苗栗地區相思樹和木油桐人工林碳和氮累積量及生產量之估算

Estimate of Carbon and Nitrogen Storages and Production of Acacia Confusa and Aleurites Montana Plantations in Miaoli Area

林國銓(Kuo-Chuan Lin) ； 杜清澤(Chin-Tzer Duh) ； 黃菊美(Chu-Mei Huang)

《中華林學季刊》 40卷2期 (2007/06) Pp. 201-218

https://doi.org/10.30064/QJCF.200706.0004

摘要

調查苗栗縣境的相思樹和木油桐人工林，伐取樣木，以胸徑建立自然對數迴歸式，並建立生物量擴展係數，估算此兩林分地上部和地下部的生物量與碳和氮在林分內之分佈，及推估造林木生產量、碳吸存量。以兩林分造林木建立之自然對數迴歸式，胸徑與各植體生物量、總生物量、樹高皆呈顯著相關。相思樹地上部生物量擴展係數為1.240Mgm^(-3)，木油桐則為0.524Mgm^(-3)。根莖比相思樹為0.238，木油桐為0.243。相思樹全林分地上部生物量為327.6Mgha^(-1)，木油桐全林分地上部生物量僅115.9Mgha^(-1)。相思樹林地上部生物量的累積高於中海拔的針葉樹人工林，木油桐地上部生物量則低於樹齡相近的針葉樹人工林，但均遠低於國外熱帶人工林者。此兩林分造林木地上部生物量的連年生長和平均生長兩曲線，兩樹種皆尚未相交。相思樹各植體碳濃度在49.3~52.6%之間，木油桐則在46.4~49.0%間。氮濃度則以葉最高，樹幹最低。相思樹各個植體氮濃度都高於木油桐和其他樹種。同時，相思樹林分的碳和氮皆集中在相思樹造林木，尤其相思樹造林木的氮量佔全林分量約90%，此與木油桐林分有約45%的氮分佈在木油桐以外的其它喬木、灌木等不同樹型上不同。相思樹林分至43年生時相思樹全株平均生產量為5.02Mgha^(-1)yr^(-1)；木油桐林分至22年生時木油桐全株平均生產量為4.38Mgha^(-1)yr^(1)。相思樹的平均生產量高於木油桐。如換算成碳年平均吸存量則相思樹為2.48Mgha^(-1)yr^(-1)，木油桐為2.15Mgha^(-1)yr^(-1)。

關鍵字

生物量擴展係數 ； 碳吸存量 ； 自然對數迴歸式 ； 人工林 ； 根莖比

並列摘要

Two stands of the Acacia confusa and Aleurites montana plantations in Miaoli county of central Taiwan were investigated. We cut down sample trees in order to build allometric equations and biomass expansion factors. Above-and below-ground biomass and carbon and nitrogen distribution of the plantations were calculated, and production and carbon sequestration of planted trees were estimated as well. According to the natural logarithmic equations by using data of the harvested trees, the biomass of each component, the total biomass of the trees, and tree height were significantly (p＜0.05) related to the diameter at breast height (dbh) for each planted species. The expansion factors of aboveground biomass calculated from the means of the sample trees were 1.240 and 0.524 (Mg m^(-3)), and the estimated root/shoot ratios were 0.238 and 0.243 for the Ac. confusa and Al. Montana stands, respectively. The estimated aboveground biomass was 327.6 and 115.9 Mg ha^(-1) for the Ac. Confuse and Al. montana stands, respectively. The aboveground biomass storage of the Ac. Confuse stand was higher than that of the coniferous plantations in middle elevation of Taiwan, while the biomass in the Al. montana stands was lower than that of the coniferous plantations with similar ages. But the biomass storages in both stands were much lower than those of tropical plantations abroad. Curves of current annual increment and mean annual increment for aboveground biomass did not cross in both stands yet. Carbon concentrations of plant components were from 49.3 to 52.6% for Ac. confusa and from 46.4 to 49.0% for Al. montana. Among tree components, leaves had the highest and the bole had the lowest N concentration. Nitrogen concentrations of all tree components of Ac. confusa were higher than those of Al. montana and other tree species. In Ac. confusa stands both carbon and nitrogen were concentrated in the planted Ac. confusa, which accounted for 90% of nitrogen storage. On the contrary in the Al. montanas tand 45% nitrogen was accumulated in other tree species and bushes. Annual mean biomass production of whole planted tree (5.02Mgha^(-1)yr^(-1)) for the Ac. Confuse stand (at the age of 43) was higher than that of the Al. montana stand (at the age of 22) (4.38Mgha^(-1)yr^(-1)). Transferring to annual mean carbon absorptions of planted trees were 2.48Mgha^(-1) yr^(-1) and 2.15Mgha^(-1)yr^(-1) for the Ac. confusa and the Al. montana stands, respectively.

並列關鍵字

Biomass expansion factor ； Carbon sequestration ； Natural logarithmic equation ； Plantation ； Root/shoot ratio