EFFECT OF SOIL DISTURBANCE ON BLACK SPRUCE (PICEA MARIANA) NUTRITION AND GROWTH IN BOREAL FOREST PRONE TO PALUDIFICATION IN THE CLAY BELT OF EASTERN CANADA

摘要

Concerns have been expressed about a reduction in seedling growth following careful logging in the black spruce-feathermoss forests in the Clay Belt in eastern Canada. As oppose to fire, where soil organic matter is bumed, careful logging leaves the organic horizon relatively intact and may lead to paludification. Recent studies have suggested that mineral soil exposition following wildfire improves the regeneration of pioneers species that may be beneficial to nutrient cycling and reduces Sphagnum and ericaceous shrubs colonisation. Also, it has been demonstrated that following overstory removal, suppression effect on black spruce advance regeneration persists for a long period in peatland forests. To offset these problems, mechanical site preparation and prescribed burning have been suggested as means to enhance early tree growth and improve the forest productivity of these sites. The main objective of this research was to determine how soil disturbance (natural and mechanical) affects soil fertility, nutrition and consequently black spruce growth.