Open access publications in the SLU publication database

Abstract

The phenology of Pinus sylvestris (L.) and Picea abies (L.) Karst. seedlings. stored during winter in a cold-store (-5°C) and outdoors. respectively. was studied after planting-out on different dates from May to end of July. Seasonal changes in nitrogen and starch content were followed during the summer of planting. In pine and spruce seedlings planted from mid June to end of July. negative effects on dry weight, shoot and needle growth. bud diameter. and frost hardiness were observed. These effects were most pronounced for cold-stored seedlings and still evident after three growing seasons. Needle starch levels showed equal variations for early plantings. independently of storage treatment. but differences increased successively for later planting dates. Cold-stored seedlings showed. on all planting dates. a rapid increase in needle starch concentration. Seedlings stored outdoors had high levels of starch on early. and low levels on late planting dates. High levels of starch were found in the root system for seedlings planted in May. The results of the starch determinations were similar for both species. The nitrogen concentration in the old needles of the two species was low after planting for both storage treatments. Late planting dates resulted in low levels of nitrogen in current needles.