台東地區相思樹與楓香兩人工林碳累積量

Estimate of Carbon Storage of Acacia confusa and Liquidamber formosana plantations in Taitung Area

相思樹州（Acacia confuse Merr.）和楓香（Liquidamber formoana Hance）為台灣最重要的闊葉樹造林樹種之一。本研究以台東縣約30年生的相思樹和約25年生楓香兩林人工林為對象，伐取樣木，估算其造林木之生物量和生長量，建立根莖比和擴展係數等參數和迥歸式，並估算其碳吸存量和林分碳貯存量。結果顯示，根莖比相思樹為0.296，楓香為0.216，相思樹較高，且與熱帶闊葉林平均值相近。兩樹種胸徑生長20年生前楓香生長較快，20年生後相思樹生長較快。地上部生物量連年生長和平均生長皆隨年齡呈上升趨勢，兩曲線尚未相交。相思樹林造林木全株生物量為126.6M gha^(-1)，楓香林造林木則為186.3Mg ha^(-1)。造林木植體的地上部碳平均濃度，相思樹為48.3%，楓香為48.8%。林分造林木全株碳貯存量，相思樹為60.1Mg ha^(-1)，低於楓香的90.4Mg ha^(-1)。林分造林木年平均碳吸存量，相思樹立木全株碳吸存量為3.50kg tree^(-1)yr^(-1)，林分全株碳吸存量為1.85Mg ha^(-1)yr^(-1)；楓香立木全株碳吸存量為2.78kg tree^(-1)yr^(-1)，林分全株碳吸存量為3.03Mg ha^(-1)yr-^(-1)。土壤碳貯存量兩林分相近，約為86.0-86.4Mg ha^(-1)。 Acacia confusa Merr. and Liquidamber formosana Hance are very important planted broadleaf species in Taiwan. Two plantations in Taitung county of eastern Taiwan were investigated, one was A. confusa at age 30 and the other was L. formosana at age 25. We cut down sample trees in order to estimate production and growth of planted trees and build parameters such as biomass expansion factors and root/ shoot ratios and allometric equations. Above- and below-ground carbon distribution of the plantations were calculated, and carbon sequestration of planted trees were estimated as well. The estimated root/shoot ratio was 0.296 for the A. confusa trees, which was higher than that of the L. formosana trees, 0.216, and similar to that of tropical broadleaf forests. The dbh growth of the L. formosana trees was higher than that of the A. confusa trees before age 20, and was lower after age 20 on the contrary. Curves of current annual increment and mean annual increment for aboveground biomass increased with age for both species and did not cross in both stands yet. The estimated entire planted tree biomass was 126.6 and 186.3 Mg ha' for the A. confusa and L. formosana stands, respectively. The average aboveground carbon concentrations planted trees were 48.3% for the A. confusa trees and 48.8 % for the L. formosana trees. The carbon storages of entire planted trees were 60.1 and 90.4 Mg ha^(-1) for the A. confusa and L. formosana stands, respectively. Transferring to annual mean carbon absorptions of entire single and all planted trees were 3.50 kg tree^(-1) yr^(-1) and 1.85 Mg ha^(-1) yr^(-1) for the A. confusa stands, respectively; and 2.78 kg tree^(-1) yr^(-1) and 3.03 Mg h^(-1)' yr^(-1) for the L. formosana stands, respectively.

Acacia confusa Merr. and Liquidamber formosana Hance are very important planted broadleaf species in Taiwan. Two plantations in Taitung county of eastern Taiwan were investigated, one was A. confusa at age 30 and the other was L. formosana at age 25. We cut down sample trees in order to estimate production and growth of planted trees and build parameters such as biomass expansion factors and root/ shoot ratios and allometric equations. Above- and below-ground carbon distribution of the plantations were calculated, and carbon sequestration of planted trees were estimated as well. The estimated root/shoot ratio was 0.296 for the A. confusa trees, which was higher than that of the L. formosana trees, 0.216, and similar to that of tropical broadleaf forests. The dbh growth of the L. formosana trees was higher than that of the A. confusa trees before age 20, and was lower after age 20 on the contrary. Curves of current annual increment and mean annual increment for aboveground biomass increased with age for both species and did not cross in both stands yet. The estimated entire planted tree biomass was 126.6 and 186.3 Mg ha' for the A. confusa and L. formosana stands, respectively. The average aboveground carbon concentrations planted trees were 48.3% for the A. confusa trees and 48.8 % for the L. formosana trees. The carbon storages of entire planted trees were 60.1 and 90.4 Mg ha^(-1) for the A. confusa and L. formosana stands, respectively. Transferring to annual mean carbon absorptions of entire single and all planted trees were 3.50 kg tree^(-1) yr^(-1) and 1.85 Mg ha^(-1) yr^(-1) for the A. confusa stands, respectively; and 2.78 kg tree^(-1) yr^(-1) and 3.03 Mg h^(-1)' yr^(-1) for the L. formosana stands, respectively.