1. Harmonised indicators
Development of Harmonised Indicators and Estimation Procedures for Forests with Protective Functions against
Natural Hazards in the
Alpine Space
Harmonised indicators

2. Indicators selected for:
Forest area
Coarse scale
Fine scale
Hazard Potential
Damage Potential
Protective effect

3. Forest area: Coarse and fine scale According FAO Minimum crown cover
Minimum area
Minimum height

4. Forest area: Coarse and fine scale According FAO
Minimum crown cover 30%
Minimum area 5000m²
Minimum height 2m

5. Hazard potential: Coarse and fine scale Avalanche Snow height
Snow cover region and altitude
Slope
Planar curvature
Minimum forest area

6. Hazard potential: Avalanche
Alpine Region
Altitudinal zone
(hazard potential)
Code
Region 1 2
Austria
A100
Vorarlberg
≥ 700 m
≥ 900 m
A210
Northern Alps – West Zone
≥ 800 m
≥ m
A220
Northern Alps – Middle Zone
≥ 750 m
A230
Northern Alps – East Zone
≥ 900 m
A310
Western Central Alps – West Zone
≥ m
A320
Western Central Alps – Middle Zone
≥ m
≥ m
A330
Western Central Alps – East Zone
≥ m
A400
Eastern Central Alps

7. Hazard potential: Coarse and fine scale Avalanche Slope 28° – 55°
Planar curvature -2 – 0.2
Minimum forested area 5000m²

8. Hazard potential: Coarse and fine scale - Avalanche Climatic
avalanche hazard potential
Slope gradient
- 28°
>28 – 34°
>34 – 39°
>39 – 55°
> 55°
Avalanche hazard potential of slope gradient 1 2 3
Avalanche hazard potential (AHP)

9. Hazard potential: Coarse scale Rockfall Slope
Outside the forest mask and inside the rock mask a slope threshold of 43°
Inside the forest mask a slope threshold of 39°

10. Hazard potential:
Coarse and fine scale Rockfall
Slope

11. Damage potential: Coarse and fine scale Data availability?
Buffer zone 25m

12. Protective effect: Avalanche Coarse scale Total crown cover
Coniferous crown cover

13. Protective effect: Avalanche Coarse scale Total crown cover
Coniferous crown cover

14. Protective effect: Avalanche Fine scale Total crown cover
Coniferous crown cover
Tree height
Gap length

15. Protective effect: Avalanche Fine scale Total crown cover
Coniferous crown cover
Tree height (AHP 1: -2m, AHP 2/3: 5m)

16. Critical gap length (m)
Protective effect:
Avalanche
Fine scale
Gap length
Slope (°)
Critical gap length (m) 30 60 35 50 40 45

17. Protective effect: Rockfall Coarse scale Forested slope length
Basal area

18. Level of protective effect of forest
Rockfall
Coarse scale
Forested slope length (>200m)
Basal area
Basal area
Level of protective effect of forest
≥ 25 m2/ha
1 – high
15 – 25 m2/ha
2 – medium
< 15 m2/ha
3 – low

19. Protective effect: Rockfall Fine scale Forested slope length
Fraction of gaps
Stem density
DBH
(Stone size)

20. Protective effect: Rockfall Fine scale
Forested slope length ( > 200m %)
Fraction of gaps (gap < 25%)

21. Protective effect: Rockfall Fine scale Stem density DBH Stone size
Trees/ha
DBH
Small
>600
>12 cm
>400
≤400
≤12 cm
Medium
>24 cm
>300
≤300
≤24 cm
Large
>200
>36 cm
>150
≤150
≤36 cm
Protective effect
1 - high
2 - medium
3 - low