| Using water balance pricinple and principle of maximum capcity of forest inception storage, surrounding 5 indexes, function of water conservation of 26 economic and protection forests were studied in this thesis. Acording to multidimensional space theory and the law of coordinates evaluation, water conservation function of 26 forests were analyzed, the sequence of good function was obtained. The author caculated the ecological and economical value, modified the interrelated formula, established a math model about value of forest water conservation and 6 common indexs.The main results are as follows:1. Precipitation interception function of three layers of different forest type: As the amount of rain turns from 4.5mm to 27mm, canopy interception storage and interception percentage turns from 1.38mm to 4.68mm and 30.65%~15.16% accordingly; Canopy interception storage also relates to crown closure and forest mixed type; The author put forward that canopy water holding capacity can be used to evalue the capacity of canopy interception, and they are linearity related.The range of litter holding storage of 26 forests is 0.21-3.84mm, and increase followed by the thickness and amount of litter; the water absorb rate of litter is fast in early period, esp. before 0.25hr, can get 0.44-2.38kg/(m2 · h), then turns slow, stops after 24hr.The maximum soil saturation water holding storage can get 1569.9t/hm2, the water holding capacity by unit area is 336.9 t/hm more than CK; Infiltration rate in broad leaved forest stand is highest, and needle-leaved forest lowest.2. Effect on water mass storage by economic forest and protection forest: Forest in research area can hold 7.21 × 106m3 precipitation storage annual. The storage by unit forest area is 1361.l~1610.4t/hm2, 1hm2 forest can increase groundwater runoff 189.0-251.7t.Dry farming methods in economic forest stand can save, conserve water, can increase water resource mass srorage. Soil water content by treatments is 4.3%~39.3% higher than CK.Soil detention storage increases 23.9%~34.6%. The amount of evapotranpiration in a week and water deficiency are 2.1mm~2.8mm and 0.5~4.8mm lower than CK.3. Effect on water quality by forest: The research showed that the water quality in Huangqian reservoir measured up to Chinese III type of surface water. Some indexes measure up to I type. The water quality in 2001 and 2002 is at best level, and has no supersede.4. Anti-erosion capacity of economic forest and protection forest: Mixed forest has the lowest throughfall rain coefficient at the range of 78.48%~80.93%, whose capacity of anti-erosion is the best. The coefficient of needle leaved forest is 78.90%~81.85%, stands in the moddle. That of broad-leaved forest is 82.34%, stands the lowest one. When the size of raindrops are close, the kinetic energy of raindrops relate mainly with the height of canopy. The canopy can reduce raindrop potential energy 938.7~1733.0J/m2.Soil mass erosion relates close to the thickness of litter. Soli mass erosion can increase 339~861t/km2 · a without the cover of litter. Litter can reduce soil erosion 30%~57.14%. Roughness of litter and capacity of anti-erosion increase according to plant cover degree.5. Comprehensive evaluation to water conservation function of economic forest and protection forest: By the sequence of water conservation function of 26 forests, it was founded that none of the 26 forest can get all the best indexes, comprehensive evaluation should be put forward.The plant type who has best comprehensive function is needle-broad mixed forest, which scored 0.1047, and broad leaved mixed forest, broad leaved forest, tree-shrub mixed forest, needle mixed forest, needle leaved forest, shrub forest, economic forest, shrub and grass scored 0.1047, 0.2298, 0.3653, 0.4106, 0.5037, 0.5870, 1.2860, 1.5575, 2.172 by sequence. The forest has best comprehensive function is No.4 forest, which scored0.1287. The forest has worst comprehensive function is No. 16 forest, which scored 2.6751.The auther choosed 13 forests which have the better comprehensive water conservation function, 12 forests which have the better canopy interception function, 12 forests which have the better litter holding water function, 11 forests which have better soil holding water function, 11 forest which have better soil infiltration function, 7 forests which have better anti-erosion function.6. Economic evaluation to water conservation of economic forest and protection forest: The author improved on the caculation method on substance mass and economic mass of forest water conservation, suggested the final infilation amount under 120min rainstorm scale should be added, discussed the problem of willing to pay, worked out the society level coefficient (l=0.468), and modified the economic value.The research showed that, the forest water conservation mass were 85.99 million t, economic value was 229.94 million yuan, water conservation increment were 26.05 million t, economic value was 96.70 million yuan, 25.21 million t water quality was improved, economic value was 25.21 million yuan, the sand entering in Huangqian reservior without forest protetion increased 366.9 thousand t and 450.43 thousand t annually, the value of anti-erosion function was 981.1 thousand yuan.The remarkable tested linearity regression equation of unit area forest and 6 common indexes was etablished. That can provide many conveniences to the work of forest economic evaluation. |
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