Implementing storm damage in a dynamic vegetation model for regional applications in Sweden

Abstract

Wind is the dominant agent of damage in forests in Western Europe. Traditional winddamage models calculate a probability for damage or a critical wind speed at which damage occurs. However, in a dynamic vegetation model actual damage to stands and individual trees is needed to get a dynamical progression of the vegetation. We present a prototype for a new approach to modelling forest wind damage at the regional scale, which we incorporate within a dynamic vegetation model. The approach is based on knowledge from both empirical and mechanical models and calculates the damaged fraction of a cohort based on wind load and a sensitivity that depends on the current physical state and history of the cohort in relation to the ecosystem. The modelling concept has been developed, calibrated and evaluated for Swedish conditions but can be applicable to other similar areas with minor modification. Because of the stochastic nature of local wind load and the difficulty of describing the stand-level exposure, the ability to explain observed damage at stand level was low. Regional level variation in damage, which more depends on the wind load, was however explained reasonably well (R 2 = 0.43). We suggest that this is a useful concept for evaluating alternatives of forest management under different climate scenarios in the process of adaptation to future storm-damage risks. KeywordsDynamic vegetation model LPJ-GUESS; storm damage; windthrow; boreal forest; forestry

Comparing correlative and process-based modelling approaches in a boreal forest identifies important areas for model development

“…In Lagergren et al (2012), species-specific storm sensitivity ranked the three tree species in line with results from tree puling experiments (Peltola et al 2000), i.e. P. abies (1.0) < P. sylvestris (0.5) < deciduous species (0.1).…”

Comparison and validation of three versions of a forest wind risk model

“…Recent work by Albrecht et al (2013) found no difference in the vulnerability of Douglas-fir and Norway spruce even though earlier work had suggested Douglas-fir was probably less vulnerable (Schmidt et al, 2010). Recent review studies have concluded that the most consistent factors to predisposing forest stands to wind damage are tree height, recent thinnings (approximately within the previous 5 years; Lagergren et al, 2012;Valinger and Fridman, 2011) and saturated soils (Colin et al, 2009;Hanewinkel et al, 2013).…”

Integrated and systemic management of storm damage by the forest-based sector and public authorities

“…3). Adaptation and mitigation strategies are well described, especially in regard to forest management (Heinonen et al 2009;Schelhaas et al 2010;Lagergren et al 2012;O'Hara and Ramage 2013;Subramanian et al 2015). However, the sum of individual strategies does not guarantee the effectiveness of the global strategy, and systemic mitigation measures should be taken as complementary to them.…”