Nitrogen Deposition Map (IMAGE) University of California - Riverside Caption Nitrogen deposition (gray-scale) and critical loads for nitrogen deposition (colored symbols). Non-canopied sites are portrayed with triangles, and the canopy sites with circles. Credit UC Riverside Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.