Labrador, Canada is the last relatively undeveloped landmass of Boreal and subarctic Canada. Its land area is over 288,000 km 2 , with less than 1% developed, and a human population of below 30,000. Labrador is greater than 60% forest-and woodlandcovered and over 30% tundra, soil and rock barrens. We review the ecology and distribution of forests, woodlands, and related vegetation of Labrador within the context of climate, forest site index, landform, soils, and disturbance. Recent ecosystem management through a public planning process with emphasis on past and future comanagement and development with traditional and western scientific principles is currently underway. Plant-animal interactions, traditional uses by aboriginal groups, and early history are also reviewed.

. 1998. Nutrient removals with harvesting and with deep percolation from white birch (Betula papyrifera [Marsh.]) sites in central Newfoundland. Can. J. Soil Sci. 78: 127-137. The effects of conventional stem-only and whole-tree harvesting on nutrient losses in biomass removal and in leachate fluxes over a 3-yr period after cutting three white birch stands in central Newfoundland were determined. Losses of nutrients in biomass were proportionately greater with more intensive harvesting as tree components with higher nutrient concentrations (branches, foliage) were removed. Stemonly harvesting removed 126, 9, 51, 126 and 23 kg ha -1 of N, P, K, Ca and Mg in biomass, respectively. Whole-tree harvesting led to a 19% increase in biomass removal as compared to stem-only harvesting, but nutrient removals with whole-tree harvesting increased by 127% for N, 138% for P, 151% for K, 72% for Ca and 90% for Mg. Nutrient losses in deep percolation of soil solution during the first 3 yr after harvesting were generally greater following stem-only than whole-tree harvesting. This may be the result of increased leaching from slash, increased mineralization beneath slash, and retardation by slash of the successional vegetation that could act as a nutrient sink. In the first 3 yr following harvesting, leaching losses after whole-tree harvesting were 4, 0.2, 8, 23 and 7 kg ha -1 of N, P, K, Ca and Mg, respectively, as compared with 9, 0.1, 7, 28 and 9 kg ha -1 of N, P, K, Ca and Mg after stem-only harvesting. Nutrient losses in leachate were generally small compared to losses in biomass removal.

No abstract

Abstract. Betula papyrifera (White birch) is a common tree throughout the boreal forest of Canada; makes up 12% of the total tree volume in insular Newfoundland. It forms pure stands after harvesting and wildfire disturbance and it is a common component in most softwood stands. Little is known regarding the environmental impact of whole‐tree or conventional harvesting of this species and variation in impact related to variation in soil and site conditions. This study investigates litter and organic matter production and related site ecology in nine medium to high quality Betula papyrifera stands in three locations in central Newfoundland on a variety of land form and drainage conditions. Three sites, Badger West (BW), Moose Pond (MP) and Middleton Lake (ML) were selected. The ML site has the highest quality (with the best height/age ratio, 18 m/60 yr, and height/DBH ratio, 18 m/30 cm, followed by MP and BW. Litter depth on well developed moders or mulls was usually 2 ‐ 3 cm and varied from 1 ‐ 15 cm. Forest floor depths (measured in 324 profiles) rarely reached 20 cm and was commonly 5 ‐ 10 cm; it varied with position and site. Total and available nutrients indicate that B. papyrifera produces one of the highest ‐quality organic matter types of the local forest types and is important in improving site quality. The mean N‐concentration in green foliage (2.21%) and trapped litter (1.03%) was highest at the best quality site ML, followed by MP and BW. The concentration of calcium, 0.85%, was highest at the poorest quality site. Four years after harvesting, litter depth significantly decreased in all sites and treatments with the exception of the BW whole‐tree harvest treatment. Total forest floor depth significantly decreased at all sites in the stem‐only harvest treatment as well as the MP whole‐tree harvest treatment. There was a significant decrease in available nitrogen following harvesting in both treatments at both the MP and BW sites. Change in available phosphorus was insignificant, with the exception of an increase in the MP stem‐only harvest treatment. There was a significant decrease in available potassium at both the ML and BW whole‐tree harvest treatments, but a significant increase in the stem‐only harvest treatments at ML and MP. There was a significant decrease in available calcium in both treatments at both the MP and BW sites.