A comparative study of the dendroclimatic potential of selected tree species of the tropical dry and wet woodlands of Zambia

Environmental challenges have had a negative impact on African forest resources, which has subsequently adversely affected some ecosystem services that are required for the survival of people. We conducted a comparative study in the wet and dry woodlands in Zambia to establish the formation of tree growth rings and determine the relationship between the growth ring width and rainfall. Through the four successful Africa Dendrochronological Fieldschools that were conducted from 2021 to 2024, we collected samples from the wet miombo woodlands on the copperbelt province and the dry miombo and Baikiaea woodlands on the southern province of Zambia. From 2021 to 2023, we recorded 49 tree species from the wet miombo woodlands and found that the Fabaceae family plants had the highest species richness with 28.5%. We determined a series intercorrelation of 0.45 and average mean sensitivity of 0.465 from a master chronology of 14 tree species. The dendroclimatic study found a significant positive relationship (r-value =0.589, p-value = 0.0005) between ring width of a mixed species chronology of Brchaystegia longifolia and Julbernadia paniculata, and precipitation totals for Zambia’s wet season (October–April). In 2024, studies were conducted in the dry miombo and Baikiaea woodlands. Through this study, 16 distinct species were identified in the Baikiaea woodlands with Baikiaea plurijuga being the abundant species. We determined series intercorrelation of 0.31 and an average mean sensitivity of 0.50 from a mixed tree species from the Baikiaea woodlands. A precipitation correlation with Brachytegia longifolia from the miombo woodlands found that previous December and Current March precipitation have positive influence on tree growth. In both, dry and wet woodlands, we found that trees produce annual growth rings that are responsive to seasonal climate, and are useful for dendrochronology