Hydraulic traits of co-existing conifers do not correlate with local hydroclimate condition: a case study in the northern Rocky Mountains, U.S.A.

In this study, we examined the inter- and intra-specific variation of hydraulic traits of three conifers of the Northern Rockies: Pinus ponderosa, Picea engelmannii, and Pseudotsuga menziesii to understand the mechanisms that allow different plant species to co-exist across a watershed. We quantified differences in plant xylem water potential (ψ), xylem tissue vulnerability to cavitation (P, or ψ causing 50% loss of hydraulic conductivity), and safety margins for co-occurring trees from low and high elevations. We then investigated xylem vulnerability to cavitation with rooting depth.