RESPONSES OF PINUS-RESINOSA OF NEWFOUNDLAND TO WILDFIRE

Natural Pinus resinosa (red pine) stands in Newfoundland are restricte d to 22 small, dry, nutrient-poor sites. A short wildfire cycle (15 - 30 yr) of both surface and crown fire regulates stand perimeters and i s the main factor in regulating stand development. At the nucleus of c urrent stands < 100 yr old, a few trees > 200 yr occur, usually showin g multiple fire scars. Stem char heights confirmed an increased flamma bility of the stand and tree mortality for fires moving in the upslope position, as well as for mixed Pinus resinosa-Picea mariana stands. A ll P. resinosa stands are severely nutrient-deficient. Leaf concentrat ions of N, P and K were below or near the reported critical values. Nu trient concentrations were highest three months after a surface fire, but dropped considerably one year later. A gradual increase to near po st-fire levels is achieved four years after fire. Foliar nutrient conc entrations were positively correlated with average width of the annual rings. Aspects of the ericaceous understory dynamics and its relation to P. resinosa regeneration are also discussed.