Survival and development of Liaodong oak stump sprouts in the Huanglong Mountains of China six years after three partial harvests

The survival and development of Liaodong oak (Quercus liaotungensis Koidz) stump sprouts were studied for 6 years under leave-tree, as well as 60 and 75% crown closure uniform shelterwood in the Huanglong Mountains of China. Stump sprout survival rate, number of sprouts, and sprout height under the three partial harvests during the first year post-harvest did not differ. Six years post-harvest, 78.32% of the stumps had living sprouts. No variation in sprout survival was found among the treatments throughout the study period. The number of living sprouts per stump was 13.77 +/- A 0.50 in the first growing season after harvest, and dropped to 6.49 +/- A 0.22 after 6 years. This result indicated the occurrence of self-thinning within the sprout clumps. Moreover, the height of dominant sprout increased from 52.88 +/- A 1.62 cm (in the first year) to 132.82 +/- A 2.35 cm (in the sixth year) post-harvest. Sprout height in the leave-tree harvest type was higher than those in the two shelterwoods in the fifth and sixth years after logging. Annual height growth was approximately 8-96 cm during the first growing season, and then decreased at a rate of 1-44 cm per year in the following years. A negative relationship was found between sprout height and the number of sprouts per stump. This result indicated a trade-off between the number of sprouts and height growth. The number of sprouts per stump decreased by about 0.2 stem for each 1 m(2)/ha increased in residual basal area. Therefore, sprouting may play an important role in the restoration of the secondary forest after harvesting.