HR: 0800h
AN: B51A-0059    [Abstracts]
TI: Effect of Ecosystem Warming on Boreal Black Spruce Bud Burst and Shoot Growth
AU: * Bronson, D R
EM: drbronson@wisc.edu
AF: University of Wisconsin-Madison, Department of Forest Ecology and Management 1630 Linden Dr, Madison, WI 53706, United States
AU: Gower, S T
EM: stgower@wisc.edu
AF: University of Wisconsin-Madison, Department of Forest Ecology and Management 1630 Linden Dr, Madison, WI 53706, United States
AU: Tanner, M
EM: myront@mstinc.com
AF: Measurement Systems Technology, 79 Sam Road, Lodi, WI 53555, United States
AU: Van Herk, I
EM: ivanherk@wisc.edu
AF: University of Wisconsin-Madison, Department of Forest Ecology and Management 1630 Linden Dr, Madison, WI 53706, United States
AB: The boreal forest is predicted to experience the greatest warming of any forest biome during the next 50-100 years, but the effects of warming on vegetation phenology are not well known. The objectives of this study were to (1) examine the effects of whole ecosystem warming on bud burst and annual shoot growth of black spruce trees in northern Manitoba, Canada and (2) correlate cumulative degree-days to the occurrence of bud burst. The experimental design was a complete randomized block design that consisted of four replicated blocks. Each replicate block was comprised of four treatments: soil warming only or heated outside (HO), soil and air warming or heated inside (HI), control outside (CO), and no soil or air warming inside the chamber, control inside (CI). On average shoot bud burst occurred seven days earlier in the HI than HO, CO, and CI treatments. Shoots required 71 more cumulative degree days (CDD₀) to achieve bud bust in the HI than CO. In year one of the treatments, HI shoots burst before other treatments (HO, CO, CI), but annual shoot growth was less than CO. However in the second and third year of warming annual shoot growth was significantly greater for both HI (p = 0.001) and HO (p = 0.008) than CO and CI. Empirical results from this study suggest that climate warming may cause a possible shift in carbon allocation for boreal black spruce forests.
DE: 0428 Carbon cycling (4806)
DE: 0429 Climate dynamics (1620)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0476 Plant ecology (1851)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting