Follow-up Report | Shiramaki Forestry and Biodiversity

Shikoku no Migishita Ki no Kaisha, in collaboration with Mitsui Consultants Co., Ltd. and the Japan Forest Technology Association, conducted a survey on the impact of Shiramaki forestry on the biodiversity of satoyama forests and presented the findings at the 137th meeting of the Japanese Forest Society.

(This initiative is a follow-up to the 'Research on Biodiversity Assessment of Satoyama Forests' announced in 2024.)

Shiramaki forestry is a traditional charcoal forest management practice inherited in the southern part of Tokushima Prefecture, where evergreen broad-leaved (lucidophyllous) trees are abundant.

Satoyama forests were once deeply connected to human life, providing firewood, charcoal, mushroom logs, fallen leaves, and edible wild plants. However, since the fuel revolution, the demand for firewood and charcoal has significantly decreased, leaving many satoyama forests unused. Abandoned satoyama forests are facing various issues, such as the increased diameter and aging of trees, simplification of forest structure, insufficient light on the forest floor, and the spread of Japanese oak wilt.

In this survey, we examined the forest structure, vegetation, insect fauna, soil, and light environment, targeting abandoned forests, recovering forests, and continuously managed forests.

What emerged from the survey is that the characteristic of Shiramaki forestry is not merely 'cutting the forest to brighten it.'

In Shiramaki forestry, we do not clear-cut the forest at once. Instead, we keep the tree height low while leaving certain trees and trunks; this 'selective cutting dwarf forest renewal' is a key characteristic of the practice.

Additionally, the fishbone-shaped hauling road network traditionally called 'Yari' or 'Sade,' and small-scale work roads applying this concept in a modern way, create fine forest edges within the forest. Combined with low tree heights, this may create an environment where light can easily reach the forest floor even when the canopy is closed.

In other words, it is considered that Shiramaki forestry creates a complex environment as a satoyama forest in the 'middle' rather than making light/canopy closure or disturbance/stability contradictory.

This complexity may lead to a forest environment that supports rich understory vegetation and ground beetles (Carabidae) that are vulnerable to disturbance.

Appropriately cutting, using, nurturing, and returning it to the forest.

We will continue to nurture and promote Shiramaki forestry not just as a technology of the past, but as practical wisdom for regenerating the satoyama of the future.

Presentation Title:
'Study on the Impact of Shiramaki Forestry on Biodiversity in Satoyama Forests'

Joint Presentation:
Mitsui Consultants Co., Ltd.
Japan Forest Technology Association
Shikoku no Migishita Ki no Kaisha