Intraspecific variation of leaf traits in several deciduous species in relation to length of growing season.
Effects of growing season length on leaf traits were studied in three deciduous species (the herbs Peucedanum multivittatum and Potentilla matsumurae, and the shrub Sieversia pentapetala [Geum anemonoides]) found along an alpine snowmelt gradient (snow-free period ranging from 69 to 117 days), and in four deciduous species (the trees Betula platyphylla var. japonica, Betula ermanii, Alnus maximowiczii and Quercus mongolica var. grosseserrata [Q. crispula]) found along an altitudinal gradient (ranging from 140 m to 1900 m) in Hokkaido, northern Japan. Along these gradients, leaf life-span generally decreased while specific leaf area (SLA) and nitrogen concentration (leaf N) increased with a shorter growing season. In each species on the snowmelt gradient, there was a negative correlation between leaf life-span and SLA, and between leaf life-span and leaf N, respectively. These factors were not tested for the trees. A positive correlation was found between SLA and leaf N in all species. Production of high nitrogen leaves which had a lower initial carbon investment (leaf construction cost) was considered to be a response to maintain the carbon balance under the condition of a short growing season.