THE INFLUENCE OF DESICCATION AND HEELING-IN OF SEEDLINGS ON THE GROWTH OF NORWAY SPRUCE AND DOUGLAS-FIR PLANTATIONS

Three-year-old bare-root seedlings of Douglas-fir and Norway spruce were carefully planted using hole planting on a clear-cut area of 0.30 ha. The seedlings were exposed to desiccation in the shade of a neighbouring mature stand for different period (0-240 min) before planting. Half of the seedlings were heeled in for 11 days before planting. Water loss from above-ground part of seedlings and root system were measured. Douglas-fir and Norway spruce showed the same water loss rate during desiccation. In both species, root system was losing water more quickly than above-ground part of seedlings. Long exposition to desiccation influenced negatively height growth and root collar diameter in the 1st year of growth. Mortality did not exceed 20% in the seedlings with the longest period of desiccation. Careful heeling-in for 11 days did not negatively affect height increment or root collar diameter. Heeled-in seedlings had shorter newly sprouted needles and lower content of sugar in needles.