Postdrainage forest productivity of peatlands in Sweden

Abstract

The objective of this investigation was to determine a method for grouping and classifying peatlands in Sweden on the basis of site quality after drainage. Initially, sites were grouped in six vegetation types, defined by the presence and abundance of certain species in the field layer. Then, pure and mixed stands of mainly Pinussylvestris, Piceaabies, and Betulapubescens, for which the original vegetation type was known, were investigated. Data from temporary sample plots on these previously drained areas were used to reconstruct stand development after drainage. The reconstruction was based on single-tree functions derived from regression analysis. A computer routine was used to calculate stand yield in the period between ditching and data collection. With the use of this productivity analysis, the initial classification into vegetation types was revised and expanded to eight site types. From the same analysis, stand functions for form height and basal area increment were derived. These functions were used to calculate forest productivity on peatlands by simulation of postdrainage stand development. For each site type, postdrainage productivity was calculated for different climatic conditions and expressed in cubic metres per hectare annually. The accuracy of the productivity figures is discussed. A key for determining site types is presented.