and Euphorbia macroclada species were defined as the indicator species for the third group, which was established in the low elevation above sea level. The mineral nutrients of this group were less than the second group.