Predisposition assessment modelling
|Keywords:||Forestry; Predisposition; Ips typographus; Silviculture; Geographic information systems|
|Full text PDF:||http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/12194|
Dissertation submitted for obtaining the degree of Master in Environmental Engineering Over the last decades outbreaks of the bark beetle Ips typographus (L.) assumed a high importance in forestry due to the economic losses caused, amounting to 3 million m3 the volume of wood damaged in 2009 in Austria. In natural systems, such events result from a dynamic interaction among several factors, the integrated analysis of which can depict the predisposition level of a stand, or site, to I. typographus outbreaks. The objective of this thesis was the development of a Predisposition Model for Rosalia Forest, located in the state (Land) of Vienna in Austria. Wind and snow storms are two of the main factors that lead to a higher level of risk, as high quantities of fallen timber become available, constituting a favourable breeding habitat for I. typographus communities to proliferate. Terrain and stand related data can be translated into parameters that are registered and studied using Geographic Information Systems, in order to obtain predisposition results to wind and snow damage and ultimately overall predisposition assessments to insect infestations. Stand and site related parameters from spatial and inventory data were analysed and scored according to an Assessment System previously formulated. In order to allow for different analysis and adjustments the Model was developed in a mask-like structure. Results on predisposition for the Rosalia Forest were spatially analysed and statistically processed. It was concluded that the majority of the stand area fell in the Medium predisposition class. This was due to the diversified age structure of the stand as well as to a relatively low proportion of the host species Picea abies present in this site. The model developed not only allows for the assessment of bark beetle predisposition according to an Assessment System based on an extensive compilation of literature, but can also be used as a working tool for further sites and scenarios by entities aiming at the management of the risk of I. typographus infestations.