Exercise: Mapping storm damaged forest areas

Definition of storm damage

Mapping of forest damages caused by storms using visual interpretation of very high resolution digital ortho photos (DOP) need clear definitions and characteristics which are usually documented as interpretation keys. Here, clearings are defined with a minimum area = 0.2ha, minimum width = 20m, minimum tree crown cover = 10%.

Characteristics of windthrow areas depend on the time between storm events and the availabiltiy of optical remote sensing images but also on the status and progress of logging and clearing operations at the time of the image aqcuisition. Typical characteristics for recognizing storm damages are: horizontal complete trees with root plates, root plates, stumps with fresh cross section, piles of logs for storage / skidding, piles of branches, skid roads and tracks, no or few ground vegetation.