Threats to urban trees from globalisation and a changing climate.

Threats to the urban environment from globalisation and a changing climate.

The global climate is changing as a result of human activity; the earth is warming up. Natural causes have played a part but the atmospheric warming observed over the last fifty years has been attributed to the burning of fossil fuels, land clearing and other activities that have increased the concentrations of greenhouse gases in the atmosphere.

The gradual warming of the earth’s climate will also impact other variables such as rainfall, humidity and wind speed. Weather patterns may also be impacted with warmer wetter winters, longer and hotter dryer summers anticipated. These environmental changes may affect the growth rates of trees, the distributions of individual species and provide abiotic threats such as draught and water stresses. (Broadmeadow & Ray, 2005, 69)

Climate change impact is already noticeable, tree species well suited to the climate in which they were planted 20-50 years ago can become maladapted to changed temperature and precipitation conditions on a site. This creates stresses on individual trees, reduces their geographic range and in vulnerable locations, they succumb to drought, pest or disease.

Future Urban Tree Management

Urban planners must consider how to manage the future urban tree population with reference to individual species adaptation to climate change. Research demonstrates that increasing the urban forest will reduce the impacts of climate change to its residents. Yet this must be done with caution and care. To aid such decision making processes there are a number of tree growth model simulators being developed to provide guidance to planners as to species selection with regards to their usability, when developing urban forests. These concerns must be at the forefront of any planners mind when it comes to selecting tree species for urban developments.