engleski

Which Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) provenances provide the best productivity in hilly area of Croatia?

1. Background Recently raised questions on adaptability of native tree species to climate changes pointed to Douglas-fir as species suited for rapid reforestation and increase of stand resistance. First results on provenance research needs to be confirmed in later stages of stand development, so paper answers two questions: (i) are there differences in growth of 14 Douglas- fir provenances still in fifth decade of stand development and (ii) which provenances should be used and which omitted from the further use in hilly area of Croatia? 2. Materials and methods Productivity of 14 provenances was evaluated on the basis of height, diameter at breast height and volume in 46th year after planting. Growth dynamics was also statistically analysed using a repeated measures analysis of variance, for which purpose we partially used published data from the 2010. 3. Results Analysis excluded Castle Rock and Shady Cove (Oregon) provenances by their low values of all analysed growth indicators, as well as provenances Castle Rock, Elma and Hvidilde by their high values. Average values of tree volume range from 0.53 m3 (Shady Cove) to 2.05 m3 (Castle Rock), while the tallest trees belong to provenance Elma (29.6 m). 4. Conclusions Different growth dynamic of provenances is confirmed for later development stage, so further monitoring is still required. Clear guidelines for the selection of provenances for practical forestry distinguish provenances from lower altitudes of the Washington Federal State, Denmark and Bulgaria as the most productive. Provenances Shady Cove and Salmon Arm are not advised to be used in the future.

Reforestation ; diameter at breast height ; tree height ; tree volume

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