Vitas, A. 2011. Seasonal Growth Variations of Pine, Spruce, and Birch Recorded by Band Dendrometers in NE Lithuania. Baltic Forestry 17(2): 197-204

We present the 1976-2010 results of a study on seasonal circumference growth carried out in NE Lithuania. The growth variations were recorded every three days using manual band dendrometers installed on 29 trees: 23 Scots pines (Pinus sylvestris L.), 3 Norway spruces (Picea abies (L.) Karsten) and 3 silver birches (Betula pendula Roth). The average onset of the growth was observed between May 6-10 and the cessation between August 28-30; growth on average lasted for 111-117 days. The growth onset and cessation time were highly variable among individual trees. A tendency for an earlier onset and cessation, and for an increase in growth duration from 1976 to 2010 was observed. Pine and spruce reach their maximum growth in June, while the birch culminated in July. Birch demonstrated much slower growth in April and May in comparison to pine and spruce. Our study has revealed a tendency of an increasing growth rate during April-June and an inverse trend in July and August.

Key words: band dendrometer, circumference measurement, Norway spruce, Scots pine, silver birch