Geographical areas in Queensland are allocated 1 of 4 levels of timber decay hazard related to rainfall days per year and rationalised to local government boundaries.
Above-ground decay hazard zones are Ag:A, Ag:B, Ag:C, Ag:D
In-ground decay hazard zones are Ig:A; Ig:B, Ig:C, Ig:D.
Climate is one of the most significant environmental factors affecting the serviceability and performance of construction timbers. Subtropical to tropical climates with periods of warm temperatures and high humidity pose a higher risk of attack by fungal organisms that cause decay than drier climates.