Survival and Yield of Pinus sylvestris L. as Related to Provenance Transfer and Spacing at High Altitudes in Northern Sweden

Eleven 27 to 29-year-old Scots pine provenance trials were studied in areas 400 m or less below timberline in northern Sweden. Functions describing geographic variation in the local provenance showed that survival as well as height and volume growth decreased with increasing latitude and elevation. Survival decreased by 7% per degree increase in latitude and 16% per 100 m increase in elevation. Beeting increased the survival by on average 2.4%, but less at high latitudes and altitudes. Tree height and volume per hectare decreased by 0.8 m and 15 m(3), respectively, per degree increase in latitude and by 1.3 m and 24 m(3), respectively, per 100 m increase in elevation. Transfer functions for provenances at different sites showed that the effect of latitudinal transfer on survival was reduced close to timberline. On average, a southward transfer of one latitudinal degree increased survival by about 7%, which is lower than in previous studies. No altitudinal transfer effects on survival were detected. Volume/ha was increased by southward transfer in northern parts of the area. Spacing had only a slight effect on performance and did not influence the functions presented.