A diversity survey of mountainous forests trees in North of Iran.
Biodiversity is an essential case for life continuance, economical affairs and ecosystems function and resistance . This study tries to examine the relationship between the richness and evenness of broad leaf trees in north of lran with height from the sea level and to use the results in managing these forests. Generally biodiversity measurement typically focuses on the species level and species diversity is one of the most important scales . Generally the site biodiversity is impressed by environmental factors and the physiographic factor of land as the height from sea level is one of the most important factor in this case [8,10,13]. For this purpose, various researchers have examined biodiversity by separately considering different physiography factors such as ,the height from sea level, slope and direction, they have mentioned that by height increase from sea level the average temperature of the weather decreases and with regard to other climatic factors it leads to the formation of climatic regions there botanical regions with specific species diversity are formed . The specific environmental communities in forests have been led to occurrence of different forest communities. There fore to that more biodiversity would cause more fertility and ecological resistance .
Materials and Methods
Tonekabon forests with an area of 15545 hectare are located in 20- kilometers far from the south of Tonekabon (North of Iran) and have a minimum and maximum altitude range of 250-2250 m above sea level. (Fig. 1).
According to Tonekabon meteorology station records, in the last decade the area has had the average rain of 1100 millimeter and an average annual temperature of about 12.7[degrees] C. Besides, the mean differences of the coldest and hottest month of the year are 24.7[degrees] C. which shows a relatively temperate weather. The relative humidity of the region fluctuates between65-95 percent. From pedological point of view the soils are often alkaline and in some places neutral [3,11]. The soil texture in most of the area is heavy clay to semi-heavy sand with average to low permeability. In this study in order to obtain newer data a sample has been chosen and its physico-chemical conditions have been studied. The results of the experiments are shown in table1.
[FIGURE 1 OMITTED]
The natural plant incorporation of Siahkal forests include species like Fagus Orientalis, Carpinus betulus, Quercus castaneifolia, Alnus subcordata, Acer velutinum, Acer cappadocicum, Ulmus glabra, Fraxinus excelsior, Cerasus avium, Diospyrus lotus, Parrotia Persica, Pterocarya fraxinifolia, Gletidschia caspica, Taxus baccata, and shrubs like Mespilus germanica, Crataegus, Prunus divericata and Ilex Spicigera. (Sabeti, 1994).
In order to study the diversity of tree species of Tonekabon forests, first on the topography map of the area under investigation those areas which have been under the protection of forestry or were being used were excluded and from the remaining places only those which have not been used or manipulated at all were chose for the study. The chosen places have been classified into 10 altitudes for the minimum (100 m) to maximum (3520 m) altitude range from sea level (Table 2). In each altitude range, 4 sample 70 x 70 m lozenge pieces (Totally 40 pieces) were randomly chosen and carefully surveyed for the study.
Results and Discussion
Biodiversity is much more extensive and widespread to be perfect and completed by a survey of some species. It includes complex methods and processes which interrelates living things to each other or to their ecology. In this regard, their genetic structure can be specified and the process by which a system can remain dynamic, active and self-systematizing be determined .On the other hand, species diversity, depending on the level to be studied (whether ecology, species, genetic diversity) has different meaning and uses. And in each of the levels mentioned the form and combination of biodiversity is of greater importance. So in relation to a complex mechanism like ecosystem of forest which possesses a perpetual dynamics, biodiversity should be studied by considering all its various aspects. This study indicated that the diversity of tree species is high in the site under investigation above. However, it is clear that to arrive at a generalization with regard to the changes in tree species or generally speaking woody species with increase in altitude from sea level, similar studies are necessary in different sites and at different conditions. In this zone species richness and plant diversity of woody species is particularly low in oriental beech forests (Fagus orientalis Lipsky) which are due to beech dominance . The results of this study indicates that with increase in altitude from sea level, species richness decrease while species diversity and evenness continue to rise so that the maximum species diversity is observed at the altitude range of 1 to 3 (350-750 m) and the least diversity of species can be observed from 250 m above. Besides, from 1000 meter above sufficient quantity of oriental beech can be observed. (Fig. 2).
This study in terms of tree species breeding abundance has come to the conclusion that lower and higher elevation stands due to heavy overgrazing are experiencing a poor condition while middle elevation stands enjoy a stable good quality situation. The distribution of trees in the diameter classes shows a normal, decreasing feature distribution, which is a prime character of natural forests. Fig. 3 and 4.
[FIGURE 2 OMITTED]
This survey clearly proves that traditional human interventions on species diversity and especially on breeding process have a deep negative impact. Therefore to select a site for scientific investigation it is suggested that those sites do not suffer from overgrazing and human activities. This must be especially true when it comes to important subjects such as biodiversity or diversity of woody species. This research showed that qualitative and quantitative parameters of plant species in relation to elevation above sea level changes in time. These changes are the results of inherent characteristics of the forest stand involved and the general conditions of the stands. The cognition of information diversity and understanding the genetic sources of woody species in forest stands of northern Iran and finding their relation to the concept of elevation above sea level is a subject that requires more investigation and scientific though. In this regard, study and cognition of genetic diversity of forest stands of northern Iran is of great importance that must be carefully considered.
Generally the confirmation and resistance of wooden species in different regions differ by the influence of factors such as the soil climatic factors the species kind structure and combination of species and being above the sea level . various ecological factors have an important influence on the formation extension and resistance of wooden species. Meanwhile topography has the most direct and indirect effect on wooden species . The reduction of biodiversity in mountainous heights maybe due to unfavorable thermal conditions and the increase of evenness in these heights. Generally the most richness and variety is noticed in the middle heights and this altitudinal boundary . An this research the most species diversity is noticed in 350 - 750 meters above the sea level and the least species diversity is noticed at the Rang of 1550-1750 m altitude. since the environment temperature is favorable the amount of species richness is more in the lower heights.
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Mir Mozaffar Fallahchai
Department of Forestry,Lahijan Branch,Islamic AzadUniversity, Lahijan,Iran
Mir Mozaffar Fallahchai; A diversity Survey of mountainous forests trees in north of Iran.
Mir Mozaffar Fallahchai, Department of Forestry, Lahijan Branch, Islamic Azad University, Lahijan, Iran.
Table 1: The general physical and chemical characteristics of soil in the research are. Texture Sand Silt Clay K P N pH Si-cl-1 18 40 40 170 15 0.121 5.9 Table 2: Altitude range and limit values in The research area. Altitude Limit values in range The range(m) 1 250-450 2 451-650 3 651-850 4 851-1050 5 1051-1250 6 1251-1450 7 1451-1650 8 1651-1850 9 1850-2050 10 2051-2250 Figure 3: Mean diameter of various trees at different altitude Altitude Mean diameter Classes (m) (cm) 350 30.24 550 23.88 750 29.72 950 42.85 1150 35.83 1350 36.80 1550 30.02 1750 27.78 1950 26.97 2150 16.91 Notes: table made from bar graph. Figure 4: The distribution of number of trees in the diameter classes. Diameter Number Classes (cm) of trees 10 1305 15 787 25 604 30 330 35 330 40 266 45 257 50 177 55 186 60 160 65 139 70 117 75 107 80 53 85 52 90 42 95 31 100 35 105 22 110 15 115 13 120 3 125 4 130 2 135 4 140 2 145 2 150 1 Note: table made from bar graph.
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|Title Annotation:||Original Article|
|Author:||Fallahchai, Mir Mozaffar|
|Publication:||Advances in Environmental Biology|
|Date:||Sep 1, 2011|
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