Meeting management goals in an urban forest : vegetation dynamics and prescriptions in Stanley Park

As urban areas grow, urban trees attract more attention from city governments, foresters, arborists and citizens because of the ecological services and amenities they provide and also the hazards they pose. The term ‘urban forest’ has a wide variety of meanings. These meanings are are rarely functional. Urban trees live in habitats where human interventions in ecological processes and environmental conditions range from severe to minimal. One end of this gradient represents an ‘urban treescape’ while at the other end are ‘self-maintaining forests’. These terms are defined within a conceptual framework that better describes the functional range of forests found in urban areas. Management of urban forests requires techniques and concepts from both forestry and arboriculture. Stanley Park is an example of a semi-self-maintaining forest. Aerial photograph analysis shows that the forest composition and structure of the Stanley Park forest has changed substantially since the 1930’s. Windstorms in 1934, 1962 and 2006 have played an important role in this change. To characterize current conditions, data were collected from 208 sample plots to describe the forest vegetation. From these data and historical vegetation data, 15 vegetation types were defined. Data from representative plots were used to model different management scenarios in stands disturbed in 2006 and stands replanted following the windstorm in 1962. In the stands initiated following the 1962 storm, thinning over the next few years would reduce the overstory height to diameter ratios (HDR) but, because of the height of the stand, the windthrow hazard will remain high. Planting densities in the stands disturbed in 2006 were low, but there is considerable natural regeneration. Early thinning treatments will be required to achieve compositional and structural targets outlined in the Stanley Park Forest Management Plan (Vancouver Park Board 2009). Thinning should be done in the next 10 to 15 years in these stands to achieve the management goals most efficiently. The modeling tools used here can be used in other urban forest settings. They can be particularly valuable when managers must plan silvicultural treatments to reach management goals and when presenting treatment options to the public and budgetary authorities. Forestry, Faculty ofGraduat