Yasuhiro Utsumi

Xylem structure and the water transport pathway of broadleaf trees in Japan

Yasuhiro Utsumi

Kyushu University Forest



The interspecific variation of the water transport pathways in the stems of broadleaf deciduous and evergreen species growing in Japan
was studied. The large earlywood vessels in deciduous ring-porous species and evergreen semiring-porous species had a water transport
function in only the outermost annual ring, and the inner annual rings had lost their water transport function. For the other xylem-type
species, the many vessels in many outer annual rings had a water transport function. In diffuse-porous species, we categorized the
water-conducting pattern within the annual rings into three types: the first type, where water traveled through vessels in the whole region;
and the second type, where water traveled mainly through the earlywood vessels; and the third type, where water traveled mainly through the
latewood vessels. The pattern in radial-porous species was similar to that in the first type in diffuse-porous species; the pattern in
non-vessels species is similar to that in the second type in diffuse-porous species. The vessel diameter did not always determine
the water-conducting patterns of broadleaf species.