<b>Dataset: </b><b>Late Holocene climate and fire regime in eastern Taiwan inferred from sedimentary black carbon and its carbon isotopes at Liyu Lake</b>

<p dir="ltr">We analyzed the black carbon (BC) and its stable carbon isotopes in a well-dated sediment core from Liyu Lake in eastern Taiwan. Our data indicate relatively wet conditions at ~3000–2400, ~1500, and 800–0 cal yr BP, separated by drier intervals at 2400–1600 and 1400–800 cal yr BP. The timing of these wet–dry phases differs from that on Taiwan’s western, leeward side, consistent with the Central Mountain Range acting as an orographic barrier that filters a common low-frequency forcing by western North Pacific sea-surface temperatures and ENSO into distinct local hydroclimate histories. We also refine late Holocene fire history at Liyu Lake using BC flux, identifying three main fire episodes shaped by varying combinations of climate and land use. The largest peak at ~2100 cal yr BP occurred under dry conditions with limited evidence of cultivation, suggesting a predominantly climate-driven, high-fuel forest-fire regime. By contrast, the 2800–2500 cal yr BP episode is interpreted as low-intensity, largely extra-local anthropogenic burning linked to land clearance on the nearby coastal plain, whereas the last ~800 years record a strongly human-modified fire regime, with elevated BC and charcoal coinciding with increased cultivated Poaceae pollen and historical agricultural expansion. Correlations between pollen and BC further indicate that late Holocene vegetation in the Liyu catchment was primarily controlled by moisture-driven shifts between montane forest and more open vegetation, with fire acting as a secondary, climate-sensitive disturbance that amplified dry phases rather than fundamentally restructuring the forest–open land balance.</p>