1Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland
2Institute of Ecology, Department of Northeast Estonia, Pargi 15, EE-41537 Jõhvi, Estonia; Jalkanen,
Tóm tắt
A needle trace method was used to reveal the chronology of needle retention on Scots pine (Pinus sylvestris L.) in southern Finland (two stands) and northern Estonia (two stands). The average annual summer needle retention along the main stem varied from 2.2 to 3.1 in Estonian stands and between 3.4 and 4.2 in Finnish stands during the period 1966–1990. The 23-year-mean needle age was 3.0 and 2.1 years in Finland and Estonia, respectively. In all stands, the mean needle age decreased sharply in 1980s.
