Tree rings show a different climatic response in a managed and a non-managed plantation of teak (Tectona grandis) in West Africa

Abstract

Establishing large-scale plantations of teak could reduce the pressure on natural forests and sequester atmospheric carbon into durable wood. Understanding the growth dynamics of this species in plantations, outside its natural distribution area, is crucial for forest management. Stem discs of teak were collected in Ivory Coast at two sites, a non-managed plantation (Gagnoa) and a managed plantation (Séguié). All stem discs were processed using the standard dendrochronological methods in order to unravel the relationships between growth and climate. Results showed that growth is slower in Gagnoa compared to the Séguié plantation that is being thinned regularly. In Gagnoa, trees responded positively to April rainfall, i.e., during the early stage of tree-ring formation, and negatively to September-October rainfall, i.e., during the short dry period. In Séguié, trees responded positively to July rainfall, i.e., during latewood formation, under decreasing rainfall. At both sites, tree growth was influenced by sea-surface temperature anomalies during the summer in the Gulf of Guinea. Teak growth in Séguié could be additionally linked to El Ninõ events, specifically during three major episodes (1976-77, 1982-83 and 1997-98).