Moderate to large earthquakes can increase the amount of water feeding stream flows, raise groundwater levels, and thus grant plant roots more access to water in water-limited environments. We examine tree growth and photosynthetic responses to the Maule M_w 8.8 Earthquake in small headwater catchments of Chile’s Mediterranean Coastal Range. We combine high-resolution wood anatomic (lumen area) and biogeochemical ( of wood cellulose) proxies of daily to weekly tree growth on cores sampled from trees on floodplains and close to ridge lines. We find that, immediately after the earthquake, at least two out of six tree cores show changes in these proxies: lumen area increased and decreased in the valley trees, whereas the sign of change was reversed in trees on the hillslope. Our results indicate a control of soil water on this response, largely consistent with models that predict how enhanced post-seismic vertical soil permeability causes groundwater levels to rise on the valley floor, but fall along the ridges. Statistical analysis with boosted regression trees indicates that streamflow discharge gained predictive importance for photosynthetic activity on the ridges but lost importance on the valley floor after the earthquake. We infer that earthquakes may stimulate ecohydrological conditions favoring tree growth over days to weeks by triggering stomatal opening. The weak and short-lived signals that we identified, however, show that such responses are only valid under water-limited instead of energy-limited tree growth. Hence, dendrochronological studies targeted at annual resolution may overlook some earthquake effects on tree vitality.