Toward establishing detailed baseline tree phenology responses to climate drivers for the central Congo Basin

ATBC 2018

Koen Hufkens1, Elizabeth Kearsley1, Kim Jacobsen1,2, Innocent Banzi Ngulu-Ukulu1, Hans Beeckman2, Piet Stoffelen3, Filip Vandelook3, Sofie Meeus3, Jan Van den Bulcke4, Michael Amara5, Leen Vanhirtum5, Hans Verbeeck1.

1Computational & Applied Vegetation Ecology laboratory, Ghent University, 2Xylarium, Royal Museum for Central Africa, 3Botanic Garden Meise, 4Laboratory of Wood Technology, Ghent University, 5State Archives Belgium.

The African rainforest, is the second largest on Earth, stores up to 66 Pg of carbon and is presently a persistent carbon sink (0.34Pg C yr-1). Recent studies have shown that these forests are being subjected to a long-term drying trend. These drought events can substantially alter forest structure and tree functioning, providing large feedbacks to the climate system, raising fears over the drought resilience of tropical tree species through acclimation and the persistence of this important terrestrial carbon sink.

Our understanding of plant and by extension forest responses to climate change rely heavily on consistent long-term observations. However, measuring traits of tropical plant species is particularly demanding, and established long-term observation programmes are rare. Despite these challenges some long-term (historical) records of phenology observations, important plant traits and indicators of climate change and growing season variability, do exist.

The historical archives of the Institut National d’Etudes Agronomique du Congo Belge (INEAC) span approximately five decades (~1910 – 1960) of observations across the Congo Basin and hold vast amounts of data including forestry, climatological, ecological and biodiversity data with great potential and relevance for basic and applied forestry research. We combine past and ongoing transcription efforts of historical INEAC data in a concise analysis representative of the central Congo Basin. In particular we use historical INEAC phenological and climatological data recovered during the Jungle Rhythms citizen science project ( and the ongoing “Congo basin eco-climatological data recovery and valorisation (COBECORE)” project respectively (

We summarize initial findings covering >500 species, 2492 individuals and a total of >25K observation years. In particular we discuss the seasonality and synchronicity across all observed dominant canopy tree species in a central Congo Basin, as well as their sensitivity to the local climate, shedding light on their drought resistance and plasticity.