| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
It has been widely accepted that daily diameter changes in tree are induced by the fluctuation of water content and sap flow-of tree. The purpose of this research project is to gather information available for the development of simulation program about water relation in a whole tree, by performing simultaneous multipoint measurement of diameter changes in a tree.
Diameter changes of stem, branch and root of a Juglans nigra L. x regia L. (age 9 years, height 6 m, diameter at breast height 20 cm) were measured simultaneously. This tree was planted in an agroforestry experimental site at Restinclieres, Montpellier (France). Opto-electronic dendrometers were attached on seven portions of this tree: base of a largest branch, inner-crown, base of trunk, three horizontal roots and one tap root. Measurements were done from July to August 2003. Before the measurement, an excavation procedure of roots had been done, and confirmed that this procedure had less influence for diameter changes of roots.
The Juglans tree showed two types of diameter changes: continuous thickening growth and daily diameter changes comprising shrinkage and swelling. One horizontal root thickened most vigorously, followed by branch. Tap root showed least thickening among the seven measuring portions. Amplitude of daily diameter fluctuation was strongly size-dependent both in the upper-and under-ground parts. Remarkable time lag was recognized between trunk base and inner crown, two horizontal roots or tap root. However such time lag was not clear between trunk base and branch or one horizontal root. These results suggest non-steady state of water movement in a whole tree.
Further researches are on-going, such as anatomical investigation of internal structure of tree, simultaneous measurement of sap flow and daily diameter changes and sustainable measurement of diameter changes.
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