Five different interplanting patterns of economic crops with young Chinese fir plantations and their effects on tree growth,
competition pattern of plants, accumulation of nutrient elements and soil fertility were detected. It was discovered that the
interplanting pattern of tung oil trees (Aleurites fordii) and Mesona chinensis with
young Chinese fir plantation was the best. In the first three years, the output value was increased by 4365.0 yuan per hm~2 in RMB annually, meanwhile the tree height and chest diameter of 8-year-old Chinese fir were 0.99 m and 0.83 cm longer, respectively. At the same time, the physical-chemical properties of the forestland soil were improved, meaning that the organic matters and total nitrogen in 0-20 cm soil layer were increased by 15.64% and 19.62%, respectively, and the weight per m~3 decreased by 11.97%, meanwhile the total porosity and non-capillary porosity were increased by 14.95% and 29. 68%, respectively. Also, there were similar favourable changes in the 20-40 cm soil layer and other indices. Based on the data above, it was concluded that, taking the perennial economic crops which could spread rapidly on the ground as the ground vegetation, and economic trees which could grow rapidly at early stages as the interplanting tree variety, an ideal interplanting pattern of young Chinese fir plantation could be formed.