| A total of 14 semi-mature stands originating after fire, and single-harvest and double-harvest clearcutting operations in the boreal forests of central Newfoundland were compared with regard to tree size structure, basal area, number of stems, species composition and diversity of upper- and ground-story vegetation. Soils of these stands range from medium to poor moisture and nutrient regimes and support a black spruce-feathermoss forest type after fire. Single-harvested stands were older (52 years) followed by fire origin (45 years) and double-harvested stands (38 years). Mean diameter in single-harvested stands was 12 cm followed by 10 cm in burned stands and double-harvested stands, respectively. Average number of stems per ha was higher in burned stands (4525) followed by double-harvested stands (3258) and single-harvested stands (2443). The size structure of fire-origin and double-harvested stands showed positive skewed distributions, while single-harvested stands showed a distribution close to normal. Upper-story diversity indices of all disturbances, although low, increased from burned stands to single-harvested and double-harvested stands mainly due to a proportionate increase of balsam fir. (Abstract shortened by UMI.)... |
