平地造林對台灣林業的影響不容忽視,其中造林面積最大為台糖公司的屏東萬隆農場290.66 ha。由於枯落物收集是一項非破壞性的技術,故最常被用來推估森林的生產力、物候以及生物量轉換。本研究於屏東萬隆農場進行枯落物相關試驗,以台灣櫸、光蠟樹、土肉桂及大葉桃花心木作為研究對象,比較四樹種間的落葉特性和落葉養分濃度差異,藉此了解屏東人工造林地內養分循環的情形。枯落物一個月收集兩次,從2011年1月到2011年12月,為期一年。研究結果顯示:台灣櫸的年枯落物量2.92 Mg ha-1 yr-1,光蠟樹4.85 Mg ha-1 yr-1,土肉桂2.61 Mg ha-1 yr-1,大葉桃花心木2.55 Mg ha-1 yr-1。四樹種皆以落葉占枯落物總量的百分比最大,是枯落物中最重要的組成成分,台灣櫸91.1%,光蠟樹85.8%,土肉桂88.4%,大葉桃花心木94.2%,使枯落物和落葉呈現相當一致的季節變化。四試驗樹種的落葉型式各異,台灣櫸的落葉高峰為9~11月,光蠟樹為10~3月,土肉桂為6~8月,大葉桃花心木為1~4月。台灣櫸、光蠟樹、土肉桂的葉部養分含量為碳>氮>鈣>鉀>鎂>磷>鈉,大葉桃花心木則為碳>鈣>氮>鉀>鎂>磷>鈉。光蠟樹在落葉高峰時,氮、磷濃度有偏低的趨勢。本研究結果顯示,樹種組成不同為造成枯落物量、落葉季節及葉部養分含量差異的原因。
Afforestation for the plain area had a great influence on the forest development in Taiwan. Taiwan Sugar Corporation has 290.66 ha in the Wanlong Farm for the propose of afforestation in Pingtung County. Litterfall collection is a standard non-destructive technique for assessing the productivity, phenology, and the conversion of biomass in a forest. To make a further understanding of nutrient cycle in the plantation, this study compared the litterfall dynamics and the nutrient of falling leaves among four tree species, which were planted in the Wanlong Farm in Pingtung County. Those were Zelkova serrata, Fraxinus formosana, Cinnamomum osmophloeum, and Swietenia macrophylla. The litterfall was collected twice a month from January 2011 to December 2011 by using littertrap. The experimental results showed that the amount of annual litterfall was 2.92 Mg ha-1 yr-1 for Z. serrata plantation, 4.85 Mg ha-1 yr-1 for F. formosana plantation, 2.61 Mg ha-1 yr-1 for C. osmophloeum plantation, and 2.55 Mg ha-1 yr-1 for S. macrophylla plantation. The most important component of litterfall was leaf fall, which accounted for 91.1% for Z. serrata plantation, 85.8% for F. formosana plantation, 88.4% for C. osmophloeum plantation, and 94.2% for S. macrophylla plantation. The descending order of element contribution in annual leaf fall was C>Ca>N>K>Mg>P>Na for S. macrophylla plantation, whereas the descending order in the other tree species was C>N>Ca>K>Mg>P>Na. Nitrogen and phosphorus concentrations of foliar litter in F. formosana tended to have low content during the peak of falling season. The results showed that plant community composition were essential to explain the differences in litter production, seasonal patterns of leaf shedding, and nutrient concentrations in litterfall. The foliar K concentration decreased in July via leaching or throughfall, whereas nutrient resorption was insignificant.