Effects of Wildfire and the Presence of the Invasive Paulownia tomentosa on the Regeneration of Native Tree Species in North-Central Appalachia

Roger Williams,Haibin Wang

doi:10.3390/fire4030060

Abstract

A wildfire occurred in Shawnee State Forest located in southern Ohio that consumed 1215 hectares. Based on earlier forest inventories it was known that paulownia (Paulownia tomentosa), a non-native invasive tree species, occurred in the forest. The objective of this study was to determine if paulownia heavily colonized areas two years after the fire where the burn occurred, and if its presence had a negative impact on the regeneration (<137 cm height) of native species—red and white oaks (Quercus sp.), red maple (Acer rubrum), and yellow-poplar (Liriodendron tulipifera). Two years after the fire, paulownia had invaded the burned areas but not at significantly higher densities than occurred in the unburned areas. Fire significantly reduced the number of regenerating stems of white oak and red maple two years after the fire, whereas the number of regenerating stems of red oak increased slightly and that of yellow-poplar increased significantly. In areas where paulownia occurred that experienced wildfire, all species studied displayed a reduction in the number of regenerating stems compared to paulownia’s absence in the burn areas. Where paulownia occurred in areas not affected by the wildfire, all the native species studied displayed a reduction in the number of regenerating stems. The average heights of red oak, white oak, and red maple were significantly taller when growing in areas affected by the wildfire due to a more open canopy. However, there was no significant change in the average heights of yellow-poplar. The presence of paulownia in both the burned and unburned areas reduced the number of regenerating stems of the native species studied.

Highlights

In the field of invasion ecology, invasive plants are the most numerous and important species in terms of their negative impact on native species, and thereby pose the greatest concerns [1]
The burned areas displayed a slightly higher and non-significant number of paulownia stems compared to the unburned areas (Table 1)
The average height of paulownia stems was significantly lower in the burned areas compared to the unburned areas

Summary

Introduction

In the field of invasion ecology, invasive plants are the most numerous and important species in terms of their negative impact on native species, and thereby pose the greatest concerns [1]. Few invasive plant species may have a negative impact within their introduced ecosystems [8], those that do have the potential to cause considerable damage to the agriculture and forestry sectors [9]. The establishment of invasive species in forests is strongly promoted by disturbances that create openings in forests [10]. One such invasive species that takes advantages of these disturbances is paulownia (Paulownia tomentosa (Thunb.) Steud.), a deciduous tree native to Eastern Asia, which was introduced initially to the eastern United States in the

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