Fig. 1. Three study areas (shown in the map with striped rectangle) were located in southern Finland near Päijänne lake. Weather data, shown at top right corner, shows the monthly average temperature (°C) (values at y-axis) with line graph and rain sum (mm) (values at z-axis) with bar graph. Static trafficability map, shown in bottom right corner, is divided into 16 m × 16 m grid cells compatible with the forest resource information and each cell is classified into the following four classes (i.e. seasons): (1) Operations possible in any season, (2) Operations possible in summer, (3) Operations possible in summer during dry season, (4) Operations possible only during frost or thick layer of snow. View larger in new window/tab.
Fig. 2. The stand-level (i.e. average values) frequency distribution of the stand’s classification to “Not damaged” or “Damaged” based on the measured damage on logging tracks assessed using the Finnish forest legislation limits. Static trafficability classes at x-axis: (1) Operations possible in any season, (2) Operations possible in summer, (3) operations possible in summer during dry season and (4) operations possible only during frost or thick layer of snow.
| Table 1. The rutting damage severity (%) at stand-level in following classes: 0% i.e. undamaged, <10%, 10%–20% and >20%. Damage severity describes the relative length of track that is seen as damaged in above mentioned four classes. Track is damaged if there is over 1-meter long rutting with higher depth than 10 cm in mineral soils and 20 cm in peatlands. | ||||||||
| Damage severity | Correct timing | Incorrect timing | ||||||
| 0% | <10% | 10%–20% | >20% | 0% | <10% | 10%–20% | >20% | |
| Stands, n | 25 | 3 | 3 | 5 | 12 | 9 | 5 | 5 |
| % | 69.4 | 8.3 | 8.3 | 13.9 | 38.7 | 29.0 | 16.1 | 16.1 |
| Table 2. Percentage of “not damaged” and “damaged” logging tracks in relation to Finnish legislation limits (Ministry of Agriculture and Forestry 1996) when the timing of the harvest either matched with or differed from the static trafficability map class. Track count (n) is shown in parenthesis. Static trafficability classes were: (1) Operations possible in any season, (2) Operations possible in summer, (3) operations possible in summer during dry season and (4) operations possible only during frost or thick layer of snow. | ||||
| Static trafficability class | Correct timing | Incorrect timing | ||
| Not damaged, % (n) | Damaged, % (n) | Not damaged, % (n) | Damaged, % (n) | |
| 1 | 94.2 (49) | 5.8 (3) | - | - |
| 2 | 100.0 (34) | 0.0 (0) | 94.7 (18) | 5.3 (1) |
| 3 | 67.7 (21) | 32.3 (10) | 87.1 (27) | 12.9 (4) |
| 4 | 38.5 (5) | 61.5 (8) | 78.8 (26) | 21.2 (7) |