2018 Volume 60 Issue 2 Pages 71-82
Soil scarification is a natural regeneration practice in which both understory dwarf bamboo and surface soil are removed using civil engineering machinery. We provide a historical review of soil scarification practices in Hokkaido, the northernmost island of Japan. Soil scarification has been conducted widely in Hokkaido since the 1960s. It has been shown to be efficient for natural regeneration where Betula spp. are dominant. As a low-cost reforestation technique, soil scarification has recently received renewed attention regarding a large area of Abies sachalinensis plantation facing a final cutting period in Hokkaido. On the basis of past findings focusing on soil disturbance, scarification practices should strike a balance between maintaining soil physicochemical quality and entirely removing dwarf bamboo, Betula trees show better growth in scarified stands than in stands regenerated without scarification, and soil scarification may significantly reduce nutrient status. Previous reports on scarification-regenerated birch forests were derived mainly from young stands (<20 years old). Thus, it remains unclear how much timber of specific volume and size can eventually be harvested from scarification-regenerated birch forest. To achieve well-executed birch forest management, current scarification practices need to be improved depending on local conditions. Some issues still need to be addressed, for example, a countermeasure to tall forbs of concern in low-altitude areas and investigation of the causes of previously failed scarification practices.