Putting diversity indices into practice

Uneven-aged stands are diverse, both in spatial distribution of trees and in tree characteristics. The structures and natural processes in these stands are hard to describe, as are the planned and executed silvicultural operations. For clear and objective management planning in uneven-aged stands it has often been suggested to use diversity indices to describe aspects of stand structure such as diversity in species and size. However, an understanding of the meaning of these one-dimensional measures is complicated by i) the ambiguity of the concept of diversity, ii) the great diversity in structures, dynamics and silvicultural operations in uneven-aged stands, and iii) the indices' dependence on sampling design. Most diversity indices require the user to have sound theoretical and empirical knowledge. The meaning given to an index is a particular viewpoint of reality unique to each individual, depending on personal theoretical and empirical knowledge of the index, and the variable context in which the index is understood. From this viewpoint the objectivity of indices rests solely at the debate among the manager and others involved, converging to a consensus on the meaning of an index. Introducing diversity indices into forest management in the Netherlands requires care and thought, as well as the involvement of managers and other potential users. A number of selection criteria are recommended for choosing useful indices to describe aspects of structure. Given that few data are available in the Netherlands and that there is little empirical knowledge, special attention should be given to learn using the selected diversity indices from experience.