Evaluation of a visual assessment method for tree condition of eucalypt floodplain forests

Authors

  • Nicholas J. Souter,

  • Shaun Cunningham,

  • Stuart Little,

  • Todd Wallace,

  • Bernard McCarthy,

  • Mark Henderson


Nicholas Souter is Principal Scientist at EcoKnowledge (130 Franklin Street, Adelaide, SA 5000, Australia; Tel: (08) 8410 7717; Fax: (08) 8388 5794; Email: nick@ecoknowledge.com.au). Shaun Cunningham is a Research Fellow at the Australian Centre for Biodiversity (Monash University, Vic. 3800, Australia; Tel: 3 9902 0142; Email: shaun.cunningham@monash.edu). Stuart Little is a Project Officer – Environmental Monitoring at the Murray-Darling Basin Authority (GPO Box 1801, Canberra, ACT 2601, Australia; Tel: (02) 6279 0568; Email: stuart.little@mdba.gov.au). Todd Wallace is the Officer in Charge, Bernard McCarthy is an Aquatic Ecologist and Mark Henderson is a Research Technician at the Murray-Darling Freshwater Research Centre (PO Box 3428, Mildura, Vic. 3502 Australia; Tel: (03) 5051 4053; Email: t.wallace@latrobe.edu.au, b.mccarthy@latrobe.edu.au, m.henderson@latrobe.edu.au). This project was commissioned by the Murray-Darling Basin Authority to address the need for a consistent tree assessment method for use at The Living Murray Icon Sites in South Australia, Victoria and New South Wales.

Abstract

Summary  For decades the floodplain forests of the River Murray have endured the effects of prolonged water stress. This has resulted in significant crown dieback and loss of condition. The Living Murray (TLM) initiative aims to restore the ecological health of six Icon Sites along the River. The two eucalypts River Red Gum (Eucalyptus camaldulensis) and Black Box (Eucalyptus largiflorens) that dominate the forests at five of the six Icon Sites are undergoing widespread decline. To enable effective management and restoration of these forests, we developed a standardised tree condition assessment method. Named the TLM tree condition assessment method, it utilises visual assessment of a range of tree crown variables (extent and density of the foliage in the crown, epicormic growth, new tip growth, reproductive activity, leaf die-off, mistletoe infestation) and measurements of bark condition, diameter at breast height and dominance class. This article describes the TLM tree condition assessment method and assesses it for consistency between multiple observer teams after limited training. The level of observer agreement between six teams each comprised of two observers was assessed for seven of the ten variables. Intra-class correlation was used to compare scores of 30 River Red Gum trees assessed on Gunbower Island on the River Murray. The level of agreement for all variables was statistically significant with six of seven variables having correlation coefficients over R = 0.5. The TLM tree condition assessment method was found to provide accurate estimates of a range of tree variables that can be used to determine tree condition. The TLM tree condition assessment method provides a valuable monitoring tool that can be used to assess management interventions, such as management flooding and silvicultural thinning.

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