Cambial Growth Season of Brevi-Deciduous Brachystegia spiciformis Trees from South Central Africa Restricted to Less than Four Months

Abstract

We investigate cambial growth periodicity in Brachystegia spiciformis, a dominant tree species in the seasonally dry miombo woodland of southern Africa. To better understand how the brevi-deciduous (experiencing a short, drought-induced leaf fall period) leaf phenology of this species can be linked to a distinct period of cambial activity, we applied a bi-weekly pinning to six trees in western Zambia over the course of one year. Our results show that the onset and end of cambial growth was synchronous between trees, but was not concurrent with the onset and end of the rainy season. The relatively short (three to four months maximum) cambial growth season corresponded to the core of the rainy season, when 75% of the annual precipitation fell, and to the period when the trees were at full photosynthetic capacity. Tree-ring studies of this species have found a significant relationship between annual tree growth and precipitation, but we did not observe such a correlation at intra-annual resolution in this study. Furthermore, a substantial rainfall event occurring after the end of the cambial growth season did not induce xylem initiation or false ring formation. Low sample replication should be taken into account when interpreting the results of this study, but our findings can be used to refine the carbon allocation component of process-based terrestrial ecosystem models and can thus contribute to a more detailed estimation of the role of the miombo woodland in the terrestrial carbon cycle. Furthermore, we provide a physiological foundation for the use of Brachystegia spiciformis tree-ring records in paleoclimate research.

Tree Growth Rings in Tropical Peat Swamp Forests of Kalimantan, Indonesia

“…This marginal parenchyma is a widespread feature in many tropical families [49]. The time for its formation at the end of a growing period might be relatively short [51] and the inducing factor probably weak. The formation of dense wood at the end of a growth zone (late wood), however, is a process over a longer period where several cell rows must be involved for the ring to become visible.…”

Dendrochronological potential of Millettia stuhlmannii in Mozambique

“…However, the only possible conclusion from this experiment is that panga-panga forms annual rings. Further studies to determine the onset and growing season length using this technique should be undertaken (e.g., Trouet et al 2012). Despite frequent treering anomalies (wedging rings, and missing rings), crossdating between six series was successful and a pilot ring width chronology was developed, though we were only able to easily cross-date about 25 % of sampled trees.…”

“…Direction of growth is left to right in each image Trees phloem rays, respectively. Although callus tissue in most woody plants is produced by vascular rays, Trouet et al (2012) found that in Brachystegia spiciformis Benth., cambium cells are responsible for callus tissue production and this process may continue even after the dormancy of the cambium.…”

Tree Rings and the Chronology of Ancient Egypt

“…The utility for tree-ring research for these species in Egypt has yet to receive adequate examination (Creasman, in press). African frankincense trees [Tolera et al 2013] and certain tropical species [Trouet et al 2012]; N.B. However, none of the Egyptian varieties has undergone a thorough evaluation.…”