Data from: Early snowmelt by an extreme warm event affects understory more than overstory trees in Japanese temperate forests

We conducted a warming experiment (four 20 m by 20 m plots) in temperate
forests of Japan to determine the effects of earlier snowmelt on both
understory dwarf bamboo plants and overstory birch trees. Our experimental
treatment advanced snowmelt by about 10 days and increased soil
temperatures that were associated with increased rates of soil nitrogen
(N) mineralization and nitrification. Furthermore, these changes led to
lower C:N ratios of leaves together with the greater growth of understory
bamboo vegetation, with no changes in leaf C:N or growth rates of
overstory birch trees. Together, our results demonstrate that advancing
snowmelt by an extreme warm event in temperate forests
is likely to affect N cycling and will benefit understory vegetation
without a commensurate change in overstory vegetation, likely due to the
increase in available soil N. This is the dataset of plant
growth, soil N properties, and plamnt leaf traits obtained by the field
snowmelt manipulation experiment.