Growth and survival of lodgepole pine and Scots pine after 25 years in a reciprocal transplant experiment in Canada and Sweden

Abstract

Lodgepole pine is native to western North America, but it is also planted as a fast-growing alternative to Scots pine in Sweden. The production of these two species, when grown as native and as exotic species, was compared in a transcontinental two-species provenance experiment. The tests were planted in 1986 on five sites in northwestern Canada and two sites in Sweden, and included full-sib families, half-sib families, seed orchard collections and natural stand seed collections of both species. After 25 years, lodgepole pine produced 48% more volume (m 3 ha −1 ) and had 27% higher survival than Scots pine at one Swedish site, and had similar volume production and survival at a second. In the five Canadian sites, Scots pine produced on average 22% more volume than lodgepole pine. The variation between sites was, however, large. This higher volume of Scots pine in Canada could be due to higher survival (+28%) and less frequent damage; but higher top height for lodgepole pine in Canada indicated higher potential productivity. The results indicate that an exotic species may produce more than the native species, possibly thanks to higher survival, but it is also possible to increase production with successful population selection of the native species.

Damage by pathogens and insects to Scots pine and lodgepole pine 25 years after reciprocal plantings in Canada and Sweden

“…Moose seems to prefer Scots pine over lodgepole pine at fertile sites, but prefer lodgepole pine at poor sites (Niemelä & Danell 1988). Top height, stem diameter and volume production were all lower at Garsås, despite its more southern location than at Renberget (Fries et al 2015) indicating that…”

“…that an exotic tree species in a new environment may have higher fitness than an indigenous species due to the absence of restrictive pests and pathogens endemic in its native range. However, the exotic species have less clearly superior survival rates when the 10% best seed-lots are compared, indicating that it may be possible to find sufficiently well adapted materials of either exotic or indigenous species to ensure good survival and also production rates (Fries et al 2015).…”

“…At the four southern sites 49.2% of trees of seed-lot L57 were infected, compared to 81.2% for those originating from other operational seed-lots. Based on the production data reported by Fries et al (2015), western gall rust caused ca. 25% growth reductions of both lodgepole and Scots pine trees (Table 6).…”

“…Growth measurements presented and described by Fries et al (2015) were used in the analyses of western gall rust effects on volume production. At the southern Swedish site, Garsås, both species were heavily damaged by pine weevil (Hylobius abietis) at a young age, then later by moose: only 35% of the plots had more than 20 of 64 living trees and only these plots were evaluated.…”

“…A previous paper addressed variations in productivity between species and sites (Fries et al 2015). However, few studies have adequately evaluated the damage by pathogens, insects and animals at a higher age and the aim with the present study was to: (1) evaluate the occurrence of damage by various fungi, insects and mammals on the two species as native and exotic species, (2) evaluate differences between provenances and between plus tree progenies and operational stand collections in susceptibility to those threats, and also damage by snow and wind, (3) evaluate genetic differences in susceptibility to western gall rust and mountain pine beetle, and (4) judge the risks of severe consequences due to large-scale outbreaks of diseases or insects when lodgepole pine or Scots pine is used exotically in forestry in Sweden or Canada.…”