%0 Articles
%T Influence of clear-cutting on the risk of wind damage at forest edges: A GIS-based integrated models approach
%A Hongcheng, Zeng
%D 2006
%J Dissertationes Forestales
%V 2006
%N 16
%R doi:10.14214/df.16
%U http://dissertationesforestales.fi/article/1799
%X This study aimed at investigating how forest management affects the wind flow over a forested region and the consequent risk of wind damage at forest edges. For this purpose, a GIS software ArcGIS was used to integrate the models that simulate airflow (WAsP), wind damage (HWIND) and forest growth (SIMA) (Papers II-IV). Heuristics was also used to optimise the temporal schedules and spatial patterns of clear-cuttings regarding the risk management of wind damage and timber harvesting objectives (Paper IV). The integrated models were applied to analyse how clear-cuttings affect the speed and frequency of local winds (Paper I) and the short- (Paper II) and long-term risk of wind damage (Papers III-IV) in a management unit located in central Finland. In papers II and III, the risk of wind damage at current forest edges (Case I) was compared with two alternative situations in which new clear-cuts were carried out if stands reached the minimum acceptable size or age (Case II) or if the stand age exceeded 100 years (Case III). In this study, the risk of wind damage was evaluated in terms of number of stands, their areas and length of vulnerable edges for different critical wind speeds and annual risk probabilities (Papers II-IV).
In Paper (I) it was found that at the regional level the mean wind speed was not affected although the surface roughness changed due to clear-cuttings. However, locally the occurrence of high wind speeds increased. In Paper (II), it was found that, in spite of intensive clear-cuttings (Case II), the short-term risk of wind damage may not necessarily be increased at a regional level. This was because the most vulnerable older stands were cut. Compared to the intensive clear-cutting regime (Case II), it was also found over 20 years simulation period on average only 7% less vulnerable edges in the less intensive clear-cutting regime (Case III) (Paper III). An even flow timber harvesting objective (e.g. every 10 years interval) also affected the temporal and spatial pattern of clear-cuttings over the 30 year simulation period and limited the possibility of minimizing the risk of wind damage at a regional level (Paper IV). However, the risk of wind damage could be reduced by aggregating clear-cuttings and/or avoiding them at the edge of stands with a highest probability to be damaged.
As a conclusion, the integrated models approach presented in this study could, in general, help forest managers to better understand the influence of any forest management options (e.g. new clear-cuttings) on the short- and long-term risk of wind damage both at a stand and a regional level. Moreover, the methodology applied in this study could further help to provide optimal forest management for short- and long-term planning in regard to the risk management of wind damage and timber harvest objectives.