Improvements in timber production of Chinese fir (Cunninghamia lanceolata) per unit forest area in China via tree breeding Status and challenges

Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] is a fast-growing tree species that is widely planted for timber production in southern China. Many high-quality breeding systems for Chinese fir have been developed using genetic methods. Here, we systematically review progress in increasing Chinese fir timber volumes per unit forest area in China, using genetic methods. We comprehensively assess the objectives, strategies, and primary accomplishments of the first to fourth generations of a Chinese fir breeding program. Furthermore, we propose a genetic improvement program and protocol for Chinese fir, and outline several recommendations with respect to the main challenges associated with using genetic methods to increase timber yields. Finally, we present a series of proposals to increase Chinese fir timber production in China. This review offers insight into genetic improvements that have increased timber volumes of Chinese fir over four generations of breeding, and provides direction for future genetic improvements to wood properties.