City of Greater Geelong - Urban Forest
Authors: MURRAY HERRON, ALI JALALI, PARAS SIDIQUI, EMMA DUNCAN
What might the City of Greater Geelong look like if we could change the city into an urban forest?
This research initiative is investigating what could happen if we took the current tree coverage in the LGA of the City of Greater Geelong and increase it by 20%, 50% and 90%.
The number of current trees in the city of Greater Geelong was multiplied to 20%, 50% and 90% of newly proposed planted trees. For plantation of trees, open areas or cleared areas such as land without buildings, roads and water bodies were considered. Target numbers were set to 500 trees per hectare based on the Ecological Vegetation Class (EVC) benchmark. The study showed that currently, city LGA contained approximately 5 million trees. The 20% increase in plantation indicated that another randomly distributed 6.5 million trees would be added to the existing trees so that the resulting number would be about 11.6 million trees. Hence, a 90% reforestation would mean 47 million additional trees, resulting in 52 million trees compared to around 5 million existing trees. The study presents a virtual scenario of a city in the forest, where the city LGA may get covered by trees with a different per cent increase in plantations.
The use of trees and vegetation in the urban environment brings many benefits, such as reduced air temperature, lower energy use, reduced air pollution, protection from harmful exposure to ultraviolet (UV) rays, decreased stormwater runoff, potentially reduced pavement maintenance and other quality-of-life benefits. The research has further indicated that peak air temperatures in tree groves are 5oC cooler than over open terrain, suburban areas with mature trees are 2oC to 3oC cooler than new suburbs without trees. Furthermore, an increase in tree cover per cent will significantly reduce the UHI effect by 1oC to 2oC; however, further research is required in this context.