Influence on Soil Properties of Prescribed Burning under Mature Red Pine.

摘要

Prescribed burns were conducted in 90-year-old red pine stands to facilitate pine seedling establishment by retarding shrub competition and by reducing the thickness of the organic layer on the surface of the mineral soil. The burns were conducted annually, biennually,or at 6to 9-year intervals in either the growing season or the dormant season. The more frequent summer burns were most effective in reducing shrub vegetation and in preparing a good seedbed. All burning treatments reduced the amount of organic matter,nitrogen,and phosphorus in the forest floor and raised its pH. The more frequent burning treatments also reduced the amount of calcium,magnesium,and potassium in the forest floor. Cation exchange capacity,nutrients,and pH were generally increased slightly in the mineral soil by burning. Phosphorus and pH increases induced by burning were greatest in the 0-4inch soil layer,whereas the largest increase for other soil properties was usually in the 4-20inch soil layer.