Biografi

Jeg er økolog med en spesiell interesse for hvordan naturlige og menneskeskapte prosesser påvirker arter og økosystemer over tid. Mitt nåværende hovedfokus er skogsøkologi og hvordan tilstedeværelsen av arter i skog påvirkes av viktige faktorer som arealbruk, fremmede arter, sykdom og klimaendringer.

Nøkkelord: Bevaringsbiologi, Langtidsendringer, Lukkede hogster, Overvåkning av arter, Skogøkologi og Skogsertifisering.

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Sammendrag

• This chapter summarises biodiversity responses to continuous cover forestry (CCF). The comparator throughout this chapter is rotation forestry (RF) and its main harvesting method—clearcutting—unless otherwise stated. • Research on the biodiversity effects of logging methods applied in CCF (mostly selection or gap cutting) mainly concerns the short-term effects of measures taken in mature, originally fairly even-aged forests, at best 10–15 years after cutting. Thus far, no surveys or chronosequences cover the whole rotation period (60–100 years). • Continuous cover forestry is likely to beneft species that suffer when the tree cover is removed, such as bilberry and its associated species. Species requiring spatial continuity in host trees or canopy cover may also benefit. • Selection cutting may preserve the majority of species in the mature forest, but the most sensitive species may decline or even disappear. Gap cutting (diameter 20–50 m) affects forest-interior species relatively little, but species’ abundances in gaps change with increasing gap size. Shelterwood cutting seems to closely resemble selection cutting in terms of species responses. In the long term, however, shelterwood cutting results in an even-aged and sparse overstorey, which does not produce the biodiversity benefits of CCF. • Species that have declined due to forestry mostly require large living and dead trees. The preservation of these species is not ensured by CCF alone, but requires deliberately maintaining these structural features. • A mosaic of different forest-management practices within landscapes may provide complementary ways to maintain rich biodiversity.

Sammendrag

There is an increasing interest in continuous cover forestry (CCF) as an alternative to clearcutting to promote multi-objective forests and preserve continuous maintenance of forest cover. Here, we assessed the effect that an increased use of CCF harvesting methods (shelterwood and selection cutting) in Norwegian forests can have on carbon sequestration. Thus, we simulated CO2 uptake in Norwegian forest stands throughout the 21st century under three scenarios that represent different levels of clearcutting and CCF harvesting methods, keeping the annual harvest volumes constant across all scenarios. The three scenarios are: 1) Business-as-usual (reference scenario where 3.5% of the harvested volume is obtained using CCF harvesting methods); 2) Harvested volume using CCF harvesting methods is increased to 15%; 3) Harvested volume using CCF harvesting methods is increased to 25%. Increasing the proportion of CCF would increase CO2 removals in the long-term (2100), resulting in an additional uptake of nearly 32 and 24 Tg CO2 when increasing CCF up to 25% and 15%, respectively. However, the simulations also showed that to be able to harvest the same timber volume as in the reference scenario that reflects current practice, an increased proportion of CCF would also require logging on a larger proportion of the forest area. CCF could have also positive implications for certain aspects of biodiversity, such as species that require shaded conditions, but harvesting across a larger total area could negatively impact other animals, plants and fungi.

Sammendrag

Clear-cutting can resemble natural disturbances like forest fire, but key differences exist in biological legacy. One way to enhance similarity is by preserving structural features of old-forests, such as retention trees, within harvested areas. The latest Programme for the Endorsement of Forest Certification (PEFC) standards require not only the preservation of retention trees but also their mapping for centralized reporting. This study evaluates the accuracy of retention tree density and volume predictions using airborne laser scanning (ALS) data with low (2 pulses/m2) and high (~100 pulses/m2) pulse densities, with and without spectral data. We also assess the feasibility of large-area predictions with minimal field data by testing both in-situ and ex-situ sources. The study was conducted in a managed 1300 ha forest in southeast Norway. Three reference datasets were used: (1) 630 in-situ retention trees across 27 stands (for species and DBH predictions), (2) 1604 ex-situ sample trees (for DBH predictions), and (3) 150 ex-situ annotated segments (for species predictions). Retention trees were identified using an individual tree segmentation approach, using adaptive local maxima window size and applying an adaptative height threshold to filter regeneration. ALS at 2 pulses/m2 alone provided reliable total density and volume predictions, while adding spectral data improved species-specific predictions. Species predictions were relatively stable across data source (kappa=0.556 for in-situ, 0.519 for ex-situ), but DBH predictions were notably underpredicted with ex-situ data (RMSE=9.40 cm, MSD=-4.55 cm) compared to in-situ data (RMSE=8.84 cm, MSD=0.20 cm). Using adaptive segmentation methods enhances scalability. We recommend sampling ~40 in-situ retention trees to develop DBH-height models and delineating ex-situ annotated segments for species predictions. This approach balances accuracy and efficiency while enabling retrospective analysis using national ALS datasets and orthophotos.