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iForest -Biogeosciences and Forestry
IntroductionOperational forestry is limited by social, ecological, economic, and legal constraints. In Spain, as in many countries around the world, forestry science originated in the Central Europe of the late eighteenth cen tury, when the main concern was wood/fuel supply and game protection. As is well known, forestry possesses a long-term nature arising from long tree life-spans that, in tem perate zones, can cover several human ge nerations. In this context, historical analysis of forest organization can be used to develop criteria and indicators to evaluate the ma nagement processes in different forest areas effectively. In spite of its limitations, this kind of retrospective studies is acknow ledged in adaptive management as a source of valuable information for shaping forest management practice. Historical studies are an attempt to demonstrate changes in ma nagement indicators, including the number of trees per hectare or wood volume by using certain variables or parameters. By doing this, we can study the long-term sustainabi lity of the management methods used. As forest management has a multidimensional impact on forests and forest communities, the best strategy in analysing management effects is to include the largest possible num ber of indicators provided by the forests management plans. Over the last decade, dif ferent analyses have been performed on changes in organized forests to observe the response to various management models (Charnley et al. 2008). The greatest diffi culties in carrying out these types of studies are the limited amount of reliable document sources (mainly management plans), because document structure changes as legal regula tions evolve. The numerical data are there fore difficult to compare, and only general trends can be defined. The limited span of this kind of studies is not strange, conside ring the difficulty of obtaining long-term, re liable, comparable data sets. In southern Europe, Spain is the only country where forest management plans have been applied effectively and indicators reflecting the silvi culture applied in the past can be analysed thoroughly. It is important to emphasize that, in most cases, the organization of Spanish forests has not included economic variables in forest management as clearly stated ob jectives. Revenue and expense information is rarely included, and it is very difficult to find the information needed to perform a proper economic evaluation. Although retrospective evaluations of forest management results are generally performed on individual forests, we can gain insight on a landscape approach over a long-term period by studying opera tional forestry documents.Forest model, permanent plot, and tempo rary plot approaches have been defined as useful tools for evaluating forest manage ment practices. All these methods have dif ferent limitations (mainly spatial and tem poral) and conclusions drawn from such studies can be limited by the monitoring design. As usual in forestry research, one of the ma...
