Conclusions
Species Distribution Models (SDM) are very powerful tools. They will become increasingly important as the effects of climate change continue to plague the forestry industry. However, the interpretation of these models needs to be revisited. The context in which an SDM is used may infer different conclusions. There is a distinct difference between relative and absolute growth values. Absolute growth values are important in determining whether a tree species is simply able to grow in a habitat. Absolute growth values are more of a reflection of the abiotic growing conditions in a habitat; a country with a longer growing season will produce taller trees. Certainly in this context, the previously developed SDM failed. Pinus contorta showed stronger absolute growth performance in non-suitable habitats. However, the question should not be "Can a species grow?" Rather, a reforestation strategist should ask "Is it economically and ecologically viable to grow this species in this country alongside these local species?" Inter-specific competition is something that must not be overlooked.
In terms of relative growth and interspecific competition, Sweden is an informed choice for Pinus contorta reforestation. It was able to outcompete both Pinus sylvestris and Picea abies, two established and valuable forestry species in Sweden. On the other hand, Germany would not be an informed choice for reforestation. For similar reasons, Pinus contorta was outcompeted by all five forestry species used in this analysis.
Of course, there are other aspects that should be considered in reforestation strategies that go beyond this project. Most notably, the influence that potential pests and novel diseases may have on the success of a reforestation project. Mountain Pine Beetle has infamously destroyed 50% of British Columbia's total volume of commercial Pinus contorta, leaving a lasting impression of the effects of climate change on the forestry industry. Informed reforestation is a key mitigation strategy to climate change!
In terms of relative growth and interspecific competition, Sweden is an informed choice for Pinus contorta reforestation. It was able to outcompete both Pinus sylvestris and Picea abies, two established and valuable forestry species in Sweden. On the other hand, Germany would not be an informed choice for reforestation. For similar reasons, Pinus contorta was outcompeted by all five forestry species used in this analysis.
Of course, there are other aspects that should be considered in reforestation strategies that go beyond this project. Most notably, the influence that potential pests and novel diseases may have on the success of a reforestation project. Mountain Pine Beetle has infamously destroyed 50% of British Columbia's total volume of commercial Pinus contorta, leaving a lasting impression of the effects of climate change on the forestry industry. Informed reforestation is a key mitigation strategy to climate change!