Nitrogen and phosphorus distribution for five plantation species in southwestern Wisconsin

Nutrient distribution was determined in the soil and vegetation for 28-year-old red oak (Quercus rubra L.), European larch (Larix decidua Miller), white pine (Pinus strobus L.), red pine (Pinus resinosa Ait.) and Norway spruce (Picea abies (L) Karst.) plantations on a similar soil in southwestern Wisconsin. The concentration and content of several soil nutrients differed among the five species, but no consistent patterns were observed between deciduous and evergreen species. Current foliage nitrogen (N) and phosphorus (P) concentration for European larch and N concentration for red pine decreased down the canopy but did not differ significantly among canopy positions for the other tree species. In general, total N and P content were greatest in the upper 30 cm of soil followed by aboveground vegetation and forest floor. Total N and P content in aboveground vegetation were positively correlated to leaf longevity (r² = 0.83, P < 0.05 for N; r² = 0.79, P < 0.05 for P); aboveground N and P content (kg ha^-1) were 258 and 26 for red oak, 261 and 41 for European larch, 500 and 57 for white pine, 431 and 49 for red pine, and 687 and 97 for Norway spruce. We estimated that whole tree harvesting (stem + branch + foliage) would remove 120-380% more N and 100-610% more P than stem-only harvests in these plantations.