Results and Discussion
Douglas fir height relative to the model is loosely positively correlated with its associated habitat suitability (or probability of presence) in the bioclimate envelope model (Figure 5a). Areas previously modeled with higher probability of presence in its bioclimate envelope model generally correlated with faster relative tree growth (adjusted r2=0.1086). For the Lodgepole pine model however, tree growth rates relative to our height growth model appeared was slightly negatively correlated with the bioclimate envelope model results (adjusted r2=0.022) (Figure 5b).
Interestingly, when climatic variables are taken into account with each respective model (Figure 5), it is visibly apparent that relative precipitation and temperature are consistently lower in areas where bioclimate suitability is highest for Lodgepole pine, whereas a consistent trend is not as readily apparent in the Douglas fir model.
Interestingly, when climatic variables are taken into account with each respective model (Figure 5), it is visibly apparent that relative precipitation and temperature are consistently lower in areas where bioclimate suitability is highest for Lodgepole pine, whereas a consistent trend is not as readily apparent in the Douglas fir model.
Figure 5: Correlation analysis between relative height growth and bioclimate suitability of Douglas fir provenance trials (5a and 5c) and Lodgepole pine provenance trials (5b and 5d). Climate trends for the areas are also identified with Mean Annual Precipitation (5a and 5b) and Mean Annual Temperature (5c and 5d) of Provenance trial location.
This study has demonstrated a relative correlation between previously developed Douglas fir bioclimate envelope models. However, Lodgepole pine bioclimate envelope models do not generally reflect tree growth rates demonstrated with provenance trials in Europe.
Differences in the effectiveness of Bioclimate suitability models maybe a result of the relative importance of climatic variables selected by each respective models. For example, as previosuly illustrated in Table 2 (within data and methods), the model developed by Isaac-Renton et al (2014) for Douglas Fir included factors such as Growing degree days above 5 degrees Celsius, and Hargreave's climatic moisture deficit index (Wang et al 2012), whereas the climatic variables used to develop the bioclimate model by Herva M (2015) were primarily based on temperature and precipitation.
Using a bioclimate model with provenance trials may provide additional insight on the boundaries of the fundamental niche for each species within North America. Also, by comparing the relative success of Lodgepole pine in competing with native species' in its predicted range in Europe, and assessing damaging factors such as insect and disease occurrences, a more reliable bioclimate model may also be developed for the European realized niche for these tree species.
Differences in the effectiveness of Bioclimate suitability models maybe a result of the relative importance of climatic variables selected by each respective models. For example, as previosuly illustrated in Table 2 (within data and methods), the model developed by Isaac-Renton et al (2014) for Douglas Fir included factors such as Growing degree days above 5 degrees Celsius, and Hargreave's climatic moisture deficit index (Wang et al 2012), whereas the climatic variables used to develop the bioclimate model by Herva M (2015) were primarily based on temperature and precipitation.
Using a bioclimate model with provenance trials may provide additional insight on the boundaries of the fundamental niche for each species within North America. Also, by comparing the relative success of Lodgepole pine in competing with native species' in its predicted range in Europe, and assessing damaging factors such as insect and disease occurrences, a more reliable bioclimate model may also be developed for the European realized niche for these tree species.
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