The tree cover of the City of Syracuse was evaluated for ecosystem service provisions including air pollution removal and changes in building energy use at three time intervals – 1999, 2001, and 2009 – using the iTree Eco model. Between the first two points in time, the tree cover experienced a small decline, but rebounded in the years that followed, primarily driven by the natural regeneration of Rhamnus cathartica, or Common Buckthorn, a pioneer species that has taken root in the region following a major storm in the early 1990s.
While the canopy technically increased, the energy savings in buildings decreased during the same period, from $1.7M in 1999 to $1.1 M in 2009. This inverse trend is a result of the short and short-lived canopy contribution of the Buckthorn, which has grown in primarily vacant land and hedgerow areas where the shade value is lost. In addition, the introduction of pests are contributing to the increased mortality of mature shade trees.
- Urban forests are not static and require assessment at multiple points in time to understand change
- Canopy cover, and thus ecosystem service provision, can fluctuate based on a range of natural events including pests, drought, expansion of invasive species, etc.
- Forest structure and species composition impacts ecosystem service provision.