Baltimore Forest Stewards and the Urban Forest

摘要

Baltimore, Maryland, like many U.S. cities, plants new trees to counter the loss of urban tree canopy and to increase ecological sustainability (Pincetl 2010; Zhou et al. 2011; Nowak and Greenfield 2012). Preserving canopy-cover in Baltimore also entails limiting the loss of older trees with extensive canopies—small trees contribute less canopy per tree and have a higher mortality rate than bigger trees (Nowak et al. 2004; Nowak and Greenfield 2012).Across Maryland, canopy declines are mainly due to conversion of forest to urban land uses (MDNR 2003; Zhou et al. 2011). Parcelization, or the division of a forest into separately owned parcels, can increase canopy loss (Avins 2013). Forested parcels smaller than one acre are not protected by the statewide Forest Conservation Act; therefore, forests spanning many small parcels are not protected from development, as each parcel is considered separate under the law (Howell and Ericson 1997; MDNR 2003). Risk of forest fragmentation and parcelization is highest in urban areas, and when these parcels span multiple owners they are susceptible to development (Avins 2013). Forest fragmentation by parcelization can be limited by preserving existing forest patches, planting in gaps within patches, and planting along the edge of existing patches (Nowak et al. 2004).