評估平地造林地之土肉桂、水黃皮及楓香的生長與CO_2吸存量

Evaluating Growth and CO_2 Sequestration of Cinnamomum Osmophloeum, Pongamia Pinnata and Liquidambar Formosana in Flat-land Afforestations

陳忠義(Chung-I Chen) ； 王亞男(Ya-Nan Wang) ； 徐唯恩(Wei-En Hsu) ； 吳亭潔(Ting-Chieh Wu) ； 余瑞珠(Jui-Chu Yu) ； 吳宗賢(Chung-Shien Wu)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 26卷4期 (2012/12) Pp. 251-260

https://doi.org/10.6542/EFNTU.201212_26(4).0002

摘要

林木利用光合作用吸收CO_2並貯存碳源。林木的碳吸存量反應在生長表現上，林木材積是陸地上主要的碳貯存源之一，因此估算林木的CO_2吸存量，為森林經營的重要議題之一。然而，台灣對林木CO_2吸存量的研究，多集中在山區之造林木，而平地造林的林木CO_2吸存狀況則缺乏完善資料。本研究以屏東縣萬隆農場平地造林為試驗地，調查6年生及7年生之土肉桂、水黃皮、楓香的生長表現，並計算三種樹種之CO_2吸存量。調查結果顯示6年生土肉桂之平均胸徑為5.39cm，水黃皮為4.32cm、楓香為5.23cm；7年生土肉桂之平均胸徑為6.89cm，水黃皮為5.84cm、楓香為6.56cm。胸徑與冠幅的迴歸分析顯示三樹種皆未達鬱閉飽和，且楓香在冠幅生長上有較大的伸展空間。累積CO_2吸存量以7年生楓香之41.38MgCO_2/ha最高，7年生水黃皮之18.62MgCO_2/ha最低。與前人研究比較，三樹種之累積CO_2吸存量均偏低，但三樹種之造林後續CO_2吸存年增量方面，皆高於前人研究之其他樹種，表示本研究之三造林樹種仍具良好的生長潛力。整體而言，三試驗樹種以楓香的生長表現最好，其後續的CO_2吸存潛力最高，是三種樹種中最適合萬隆農場的造林樹種。土肉桂及楓香的形狀比較高，將來樹高增長後，可能具低抗風力的缺點，此缺點是否可以高密度栽植來彌補，仍需要進一步研究。

關鍵字

造林 ； 土肉桂 ； 水黃皮 ； 楓香 ； 生長表現 ； 碳吸存量

並列摘要

Trees sequestrate carbon by using of photosynthesis, which is one of the major ways for carbon sequestrations in the world. As a result, evaluating the ability of trees on CO_2 sequestration becomes an important issue in forestry. In Taiwan, efforts of evaluating CO_2 sequestration are mostly trees growing in mountain areas. Investigation of CO_2 sequestration on flat-land trees needs to be estimated and analyzed. To this end, the growth and CO_2 sequestration of three tree species, viz., Cinnamomum osmophloeum, Pongamia pinnata and Liquidambar formosana, was estimated at Wan-Long farm in Pingtung. The results reveal that the average DBHs estimated from 6-year-old trees of C. osmophloeum, P. pinnata and L. formosana are 5.39cm, 4.32cm, and 5.23cm, respectively and 7-year-old trees, average DBHs are 6.89cm, 5.84cm, and 6.56cm. The accumulative CO_2 sequestration of three tree species is relatively low comparing to other species. This indicates that the trees afforested at Wan-Long farm might suffer from stunted growth.Comparing the annual amount of CO_2 sequestration between 6- and 7-year old trees, the three species are higher than other species investigated previsously. This result implies that the three tree species have good growth performance, although they were stunted in their early life cycle. Collectively, based on the evaluation of CO_2 sequestration, L. formosana is one of the most suitable tree species afforested at Wan-Long farm. Both C. osmophloeum and L. formosana have great ratios of heights to DBHs, suggesting that they may encounter great damage from typhoons.

並列關鍵字

Afforestation ； Growth ； CO_2 sequestration ； Cinnamomum osmophloeum ； Pongamia pinnata ； Liquidambar formosana