Abstract

Uapaca kirkiana (Muell. Arg) is an important multipurpose indigenous fruit tree in the Zambezian ecoregion whose studies are limited. Six U. kirkiana provenances and their families were studied from a 12-year old alpha-lattice designed provenance trial at Nauko in Machinga, Malawi for their growth and carbon sequestration potential. Growth performance variables height, crown width, diameter and survival were assessed. Allometric models were also developed for estimation of carbon stocksthrough wholesome destructive sampling of trees.Phalombe provenance (4.7 ± 0.87m) outgrew all the other provenances in height with Dedza (4.43 ± 1.06m) attaining the least height growth. No significant differences were detected amongst the mean heights for the provenances (F = 2.06, p = 0.069). Family height however differed significantly, varying between 3.06 ± 1.05m and 5.95 ± 1.08m (F = 1.60, p = 0.001). Widest crown was observed in Dedza provenance (2.27 ± 0.86m) while Luwawa produced the narrowest (1.98 ± 0.85m) and thevariation between the two crowns was the only significant difference (F = 2.75, p = 0.018). No significant differences were detected amongst the family means signifying low genetic control of crown traits (F = 1.02, p = 0.438). Phalombe provenance (8.59 ± 2.19cm) was again the most superior performer in diameter growth, significantly varying from other provenances such as the least performer, Kasungu (7.6 ± 2.42cm; F = 4.49, p = 0.000). Diameter growth at family level also varied significantly ranging between 5.2 ± 1.11cm and 10.7 ± 1.89cm (F = 1.65, p = 0.000). Provenance survival rates ranged between 54 and 69% for Litende and Luwawa provenances respectively while the overall survival for the provenances was 64%.Allometric models generated were able to explain between 54.6% and 92.4% of variation in all the response variables. Total carbon estimated from lines of best fit for the provenances varied between 10.09 ± 6.64kg tree-1 for Luwawa and 12.47 ± 6.94kg tree-1for Phalombe (F = 2.67, p = 0.021). When survival rates were considered, Phalombe was estimated to sequester 774kg ha-1 with Litende the least carbon sequestering provenance at 135kg ha-1. Dedza was the second prolific provenance, sequestering 745kg ha-1. Significant differences were detected in the carbon sequestered by the component parts of the provenances and families. Phalombe was generally the overall superior provenance in terms of growth and carbon sequestration potential by the six provenances. Some best performing families were also from this provenance. However there is still need to conduct further multi locational studies to establish how the provenances would perform in other environmental conditions and make the models predictive in a wider range of conditions.

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School	: Not specified
Issued Date	: 2013

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