Long-term behaviour of timber constructions in torrent control

Research question / purpose
Timber is widely used for protection measures in torrent control. However, life span of woody constructions such as timber check dams is limited mainly due to fungal decay. In practice a controversial discussion has been going on if either Norway spruce (Picea abies) or silver fir (Abies alba) is more enduring and if bark removal increases resistance against fungal decay.
Description
This dataset contains monitoring information on a series of 15 timber check dams built in 1996 in Hergiswil, Switzerland. The constructions were alternatively realised with Norway spruce and silver fir, half of them each with remaining and removed bark, respectively. The data includes the identification of decayed zones with a simple practical approach (i.e. measurement of the penetration depth of a slotted screwdriver No. 3) from a total of 12 repeated surveys from 2001 to 2025.
The following information is contained (by column and column title):
• Identification of decayed zone (column title “Decay_Id”)
• Year of survey (column title “Year”)
• Identification of check dam (column title “Check dam”)
• Degree of decay (column title “Degree of decay”): 2 = reduced wood strength (penetration depth 2-10 mm); 3 = low wood strength (penetration depth - 10 mm)
• Sectors 1 to 7 of check dams (column title “Sector”)
• Element of check dam (column title “Element”): LH (longitudinal log, German: “Längsholz”), Z (transverse log, German: “Zange”), FH (infill log, German: “Füllholz”)
Plan of check dams and additional information on monitoring surveys: survey information (PDF)