© 2004 Heron Publishing—Victoria, Canada
Why do trees decline or dieback after a strong wind? Water status of Hinoki cypress standing after a typhoon
Masafumi Ueda (1, 2) and Ei'ichi Shibata (3)
1. Nara Forest Research Institute, Takatori, Nara 635-0133, Japan / 2. Corresponding author (uedam@nararinshi.pref.nara.jp) / 3. Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan / Received March 21, 2003; accepted October 26, 2003; published online April 1, 2004
Summary
We examined the water status of Hinoki cypress, Chamaecyparis obtusa (Siebold & Zucc.) Endl., trees after a severe typhoon to determine possible causes of the decline and dieback that can occur
in what appear, at first, to be healthy trees in typhoon-damaged forest stands. We found that in apparently healthy trees
in a storm-damaged stand, the water conducting area of the trunk cross section was greatly reduced compared with that of similarly
sized trees in a nearby undamaged stand. Although leaf specific hydraulic resistance (Wl) from soil to leaf and from trunk to leaf was higher in trees from the storm-damaged than the undamaged stand, Wl values from soil to root were similar. Diurnal patterns in the rates of change in trunk diameter differed between trees in
the damaged and the undamaged stand. We conclude that increased aboveground hydraulic resistance caused by a reduction in
trunk water conducting area could be a major reason for the decline and dieback of apparently healthy trees in typhoon-damaged
stands.
Keywords:
Chamaecyparis obtusa, diameter change, hydraulic resistance, water stress.
