A model of coppice biomass recovery for mallee-form eucalypts
2022
Brooksbank, Kim | Goodwin, Adrian
Planting mallee-form eucalypts amongst crops has the potential to remedy environmental degradation caused by land clearing in low rainfall regions, whilst also providing income through carbon-sequestration or periodic coppicing. Management options can be supported by models of biomass and coppice recovery, and this paper presents the first empirical coppice growth model for mallee eucalypts. Uncoppiced and coppiced belt-planted Eucalyptus polybractea, E. loxophleba and E. kochii were harvested and roots excavated to provide estimates of shoot and root biomass for analysis and model development. Allometric models of shoot biomass were appropriate for both uncoppiced and coppiced trees, but models of root/total biomass ratio for coppice depended on site quality and age, and could not be modelled allometrically. Mean root/total biomass proportions for uncoppiced trees were estimated (with standard errors) to be 0.38 (0.009), 0.50 (0.031), and 0.46 (0.021) for E. polybractea, E. loxophleba, and E. kochii respectively and were sensitive to site quality but insensitive to age. The time taken to regain pre-coppice shoot biomass was about half that of full pre-cut root/total biomass ratio recovery, and was affected by coppicing age and site quality. A conceptual model of coppice growth indicated that coppiced stands may produce more total biomass than uncoppiced stands of the same age.
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