Figure 1
From: Centennial-scale reductions in nitrogen availability in temperate forests of the United States
Locations of 49 sites sampled for wood δ15N in the continental U.S.A. Woody cover (green) is from the Commission for Environmental Cooperation. Full site information is available in Supplementary Table 1. Map was generated in ArcGIS 10.1 (https://www.arcgis.com/features/index.html).
