ComPArison of Seedling Phenology and Growth Rhythm of Different Strains of Chinese Fir

In order to comPAre the phenology and growth rhythm of different Chinese fir strains, Yang 020 Chinese fir clones and Yang 061 Chinese fir clones from the State-owned Forest Farm in Yangkou, Fujian Province and Cunninghamia lanceolata‘Luotian’ from Hubei Province were studied.From February 2021 to February 2022,the phenology, seedling height, ground diameter, lateral branch number, lateral branch length, lateral branch base diameter and lateral branch angle of different strains of Chinese fir were measured regularly, and the differences in seedling phenology and growth rhythm of different strains of Chinese fir were comPAred.The results showed that the seedling phenology of different strains of Chinese fir was different.The bud activity of Yang 020 and Yang 061 was earlier than that of C.lanceolata‘Luotian’,and the shoot growth period was longer.The growth of lateral branches showed more obvious difference in phenological rhythm.The formation and growth time of lateral branches of C.lanceolata‘Luotian’ was earlier, while that of Yang 061 was the latest.But the difference of growth rhythm between different strains of Chinese fir was not obvious.The annual growth of seedling height, ground diameter and lateral branch length of different strains of Chinese fir showed an obvious "slow-fast-slow" rhythm.The growth process of Chinese fir seedling can be divided into slow growth period, fast growth period and growth stagnation period.