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Precipitation thresholds and drought‐induced tree die‐off: insights from patterns of P inus edulis mortality along an environmental stress gradient
Author(s) -
Clifford Michael J.,
Royer Patrick D.,
Cobb Neil S.,
Breshears David D.,
Ford Paulette L.
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12362
Subject(s) - precipitation , canopy , drought stress , vapour pressure deficit , ecology , growing season , environmental science , atmospheric sciences , physical geography , geography , biology , horticulture , botany , geology , transpiration , photosynthesis , meteorology
Summary Recent regional tree die‐off events appear to have been triggered by a combination of drought and heat – referred to as ‘global‐change‐type drought’. To complement experiments focused on resolving mechanisms of drought‐induced tree mortality, an evaluation of how patterns of tree die‐off relate to highly spatially variable precipitation is needed. Here, we explore precipitation relationships with a die‐off event of pinyon pine ( P inus edulis Engelm.) in southwestern N orth A merica during the 2002–2003 global‐change‐type drought. Pinyon die‐off and its relationship with precipitation was quantified spatially along a precipitation gradient in north‐central N ew M exico with standard field plot measurements of die‐off combined with canopy cover derived from normalized burn ratio ( NBR ) from L andsat imagery. Pinyon die‐off patterns revealed threshold responses to precipitation (cumulative 2002–2003) and vapor pressure deficit ( VPD ), with little to no mortality (< 10%) above 600 mm and below warm season VPD of c . 1.7 kPa. [Correction added after online publication 17 June 2013; in the preceding sentence, the word ‘below’ has been inserted.] Our results refine how precipitation patterns within a region influence pinyon die‐off, revealing a precipitation and VPD threshold for tree mortality and its uncertainty band where other factors probably come into play – a response type that influences stand demography and landscape heterogeneity and is of general interest, yet has not been documented.