Structure of old Pinus sylvestris dominated forest stands along a geographic and human impact gradient in mid-boreal Fennoscandia

Abstract

Stand structural characteristics were examined in old Pinus sylvestris dominated sites in three regions along a broad geographic and human impact gradient in mid-boreal Fennoscandia. The study regions were: 1) Häme in south-western Finland, with a long history of forest utilization, 2) Kuhmo in north-eastern Finland, with a more recent history of intensive forest utilization, and 3) Vienansalo in Russian Karelia, still characterized by a large near-natural forest landscape. Within each region the sampled sites were divided into three human impact classes: 1) near-natural stands, 2) stands selectively logged in the past, and 3) managed stands treated with thinnings. The near-natural and selectively logged stands in Häme and Kuhmo had a significantly higher Picea proportion compared to stands in Vienansalo. In comparison, the proportions of deciduous tree volumes were higher in near-natural stands in Vienansalo compared to near-natural stands in Häme. The pooled tree diameter distributions, both in near-natural and selectively logged stands, were descending whereas managed stands had a bimodal diameter distribution. Structural diversity characteristics such as broken trunks were most common in near-natural stands and in stands selectively logged in the past. The results demonstrate the higher structural complexity of near-natural stands and stands selectively logged in the past compared to managed stands, and highlight that old near-natural stands and stands selectively logged in the past vary widely in their structures. This obviously reflects both their natural variability but also various combinations of pre-industrial land use and human impact on fire disturbance. These factors need to be acknowledged when using "natural" forest structures as a reference in developing strategies for forest management, restoration and nature conservation.

Modeling species co‐occurrence by multivariate logistic regression generates new hypotheses on fungal interactions

“…Some of the stands are located in southernmost Finland with a long history of forest use, and others in eastern Finland where intensive large-scale forestry started relatively late and the proportion of natural and seminatural forests is higher than in southernmost Finland (Rouvinen et al 2002, Lilja andKuuluvainen 2005).…”

Boreal Forests of Kamchatka: Structure and Composition

“…120 years of stand age [39], while in New Zealand CV and skewness declined in maturing stands, causing a contradictory transition towards a normal distribution [53]. A declining distribution of stem sizes is often considered a signal of old-growth [27], but selectively-logged stands can have a similar pattern [64], and stands with remarkably different histories often have similar size distributions [65]. In northeast USA, old-growth forests do not converge on a standard diameter distribution but have a high variance in stem size with low densities of live trees [63].…”

Large-Scale Landscape Composition and Capercaillie (Tetrao urogallus) Density in Finland

“…In managed boreal forests (> 90% of forests in Finland) the late-successional stages may be degraded by thinnings because of the simplified stand structure (see e.g. Uuttera et al 1997, Lilja & Kuuluvainen 2005. The role of different forest successional stages as capercaillie habitats may also vary due to the variation in the forest stand structure between regions.…”