碩士 / 國立中興大學 / 水土保持學系所 / 95 / Casuarina trees were planted as windbreak belts along the perimeters of the Taichung Harbor for thirty years. Due to the harsh local environments and strong typhoon attacked in recent years, numerous Casuarina trees have died. As a result, various canopy gaps in the intended windbreak belt have been created. This study was mainly conducted to understand the influences of these canopy gaps on the local microclimate in the windbreak belt, by the multi-layer anemometer, instruments of microclimate, and TDR (Time-Domain-Reflectometry) soil moisture observations. The results of this study may be useful for coast windbreak management.
The results indicated that the soils in the forest zone of Taichung harbor is sand with extremely low organic matter content. This is unfavorable to grow and sprout in forest. The bulk density and particle density of soils in each canopy gaps are between 1.44∼1.48 g/cm3 and 2.28∼2.46 g/cm3 respectively and have no conspicuous difference. The average porosity of the soils is 38% in the experimental areas. Casuarina trees have good salinity tolerance , and the electrical conductivity experiment shows that the soil salinity level is low. As a result, it has small influences on growing of Casuarina trees.
Moreover, the smaller canopy gap is, the smaller air temperature difference is, but the relative humidity is higher (more than 78%). The atmospheric pressure and soil moisture have little difference in different canopy gaps of forest. The soil moisture in the fully stocked forest land, forest land with a small and medium canopy gap is 0.4% higher then it in forest land with a large canopy gap and the check plot. The daily sunshine duration, radiation, illumination, evaporation, and soil temperature appeared to positively related to canopy gaps.
The average height of Casuarina trees in the study area lies between 10∼13m, and the height of cone lies between 7∼9m approximately. Most seeds can float 10.8∼17.2m by wind, a few can float even farther. Therefore, it is proposed that 30m to be used as the thinning interval.
| Identifer | oai:union.ndltd.org:TW/095NCHU5080026 |
| Date | January 2007 |
| Creators | Chi-En Liu, 劉奇恩 |
| Contributors | 黃隆明 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 95 |
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