Forest Resources in Taiwan
Jih-Cheng
RU Keywords : Aerial Photo, Forest Resources,
Forest Growing Stock, Biodiversity.Director, Agricultural and Forestry Aerial Survey Institute No 61-3, Chao-chou Street, Taipei, TAIWAN Tel:(886)-2-23931837 Fax:(886)-2-23931870 E-mail: nn240918@ms19.hinet.net TAIWAN Abstract : The island-wide forest resource inventory has been implemented three times since 1945. Each time the aerial photographs were used for stereo-interpretation, trans-plotting and plot sampling. During the period from July 1990 to June 1993, a total of 32,730 aerial photographs taken by the Agricultural and Forestry Aerial Survey Institute were used for the 3rd island-wide forest resource inventory. The object of this paper is to introduce the process in aerial photography and present status of the forest rsources in Taiwan. Forest is the largest ecosystems in land area. The biodiversity and global climate change are closely related to the forest. During this time, the forest resource conservation and sustained yield management play an important role in the nation's policy. <> Introduction Four hundred years ago, Taiwan was called "Ihla Formosa "--the beautiful island--for its lustrous landscape. Forests have not only been the home of abundant flora and fauna but also protected the national land, provided the water resource for our daily life and recreation sites. All our basic necessities such as food, water, clothing, housing, transportation, education and recreation are closely related to the forests. Forest resources include the timber resource, water resource, biological resource, recreation resource and other ecological resources etc. Aerial Photography The island-wide forest resource inventory has been implemented three times since 1945. Each time the aerial photographs were used for stereo-interpretation, trans-plotting , plot sampling, and data compilation. Prior to the implementation of the island-wide forest resource inventory, aerial photography must be taken covering all of Taiwan. During the period from July 1990 to June 1993, a total of 32,730 aerial photos in panchromatic film, focal length 6", at scale of 1/17,000-1/20,000 taken by the Agricultural and Forestry Aerial Survey Institute were used in the 3rd island-wide forest resource inventory. The flight line spacing is 2.5 km interval divided into 78 flying lines, north-south covering the entire island. The forward overlap is 60%-90%; side overlap 30%. Among these photographs, a total of 286,925 photo points and 3,996 ground plots were selected by double sampling for computations of land-use, forest area, timber volume, forest soil, wildlife and recreation, forest land classification. The photo base maps both B&W and color at scale of 1/5,000 and 1/10,000 were used as a base map for trans-plotting and field survey. Investigating works included:
Forest Land Area According to the data of the third aerial survey of forest resources in 1995, there are 2,102,400 hectares of forest land occupying 58.53% of the total island base (3,591,500 hectares). The non-forest land area 1,489,100 hectares occupying 41.47%. Among the forest land areas, the conifer forests occupy 438,500ha., or 20.86 %, conifer and hardwood mixed forests 391,200ha., or 18.61 %, hardwood forests 1,120,400ha., or 53.29 % and bamboo forests 152,300ha., or 7.24%. (Table 1)
Among the forest land area, of which the natural forest is 1,527,500ha, occupying 72.7%, plantation forest is 422,600ha occupying 20.1%, and bamboo forest 152,300ha occupying 7.2%. (Table 2)
Table 3 Forest Land by Major Ownership
Table 4 Forest Growing Stock by Major Forest Type
Ownership of Forest Land The ownership of forest land can be divided by national, public and private land. The national ownership including aborigines reserves, accounts for 88.92%, while the public and private ownership only 11.08%.(Table 3) Forest Growing Stock The estimated forest growing stock of the whole island is 358,744 thousand cubic meters, this number breaking down into 310,533 thousand cubic meters of natural forest or 86.56%, 47,676 thousand cubic meters of plantation or 13.29%, 535 thousand cubic meters of trees in bamboo forest or 0.15%. The average forest growing stock per hectare of the whole island is 203 cubic meters in natural forest, 113 cubic meters in plantation. (Table 4) Forest Type The forest in Taiwan supports a very rich flora. Under the influence of the climate, humidity and altitude, forest types can be divided into tropical, warm, temperate, and frigid forest zones. There are more than 200 species with high economic value, such as Taiwan zelkova, Formosan michelia, Stout camphor tree, Griffith's ash, Taiwan red cypress, Taiwan yellow cypress, Taiwan hemlock, and Taiwania just to mention a few. The excellent timber of Taiwan red cypress and Taiwan yellow cypress is well known in the world. Many plantations are established mainly with Japanese cedar, China fir, Taiwania, Taiwan red cypress, and Taiwan Acacia. Under the favorable environments, trees survive and are quickly established. The main forest types in Taiwan are briefly described as follows: Spruce-fir type: Spruce and fir are major trees and grow in pure stand of the most inaccessible region. They are found at elevation above 2,500 meters. Hemlock type: This is one of the most significant conifer types. It is distributed between 2,000 and 3,000 meters above the sea level, usually mixed with fir at higher elevations but with pine or temperate hardwoods at lower elevations. Cypress type: This is the most valuable species in Taiwan. It is composed of red and yellow cypress (Chamaecyparis spp.). They are found between 1,500 and 2,800 meters above the sea level, and either in pure stand or mixed stands. Pine type: It is found at elevation between 300 and 2,800 meters, being in the most easily accessible area of the natural conifer forests. The Taiwan red pine has a wide range with good stocking. Miscellaneous conifer type: China fir and Japanese cedar are exotic species and usually planted even-aged pure stands. This forest type also includes other native conifers, mixed mostly with hardwoods. They seldom exist as pure stand. Conifer-hardwood mixed type: It is distributed between the temperate hardwood zone and the conifer zone. Elevation ranges from 1,500.to 2,100 meters. Hardwood type: Distributing at elevations ranging from the sea level to 2,000 meters, this is the most easily accessible forest in the low elevation. The major species are members of Lauraceae and Fagaceae . Bamboo type: This type is common throughout the island. The large pure stand of Phyllostschys spp. is found only in the central part of the island at the intermediate altitudes. The important Ma Bamboo (Sinocalamus latiflorus) is found at elevations below 1,300 meters, however, Makino Bamboo (Phyllostachys makinoi), at elevations from 100 to 1,000 meters and Moso Bamboo (Phyllostachys edulis), from 1000 to 1,600 meters. Water Resource Water is a finite resource. Fresh water is one of the most precious resources in the world. Rainfall is the main source of water for Taiwan. The average annual rainfall is 2,500 mm. and ranges from 1,100 mm. to 4,980 mm. It is 3.44 times of the world average and rank at 19 of the world's abundant rainfall countries. Owing to the dense populations, the rainfall per capita is only 4,107 cubic meters, which is less than a sixth of the world average and become the country of water shortage. Taiwan is very mountainous with a central axis stretching from north to south. The concentrated precipitation makes 55% of the rainfall flow into the sea that cannot be used effectively. Fortunately, there are 2,102,400 hectares of forest land covering the island, which can postpone the surface run off into the sea. Besides, the forest soils have the function of reserving water and purifing the water quality. According to the research, the capability of the forest water conservation is 26% higher than the farmland. Therefore, water fosters forests and forests conserve water resources. Biological Resource Because of the unique natural environment, Taiwan has an estimated 150,000 to 200,000 species of organisms. The relatively well known are 4,200 species of vascular plants, 61 species of mammals, 460 species of birds, 150 species of freshwater fish, 81 species of reptiles, 32 species of amphibians, 400 species of butterfly and more than 20,000 species of insects. The poorly known are fungi, bacteria and nematodes. Therefore, Taiwan can be said a huge living natural museum, All of their habitats are forest and its surroundings, such as natural forests, plantations, bamboo forests, coastal shelters, swamps and mangroves etc. Therefore, forest is the homeland of organism. Recreation Resource The forest distribution of Taiwan from the seacoast to the elevation 3,952m of Yu-shan. The vertical distribution has lots of biodiversity. No matter the natural forests or plantations, are the best places for outdoor recreations. At present, there are 20 forest recreation areas and 5 millions visitors annually. The recreational income has more than the value of timber production. Other Ecological Resources Under the complexity of topography and unique environments, Taiwan is one of the highest biodiversity areas in the world. In order to protect the rare flora, fauna and ecosystems resources, 39 nature reserves with the areas of 390,000ha have been set up by the Taiwan Forestry Bureau since 1974. There are 6 national parks in Taiwan of which 95% of the land areas are in the national forest. The stock of biodiversity in Taiwan, as anywhere, provides components most suited to that region, and in part unique. Thus about a fourth of the organisms found in Taiwan occur nowhere else on Earth. Understanding, protecting, and sustainably utilizing this island's biodiversity, protecting Taiwan's natural resources are our responsibility. Therefore, strong efforts have been made to conserve the biodiversity of Taiwan. Conclusion Forest is a renewable resources. If properly managed, it continues to grow and provides benefits to society and mankind forever. But forest construction is a long-term enterprise, which cannot be accomplished in a single day. The forestry practice in Taiwan has been changed from the simple reforestation and harvesting to all-out ecosystems management basis. We believe that the foresters would contribute significantly to the sustainable future of Taiwan. References
|