GALES is a mechanistic/empirical model developed to calculate the critical wind speed (CWS), leading to overturning or stem breakage inside or on the edge of unthinned or lightly thinned coniferous forests in Britain (Gardiner (1999) developed a mechanistic model HWIND to assess wind and snow damage at the edges of Finnish forests.
A modified version of HWIND is also used with an airflow model, wind atlas analysis and application program (WAs P) (Mortensen , 2004) in the WINDA system (Blennow and Sallnas, 2004) for assessing the stand risk in Sweden.
In addition to the wind damage assessment models, other techniques such as decision trees could be used to supply practical information for forest management.
Although the wind damage models can indicate the most risk stands in terms of CWS, the information has practical limitations in its direct applicability.
A growth model Silve-no-Mori was linked with Forest TYPHOON to estimate wind damage risk over a 50-year period.
After assessing the wind damage risk, risk stands were displayed using a geographic information system.
The tools are based on directly linking tree mechanical behaviour and forest airflow to predict stand vulnerability and potential damage risk.
Forest Research in Britain has developed a windthrow risk assessment model Forest GALES, which includes a predictor of wind climate named detailed aspect method of scoring (DAMS) (Quine and White, 1993) and a predictor of stand vulnerability named geographical analysis of the losses and effects of storms (GALES) (Gardiner , 2000).
Consequently, such damage has not been studied from the long-term perspective of wind damage risk.
In other words, wind damages in forests were only observed on the basis of location, volume and area in order to determine economic losses (Matsuzaki and Nakata, 1994) and ignored the impact of crop characteristics and local airflow patterns.