施肥、光環境及植株密度對木賊葉木麻黃初期生長之影響

Effects of Fertilization, Light Environment, and Seedling Density on the Initial Growth of Casuarina equisetifolia

黃俊元(Chun-Yuan Huang) ； 謝漢欽(Han-Ching Hsieh) ； 陳朝圳(Chaur-Tzuhn Chen) ； 陳建璋(Jan-Chang Chen)

《台灣林業科學》 35卷2期 (2020/06) Pp. 143-160

https://doi.org/10.7075/TJFS.202006_35(2).0003

摘要

臺灣東部海岸地區屬於沙岸類型之海岸林，常因颱風暴潮造成林木死亡產生孔隙，影響海岸防風林之保安功能。為了提供東部海岸易受暴潮危害之高風險地區造林方法，以及發展具實務性之直播造林育林體系，本文目的為探討施肥、光環境及植株密度對木賊葉木麻黃幼苗初期生長之影響。試驗結果顯示，以保護管凹地直播育苗系統培育之幼苗，其初期生長施3～5 g緩效性肥料，可有效促進幼苗生長，符合實務作業之需；施肥證實顯著促進幼苗初期生長，但對1年生苗木，施追肥並無促進生長之效。1年生苗木經間拔試驗1年後，間拔處理之平均地徑淨生長為2.5±0.0 cm（對照組1.8±0.1 cm），樹高淨生長為161±2 cm（對照組142±4 cm），樹冠幅淨生長為119±2 cm（對照組91±4 cm），以及主幹之平均傾斜角度為6°±0°（對照組10°±1°），除樹高外，其他處理間均具有顯著差異。保護管內的相對光度需＞ 40%，才能提供幼苗初期生長所需的光照強度。本研究成果可提供海岸林直播造林之實務作業參考，可有效促進幼苗生長及形態品質，提高造林成效。

關鍵字

木賊葉木麻黃 ； 直播 ； 施肥 ； 相對光度

並列摘要

Coastal forests are located on sandy shores on the east coast of Taiwan, where they are often hit by storm surges causing trees to die and producing gaps that impact the protective functions of the forests. To offer a method of afforestation in areas of high risk of damage from storm surges in eastern coastal areas and develop a practical silvicultural technique for the direct seeding for afforestation, this study investigated the effects of fertilization, the light environment, and seedling density on the initial growth of Casuarina equisetifolia. Seedlings were cultivated by the silvicultural regime of indentation seeding with seed shelters fertilized with 3~5 g of controlled-release fertilizer. Results revealed that this method was able to efficiently promote the initial growth of seedlings, which was sufficient for practical operations. The initial growth of seedlings was promoted by fertilizer, but no significant differences were found between top-dressing and no top-dressing treatments for 1-yr-old seedlings. At 1 yr after the experiment of thinning of 1-yr-old seedlings, in addition to the tree height, we found that saplings exhibited a significant growth increment under thinning treatment with 2.5±0.0 cm in average basal stem diameter (vs. 1.8±0.1 cm in the control), 161±2 cm in tree height (vs. 142±4 cm in the control), 119±2 cm in canopy diameter (vs. 91±4 cm in the control), and 6°±0° in the angle of inclination of the trunk (vs. 10°±1° in the control). The relative light intensity in the tube of the seed shelter required over 40% which was vital for the initial growth of seedlings. Results of this study offer application of practical operations for direct seeding of coastal forests, which can efficiently promote seedling growth, morphological quality, and seedling establishment.

並列關鍵字

Casuarina equisetifolia ； direct seeding ； fertilization ； relative light intensity