海岸竹枝籬堆砂功效評估及植物定砂功能調查

Evaluation on Sand-deposition Efficiency of Bamboo Branch Fence, and Investigation on sand-fixing Function of Coastal Plants

甘偉航(Wei-Hong Kan)

《林業試驗所研究報告季刊》 3卷4期 (1988/12) Pp. 225-240

https://doi.org/10.7075/BTFRI.198812.0225

摘要

本調查利用苗栗縣政府，在後龍海岸，編設之堆砂籬，略加處理後，調查季風之風力概況，堆砂籬堆砂情形。選用定砂植物六種，在海岸第一線種植，調查距離海岸100m區域以內，定砂植物之生長發育、定砂量及其耐埋性，以探討植物定砂之功能，結果：風速於季風起時，前往海岸調查，最強近14m/s，下午較上午風力爲強，地上高0.5m平均9.5m/s，變異範圍7.0-11.5m/s。靜砂籬不同籬數之堆砂效果，3道籬效果甚好（14.1立方公尺）。不同籬況之堆砂籬，係以竹枝籬堆砂效果較好（15.5立方公尺），而認爲現行竹枝籬編籬密度、作業方式適當。定砂植物之成活率，初以馬鞍藤最高(94.9%)，於東北季風後期調查，海馬齒莧最高(44.5%)，次爲貓鼠刺，馬鞍藤，其他全枯。在海岸前端，定砂植物，植後3個月，馬鞍藤覆蓋厚度爲7.3-15.5cm，單株最長7.30m，試區被覆率83-96%，其生長發育與海岸後端沙丘上，原有之馬鞍藤殆等；本種於埋砂厚度11cm仍可萌芽。貓鼠刺蔽覆厚度爲42-53cm，砂丘上背風面一年生長之長度爲66-230cm，被覆率85-100%，其生長一年後，堪耐全年堆砂高度70cm之掩埋。濱刀豆於東北季風後期調查，已無一存，肯定不適海岸前線定砂之用。植物之定砂功能，馬安藤生長發育甚速，惟較易風枯，截砂量較貓鼠刺少，故海岸被馬安藤覆蓋者，少有因之形成沙丘。貓鼠刺在東北季風期，強風處，植株呈半枯狀態，截砂力大，單叢之發展，往往造成塚狀砂丘，形成海岸之特殊地形。

關鍵字

竹枝籬 ； 堆砂量 ； 定砂植物 ； 定砂功效

並列摘要

Before January 8, 1986, the fences of bamboo branch were set up at the coast area of Hou-Lung, Miao-Li. Six species of sand-fixing plants were planted to the frontline of coasts. Wind velocity, sand deposition and the volume of sand fixed by plants were investigated. The results were summaried as follows:
As a result of investigation in the strong wind lasting period of monsoon, the strongest wind velocity is approximately 14m/s, it is stronger in the afternoon than in the morning so far as the wind force is concerned, the average wind velocity at an altitude 0.5m above the ground is 9.5m/s with a variable range of 7.0-11.5m/s. Sand deposition efficacy of the fence with different number of fences indicates that the three-line fence is considerably effective (14.1m^3). Fence with different stauts shows that the sand deposition efficacy of bamboo-branch fence is better (15.5m^3) and that the current fence combination density of bamboo-branch fence and the operating method thereof are suitable. So far as the survival rate of sand-fixing plant is concerned, in the initial phase, Ipomoea pes-caprae is maximum (94.9%); in the late period of northeast monsoon. Sesuvium porlulacastrum is maximum (44.5%), next come Spinifes littoreus and Ipomoca pcs-caprae, and all the rest withered. After planting the sand-fixing plant such as Ipomoea pes-caprae with a covering thickness of 7.3-15.5cm at the front end of coast for the three months, the longest single plant is 7.30m with a covering rate of 83-96%, and the growth and development there of is almost the same as the original Ipomoea pes-caprae on the dune at the rear and of coast, and this plant with a sand-burying thickness of 11cm still can sprout. The Spinifex littoreus with a covering thickness of 42-53cm in the leeward on the dune grows 60-230cm long with a covering rate of 85-100% for one year, and after growing for one year, can tolerate the burying with a sand-deposition height of 70cm for one whole year. Through an investigation in the latter period of northeast monsoon, none of Canavalia lineata survived, and we can make sure that it is never suitable for fixing sand on the frontline of coast. So far as the sand-fixing function of these plants is concerned, Ipomoea pes-caprae grows and develops very quick but it is easily withered by the wind and its sand-intercepting volume is less than that of Spinifex littoreus, so that the coast coverd with Ipomoea pes-caprae is seldom to from a dune. In the period of northeast monsoon, Spinifex littoreus in the position facing with the wind is in a state of half withering but has a strong sand-intercepting force, and the development of single cluster thereof always forms a grave-shaped dune as a special terrain on the coast.

並列關鍵字

Sand-deposition efficiency ； Bamboo branch fence ； Sand-fixing function ； Coastal plants