Effect of high-intensity directed fire in different seasons on survival and sprouting of three invasive species: Lonicera spp. (bush honeysuckle), Paulownia tomentosa (Royal paulownia), and ligustrum sinense (Chinese privet)

Background/Question/Methods

Invasive plant species are widely recognized as a serious problem. The introduction of non-indigenous species to new habitats has been primarily through human influence. Non-indigenous species can cause local extinction or a vast decline in some native species populations by increasing competition, as well as reducing biodiversity through modifications of their habitat. The control measures currently used to manage invasive species commonly involve herbicides that can be toxic to other plants, people, and wildlife, such as reduction of nutrients to non-target species, mortality in tadpoles, deformation of fish, and reduced fertility and sexual development in frogs. There is a need for new methods for ecological restoration through the removal of invasive species that do not use herbicides but are similarly efficient to herbicide-based methods. In this study royal paulownia and Chinese privet were divided into two diameter size classes that were burned for two different lengths of time using a propane-powered torch. Honeysuckle was burned for the same length of time and all species were burned during three seasons.

Results/Conclusions

Greatest mortality occurred for paulownia when treatments were applied in summer and when burned for 30 s in diameter size class 3.8 cm to 20.1 cm and when burned for 60 s in diameter size class 20.2 cm to 68.6 cm. The greatest mortality for Chinese privet and honeysuckle occurred in spring and summer. No differences occurred in mortality for Chinese privet stems burned for the various lengths of time in either diameter size class.