Timo Kuuluvainen, Tuomas Aakala. (2011). Natural forest dynamics in boreal Fennoscandia: a review and classification. Silva Fennica vol. 45 no. 5 article id 73. https://doi.org/10.14214/sf.73

Keywords: disturbance; age structure; stand replacement; cohort; gap; patch; natural disturbance emulation

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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 disturbance-succession 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 m²) and 4) gap dynamics driven by tree mortality at fine scales (< 200 m²). 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.

Kuuluvainen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: timo.kuuluvainen@helsinki.fi
Aakala, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ta@nn.fi

article id 72, category Review article

Ekaterina Shorohova, Daniel Kneeshaw, Timo Kuuluvainen, Sylvie Gauthier. (2011). Variability and dynamics of old-growth forests in the circumboreal zone: implications for conservation, restoration and management. Silva Fennica vol. 45 no. 5 article id 72. https://doi.org/10.14214/sf.72

Keywords: late-successional forest; disturbance regimes; stand dynamic types; cohort dynamics

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Due to the unprecedented loss of old-growth forests to harvesting throughout circumboreal regions an understanding of similarities and differences in old-growth dynamics is needed to design effective restoration, management and conservation efforts. This paper reviews concepts, prevalence and variability of old-growth forests across landscapes, and evaluates different stand scale dynamics at the old-growth stage across the circumboreal zone. Old-growth historically dominated many boreal forest landscapes in both Eurasia and North America. Throughout much of North America, and to some extent in western Siberia, the natural prevalence and development of old-growth forests are regulated by the occurrence of stand-replacing fires. In eastern North America and Siberia, insect outbreaks may, however, be more important. Insect outbreaks as well as recurrent non-stand replacing surface fires and windthrows, when occurring at the old-growth stage, often form stands characterized by several tree age-class cohorts. This multi age-class forest development type is common in Europe and eastern Siberia but its prevalence and importance in boreal North-America is not well documented. Similarities in successional dynamics across the circumboreal region are found in the development of mono-dominant even-aged stands, the replacement of shade intolerant tree species by shade tolerant species, as well as in all-aged stands driven by small-scale gap dynamics. The message to land managers is that the focus should not only be on setting aside remaining old-growth forests or in restoring static old-growth attributes, but also in emulating natural disturbances and successional dynamics at landscape and regional scales to maintain natural variability in old-growth attributes through time.

Shorohova, Saint-Petersburg State Forest University, Saint-Petersburg, Russia & Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland (ekaterina.shorohova@metla.fi) E-mail: shorohova@ES13334.spb.edu
Kneeshaw, Université du Québec à Montréal, Centre d’étude de la forêt, Montreal, Canada E-mail: dk@nn.ca
Kuuluvainen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland E-mail: tk@nn.fi
Gauthier, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, Canada E-mail: sg@nn.fi

article id 411, category Review article

Arthur Groot, Sylvie Gauthier, Yves Bergeron. (2004). Stand dynamics modelling approaches for multicohort management of eastern Canadian boreal forests. Silva Fennica vol. 38 no. 4 article id 411. https://doi.org/10.14214/sf.411

Keywords: boreal forests; Canada; dynamic models; multi-cohort forest management

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The objective of this paper is to discuss approaches and issues related to modelling stand dynamics for multi-cohort forest management in eastern Canadian boreal forests. In these forests, the interval between wildfires can be rather long, and the development of natural forest stands may include the establishment, growth and mortality of several cohorts of trees. Later cohorts are characterised by increasing structural complexity, including spatial heterogeneity and irregular tree size distribution. A multi-cohort forest management framework has been proposed to maintain this complexity, and associated biodiversity, on the landscape. Multi-cohort forest management planning requires forecasts of the development of stands with complex structure in response to silvicultural treatment and to natural disturbance, but current stand dynamics models in the region are applicable mainly to even-aged mono-specific stands. Possible modelling approaches for complex stands include i) the adaptation of current whole-stand growth and yield models, ii) distance-independent, empirically-derived individual-tree models, such as the USDA Forest Service Forest Vegetation Simulator, and iii) distance-dependent, empirically-derived or process-oriented individual-tree models. We conclude that individual-tree models are needed because observational data for fitting whole-stand models are not available for the full array of silvicultural treatments and natural disturbances encompassed by multi-cohort forest management. Predictive accuracy is a concern with individual-tree models, and the incorporation of coarse-scale constraints into these models is a promising means to control error.

Groot, Great Lakes Forestry Centre, Canadian Forest Service, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5, Canada E-mail: agroot@nrcan.gc.ca
Gauthier, Laurentian Forestry Centre, Canadian Forest Service, 1055 du P.E.P.S., P.O. Box 3800, Sainte-Foy, QC, G1V 4C7, Canada E-mail: sg@nn.ca
Bergeron, University of Quebec at Abitibi-Temiscamingue, 445 Boul de l’Université, Rouyn-Noranda, QC, J9X 5E4, Canada E-mail: yb@nn.ca

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