In the northern region, Paulownia lankao grows fastest, and its height growth has obvious stages, which can be naturally grafted by strong long branches formed by adventitious buds or latent buds. After planting for 2 ~ 8 years, it naturally grows upward through grafting. In the whole growth process, it can be naturally grafted 3 ~ 4 times, and some can be naturally grafted 5 times. 1 the height growth of natural grafting is the largest, which can reach more than 3 meters, and then gradually decreases. The annual growth peak of DBH is 4 ~10 years. The peak of annual volume growth occurs in 7 ~ 14 years, and the time and value of this peak depend on soil conditions and tending management measures sooner or later.