Artikkelit kirjoittajalta Matti Maltamo

The structure of peatland forests were compared between different site quality classes, drainage phases, and different forest ownership groups. The comparisons and statistical tests were made in terms of the number of tree species, range of diameter distribution and the estimated number of tree storeys, separately for spruce- and pine-dominated mires. The statistical tests were performed with multivariate analysis of variance and covariance. Tree storeys were estimated with objective rules from the peaks of continuous diameter distribution smoothed by the non-parametric kernel-estimation. The data used from the 8th National Forest Inventory of Finland. On average the mean values of the chosen stand structure characteristics differed significantly between the site quality classes. The stands had a more diverse structure the more fertile the site was. When examining the differences between the post-drainage succession phases, a decrease of the stand structure diversity was observed in the recently drained peatlands. After this, the mean values of the stand structure characteristics increased and exceeded the values of undrained peatlands at latest in the transformed post-drainage succession stage. Statistically significant differences in the means of stand structure characteristics between the forest ownership groups were not observed. It seems that drainage and possible cleaning cuttings have been made with the same intensity regardless of the particular forest ownership group. It is also possible that drainage causes so drastic change in growing conditions that small differences in the intensity of cleaning cuttings between forest ownership groups are disappeared. The results correspond to the results of previous studies which have examined different stand structure characteristics. The forest on drained peatlands maintains an uneven-sized structure for quite a long period after drainage. In order to preserve habitat diversity this structure of the peatland forests should be maintained in subsequent forest management practices. Key words: drainage, habitat diversity, peatland forest management, structure of forest stand.

• Uuttera, The European Forest Institute, Torikatu 34, FIN-80100 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo
• Maltamo, Sähköposti: ei.tietoa@nn.oo
• Hotanen, Sähköposti: ei.tietoa@nn.oo