Conifers in the Urban Forest

Summary

Trees in the urban landscape are key components of green infrastructure.  Green infrastructure is the aggregate of plants and green spaces in the urban landscape.  This infrastructure serves many functions within the urban area and provides a multitude of benefits which are becoming increasingly more valuable as municipalities look to remediate environmental issues caused by urbanization.  The value of the urban forest is an integral part of securing funding and support for urban forestry initiatives: the higher the value the more support is gained, and the more benefits accrued.  The majority of species that make up urban forests across the United States and Canada are broadleaf deciduous species.  Many of the benefits that urban trees provide are attributed to their canopies (i.e. rainwater interceptions, pollution absorption, wildlife cover, etc.).  When these trees drop their leaves during autumn, the benefits of their canopies affectively drop to negligent levels. Especially in regions where rainfall events occur mostly during this leaf-off season, the additional canopy cover afforded by evergreen tree species in concert with the canopy architecture and density of evergreen conifers specifically, could prove to be highly valuable in regards to canopy-dependent tree benefits.  A greater use of conifers as urban trees will also lead to a greater species diversity in the urban forest which helps make the ecosystem more stable and resilient in the face of pest and disease outbreaks.  This paper presents rationale for the increased use of conifers in the urban landscape, discusses possible issues associated with evergreen conifers, recommends design uses, and finally shows that a distinct gap in the literature exists in regards to research on conifers in the urban landscape.