Environmental impacts of harvesting white spruce on Prince Edward Island

Abstract: An increased trend toward whole-tree harvesting in the Maritimes region of Canada, followed by the planting of different tree species, highlighted a need to investigate the potential impacts of different harvesting methods on nutrient loss and the growth rates of different tree species planted in the treated areas. Thus, in 1990, a harvesting study with three main treatments was conducted in an old-field white spruce (Picea glauca (Moench) Voss) stand in Prince Edward Island, Canada. The treatments included whole-tree harvesting (WTH) with chain saws, in which almost all the aboveground biomass was removed from the site, stem-only (SO) harvest, consisting of chainsaw felling and removal of only the merchantable boles from the site, and control (CON), an uncut area. Glass-body lysimeters, connected to hanging-bottle vacuum generators, were installed at three depths to collect soil solution. The leachates collected over a 6-year period (1991–1997) were analyzed for pH and various anions and cations. Soil temperatures were also measured at three depths. The hourly mean temperature immediately below the organic horizon in the WTH blocks was 8–10°C more than that in SO blocks. The daily mean temperature showed a similar pattern. Concentrations of nitrate and hydrogen ions were higher in the leachates collected from SO blocks than from WTH blocks. The estimates of calculated quantities of nutrients lost from WTH blocks were higher than those from SO blocks. Ground vegetation recovered within 2 years following harvest and the calculated Shannon–Weiner biodiversity index showed no difference in index values among different treatments. The height growth of trees planted during May 1992 in the harvested blocks is greater in SO blocks than in WTH blocks. Planted eastern white pine (Pinus strobus L.) trees are generally taller than planted white spruce trees. [Copyright &y& Elsevier]