Figure 2

Modeled xylem water potential (MPa) in lodgepole pine (A-C), western larch (D-F) and Douglas-fir (G-I) canopies exposed to plumes arising from firelines with various rates of spread (R, m min⁻¹) and intensities (I, kW m⁻¹). R = 1 and I = 200 (A, D, G); R = 2 and I = 400 (B, E, H) and R = 8 and I = 1600 (C, F, H). Only the foliage elevated enough to have survived heating in the plume is included in this figure. Two wind conditions were simulated: no wind (dashed line) and 3 m s⁻¹ (solid line). A plume model was used to estimate atmospheric vapor pressure deficit as an input to a stem hydrologic model to predict stem water potential. The dashed line represents the water potential where a 50 % loss in hydraulic conductivity is expected (Pinol and Sala 2000). Fire and physiological parameters used in the models are in Tables 1 and 2, respectively.