The influence of seed origin on stand variables of Scots pine (Pinus sylvestris L.) provenance trial in Ahunapalu

The aim of the present study is to analyse the influence of seed origin on the growth performance in Scots pine provenance trial at the age of 33 and 43 years. The provenance trial plantation with 18 provenances of Scots pine were established in Estonia, Järvselja Training and Experimental Forest District (58°19'47, 21"N. Lat. and 27°16'2, 79"E. Long) under the supervision of E. Pihelgas in 1965, using seeds from different regions of the former Soviet Union. The northernmost seeds were received from Arhangelsk province, Russia, (63° N. Lat.) and the southernmost seeds from Borjomi Forest Enterprise, Georgia, situated 800 m above sea level (42° N. Lat.). The westernmost seeds were from Latvia, Lithuania and Ukraine (23-24° E. Long.). Seeds of Estonian pine seedlings originated from the forest districts of Järvselja, Sõmeru, Vihula, Sagadi and Koorküla. Data used for above-mentioned study was collected during the years 1998 and 2008.

Statistical analysis was conducted using the software package R. The statistical analysis of the data obtained from provenance trials showed that under Estonian circumstances density, height and breast height diameter were stand variable which were depending on seed origin the most. The average survival percentage of progenies from southern provenances (with the northern latitude less than 52°) was lower than that in case of the progenies of the northern seed origin; a strong linear relationship was found between the stand breast height diameter and the northern latitude of seed provenance. The average breast height diameter of the stands from southern origin was larger than that of the stands from northern origin, whereas the plots of northern seed provenances had bigger survival percentage (density) than that of plots grown from southern seeds. Thus, the plots of northern seed origin had poorer conditions for diameter growth. The stands of northern seed provenance had slightly lower average height than that in the stands of southern seed origin.