How spruce and pine fare in a wooded meadow without management for a century

Abstract

Spruce (Picea abies) and pine (Pinus sylvestris) dominate much of Scandinavia, but it is unclear how these species fare in places not subjected to forestry. Currently, evidence suggests that in the absence of disturbance, spruce will increase while pine will decrease. The term “sprucification” has been coined to describe the landscape-wise change. We tested this prediction in a 3.4 ha wooded meadow in southern Sweden set aside for free development in 1922. Comparing with older data, we assessed how tree density, basal area and size distribution has changed since 1937 when trees were mapped. We also estimated annual mortality and recruitment of new trees. The number of trees had declined since 1937, while the basal area had increased somewhat. Spruce but not pine had shifted its geographic distribution within the reserve. Mortality was three times higher among spruce than pine. Recruitment of new trees was modest, with most being spruce. Size distribution of spruce changed substantially over time with a loss of small trees and addition of large trees. Size distribution of pine, however, remained unaffected, except for the decline in the number of small trees. On balance, despite a century of free development, there was no clear evidence for sprucification in this former wooded meadow, now a dense mixed forest.