Phenological Variability of Pinus sylvestris L. Provenances in the International Provenance Test in Kupres, Bosnia and Herzegovina

Scots pine (Pinus sylvestris L.) is an important forest tree species growing on different soils in Bosnia and Herzegovina. Phenological traits are relevant practical indicators of the adaptability and adaptedness of forest tree species. This research aims to determine the dates of the beginning and the end and duration of phases of bud breaking and elongation in P. sylvestris. The results will be used in the selection of best provenances for the areas with late frosts. The materials used were P. sylvestris plants in the international provenance test Kupres. The test was established in 2012 with 15 provenances (three from Austria, one from Bosnia and Herzegovina, two from Germany, three from Italy, one from Poland, one from Romania, one from Slovakia, two from Norway and one from Ukraine). Six phases were observed for bud breaking and elongation. Phase 1 (start of elongation, scales partly disjoined but still covering the young shoot) was recorded on 10 May in all provenances. Phase 5 (2 needles of the same brachyblasts are clearly distinct) first occurred on 6 June on some plants of every provenances except Bugojno (Bosnia and Herzegovina), Delytayn (Ukraine), and Ca Del Lupo (Italy). Understanding phenological phenomena of Scots pine is important since the occurrence of late spring frost can damage the plants of Scots pine in the environmental conditions of Bosnia and Herzegovina. Research should be continued and include an investigation of the influence of seasonal climate and climate changes.