A comparative study between Bräcke B-290 & B-390 line mounders

Abstract

In the attempt to produce larger, healthier trees at a younger age, Bracke Scarification has developed machines for site preparation called line mounders. The line mounders produce an inverted humus mound on which coniferous seedlings are planted. Two different line mounding machines were compared based on the quality of the mounds that they produced. These two line mounding machines were also compared to an excavator with a mounding head attachment. The excavator was used as a control setting because of its optimal results in quality of the mounds it produced. The quality of the mounds is dependent on site location including soil types and terrain conditions as well as the machine itself. This study was conducted in two different locations in the Grande Prairie, Alberta area. The Saddle Hills location contained soils of clay to loamy clay with gentle slopes of no more than 15%. The Rat Creek area was located south of Grande Prairie in the foothills of Willmore Wilderness Park. This location had similar soil types to the Saddle Hills and slopes up to 40%. The steeper slopes resulted in a harvest with very high stumps producing a roughness coefficient of a higher degree than that of the Saddle Hills. The two line mounders used in the comparison were a Bracke B-290 2-row Line Mounder and a Bracke B-390 3-row Line Mounder. The mattock units were of the same size on both machines with the only physical difference being the arrangement of the mattock units behind the prime mover. From this study, the Bracke B-290 2-row Line Mounder produced similar results having 92% of the mounds acceptable in both locations. The Bracke B-390 3-row Line Mounder was found to produce mounds of relatively similar quality in the Saddle Hills having 91% of the mounds useable. In the Rat Creek area the Bracke B-390 3-row Line Mounder only produced 84% useable mounds. Key Words: excavator, line mounders, mattock units, mounds, Rat Creek, Saddle Hills