| As a famous dry fruit and woody oil tree species, hickory(Carya cathayensis)is distributing in our country with high economic value. Because of management intensively and site environment, eco-environment stress of the production and management in hickory trees is not a reasonable planting density and management plan. Height, crown and diameter growth model and input-output changes of different ages of hickory are established and studied under sample surveys, data collect and analysis mathematical model. It provides a scientific basis for planting density and management plan. Main results as follows:1 Height and crown are fit for the logistic model and diameter is fit for the gompertz model in the development of hickory. The growth equations are (?) (?)the correlation coefficient R are 0.997,0.990,0.998 and the inflection points are respectively (17,6.6), (18,6.8), (29,18.5).2 Growth and management of hickory is divided three phases which bases logistic model. The rapid growth which is the first period of from 5 years to 16 years should be mainly nitrogen fertilizer, operated the shape of seedling. Between 17 and 18 years are the second phases of the turning point, the nitrogen fertilizer is reduced and phosphorus and potassium fertilizer are increased. After 18 years is the third stages of the slowly growth, it propound the rational fertilization and against intensity of management.3 In the total input-output value of a hickory tree, there is no output from the age of 3 years to llyears, less than zero of net present value between the ages of 11 years to 17 years and more than zero after 17years. The input is creasing with the growth and development of hickory, the input appears in the age of 11 years and is more than output after 17 years.4 A rational crop density is 15 plants/mu which is inferred by logistic model and total input-input value of a hickory tree. The equation of (?)could solve different densities of natural pruning areas with different age. |
PDF Full Text Request