Wisconsin street tree assessment, 2002-2003

A pilot study to assess the structure, function, and health of Wisconsin’s street trees was initiated in 2002. Almost 900 plots were established in Wisconsin’s urban areas. Table 1 provides an overview of plot-level data, population estimates, and a calculated monetary value for Wisconsin’s street trees. Wisconsin has mid-sized street trees, dominated by Norway maple (30 percent), green ash (15 percent), honey locust (8 percent), and littleleaf linden (7 percent). Field assessments of crown dieback indicated robust and healthy trees in 2002. Damage was observed on only 16 percent of trees, and the most frequently observed types of damage were cracks or seams, open wounds, and conks on the trunk. The structural and functional value of Wisconsin’s street trees approaches $1.8 billion. Carbon storage and sequestration ($7.5 million), replacement value ($1.8 billion), and pollution removal ($1.7 million/ year) are important assets to the citizens of Wisconsin. Emerging threats to Wisconsin’s street trees include the Asian longhorned beetle, which could impact 82 percent of the roadside trees, emerald ash borer (20 percent), and gypsy moth (15 percent).