PARENT SESSION
Oral Session #52: Plant Ecology: Light and Carbon Allocation.
Presiding: T. Day
Wednesday, August 7. 8:00 AM to 11:30 AM. Gila Meeting Room, TCC.

Morphological traits of tree seedlings predict variation in species performance consistent with landscape variation in northern lower Michigan.

Schreeg, Laura^*,1, Kobe, Richard¹, Walters, Michael¹, ¹ Michigan State University, East Lansing, MI

ABSTRACT- In northern lower Michigan, landscape-level variation in species composition is associated with glacial landform. To investigate the causes of this association, we conducted a reciprocal seedling transplant experiment with 5 species: sugar maple (SM), white ash (WA), red oak (RO), black cherry (BC) and black oak (BO). Seedlings were planted on three landforms: outwash, ice-contact and moraine, which represent an increasing continuum of soil nutrient and water availability. At higher light (14-26%), survival and RGR of SM and WA were higher on their native moraine than on outwash. In addition, SM and WA had significantly higher root mass ratios (RMR) and maximum rooting depths/ total mass on outwash versus moraine, demonstrating an increased investment in below-ground structure on the resource poor site. In contrast, the performance of BO did not respond to site and, morphology of BO did not vary significantly. When comparing ice-contact and moraine at lower light (3-10%), RGR and survival for SM, WA and BO were not different. For these species, RMR was greater on ice-contact than moraine, while SRA and SRL were lower. These results suggest that the plasticity of SM and WA allows some acclimation to poor environments, possibly enabling equal performance between the ice-contact and moraine, but not between the outwash and moraine. In contrast, BO is conservative in all cases, performing equally well across the gradient and showing few changes in morphology.

KEY WORDS: plant allocation, tree seedling, field experiment