City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: https://read.dmtmag.com/i/65193
Darwin, Northern Territory, Australia, is be an urban forester! The two typical seasons, the dry season, April-September, and the wet season, October- March, can display extensive rainfall variation. The 2010 dry season provided a rainfall total of just 10.4mm (.4 inches) during a 113 day period, with a mean aver- age temperature of 32 degrees Celsius (100 F). In stark contrast, the 2010-2011 wet season dumped 2959.4mm (116 inches) of rainfall at Darwin Airport weather station, for which Tropical Cyclone Carlos was mostly responsible. What's known as the Dry Tropics can be certainly both dry, and tropical. a tough place to be a tree, and a tougher place to Amenity tree selection becomes difficult when trying to compromise between drought tolerance, an ability to sustain periods of flooded/anaerobic conditions, be resistant to wind throw, and meet the site constraints and amenity expectations of the community. As I state regularly, there is no perfect tree ... but there are plenty that are close! In the past, the city has favoured species such as yel- low flame tree (Peltophorum pterocarpum), river red gum (Eucalyptus camaldulensis), weeping rosewood (Pterocarpus indicus var. pendula), African mahogany (Khaya senegalensis), and red condoo (Mimusops elen- gi). Tropical Cyclone Tracey in 1974 left Darwin denuded of vegetation. The mass planting effort following the cyclone saw many of the above species, and more, installed throughout the city's suburban streets and parks. Some have proven to be highly valuable assets; others have proven to be problematic. Melbourne has recently emerged from a decade-long drought that resulted in a steep increase in tree mortality. Melbourne Photos Courtesy Ian Shears Key elements of the strategy are to increase canopy cover and diversity of species, increase soil moisture, enhance biodiversity, and engage with the community. Research includes quantifying thermal benefits of trees in Melbourne and physiological indicators to climatic stress, identifying which species we should use in the future, and attributing economic values to urban trees. Advocacy and networking is also critical in ensuring trees and green infrastructure is integral to city planning. Corporate website: www.melbourne.vic.gov.au/urbanforest Consultation site: www.melbourneurbanforest.com.au YouTube: www.youtube.com/watch?v=BplUmxFCE8A —Ian Shears, Manager Urban Landscapes, City of Melbourne, Victoria, Australia www.urban-forestry.com Many local indigenous tree species are now being cul- tivated in nurseries for their genetic ability to withstand the rigors of the local environmental variability. The trialed use of various underutilized local tree species helps to achieve species diversity goals, limit potential effects of catastrophic pest/disease outbreak, and provide multiple ecosystem functions. Species such as white bush apple (Syzygium forte), allosyncarpia (Allosyncarpia ternata), Herbert's gum (Eucalyptus her- bertiana), white cloud tree (Maranthes corymbosa), bush currant (Carallia brachiata), and Hill's salmon gum (E. tintinnans) are all very useful Northern Territory Tree Species for various function, form and amenity pur- poses. Many introduced species are also used for their drought tolerance and heat resistance values. Challenges for many of Australia's urban foresters may include climate change, urban heat island effect, water scarcity, population increase and urban intensifica- tion, and simply finding the resources to achieve the future vision of the urban forest. All this whilst battling increased drought effects! In my position as Darwin Technical Officer Parks and Reserves, I am currently reviewing operational process- 27