Abstract:

A sampling plot investigation was conducted on the Quercus wutaishanica forests under close-to-natural plantation thinning 13.4% (light thinning) and 30.0% (heavy thinning) in Huanglong Mountain on the Loess Plateau, China. Regeneration and development of stump sprout of Q. wutaishanica during 6 years after thinning were studied. The study showed that: 1) Sprouting success, number of sprouts per stump, and sprout height differed little from light and heavy thinning after thinning 1 year. 2) Stump height and diameter had influence on the number of stump sprouts. The sprout number increased with the height of stumps,it would decrease when the height was over 20 cm,and it followed a thrice parabola. The number of stump sprouts increased as the increase of stump diameter, and then it decreased as the stump diameter increased too large. Stumps of diameter 30~50 cm had the stronger sprouting ability than of other diameter. 3) Negative relationship was found between height and number of stems, meaning that there was trade—off between sprouting and height growth.4) For 6 years after thinning, the survival of stump sprouting was 97.01%. Thinning intensity had influence on sprout development. 5) During the observation period, the height of leading sprout decreased as the increase of thinning age. The number of dead sprout increased as the sprout number increasing of each stump, indicated that stump sprouts of Q. wutaishanica could develop into big tree instead of the cut and fallen trunk. Therefore, height of stump should low below 20 cm. Thinning stump of diameter 30~50 cm was more suitable to an asexual regeneration. The measures of bud pruning and thinning sprouts after logging can accelerate the retain sprout growth. The thinning 30.0% (heavy thinning) was more advantageous to regeneration and development of stump sprouts.

Key words: Quercus wutaishanica, stump sprouts, sprouting ability, thinning intensity, height growth