Using photogrammetry to assess rutting caused by a forwarder—A comparison of different tires and bogie tracks

• Super wide base tires (940 mm) minimize rutting of forwarders.
• 940 mm tires are an alternative to bogie tracks.
• Photogrammetry is a time efficient instrument for DEM acquisition of skid trails.
• Photogrammetry derived DEMs have a high accuracy.

Rutting caused by heavy machinery during logging operations can lead to loss of trafficability which is a considerable problem in designated skid trail systems. Wide base tires and bogie tracks are common accepted technical options to minimize rut formation. In this work the suitability of 940 mm super wide base tires on trafficability preservation was tested in comparison to 710 mm wide base tires and common used ECO-TRACK™ bogie tracks. An experiment with repeated passes by a heavy forest machine (forwarder) was conducted. Digital elevation models (DEM) of the ruts were created using photogrammetry to assess rut morphology parameters: rut depth, material displacement and erosion relevant depression storage capacity. Photogrammetry was discovered to be a time and cost efficient method to provide highly resolved 3D-data with high precision. Super wide base tires distinctly reduced rut formation compared to 710 mm tires and bogie tracks by more than 50% and 40%, respectively. Displacement of soil material led to the formation of prominent bulges that can be prone to erosion. 710 mm tires and bogie tracks caused the most voluminous bulges due to their strong rut formation. The investigated tire equipment differently affected the surface depression storage of water in the skid trails due to their different lug morphology. Ruts of bogie tracks could retain significantly more surface water than ruts produced by tires. Nonetheless, the absolute depression storage in all cases is rather low, implying that erosion would occur in case of heavy precipitation.