Document: CHR-3-69-5

Resource allocation and survival of Paulownia tomentosa seedlings in a managed forest landscape.

WILLIAMS, A.C.* and B.C.MCCARTHY

Ohio University, Athens, OH 45701, USA. ¹

Abstract:
Paulownia tomentosa is a tree native to China that was introduced into the US in the 1840's. Disturbance has been hypothesized to allow P. tomentosa to become established in natural habitats. In this experiment, a range of habitats which vary in light availability were used to understand the importance of this resource for the species and to assess the susceptibility of a range of managed habitats to invasion by P. tomentosa. Seedlings were planted into five replicates of three habitats: 6-yr-old clear cuts, forest edge, and intact forest. Plants were planted inside and outside of cages which prevented small mammal herbivory. Plants were harvested after one, two and three seasons of growth. Plants growing in clear cut areas, with the greatest amount of sunlight, were largest. Forest plants were an order of magnitude smaller, although some plants survived in each treatment. Plants allocated relatively more to below-ground biomass as they grew older. Plants in the forest sites had significantly greater specific leaf areas than those in clear cut locations. Mortality outside of cages was 70% in the first year, and near 100% in the following years. Although allocation to roots in the lower light treatments is contrary to resource allocation theory, this is due to the observation the plant's above-ground biomass often dies back over the winter months, especially when very young. So, survivors had to invest in below-ground biomass probably at the expense of above-ground biomass. Paulownia tomentosa seems to be able to establish only in areas where the canopy has been totally removed. Surprisingly, the forest edge was not conducive to growth. These data suggest that forest management techniques involving the complete removal of the overstory run the risk of encouraging invasion and establishment of Paulownia tomentosa.

Keywords: non-native species, resource allocation, disturbance, Paulownia tomentosa, princess tree, empress tree, woody seedlings

This abstract is being presented at: 3:45 PM in session:
Oral Session #10: Light Relations in Plants.