Natural forest dynamics in boreal Fennoscandia: a review and classification

Abstract

The aim here was to review and summarize the findings of scientific studies concerning the types of forest dynamics which occur in natural forests (i.e. forests with negligible human impact) of boreal Fennoscandia. We conducted a systematic search for relevant studies from selected reference databases, using search terms describing the location, structure and processes, and degree of naturalness of the forest. The studies resulting from these searches were supplemented with other known works that were not indexed in the databases. This procedure yielded a total of 43 studies. The studies were grouped into four types of forest dynamics according to the information presented on the characteristics of the native disturbancesuccession cycle: 1) even-aged stand dynamics driven by stand-replacing disturbances, 2) cohort dynamics driven by partial disturbances, 3) patch dynamics driven by tree mortality at intermediate scales (> 200 m 2 ) and 4) gap dynamics driven by tree mortality at fine scales (< 200 m 2 ). All four dynamic types were reported from both spruce and pine dominated forests, but their commonness differed. Gap dynamics was most commonly reported in spruce forests, and cohort dynamics in pine forests. The studies reviewed provide the best obtainable overall picture of scientific findings concerning the characteristics and variability of the unmanaged boreal forest dynamics in Fennoscandia. The results demonstrate that the unmanaged Fennoscandian forests are characterized by more diverse and complex dynamics than has traditionally been acknowledged.

Improving broad scale forage mapping and habitat selection analyses with airborne laser scanning: the case of moose

“…Although natural processes such as fire and storms can open up forest canopies, Scandinavian forest dynamics are largely determined by silvicultural practices and clear-cutting (Kuuluvainen and Aakala 2011). Indeed, the inventory variables forest development class and tree species were never replaced by ALS variables in the best models, which likely reflected the importance of forestry practices in the dynamics of wildlife forage availability.…”

Forest restoration by burning and gap cutting of voluntary set-asides yield distinct immediate effects on saproxylic beetles

“…In these situations gap-cutting is likely to be a better option as this will increase dead wood availability and thus overall population density without inducing dramatic changes in assemblage composition. To consider gap cutting as a restoration method is also ecologically motivated by the fact that different kinds of both large and small scale disturbances historically has shaped these forest ecosystems and the species therein (Kuuluvainen and Aakala 2011).…”

“…However, non-stand replacing disturbances such as gap dynamics have historically also been important for providing variation in light and structures in substantial portions of the boreal forest (Kuuluvainen and Aakala 2011). Commercial managed forests are denser, have less variation in tree height and are less permeable to sunlight than natural forest.…”

Ecological effects of disturbance-based restoration in boreal forests

“…The strength of the NDE approach is that it provides a comprehensive framework that can bridge the gap between different management objectives (Kuuluvainen & Grenfell 2012). With increased understanding of the relative importance of different disturbance types across the boreal zone, it is now possible to develop practical applications in their integration to forest management (Gromtsev 2002;Kuuluvainen & Aakala 2011;Shorohova et al 2011). So far, NDE has been utilized both in the development of silvicultural systems that better take into account the ecosystem perspective (Hyvärinen et al 2005;Koivula et al 2014;Rodríguez et al 2015;Heikkala et al 2016;Suominen et al 2016), but also as a guide to forest restoration treatments (Kuuluvainen 2002;Similä & Junninen 2012;Halme et al 2013).…”