Adapting management to wind disturbance: national-scale carbon trajectories under alternative silvicultural strategies in Ireland

Forests are increasingly relied upon as climate mitigation assets, but their carbon sequestration capacity is vulnerable to intensifying disturbance regimes. This vulnerability is especially relevant in intensively managed production forests, where disturbance can disrupt harvest cycles and alter carbon trajectories. In Ireland, for instance, conifer forests, largely composed of Sitka spruce (Picea sitchensis (Bong.) Carr.), dominate the productive forest estate and are particularly exposed to wind damage (Gallagher, 1974, Ni Dhubhain, 1998), raising questions about the robustness of mitigation benefits under a “business-as-usual” management. In this context, this study quantifies how alternative management strategies influence the carbon resilience of Irish forests at national scale.

A windstorm disturbance scenario was implemented across the Irish conifer forest estate using the CBM-CFS3 framework (Kurz et al., 2009). Stands were initialised with attributes from the National Forest Inventory (DAFM, 2022) to represent the most up-to-date age structure and management context. The windstorm event was defined as a target affected area consistent with recent post-storm damage magnitudes in Ireland (McInerney et al., 2016, DAFM, 2025). Damage is allocated using exposure and stand structure eligibility rules informed by Ni Dhubhain et al. (2009), with susceptibility weighted by management state (e.g., recently thinned stands) and stratified by region and age class. A baseline management scenario followed standard practice in the country (thinnings and clearfell with replanting). Post-storm dynamics included a short period of on-site decomposition of downed biomass followed by static salvage prescriptions to isolate management effects.

Management was evaluated through two decision factors expected to affect both forest exposure and recovery to storm events: thinning strategy and rotation length. Results were summarised using mitigation-relevant indicators at national scale, including changes in ecosystem carbon pools (live biomass, dead organic matter, soils), the magnitude and duration of storm-induced carbon debt and the timing of recovery relative to pre-storm trajectories. This analysis was framed as a scenario-based sensitivity assessment rather than a forecast, providing an evidence base for national reporting discussions and for subsequent work extending to alternative management pathways and analyses considering the carbon stocks in harvested wood products.

Keywords: carbon dynamics, forest resilience, natural disturbance, storm damage, temperate forests.

References

DAFM 2022. National Forest Inventory of Ireland. Dublin: DAFM.

DAFM 2025. Minister Healy-Rae confirms that over 26,000 hectares of forests have suffered wind damage. DAFM. Government of Ireland.

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NI DHUBHAIN, A., BULFIN, M., KEANE, M., MILLS, P. & WALSHE, J. 2009. The development and validation of a windthrow probability model for Sitka spruce in Ireland. Irish Forestry, 66, 74-84.