Nitrate concentrations during non-snowy season (2013-2023) in a small watershed on Mt. Irumukeppu, Hokkaido, Japan.

Nitrate nitrogen concentrations (mg/L) in a small watershed at Mt. Irumukeppu, Hokkaido, where the retention forestry experiment was conducted. Values for each year are summarized by water year (July 1 of the current year to June 30 of the following year), and represent data collected and analyzed at approximately monthly intervals in the normal water level during the non-snowy season. Numbers represent watershed numbers. Six watersheds (No. 1, 2, 5, 8, 10, 11, and 15) where the treatments were implemented had different percentages of deciduous hardwoods retained when harvesting, and the percentages retained were in the order of No. 11>1>2>5>10>8. - denotes no sample.