Whitebark pine mortality pilot study complete!

Using 2017 imagery from the National Agricultural Imagery Program (NAIP), we mapped whitebark pine mortality across Glacier National Park (GNP) . These results convey that by 2017, roughly 18.41% of forested area in whitebark pine woodlands within GNP had died (almost 1 in 5!). Mortality varies quite a bit spatially, with some stands wiped out entirely by fire and snow avalanche, some showing signs of blister rust and pine beetle infestation, and some looking relatively mortality-free. Using an existing whitebark pine dataset (Hop 2007) and imagery from NAIP, we mapped live and dead whitebark pine across GNP. Although somewhat restricted by snow cover, we achieved an overall accuracy of 82.04%. Primary sources of confusion were between dead whitebark pine, bare ground and snow; a factor of similarities in spectral signatures between those land cover types. Of whitebark pine woodlands investigated, live and dead tree cover only represented about 27.2% of the classification- whitebark woodlands consist mostly of bare ground, grasslands, and shrublands, an important aspect of species management to consider.

Figure 1 is an example of known whitebark pine forests in southwest GNP.

 

Figure 1. Whitebark pine forests in southwest Glacier National Park- Snowslip, Shields, Running Rabbit, and Scalplock Mountain woodlands.

Below (Fig. 2) shows a whitebark pine forest in 2005, prior to a mortality event.

 

Figure.2 Whitebark pine forest in 2005, prior to mortality event.

Between 2005 and 2009 (Fig. 3), a mortality event took place.

 

Figure 3. Whitebark pine forest in 2009, post- mortality event.

Using 2017 NAIP imagery, we mapped whitebark pine mortality across the region. Fig. 4 gives you an idea of what that looks like.

 

Figure 4. Red polygons represent whitebark pine mortality in 2017.

Figures 5 and 6 below show visible whitebark pine mortality, and mapped whitebark pine mortality, respectively based on 2017 NAIP imagery.

 

Figure 5. A whitebark pine mortality event visible in 2017 NAIP imagery.

 

Figure 6. Whitebark pine mortality (red polygons) mapped based on 2017 NAIP imagery.