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Chemical traits that predict susceptibility of Pinus radiata to marsupial bark stripping

journal contribution
posted on 2023-05-21, 04:57 authored by Nantongo, JS, Bradley PottsBradley Potts, Noel DaviesNoel Davies, Aurik, D, Elms, S, Hugh FitzgeraldHugh Fitzgerald, Julianne O'Reilly-WapstraJulianne O'Reilly-Wapstra

Bark stripping by mammals is a major problem in managed conifer forests worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials and results in reduced survival, growth, and in extreme cases death of trees. Herbivory is influenced by a balance between primary metabolites that are sources of nutrition and secondary metabolites that act as defences. Identifying the compounds that influence herbivory may be a useful tool in the management of forest systems. This study aimed to detect and identify both constitutive and induced compounds that are associated with genetic differences in susceptibility of two-year-old P. radiata trees to bark stripping by marsupials. An untargeted profiling of 83 primary and secondary compounds of the needles and bark samples from 21 susceptible and 21 resistant families was undertaken. These were among the most and least damaged families, respectively, screened in a trial of 74 families that were exposed to natural field bark stripping by marsupials. Experimental plants were in the same field trial but protected from bark stripping and a subset were subjected to artificial bark stripping to examine induced and constitutive chemistry differences between resistant and susceptible families. Machine learning (random forest), partial least squares plus discriminant analysis (PLS-DA), and principal components analysis with discriminant analysis (PCA-DA), as well as univariate methods were used to identify the most important totals by compound group and individual compounds differentiating the resistant and susceptible families. In the bark, the constitutive amount of two sesquiterpenoids — bicyclogermacrene and an unknown sesquiterpenoid alcohol —were shown to be of higher levels in the resistant families, whereas the constitutive sugars, fructose, and glucose, as well individual phenolics, were higher in the more susceptible families. The chemistry of the needles was not useful in differentiating the resistant and susceptible families to marsupial bark stripping. After artificial bark stripping, the terpenes, sugars, and phenolics responded in both the resistant and susceptible families by increasing or reducing amounts, which leveled the differences in the amounts of the compounds between the different resistant and susceptible classes observed at the constitutive level. Overall, based on the families with extreme values for less and more susceptibility, differences in the amounts of secondary compounds were subtle and susceptibility due to sugars may outweigh defence as the cause of the genetic variation in bark stripping observed in this non-native tree herbivory system.


Australian Research Council

Hancock Victorian Plantations Pty Ltd

Radiata Pine Breeding Co Ltd

Scion New Zealand Forest Research Institute Limited

Timberlands Pacific Pty Ltd


Publication title

Journal of Chemical Ecology




51 - 70




School of Natural Sciences


Springer New York LLC

Place of publication

233 Spring St, New York, USA, Ny, 10013

Rights statement

© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2021.

Repository Status

  • Restricted

Socio-economic Objectives

Softwood plantations

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