Effects of Stumping in Different Seasons on Germination Ability of Pinus yunnanensis

The net number of sprout, cumulative number of sprout, and length of sprouts of Pinus yunnanensis seedlings were measured and analyzed in spring, summer, and autumn after stumping using annual P. yunnanensis seedlings as materials in a randomized group design. The effects of different stumping seasons on the growth of P. yunnanensis seedlings were used to screen out the reasonable stumping seasons that could improve the sprouting ability of P. yunnanensis seedlings and to explore the response pattern of sprouting ability of P. yunnanensis seedlings to the stumping seasons. The findings indicated that the net number of sprout in P. yunnanensis seedlings showed a trend of increasing and then decreasing with the growth time of the seedlings after stumping in different seasons. The cumulative number of sprout were different significantly among different stumping seasons, with stumping in the spring was significantly higher than stumping in the summer. Stumping in the spring and summer were significantly lower than stumping in the autumn. The cumulative number of sprout at 90 d after stumping was 11.6, 11.4 and 13.6. The ratio of different sprout length grades had different changes. From the point of view of the sprout grade ratio, the length of sprouts differed significantly among seasons, with stumping in the spring was significantly higher than stumping in the summer and autumn. Based on the above results, the sprouting ability of P. yunnanensis had different responses to the stumping seasons. The stumping of P. yunnanensis in spring can promote the birth of sprout and the growth of sprout, and at the same time improve the quality of sprout.