Ring Formation and Arboreal Ecology in a Wet Miombo Woodland in Zambia

Abstract

Dendrochronology records are lacking in sub-Saharan Africa. We have conducted three African Dendrochronology Fieldschools in 2021, 2022, and 2023 in the Copperbelt Province of Zambia. We identified an old forest site at the African Explosives Limited (AEL) property for our most intensive sampling and also sampled other regions such as the Nsobe Game Camp. We used a modified variable area transect to quickly quantify the basal area and stems per hectare of the trees in this wet Miombo woodland and have found 49 species. We cored all trees that fell within our plots that were 10cm or larger. Twenty-nine percent of them are from the Fabacaea family while 21 other families are represented. The majority of species had distinct banding that appear to be annual rings although work is continuing to determine if there is a strong annual climate signal in all of these species. The most common species are Pericopsis angolensis, Brachystegia sp. (longifolia, boehmii, and spciformis – in reducing order), and Julbernardia paniculata. Marquesia macroura dominates the larger size classes and Parinari curatellifolia is also common. Isoberlina (one of the dominant Miombo woodland species) is under-represented on our sites. Our oldest tree that we sampled was 170 years old and we have many over 140 years. Our strongest chronology to date is from Brachystegia boehmii (series intercorrelation = 0.49, oldest tree = 140) and we have also developed a multi-species chronology representing thirteen species of the wet Miombo woodlands (series intercorrelation = 0.41, chronology length = 143).