Study on Growth Rule of Cunninghamia lanceolata in Mixed Plantation of C. lanceolata with C. konishii

The growth rule of 24yearold Cunninghamia lanceolata plantation on Laizhou National Forestry Experimental Farm was studied with stem analysis and relevant data collected from the sample plots of C. lanceolata mixed with C. konishii. The results indicated that the largest current annual height growth rate of C. Lanceolata occurred in the 8th year, which was 1.00m/a. The mean annual height growth rate on the 2nd year and 4th year was 1.75 m and 1.20 m individually, and this index dropped steadily after the 4th year. The current annual DBH growth rate of C. Lanceolata fluctuated along the time, and there were 3 peaks as 074 cm/a, 1.27 cm/a and 070 cm/a taking place respectively in the 4th, 16th and 22nd year. The mean annual DBH growth rate changed less, there were 2 peaks with the same value as 061 cm/a individually in the 18th year and 22nd year. The largest current and mean annual volume growth rate happened separately in the 20th and 22nd year as 0003 16 m3/a and 0001 03 m3/a. The current and mean annual volume growth rate intersected in the 24th year which indicated that C. lanceolata reached quantitative mature age by this time. The Richards growth equations with high precision were developed for the tree height, DBH and individual tree volume of C. Lanceolata plantation by using Mat Lab software. These equations might provide the scientific tending and management of C. Lanceolata plantations with theoretical foundation.