Effect Of Grafting And Fertilizing On The Growth Of Paulownia Trees From Different Height Seedlings

Paulownia is an important fast-growing tree species,which is widely distributed and favored by people. The important ecological,economic and social signification of developing Paulownia greatly can alleviate timber shortage,improve farmland ecological environment,increase agricultural output and the income of peasantry to plant these trees in large areas. However,Because of its pseudo dibranch biological characteristic,main trunk height mostly is decided by the height of seedling on the natural conditions,which had greatly affected on Paulownia timber productivity. One of major subject is to cultivate high trunk and superior timber (main trunk height over 6.0m). At present,most people had realized that grafting and fertilizing are major measures to increase the height of main trunk at the same conditions. This paper dealt with the effect of grafting and fertilizing on five-year-old paulownia trees growth on different height seedlings. The results showed that one time grafting could promote main trunk growth with 4.0m and 4.5m height seedlings,the same as the diameter breast-high with 3.0m height seedlings. Both two times grafting and fertilizing can promote main trunk growth with 4.0m and 4.5m prominently,But hardly affect the growth of diameter breast-high. Compared to the CK,grafting (included one time grafting and two times grafting) can decrease the tree crown and diameter breast-high and increasethe crown length and the tree height on five-year-old paulownia with different height seedlings. In different height seedlings,4.0m and 4.5m are sensitive to the grafting,especially to the tree from 4.0m seedling in height,of which main trunk and diameter breast-high might be largest after two times grafting,which can decrease the cost of plantation establishment and increase the economic performance. Compared to the CK,Leaf area index of five-year-old paulownia is increased but transmission coefficient for defuse and radiation penetration are on the contrary as height of seedlings from which those trees growth (exception of the 5.0m height seedling) after grafting. The effect of fertilizing on the changes of intensity of illumination and valid light emission is the same as that of grafting (exception of 4.5m height seedling). Finally,after studying the relationship between the main trunk and tree crown on ten-year-old Paulownia,the results indicated that the appropriate ratio to main trunk and tree crown is 0.79 to cultivate high trunk and superior timber.