Forests and wind risk
Historically Tasmania has not been subjected to a lot of catastrophic forest windthrow; however, considering the recent trends of expanding the geographical limits of plantation development into previously undeveloped topographies means that the damage to forests from wind should not be underestimated.
If forests are not assessed for wind risk as part of the strategic forest planning process and appropriate management regimes implemented, the establishment and management of forests (plantation and native) can be severely affected by windthrow and breakage that could result in commercial failure.
Wind risk within forests is dependent upon the interaction of a number of individual factors, including the forest windthrow, stand and treatment hazards. The importance of each factor will vary from place to place and time to time.
Above: Forest wind risk is determined by windthrow, stand and treatment hazards.
The resultant forest wind risk indicates the likelihood of forests being damaged by winds and trees resulting in windthrow and/or breakage of trees.
Forest wind risk can be used to plan operations in existing forests, and also to design and plan future forests, including the strategic positioning of shelterbelts.
Private Forests Tasmania has produced ‘Forests and wind risk in Tasmania: a guidebook for foresters, landowners and planners’ to introduce them to:
- the concepts of forest wind risk;
- a method of determining the level of wind risk for an individual operation, a single coupe, a whole forest or an entire property;
- a planning framework for wind risk; and,
- windthrow management strategies to reduce forest wind risk.
And an Excel-based ‘Wind risk calculator’ to assist in the collation of data and determination of the forest wind risk.
A component influencing the windthrow hazard factor of forest wind risk is the ‘topographical exposure’ (TOPEX), where the wind exposure of a site is modified by the influence of the surrounding topography. The TOPEX can be assessed by survey in the field, or by subjective assessment, however Private Forests Tasmania has developed TOPEX-based exposure maps for Tasmania to more readily, accurately and objectively assess the topographical exposure of an individual operation, a single coupe, a whole forest, a property or an entire landscape.
"TOPEX Webmap coming soon" Please check back again
DISCLAIMER - the TOPEX maps are not quantitative risk assessments and should not be used in isolation from the ‘Forests and wind risk in Tasmania: a guidebook for foresters, landowners and planners’.
The ‘Forests and wind risk in Tasmania: a guidebook for foresters, landowners and planners’, Wind Risk Calculator.xl and TOPEX maps may be of assistance to you. However, PFT and its employees do not guarantee that they are without flaw of any kind, or are wholly appropriate for your particular purpose, and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in the guidebook, calculator or maps.
If you require further information please contact Private Forests Tasmania.