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- Wallertz, Kristina, et al.
(author)
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Överlevnad, höjd och skador i odlingstester och proveniensförsök med douglasgran i södra Sverige : resultat efter sex vegetationsperioder
- 2019
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Reports (other academic/artistic)abstract
- The ongoing climate change affects the conditions for both domestic and non-native species. Douglas fir is a tree species that can be considered to grow well in a changed climate and could become a complement to e.g. Norway spruce, to a larger extent than today. A factor that inhibits an increased establishment of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) is the knowledge of and access to suitable provenances. Södra skog and SkogForsk collected Douglas fir seeds from seven provenances in British Columbia, Canada in 2007. Four of these were coastal, latitude 48–52°N, and the other three originated from the interior area, latitude 50°N. A large experiment was conducted in 2009 and 2010, in which seedlings from the seven provenances were included, on 12 sites. Inventories have been carried out after one, three and six growing seasons. On five of those sites hybrid larch (Larix × marschlinsii Coaz) was planted in every other row and on two of the sites Norway spruce gran (Picea abies [L.] Karst.) was planted in the same way. A provenance trial with the same provenances was established in 2010 in the Tönnersjöheden Experimental Forest, with the same kind of inventories as for the large experiment. During spring 2013, many seedlings were damaged by winter desiccation and a special inventory were therefore conducted both in the large experiment and the provenance trial in order to evaluate the damages. There was no significant difference in the survival rates between the different provenances in the large experiment, after one and three growing seasons. The interior provenances Larch Hills and Three Valley had significantly higher survival rates (76 and 71 %) than the coastal provenances Caycuse River and Bowser Heaman (50 and 48 %), after sex growing seasons. Bowser Heaman seedlings were significantly taller (2,09 m) than Three Valley seedlings (1,67 m), after six growing seasons. The mean height of the 10 highest trees tended to be slightly positively correlated to higher temperature sums for coastal provenances only, but not for the interior provenances. There seems to be a potential risk of low seedling survival rates in most parts of southern Sweden, if you do not use hardy enough provenances for the climate in the area. Therefore, interior provenances are likely to be preferred. Exceptions to this are favorable climate zones, mainly in the very south of Sweden and in some coastal areas. Coastal provenances of Douglas fir were more severely damaged than those from the interior area in spring 2013, when many seedlings suffered from winter desiccation. The reason may be later development of freezing tolerance for seedlings originating from the coastal area, which could lead to damage in the autumn. The seedlings would in that case already have been weakened when they were affected by winter desiccation in April. This gives further reason for consideration to recommend the use of interior provenances with earlier winter hardening in large parts of southern Sweden.
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