關刀溪試驗地五樹種綠葉第一年的分解和養分動態變化

In Situ First-year Decomposition and Nutrient Dynamics for Foliage of Five Species in Guandaushi Site

在關刀溪台灣生態研究網的試驗地，用枝葉包法進行5種樹種（長葉木薑子、長尾尖葉櫧、杉木、山龍眼、自匏子）綠葉一年的分解研究，以瞭解葉片化學性質對分解過程的影響。分解期間各樹種剩餘重量大部分都有差異。經一年的分解，以白匏子葉剩餘重量最低（31%），杉木葉最高（68%）。年分解常數（k）可用單一負指數分解模式表示。分解期間養分的變化，氮的釋出較重量減少慢；磷、鈣、鎂的剩餘量也下降，但各樹種差異大；鉀則在分解前3個月即快速流失。木質素分解緩慢，但以白匏子和長葉木薑子葉的木質素分解較快；相對於其它養分而言，木質素在分解期間各樹種都有累積的現象。在葉片各項化學性質中，僅分解常數和初期氮濃度呈正直線相關，與初期碳氮比呈負直線相關。 Decomposition processes of green foliar of five tree species, Litsea acuminata, Castanopsis carlesii, Cunninghamia lanceolata, Helicia formosana, and Mallotus paniculatus, were examined by the litterbag method for a period of 1 year at Guandaushi TERN site, in order to understand the influences of litter chemical qualities on decomposition processes. Most mass remaining during decomposition differed among tree species. At the end of the year the mass remaining of M. paniculatus leaf (31%) was lower than those of the other four species, and that of C. lanceolata (68%) was the highest. The annual decomposition constant (k) was determined using a single negative exponential decay model for most species. The release of N was slower than the mass loss during decomposition. The mass remaining of P, Ca, and Mg decreased too, but the rates varied widely among species. Most of K was lost rapidly during the first three months ofdecomposition. Lignin decomposed slowly too, with lignin of M. paniculatus and L. acuminata foliage decomposing faster than those of other species. And in comparison with other nutrients, lignin relatively accumulated during decomposition for most species. Only the initial N concentration and C/N ratio of foliages showed the linear positive or negative relationship with the k value, respectively.

Decomposition processes of green foliar of five tree species, Litsea acuminata, Castanopsis carlesii, Cunninghamia lanceolata, Helicia formosana, and Mallotus paniculatus, were examined by the litterbag method for a period of 1 year at Guandaushi TERN site, in order to understand the influences of litter chemical qualities on decomposition processes. Most mass remaining during decomposition differed among tree species. At the end of the year the mass remaining of M. paniculatus leaf (31%) was lower than those of the other four species, and that of C. lanceolata (68%) was the highest. The annual decomposition constant (k) was determined using a single negative exponential decay model for most species. The release of N was slower than the mass loss during decomposition. The mass remaining of P, Ca, and Mg decreased too, but the rates varied widely among species. Most of K was lost rapidly during the first three months ofdecomposition. Lignin decomposed slowly too, with lignin of M. paniculatus and L. acuminata foliage decomposing faster than those of other species. And in comparison with other nutrients, lignin relatively accumulated during decomposition for most species. Only the initial N concentration and C/N ratio of foliages showed the linear positive or negative relationship with the k value, respectively.