agreeing to be on my committeeand an additional thank you to the former for guiding me through the VISTA process and all of his support throughout this degree. For being a constant source of inspiration and motivation with all of the program pivots, thank you to Emily Vogelgesang. Thank you to everyone else at Huron Pines and Huron Pines AmeriCorps who I had the pleasure to work and serve with this year. Finally, a special thank you to Shallen Gurtler, Chance Sherratz-Hayes, and Emily Bischoff for reading through the early drafts and providing outside feedback. vi Definitions The following are scientific binomials for organisms referenced in this report: Plants Autumn olive (Elaeagnus umbellata: Elaeagnaceae) Common buckthorn (Rhamnus cathartica: Rhamnaceae) Glossy buckthorn (Frangula alnus: Rhamnaceae) Jack pine (Pinus banksiana: Pinaceae) Japanese barberry (Berberis thunbergii: Berbericeae) Purple loosestrife (Lythrum salicaria: Lythraceae) Animals Kirtland's warbler (Setophaga kirtlandii: Parulidae) Sandhill crane (Grus canadensis: Gruidae) vii

<p>To prevent further erosion of pastures along the south slopes of the Vinschgau/Val Venosta (South Tyrol/Italy) about 900 ha of non-native black pine (Pinus nigra) have been afforested there between 1900 and the 1960s. This drought-tolerant Mediterranean species was supposed to be able to cope with the dry climate at degraded soils in the inner-alpine dry valley. Nevertheless, black pine in the Vinschgau has been affected by reoccurring tree vitality decline and diebacks in the last 20 years linked to repeated droughts and heat waves. Observing growth trends via tree ring analysis is usually restricted to single stands. On the other hand, remote sensing data to track tree vitality was not available in sufficient spatial and temporal resolution to be applied to complex mountain terrain until recently. This has changed with the launch of the Sentinel-2 A and B satellites in 2015 and 2017 with a spatial resolution of 10 to 20 m and a revisiting period of 5 days. To analyse the accordance of remote sensing-based vegetation indices to tree-ring based growth data, we compared twelve sites across the Vinschgau/Val Venosta with a differing degree of vitality loss in 2017 for a four-year period from 2015 to 2018. In general, less vital sites were located at lower elevation and on steeper slopes. Radial tree growth was positively correlated to spring precipitation and strongly decreased during earlier hot and dry years such as 1995 and 2003. We found high and statistically significant correlations between site-average basal area increment as well as tree ring width indices and multiple vegetation indices (Normalized Difference Vegetation Index NDVI, Green Normalized Difference Vegetation Index GNDVI, Normalized Difference Infrared Index NDII, Moisture Stress Index MSI) especially for the dry 2017 growing season and the 2018 recovery year, which had large gradients in tree vitality between sites. Overall, these results show that remote sensing-based vegetation indices can be used to scale up stand level growth data also in complex mountain terrain.</p>