T. Tange, SEASONAL-CHANGES IN PHOTOSYNTHESIS OF YOUNG CRYPTOMERIA-JAPONICA GROWING ON RIDGES AND FOOT-SLOPES, Forest ecology and management, 89(1-3), 1996, pp. 93-99
The influence of environmental factors affected by topography, especia
lly light conditions in winter, on photosynthetic capacity of field-gr
own young Cryptomeria japonica trees was studied. Trees with a large i
ncrement in height growth tended to have current year needles with hig
h photosynthetic capacity in the growing season. The change in the pho
tosynthetic capacity from October to February, corresponding to the ch
ange in chlorophyll content, differed between trees planted near a rid
ge and on a foot-slope. There was a tendency for trees with a greater
exposure to sunshine in winter, such as those near a ridge, to have a
reduced chlorophyll content in winter. The photosynthetic capacity of
I-year-old needles of sample trees near a ridge did not recover as muc
h as those on a foot-slope, even if the foliar nitrogen content was hi
gh. These results imply that the magnitude of winter injury on the pho
tosynthetic apparatus differed according to the topographical conditio
ns and strongly influenced the photosynthetic capacity during the next
growing season.