Applicatuion RS and GIS technology in identification of wood types Cupressus sempervirens for rehabitation of Deforested area in Armand watersheed , Chaharmahal Bakhtyari Provance, Iran

A.Palham Abbasi
Faculty members of Azad University - Bandar Abbas Branch
Apabbasi @ yahoo.com

S.J.Khajedin
Associate prof. Isfahan university of technology
Khajedin @ cc.iut.ac.ir

H .Khademi
Associate prof. Isfahan university of technology
hkhademi@cc.iut.ac.ir

Abstract
Germination of plants in one area is influenced by environmental factors of that area. Having information about both ecological needs of differente types and regional specifications of area which is under consideration is necessary. In this research the Potential habitat of a species of Cupressus sempervirens in aquferous watersheed of Armand Chaharmahal bakhtiyari province was determined by using RS and GIS techniques. For this purpose after collecting different maps including topography, geology, climate , soil maps of the area which is up taken from different organs, these maps were digitazed for providing essential information layers. Information layers including of rock outcrop, forest covering, Rangeland, dry land, irrigated farming lands were provided by TM data, then with refer to different scientific sources, different ecological needs of Cupressus sempervirens were provided and based on these needs and also, the properties of the area different information layer were prepared. Finally, by combining the layers with each other it was specified that about 1150 hectars belongs to suitable habitat of Cupressus sempervirens in the area considration.

Introduction
Population increase and the rise of human needs has resulted in an ever-rising on the earth`s limited natural resources. Activities like deforestation, over grazing, farming in unsuitablelands have raised several problems. During the last three decades in Iran, the average annual deforastatioin has been 130000 hectares and the average annual destraction of rangelands has been over one million hectares. For rehabitation of these forest, one useful method is to determine the potentioal of these region in order to introduce proper tree species. Nowadays, due to the increasing rate of the destraction of natural resource, it seems nrccessary to use modern techniques as RS and GIS to boost the rehabitation on these regions. To perform reforestation with the purpose of preventing erosion in Africa, Mckendry and colleagues use GIS techniques to prepare the potential rehabitat map of Eucalyptus grandis species. In this study, they only used climatic information layer. With the purpose of reforestation of Molin forest in Taiwan, Wang and Co., used RS and GIS techniques to determine potential rehabitate of Taiwania cryptomerioides tree species. In this study, they used phisiography and soil information layers.

Study area
Armand Watershed with the area of 30111 hectares is located between 50^ 42` 43" to 50^ 54` 30" E of longitude and 31^ 32` 18" to 31^ 45` 18" N of latitude within 10 kilometers from north of Lordagan city in the Chaharmahal Bakhtiyari province.

Methodology
This study was accomplished in the following three stages:

Preparation of information layers,
Preparation of ecological needs of C. sempervirens species,
Aassimilation of information layers together in order to determine the potential habitat of C. sempervirens. Figure1 briefly shows the steps of the study.

Figure1: Methodology of the study

1- Preparation of information layers:
The needed information layers was obtained from two resources:

Thematic maps of the area which are obtained from variouse organizations. In this step, the topographic map was digitized in the 1:50000 scale and information layers such as hypsometric and aspect was prepared in the ILWIS software. The geological map of the region was obtained from Iran`s geological organization and was digitized, geological information layers was prepared as well. Using raster topography map and the existing gradients in climatic reports, information layers of average annual rain, average annual temperature and the minimum of temperature was prepared. By digitizing the soil study maps of the region, the information layers of soil texture, soil depth and soil pH was prepared.
Preparation of information layers from satellite data: in this study the Thematic Mapper data (TM ) of Landsat satellite of year 1998 were used. These data were geometrically corrected using topographic map of 1:50000 with Root Mean Spuare (RMS) 11.5 meters. After geometric correction of data in order to recognize different land covers as the satellite images, false color composite (FCC) were prepared on which, land cover such as rock outcrop, forest area, shaded area, irrigated land farms, rangeland and dryland farms become clearly separated. By principle component analysis (PCA), it was found out that on PCA3, rock outcrops and on PCA1, shaded area are well recognizable. Therefore separated training sites were chosen over them and by using maximum likelihood classifier method, the information layer of rock outcrop and shaded area were prepared. To separate irrigated land farms and forest cover the normalized vegetation index (NDVI) was used. Since the satellite data of month Septamber was used, rangelands and dryland farms had the same reflection. Therefore, by using FCC image and maximum likelihood classifier method, information layers of ranglands and dryland faorms were prepared. Table 1 shows the area of various land covers in the study area.

Tabl 1: Area of various land cover in Armand watershed

Land cover	Area (hec)
Forest	16667.46
Shaded area	72.1
Irrigated land	147.5
Rock outcrop	2314.38
Rangeland & Dryland farming	10909.29

Fig 2: landuse map of the study area

2- Determination of ecological needs of C. sempervirens
C.sempervirens is a member of pinacea family and is one of the important Meditranian species. The height of this species reaches upto 20 to 25 meters and its diameter to 60 centimeters and is distributed from sea level to the height of 1800 meters in the northern and eastern slops. It is a resistable to coldness and dryness and grows in region with 300 to 1400 mm 0f annual precipitation and average annual temprature of 10-20 C^ and minimum temprature of -15 C^. C. sempervirens grows soils that vary widely. But it best grows in sand soil and deep and semi-deep, lime soils with a pH of 6 to 7.5. This Pine is a fast-growing species and grows rapidly during its youth.

3- Layer Combination
After the preparation of deferent environmental information layers such as hypsometric, aspect, geology, average annual precipitation, average annual temprature, minimum of temprature, siol texture, soil depth and soil pH and the determination of ecologic needs of C. sempervirens species, these layers were combinated according to suitability of different region which were under study.To this end, each of the environmental layers were classifierd in the form of Boolean file according to ecological needs of C. sempervirens, then all of the prepared information layers were combinated and finally the proper region, for growth of the species was determined.

Results and Discussion
In this study, the rock outcrop information layer, because of its lack of soil, the shaded area, because of unrecognizable land cover in it, and irrigated land farms, because of socio-economic problems, was considered as unsuitable regions. Regions of salt formations were separated using geological map and was considered as improper. The forest cover, rangeland and dry land farms information layers were combinated with the potential habitat map of C. sempervirens and it was determined that, of whole the habitat, how much is forest and how much is rangeland and dry land farm. After the combination of the layers, it was determined that about 1150 hectares of the study area is potential habitat of C. sempervirens, of which about 417.837 hectares is forest and 731.799 hectares is rangeland and dry land farms. Figure 3 is the map of the potential habitat of C. sempervirens in the Armand watershed.

Fig3: Potential habitat map of C. sempervirens

Reference

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Wang. S. F and Chen. C. C.. Application of ecosystem management decision support system in selecting suitable site for Taiwan. 21st Asian Conference on Remote Sensing. Taipei, Taiwan. 2000.
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