FOR200H1 Lecture Notes - Lecture 9: Soil Structure, Pioneer Species, Jack Pine
Forest harvesting: is a general term for the removal of biomass from the forest for use. Harvesting includes cutting, sometimes further initial processing (topping and trimming), and extraction. Stresses the forest by opening the canopy and increasing light penetration, temperature, and wind speed. Decreases relative humidity and moisture in the air. Exports nutrients out of the forest that would have otherwise been cycled. Soil damage, compaction, erosion, silt and sedimentation. Injuries to residual trees, seedlings and saplings, fine roots and scarring. Adverse effects on the ecosystem, habitat destruction and fragmentation. Clearcutting systems: involve the removal of all trees. Shelterwood systems: involve the retention of an overstory of mature trees, while an understory of generation becomes established. The understory is called advance growth and often occurs naturally in old forests. Seed-tree systems: involve the leading of a selected number of individual or groups of trees of superior form together with a receptive seed bed.