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Distinguishing between the effects of changes in temperature and light climate using provenance trials with Pinus sylvestris in Sweden

Persson, B., Beuker, E.
Canadian journal of forest research = 1997 v.27 no.4 pp. 572-579
height, plant characteristics, Pinus sylvestris, provenance, photoperiod, temperature, global warming, heat sums, latitude, yields, Sweden
Provenance trials have been used to project the response of forest trees to changes in temperature resulting from the expected global warming. In such experiments the differences in temperature are brought about through geographical transfers over altitude and latitude. Transfers over latitudinal distances are also accompanied by changes in light climate. To distinguish between the effects of temperature and light, studies were made in a Pinus sylvestris L. provenance series in Sweden; in the series both the sites and the provenances are distributed over large latitudinal and altitudinal ranges. The response to annual temperature sum and latitude were calculated using multiple regression analysis. Both projected dominant height at age 100 years (H100) and mean annual yield increment over the rotation responded linearly to increasing temperature sum. The response to temperature sum decreased with increasing southward transfer. Latitudinal transfers without changes in temperature sum did not affect the performance of the populations. The projected response of populations to gradual warming will be less than projected on the basis of the final or the average temperature sums over the rotation period.