Plant Physiological Ecology
Ongoing research in our lab is researching various aspects of physiological responses of plants to warming, drought, and fire. We are examining the causes of tree dieback and mortality of temperate deciduous trees under natural and experimental drought. In collaboration with Rob Dunn, we are examining the direct and indirect effects of warming on carbon and water balance of deciduous trees. In a new effort we will examine the physiological mechanisms of plant response to fire to better predict vegetation responses to changing fire regimes. Publications: Hoffmann, W.A., Marchin, R.M., Abit, P.P., & Lau, O.L. (2011) Hydraulic failure and tree dieback are associated with high wood density in a temperate forest under extreme drought. Global Change Biology, in press. Marchin, R.M., Zeng, H., & Hoffmann, W.A. (2010) Drought-deciduous behavior reduces nutrient losses from temperate deciduous trees under severe drought. Oecologia, 163, 845-854. Gotsch, S.G., Geiger, E.L., Franco, A.C., Goldstein, G., Meinzer, F.C., & Hoffmann, W.A. (2010) Allocation to leaf area and sapwood area affects water relations of co-occurring savanna and forest trees. Oecologia, 163, 291–301. Scholz, F.G., Bucci, S.J., Hoffmann, W.A., Meinzer, F.C., & Goldstein, G. (2010) Hydraulic lift in a Neotropical savanna: Experimental manipulation and model simulations. Agricultural and Forest Meteorology, 150, 629-639. Zhang, Y.-J., Meinzer, F.C., Hao, G.-Y., Scholz, F.G., Bucci, S.J., Takahashi, F.S.C., Villalobos-Vega, R., Giraldo, J.P., Cao, K.-F., Hoffmann, W.A., Franco, A.C., & Goldstein, G. (2009) Size-dependent mortality in a Neotropical savanna tree: the role of height-related adjustments in hydraulic architecture and carbon allocation. Plant Cell and Environment, 32, 1456-1466. Marchin, R.M., Bhandari, R.K., Wall, W.A., Hohmann, M.G., Gray, J.B., & Hoffmann, W.A. (2009) Are rare species less shade tolerant than common species in fire-prone environments? A test with seven Amorpha (Fabaceae) species. Plant Ecology, 205, 249-260. Hao, G.-Y., Hoffmann, W.A., Scholz, F.G., Bucci, S.J., Meinzer, F.C., Franco, A.C., Cao, K.-F., & Goldstein, G. (2008) Stem and leaf hydraulics of congeneric tree species from adjacent tropical savanna and forest ecosystems. Oecologia, 155, 405-415. Hoffmann, W.A., Orthen, B., & Franco, A.C. (2004) Constraints to seedling success of savanna and forest trees across the savanna-forest boundary. Oecologia, 140, 252-260.
	Response of temperate forest trees to extreme drought. In 2007, North Carolina was afflicted by a record drought, offering a glimpse of what may be a more common event by the end of this century.