Background

Approximately 25% of New Zealand’s plantation forests are located on steep, erosion-susceptible lands. These steepland plantations do a great job of reducing soil erosion—the contribution of NZ’s plantations to avoided erosion has been valued at nearly $1 billion per year (Yao et al. 2021). However, plantation forests are usually clear-felled when mature, and the steepland plantations are no exception. Clearfelling on erosion-susceptible lands results in a "window of vulnerability” of around six years, until the replanted trees grow large enough to protect the soil (Phillips et al. 2024). We do not want to lose the benefits of plantations in reducing soil erosion—we need to carefully stage our forest harvesting to manage the areas within the window of vulnerability, especially on erosion-susceptible land.

Planning

Local councils, landowners, and the forestry sector are working to enhance their management and mitigation of future environmental effects arising form clearfelling plantation forests on steep, erosion-susceptible land. Central to this effort is the ambitions to improve access to spatial information about forestry stand locations and recent and forthcoming harvesting locations.

Mitigation

The project aims to create an online spatial decision support tool to help visualise forestry stands, their locations and ages, and the erosion susceptibility of these areas when they have been clearfelled.

Approach

This approach aims to provide a comprehensive spatial depiction of clearfell harvest areas over time on a catchment scale, which is essential for proactive environmental stewardship.