碩士 / 國立彰化師範大學 / 地理學系 / 97 / To understand the effects of converting natural broadleaf forest to tree plantations on carbon and nutrient cycling, we compared litterfall, litter decomposition, and soil nutrients at natural broadleaf forest, Cunninghamia lanceolata plantation, and Calocedrus formosana plantation in Lienhuachih Experimental Forest between May 2007 and April 2008. I placed six litterfall traps and 78 litter bags in each of the three stands and collected litterfall and litter bags on monthly basis. I also collected 6 soil samples from each stand. The results showed that litterfall from July to October were mostly caused by typhoon disturbances. The typhoon induced lifferfall accounted for 58% (6629 kg/ha) of annual litterfall amount in natural broadleaf forest, 81% (5997 kg/ha) in Cunninghamia lanceolata plantation, and 72% (4069kg/ha) in Calocedrus formosana plantation indicating the importance of typhoon on lifferfall for all the three stands Litterfall mostly produced by typhoon disturbances in natural broadleaf forest inputted more carbon (3431 kg/ha) to forest floor than Cunninghamia lanceolata plantation (3185 kg/ha) and Calocedrus formosana plantation (2224 kg/ha). Although the intensity (33 m/s) of the first typhoon Kalmaegi in July was weaker than the strong typhoon Sinlaku (51 m/s) in September, the former induced the largest amount of litterfall amount in July indicating that intensity was not the only factor determining litterfall quantity. In natural broadleaf forest, N use efficiency was lower and P use efficiency was higher compared with many tropical forests implying that P could be more limiting than N for for plant growth. The annual C, N, Ca, Mg returns from litterfall were highest in the natural broadleaf forest followed by the Cunninghamia lanceolata plantation and lowest in the Calocedrus formosana plantation, and annual K, P returns were also highest in the natural broadleaf forest but followed by the Calocedrus formosana plantation and lowest in the Cunninghamia lanceolata plantation indicating that there were more nutrients inputs from litterfall in natural broadleaf forests than other stands. Higher litter decomposition rate in natural broadleaf forest (k = 1.57 yr-1) and Calocedrus formosana plantation (k = 1.67 yr-1) than Cunninghamia lanceolata plantation (k = 1.06 yr-1) probably resulted from lower C/N, lignin/N and higher moisture content, P concentration in natural broadleaf forest and Calocedrus formosana plantation than the Cumminghamia lanceolata plantation. The decomposition rates of Cunninghamia lanceolata plantation and Calocedrus formosana plantation were higher than mostly temperature coniferous forests indicateing that planting coniferous plantations in low altitude subtropical regions could lead to greater litter decomposition rate and nutrients release because of the warmer and more humid climate. Lower soil C and N content in Calocedrus formosana plantation were likely due to lower C (97 kg/ha/yr) and N (3 kg/ha/yr) returns from broadleaf litterfall and clay content in Calocedrus formosana plantation than in Cunninghamia lanceolata plantation (C 590 kg/ha/yr、N 24 kg/ha/yr). The loss of soil organic matter from harvesting and long-term lower C and N returns from coniferous plantations could be the cause for the lower soil C and N content in Cunninghamia lanceolata plantation than natural broadleaf forest.
| Identifer | oai:union.ndltd.org:TW/097NCUE5136008 |
| Date | January 2009 |
| Creators | Hsueh-Ching Wang, 王雪卿 |
| Contributors | Su-Fen Wang, Teng-Chiu Lin, 王素芬, 林登秋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 71 |
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