PROVENANCE DATA EXPLORATION
Provenance data exploration showed that countries outside of the projected suitable habitat had higher absolute growth rates of Pinus contorta than countries that were predicted suitable by the Species Distribution Model. Germany, Croatia and Denmark were all countries with exceptionally high absolute growth rates and low projected SDM suitability. In these countries, Pinus contorta would reach heights upwards of 8 m by age 15 (Figure 9, 11-12). This is a stark contrast to the absolute growth rates of Pinus contorta planted in suitable projected habitats countries such as Sweden and Norway. In these nordic countries, Pinus contorta had mean heights of 3-5 m at age 15 (Figure 10, 14-15).
Another important factor to consider is the effect of seed source origin. In total, there were 10 Pinus contorta seed source origins used in this analysis (Figure 1). It did appear that there were growth gradients based on seed origin. Differences were most noticeable in older stands and results were very country-specific. Generally, Central Coast Wet seed origin was the most successful provenance in non-suitable habitat countries. Boreal seed origin was the most successful in suitable habitat countries, with Central Coast Wet as a close second.
Another important factor to consider is the effect of seed source origin. In total, there were 10 Pinus contorta seed source origins used in this analysis (Figure 1). It did appear that there were growth gradients based on seed origin. Differences were most noticeable in older stands and results were very country-specific. Generally, Central Coast Wet seed origin was the most successful provenance in non-suitable habitat countries. Boreal seed origin was the most successful in suitable habitat countries, with Central Coast Wet as a close second.
The most frequent provenance trial age range was from ages 7-9, with another peak between 15-20 (Figure 5). To maximize sample sizes for analyses, these age ranges were used to compare the absolute mean heights of Pinus contorta in different countries. Both figures 6 and 7 show that Germany, the Netherlands and Denmark have higher absolute growth of Pinus contorta than Norway and Sweden . It is important to keep in mind that Germany, the Netherlands and Denmark are all countries that are are outside of the projected suitable habitat, whereas Norway and Sweden were found to be highly suitable.
Germany had a strong differentiation in growth rates by seed origin; the strongest growth delineation is seen at age 15 (Figure 9). Central Coast Wet was the most successful seed transfer. Sub-Boreal and Central Coast Dry seed origins were also very successful in Germany. Sweden showed a less apparent growth differentiation. Age 8 is almost impossible to interpret, as all seed origins seemed to have very close mean heights. Age 17 does provide more of an understanding on seed origin success: Cascades, Southern Interior and Southern Coastal showed a relatively poor growth performance to the other origins. Interestingly enough, Central Coast Wet had the highest growth in Sweden at both age 17 and age 27.
These three countries were all outside of the projected suitable habitat (Figures 11-13). In Croatia and the Netherlands, Central Coast Dry and Central Coast Wet were far more successful than any other seed origin; Boreal and Sub-Boreal showed very poor growth response. However, Denmark showed strong Sub-Boreal and low Central Coast Wet and Central Coast Dry growth. These varied results indicate how important proper seed source selection is to provenance success.
Both of these Nordic countries showed strong Boreal seed origin growth (Figure 14-15)