Researchers at USC’s Spatial Sciences Institute have discovered major reductions in tree cover for single-family homes in the Los Angeles Basin. 

From 2000-2009, the 20 largest LA Basin cities lost anywhere from 14 to 55 percent of all green cover. All of LA saw a 1.2-percent year-over-year decrease in tree and shrub cover over that stretch. Baldwin Park lost more than any other city, with 55 percent of all green cover disappearing. Other cities with major green cover losses (20 percent or more) included Compton, Downey, Pomona, San Pedro and Sylmar. 

One of the main culprits of the tree cover loss appears to be redevelopment and the resulting increase in home sizes. According to researchers, the average size of single-family homes increased from 984 square feet in 1950 to 2,349 square feet by 2004. Home expansion, yard development, and walkway installation also contribute to tree removal.

While home sizes and redevelopment are both likely to continue to increase in LA, the study does note a potential shift for the tree loss issue as well. The Los Angeles “Million Trees” campaign kicked off in 2007, with the goal of planting throughout the region. With just a two-year overlap between the campaign and this study, results in 2017 may reflect differently than those in 2009.