EFFECT OF SNOW REMOVAL ON LEAF WATER POTENTIAL, SOIL-MOISTURE, LEAF AND SOIL NUTRIENT STATUS AND LEAF PEROXIDASE-ACTIVITY OF SUGAR MAPLE

Effect of removal of snow cover in winter was investigated in an 80-ye ar-old sugar maple (Acer saccharum Marsh.) stand in southern Quebec. W e hypothesized that winter soil frost would induce some of the decline symptoms observed in sugar maple stands in southern Quebec in the ear ly 1980's. Snow was continuously removed from around trees for a one w eek (partial removal) or for a four-month period (complete removal) du ring the 1990-1991 winter. Foliage and soils were sampled periodically during the summer of 1991. The complete snow removal treated trees sh owed decreased leaf water potential and increased peroxidase activity over most of the growing season. Foliar Ca was reduced in both snow re moval treatments early in the growing season while foliar N was reduce d in the complete snow removal trees late in the growing season. Soil NO3- and K+ were elevated in both snow removal treatments at various t imes throughout the growing season. Prolonged soil frost in a sugar ma ple stand can induce lower leaf water potential, higher leaf peroxidas e activity and early leaf senescence during the following growing seas on. Soil frost may have reduced nutrient uptake without affecting sign ificantly the leaf nutrient status.