牛樟苗木樹幹直徑脹縮之連續監測及環境因子之影響

Continuous Monitoring of Stem Diameter Fluctuations of Stout Camphor Saplings under Different Environmental Conditions

黃彥三(Yan-San Huang) ； 陳欣欣(Shin-Shin Chen)

《台灣林業科學》 14卷3期 (1999/09) Pp. 307-314

https://doi.org/10.7075/TJFS.199909.0307

摘要

樹幹直徑因形成層細胞之不斷分裂而連年增大，惟因水分生理活動而有日夜脹縮之現象，兩者重合之結果使得直徑呈上下波動而長期漸增之趨勢。然而樹幹日夜之脹縮相當微小，以往雖有不少這方面的測定研究，但尚無簡易而精確的方法可供實用。本試驗以牛樟苗木為材料，將應變片貼於樹幹之內樹皮的圓周方向，測定生長箱中光度、氣溫、土壤水分及剪葉處理，對光照及黑暗時樹幹直徑脹縮之效應，同時亦就戶外日夜間之樹幹直徑變動作連續非破壞性的自動監測。此一技術對植物生理之研究及自動灌溉與節水系統的建立應有助益。試驗結果發現在戶外樹幹於夜間膨脹，黎明開始收縮，中午收縮最大，日夜間樹幹直徑差約9μm；光照與黑暗間樹幹之脹縮隨光度與氣溫的增高而增大；土壤水分減少時樹幹脹縮程度亦減小，加水後則脹縮恢復變大；剪去枝葉會使樹幹脹縮程度變小。

關鍵字

牛樟 ； 水勢 ； 應變片 ； 樹幹脹縮

並列摘要

Stem diameters of trees increase seasonally as a result of cambium activity. However, stem diameters show a trend of long-term cumulative increment accompanied by daily fluctuations, owing to changes of tree water status between day and night. Observations of shrinking and swelling in trunks have been used to describe the variations of water potential and status of soil water. In this experiment, 3-yr-old stout camphor saplings were used to measure changes in stem diameter using strain gages bonded on the inner bark in the tangential direction. Diurnal changes of stem diameter in an outdoor environment and changes in a controlled climate chamber were measured. The results show that the diurnal change in stem diameter was about 9 μm in the outdoor environment. The stem diameter change between light and dark increased with light intensity and room temperature. Stem shrinkage decreased with a decrease of soil water content and leaf quantity. Changes of stem diameter in the water-withholding treatment decreased in the light/dark cycles. It was found that continuous monitoring of stem shrinkage and swelling using a strain gage can be applied to a controlled automatic irrigation system.

並列關鍵字

Cinnamomum micranthum ； water potential ； strain gage ； stem shrinkage and swell