DIFFERENCES IN SPRING PHENOLOGY OF NORTHERN SPRUCE CLONES IN THE SEED ORCHARD OF THE TRAKAI REGIONAL UNIT OF THE PRAVIENIŠKĖS FOREST DISTRICT

Abstract

Norway spruce (Picea abies L. H. Karst.) is an economically and ecologically important species throughout Europe, but the warming climate contributes to the deterioration of the condition of spruce forests in Lithuania and Europe. The study assessed the synchrony of sporification of tree clones growing in the second-generation seed orchard of Norway spruce, located in the Pravieniškės forest district of the Trakai regional division of the State Forest Enterprise (code 08ESP031), which allows determining the possibilities of crossing between different clones. The study was conducted in 2023–2024, evaluating a part of the seed orchard clones - 549 ramets. The phenological phases of female and male strobiles and vegetative buds of each tree were assessed according to the TREES4FUTURE (2006) phenology assessment methodology. In order to facilitate comparison of clones, the observed clones were divided into 8 regions of origin and their spring phenology was compared. Such data are significant both for the improvement of the seed base and for forest selection work, as they allow the selection of clones best adapted to local conditions. It was established that both in 2023 and 2024, the clones of the Ignalina and Vilnius populations had the highest stage of vegetative buds, and the ones in Telšiai had the lowest stage.