# Research Trends and Future Direction for Utilization of Woody Biomass in Japan
## 1 Introduction  
Since the signing of the Paris Agreement, over 100 countries have pledged to achieve carbon neutrality by 2050 and are making concerted efforts to reduce reliance on fossil fuels to limit the global average temperature increase to 1.5 \({}^{\circ}\)C [1]. Woody biomass is a renewable energy source that is widely used in various fields, such as power generation and heating, and its importance is increasing daily [2]. Most European Union (EU) countries place growing emphasis on the use of woody biomass to meet their 2030 renewable energy targets [3; 4]. In 2017, woody biomass accounted for approximately 40% of the EU's renewable energy share [5], and it is already the most significant renewable energy source in some EU countries with rich forest resources [6]. Despite the controversial effects of woody biomass on climate change mitigation, the EU still considers woody biomass an important component for achieving its renewable energy targets [7]. Several studies have predicted the gradual expansion of woody biomass utilization in Europe [8; 9; 10].  
In contrast, the utilization of woody biomass in Japan is developing rapidly, although not on a large scale. Since the introduction of a Feed-in Tariff (FIT) for renewable energy in 2012, woody biomass power plants have been constructed throughout Japan, reaching approximately 130 by 2019, covering nearly the entire country [11]. However, in the Japanese power supply structure in 2019, biomass accounted for only approximately 2.6% of total power generation and 14% of renewable energy power generation. To address climate change issues, the Japanese government announced in 2020 its goal of achieving carbon neutrality by 2050. The share of biomass power generation is expected to increase from 2.6% in 2019 to 5% by 2030; however, the scale is not as extensive as that in countries with advanced woody biomass utilization, such as Finland [12].  
In the Fifth Basic Energy Plan published in 2018, the Japanese government set a target to increase the share of biomass power generation to 3.7-4.6% by 2030 [13]. However, inthe Sixth Basic Energy Plan released after the government announced its goal of achieving carbon neutrality, the share of biomass power generation increased only by 0.4%, whereas the share of other mainstream renewable energy sources, such as wind and solar power, roughly doubled [12]. Additionally, Japan's current domestic production of woody biomass is insufficient to meet demands, leading to a heavy reliance on imports. According to statistics from the Japan Forestry Agency, the import ratio of fuelwood reached 36.6% in 2021 and has been increasing in the past few years [14]. The use of large amounts of imported fuelwood undermines the original advantages of woody biomass utilization, such as regional revitalization and energy independence, and contradicts the Japanese government's aspiration to promote the use of woody biomass for energy [15]. Therefore, to clarify the current status of woody biomass utilization in Japan, this paper summarizes the research trends in Japan on woody biomass utilization using various regions of Japan in terms of both resource supply and case study and analyzes factors hindering the development of woody biomass utilization. It also discusses how Japan can optimize the utilization of woody biomass based on the experiences of countries with advanced woody biomass utilization.