I-Tree Canopy is efficient and free software for calculating estimates of tree coverage and its environmental benefits in a predefined area based on Google Earth aerial photography. Using imagery of historical maps, I-tree Canopy also can study changes in canopy over time. The land cover data from I-Tree Canopy can be used by I-Tree Hydro to analyze the effects of trees on hourly stream flows and water quality.
A nice feature of I-tree Canopy is that everyone can learn to use it. The program asks the user 1) to delineate a geographical area, 2) to provide other types of land coverage categories besides trees (building, impervious, grass, etc.), and 3) to determine for each random dot the program creates in the delineated area on the map whether this dot is a tree or something else. The percentage of tree canopy is then determined by the number of dots classified as a tree. The more dots the user includes in the project, the greater the accuracy of the estimated tree canopy coverage.
I-tree Canopy is mostly used for geographical areas such as townships, cities, and counties. However, we chose Marquand Park to demonstrate its use. Based on just 200 data points, the results indicated that 51% of the park was covered by tree canopy (red dots), and 33% covered with grass (blue dots). The estimated environmental benefit of the tree canopy were relatively modest but the park is only a small 17-acre area.