In 1987, Bracke Forecare presented the results of a trial begun twelve years previously by the company SCA Skog AB. The trial, located in an area of poor soil, highlighted the differences between planting in mineral soil patches and inverted humus mounds. While the percentage of plants that survived did not differ between the two, there was a difference in that all plants in the inverted humus were standing upright. About a third of the plants in the mineral patches were leaning or prone. After twelve growing seasons, the plants in the inverted humus had rootage about 35 times that of the plants in the soil patches, and trunk volumes of about five times the size.
Mattson & Bergsten (2003) showed that scarification in areas of low quality soil increased the growth in volume of 18-year-old Lodgepole pines by 200-500 percent compared to planting without scarification. Disc trenching increased growth by 150 percent. In average quality soil, growth increased by 100 percent on mounded and trenched sites compared to unprepared sites.