Drought effects on carbon allocation to resin defences and on resin dynamics in old-grown Scots pine

Droughts and other rapid changes in abiotic environmental conditions can predispose trees to damage by pest insects pathogens. For survival of coniferous trees, functional resin-based defences are essential, it is important know how they react at various time scales. We studied the effects differing water availabilities on mature Scots pine (Pinus sylvestris) a naturally drought-prone forest within long-term irrigation experiment. Our objectives were understand drought carbon allocation resin production analyse its influence flow pressure comparison shorter-term seasonal drought. tracked after 13C-pulse labelling experiment late summer 2017 compared observed dynamics between drought-exposed control irrigated from June August during dry hot 2018. Dry showed higher labelled than trees. Resin was with similar potentials, crown transparency. Yet, pressures particular decreased decreasing availability August. little affected short-term mostly associated suggest that because timescales direct patterns, may support long term, but period decreases short term.