Dr. Barbara Hawkins

I am fascinated by how trees withstand environmental stress over centuries, or even millennia. In Canada’s forests, the stresses of low nutrient availability and winter cold are common, yet trees survive and thrive across much of our landscape. I study how trees take up and allocate nutrients, particularly nitrogen, often with the help of mycorrhizal partners; and how they alter their physiology to tolerate freezing temperatures. I am particularly interested in co-adaptation of conifers and their mycorrhizal partners, and in variation among tree populations in stress tolerance.

My work ranges from lab experiments using ion-selective microelectrodes to measure net flux of nutrient ions in mycorrhizal roots, to field work assessing nutrient stoichiometry of foliage, fungi and soil.

• BIOL 248 - Topics in Organismal Biology
• BIOL 324 - Biology of Land Plants
• BIOL 325 - Tree Biology
• BIOL 366 - Plant Physiology

Kranabetter, Marty, J., McKeown, K., Hawkins, B.J., 2020. Post-disturbance conifer tree-ring delta N-15 reflects openness of the nitrogen cycle across temperate coastal rainforests. Journal of Ecology 109-1: 342-353

Lerstrup-Pedersen, E., Pedersen, O., De Luca, S., Hawkins, B.J. 2019. Implications of an exceptional autumn bud flush on subsequent cold tolerance of Garry oak (Quercus garryana Douglas ex Hook). Can. J. For. Res. 49:942-948

Hawkins, B.J. 2018. A Tribute: Robert John van den Driessche, Tree Physiologist, 1933-2018. Can. J. For. Res. 48:v -vii. doi: 10.1139/cjfr-2018-0351

Kranabetter, JM, Harman-Denhoed, R and Hawkins, BJ. (2018) Saprotrophic and ectomycorrhizal fungal sporocarp stoichiometry (C:N:P) across temperate rainforests as evidence of shared nutrient constraints among symbionts. New Phytologist. dos: 10.1111/nph.15380. 11 p

Hawkins BJ, May E, Robbins S (2018) Nitrate and ammonium uptake in twenty-one common moss species from Vancouver Island, British Columbia. Botany doi: 10.1139/cjb-2017-0154

Hawkins BJ, Kranabetter M (2017) Quantifying inorganic nitrogen uptake capacity among ectomycorrhizal fungal species using MIFE microelectrode ion flux measurements: theory and applications. Botany 95(10): 963-969

Kranabetter J, Hawkins BJ, Jones M, Robbins S, Dyer T, Li T. (2015) Species turnover (β diversity) in ectomycorrhizal fungi linked to NH4+ uptake capacity. Molec. Ecol. doi: 10.1111/mec.13435

Hawkins BJ, Jones MD, Kranabetter JM. (2015)  Ectomycorrhizae and tree seedling nitrogen nutrition in forest restoration. New Forests DOI 10.1007/s11056-015-9488-2

Boczulak S, Roy R, Maynard D, Hawkins BJ. (2015).  Long- and short-term temperature differences affect organic and inorganic nitrogen availability in forest soils.Can. J. Soil Sci. 95: 77-86.

von Wittgenstein NJJB, Cuong HL, Hawkins BJ, Ehlting J. (2014) Evolutionary classification of ammonium, nitrate and peptide transporters in land plants. BMC Evol. Biol. 14: 11. doi:10.1186/1471-2148-14-11