Stage 0 |
The nitrogen cycle is dominated by forest and microbial
uptake. Nitrate concentrations are very low throughout the year. No
nitrate leaches during the growing season, and low concentrations of
nitrate run off during snowmelt. |
Stage 1 |
The nitrogen cycle is still dominated by forest and microbial
uptake. Although little nitrate leaches during the growing season,
nitrate concentrations increase during snowmelt. |
Stage 2 |
The nitrogen cycle is dominated by nitrate leakage and
denitrification instead of forest and microbial uptake. The uptake of
nitrogen by forest plants and microbes decreases rapidly, and nitrate
leaches into stream water. Nitrate concentrations are also higher during
the growing season, and concentration changes are small throughout the
year. |
Stage 3 |
The nitrogen retention capacity of the forest decreases
considerably, and nitrate leakage exceeds nitrogen deposition. Nitrate
concentrations are higher than those of precipitation throughout the
year, and there is no change in seasonal nitrate
concentrations. |