Theory 119/Forestry & Fire Ecology
Drought Death Is a Margin
The claim
Forest drought mortality is set by the ratio of hydraulic demand to safety margin rather than by precipitation deficit.
01The mechanism
Trees die when embolism reaches a critical fraction of the xylem; species with narrow margins die at modest deficits.
02Predictions
- P1Mortality should track the ratio.
- P2Deficit alone should mispredict across species.
03Refutation
Mortality tracking deficit would remove the margin term.