| The growth model of tree height, ground diameter and new branches were analyzed with the Carya illinoensis grafting seedlings (species: Pawnee) in the second year of afforestation in Shihe District and Luoshan County of Henan Province as the research object, which using quadratic curves, growth curves, S-shaped curves, cubic equation curves, exponential equations, power function curves, and Logistic equations to fit the relationship between growth and growth times. The results showed that the tree height and ground diameter were best fitted by the cubic equation curve and the determination， coefficients of these two method reach 0.991 and 0.996 respectively; New branches was the best fitted by quadratic curves, with a determination coefficient of 0.996. The survey found that the annual growth time of this species in southern Henan can reach 220 d or more. With Fisher classification method, the tree height and new branches growth period of thin shell pecans can be divided into germination period, first growth peak period, second growth peak period, and later growth period, but the peak spots are different; The ground diameter can be divided into four stages: germination, early growth, rapid growth, and late growth. The ground diameter rapid growth period is longer at about 105 d. |
