Quantifying rainfall and cloud water interception in upland forests of Norfolk Island

Abstract The higher elevation (>200 m ASL) forests of Norfolk Island are regularly immersed in the clouds and scientific anecdotal evidence suggests that addition to rainfall, water is likely be collected as cloud droplets intercepted by forest canopy. This important for local hydrology ecology, yet it has never been quantified. To address this, a field measurement campaign was established measure hydrological inputs floor at two elevated (290 310 sites National Park over 524‐day period. Instrumentation included throughfall stemflow systems recording rain gauges open nearby clearings. Sites exhibited very high stem density basal area delivery dominated because funnelling characteristics dominant palm pine trees. Both showed similar behaviour with around 48% 32% total atmospheric inputs, respectively. Stemflow contributions far exceed observations from literature on cloud‐affected ecosystems which typically less than 10%. Rainfall rarely occurred absence low‐level some immersion events lasted many days hydrologic continuing extended periods despite rainfall not being observed open. Cloud interception accounted approximately 20% input both equivalent 25% extra top measured From an island‐wide perspective, calculated additional only small due limited spatial extent upland forest; however, processes unique plants, insects animals inhabit Island.