Deforestation-Induced Soil Erosion and Environmental Conservation - From 1996 to the 2020s

Deforestation-Induced Soil Erosion and Environmental Conservation - From 1996 to the 2020s

**1990s: Problem Identification**
In the 1990s, soil erosion caused by deforestation emerged as a severe environmental issue in Japan's mountainous regions. Illegal and excessive logging, especially in areas like Kyushu and the Central Japanese Alps, led to soil erosion. Large amounts of sediment flowed into rivers, causing water quality deterioration and sedimentation. The contamination of agricultural water and adverse effects on fisheries became apparent, while the risk of landslides on slopes increased significantly.

**2000s: Transition to Sustainable Management**
Entering the 2000s, the necessity of sustainable forest management became evident. The Forestry Act was amended in 2004 to enforce stricter penalties against illegal logging. Additionally, the 2007 "Global Warming Countermeasures Promotion Law" emphasized increasing forest absorption capacity, aiming to sequester 100 million tons of carbon dioxide annually. During this period, afforestation efforts intensified, with approximately 5 million saplings planted in Gifu Prefecture between 2005 and 2010. Japan's forest management practices gained international attention, and awareness campaigns were launched in 2008 to mark the International Year of Forests.

**2010s: Climate Change and Increasing Rainfall Disasters**
In the 2010s, the increased frequency of heavy rainfall due to climate change severely impacted deforested areas. Following the 2011 Great East Japan Earthquake, soil erosion in deforested disaster-affected areas, particularly in Iwate and Miyagi Prefectures, became a significant issue. The 2018 Western Japan Floods caused approximately 5 million cubic meters of sediment to flow in Hiroshima Prefecture, with sediment removal costs amounting to 4 billion yen annually. In 2015, the adoption of the Sustainable Development Goals (SDGs) highlighted forest conservation as a key objective, driving research into sustainable logging techniques and soil protection measures.

**2020s: Technological Innovation and Community-Driven Initiatives**
In the 2020s, soil erosion due to deforestation remains a persistent challenge. In the Aso region of Kumamoto Prefecture, approximately 2.5 million cubic meters of sediment flowed during the 2020 heavy rainfall disaster. Locally, the "Green Disaster Prevention Project" has planted over 120,000 trees in the past five years. Meanwhile, corporate initiatives have also evolved. Oji Paper has implemented sustainable forest management with 2,000 hectares of afforestation annually, and Sumitomo Forestry has introduced new vegetation materials incorporating water-retentive substances, reducing soil erosion by 30%.

**Conclusion**
From 1996 to the 2020s, Japan's deforestation issues have evolved through numerous challenges and solutions. Advances in technology, policy support, and cooperation between communities and businesses have driven efforts toward balancing environmental conservation and economic development. These endeavors are expected to serve as a solution to global environmental problems.