2016 Volume 33 Issue 2 Pages 81-87
Ailanthus altissima is an invasive and threatening tree worldwide. However, it is not considered as pernicious as Robinia pseudoacacia in Japan. In the field investigations of A. altissima shoot reproduction, cutting and burning increased the shoot density from 0.27 to 2.79 shoots/m2. Moreover, numbers of asexual reproduction from roots and stumps were abundant in the sites of high initial stump density, whereas numbers of seedlings were small in stump-dense sites. The size of seedlings was also smaller than that of sprouts and suckers. Under conditions of a high initial shoot density, A. altissima produced an abundance of shoots from stumps and roots. Although sexual reproduction was disadvantageous for growth and competition, A. altissima germinated from seeds and expanded its distribution where initial stumps and roots were unavailable. These observations indicate that winter cutting and burning should be avoided to prevent the proliferation of A. altissima because cutting stimulates asexual reproduction, and burning facilitates the growth of seedlings and expansion of the population through the suppression of competitors.
