FORTRESS - FOResT land use management for REsilient and Sustainable Societies

A holistic approach to forests and natural hazards

Large areas of steep forest in Norway are ready for harvesting, especially forests planted after World War II to build the country’s bioeconomy. At the same time, much of this forest has a vital protective function by reducing and preventing snow and landslides. With climate change, an increase in landslide risk in steep terrain is expected, underscoring the importance of forests' protective effect.

Why FORTRESS?

Norway currently lacks a solid management framework for protective forests. Forest owners face few restrictions or guidelines for logging in steep terrain, yet bear significant responsibility for downstream damage caused by harvesting. Existing models for calculating the landslide-mitigating effect of forests are largely based on Alpine conditions and are poorly suited to Norwegian conditions. FORTRESS will address these knowledge gaps and develop tools to value the many ecosystem services provided by forests. The goal is to create fair and safe forest management as a nature-based solution for landslide protection.

Our core areas:

• Improved process understanding: Quantify how different forest types affect the risk of snow and landslides under Norwegian weather, landscape, and climate conditions.
• Ecosystem services (ESS): Develop tools to value protective forests based on four parameters: timber, landslide protection, biodiversity, and recreation (e.g., tourism).
• Decision support: Develop a GIS-based quantitative risk assessment (QRA) tool for planners and municipalities to use directly.
• Guidelines and education: Develop national guidelines for forest management in steep terrain and build capacity among authorities and forest owners.

Case studies in the project

We focus on three main cases and several mini-cases to capture different climates, forest types, and land-use conflicts in Norway:

• Lom: Dry inland climate dominated by spruce. A hotspot for conflicts between snow/landslide risk, extensive tourism, timber production, and biodiversity.
• Sogndal: Cold maritime climate (birch and spruce). Snow-rich winters with challenges related to avalanches threatening infrastructure.
• Stjørdal: Area dominated by spruce forest. Focus area for large-scale timber production and increasing landslide risk following harvesting.

WP1: Snow avalanches and forest management

Lead: Peter Gauer, NGI

Increase understanding of how forests and logging affect snowpack and the probability of avalanche release. Includes development of guidelines for forest structure in avalanche terrain and improvements to the NAKSIN avalanche model.

WP2: Landslides and forest management

Lead: Vittoria Capobianco and Amanda DiBiagio, NGI

Collect field data on hydrology, soil, and root properties to model the stabilizing effect of forests on landslides. Will develop recommended harvesting strategies in landslide-prone terrain.

WP3: Quantification of ecosystem services

Lead: John Paul McLean, NIBIO

Develop an “ESS valuation toolbox” that systematically values timber, landslide protection, biodiversity, and recreational value in steep terrain.

WP4: Legislation and land-use planning

Lead: Mina Di Marino, NMBU

Develop scenarios and integrate project tools directly into municipal and regional planning. Will result in national guidelines for sustainable management.

WP5: Education and capacity building

Lead: Denise Rüther, HVL

Develop teaching materials for students, establish continuing education courses for professionals/forest owners, and organize annual interdisciplinary workshops.

WP6: Project management and dissemination

Lead: Kjersti G. Gisnås, NGI

Overall administration, coordination of all research and user partners, and responsibility for communication and dissemination.

Lom

Dry inland climate dominated by spruce. Conflicts between snow/landslide risk, tourism, timber production, and biodiversity.

Sogndal

Cold maritime climate (birch and spruce). Snow-rich winters with avalanche challenges.

Stjørdal

Spruce-dominated area with large-scale timber production and increasing landslide risk after harvesting.

Project owner: Norwegian Geotechnical Institute (NGI)

Research partners:

• Norwegian Institute of Bioeconomy Research (NIBIO)
• Norwegian University of Life Sciences (NMBU)
• Western Norway University of Applied Sciences (HVL)
• Austrian Research Center for Forests (BFW)

Public user partners and authorities:

• Norwegian Water Resources and Energy Directorate (NVE)
• Norwegian Agriculture Agency (LD)
• County Governors in Vestland, Innlandet, and Trøndelag
• Lom, Sogndal, and Sunnfjord municipalities

Private partners and industry:

• Skogkurs AS
• Skog og Skred AS
• Allskog, AT Skog and Glommen Mjøsen Skog
• WoodWorks! Innovation Cluster
• Visit Jotunheimen

Kick-off meeting in Sogndal, 21–22 June

FORTRESS invites all project partners to the project’s first joint kick-off meeting at the Western Norway University of Applied Sciences in Sogndal on 21–22 June 2026.

The meeting opens on Monday, 21 June at 12:00 with professional discussions on the project’s objectives from both stakeholder and management perspectives. In the evening, participants will gather for a joint project dinner at 18:00.

On Tuesday, 22 June, the individual work packages will present their status and plans for the future. The program concludes with a site visit to the case area in Sogndal from 12:30 to 15:00.

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FORTRESS will continuously publish reports and scientific articles, input to new guidelines, and news throughout the project period from 2026 to 2030.

As the project progresses, you will find updated overviews of published research, links to digital maps and GIS-based tools, and news from fieldwork and workshops.