The differing opportunities and threats posed by timber structures and climate change are outline below.
1.TIMBER STRUCTURES AND BUSHFIRES
Climate change has been related to bushfires directly and increasing temperatures have been taken as a sign that bushfires are only bound to increase in the future. An estimate puts the change in temperature due to global warming in Australia between 0.4 and 2oC by the year 2030 above the 1990 levels while the change by 2070 is projected between 1 and 6oC. (Preston & Preston, 2006) It could easily be expected that the exposure of timber to bushfires would result in the timber structures being damaged beyond repair by fires. However this is not entirely true as timber structures do not face any real threats as long as the heat from the bushfires is radiant in nature. Appropriately AS 3959-2009 specifies three classes of timber that can be used in areas at risk of bushfires. These ratings are based on the BAL (Bushfire Attack Level) ratings and include timber with a seasoned density of 650 kg/m3, 750 kg/m3 and timber that is resistant to bushfire. Timber is made resistant to bushfire through the use of the materials inherent properties, by dousing and coating with fire retardant chemicals or through the application of fire retardant substrates. (Standards Australia, 2009)
However AS 3959-2009 does not place any constraints for using special timber classes in places where no direct exposure to heat is speculated. Such regions of timber usage include the floors, wall frames, roof framing walls, ceiling lining etc. The timbers specified for use in the standard mentioned above are found abundantly in Australia. Seven kinds of timbers with high densities are specified as being fire resistant and their testing has proved the levels of endurance that could be expected with their use. Based on these pieces of evidence it can be inferred that timber can be used in increasing numbers without the risk of significant impacts from climate change on timber engineered structures. 2. Spread of Termites and Other Pests Another major impact of climate change has been its help to spread various species of insects beyond their normal modus operandi. The increase in temperatures is driving more and more species to occupy newer areas. In the Australian context there has been a net migration of a number of different plants, animal an insect species towards the south as temperatures are on the rise. The increasing temperatures provide these species with better breeding grounds that are favourable so a net migration occurs. The case of malaria moving farther down south is just one such manifestation (McMichael, 2003) where the operating areas for mosquitoes have increased as global temperatures are on the rise. A similar problem is exhibited through the spread of termites to newer locations as temperatures become more and more favourable for their breeding and growth. Regions like Victoria are more at danger than others because 30 of the 78 municipalities in Victoria do not require any anti-termite protection for buildings. This indicates that most of the buildings, houses and other structures in these municipalities will be prone to termite infestations in the near future. At present there is little to no action on the part of the government to mitigate such threats. The various builders, developers and purchasers should be alerted by the local government as to expected chances of termite and other pest based infestations. Moreover there is dire need for coordination between government regulatory agencies and etymologists in order to identify the migration patterns of termites and other such pests that could cause large damages in the future. 3.