Project No: PNC228-1011
Over the next one and half to three decades, changes to Australia’s climate are predicted to affect how growers and owners will manage their Eucalyptus globulus and Pinus radiata plantations. Forecast changes in the frequency and intensity of droughts, hotter bushfires, and emergent tree diseases and pests threaten where plantation managers can plant with the confidence of getting a healthy tree crop in the future, and how they should look after their trees.
Now researchers from CSIRO Land and Water Flagship, with support from FWPA, have modelled predictions of plantation productivity for 2030 and 2050 under a range of likely climate scenarios. As a consequence, the Australian plantation industry now has a greatly improved capacity to quantify and manage both the risk and impact associated with climate change and variability, from the scale of a region down to a site.
Data was considered from five key Australian forestry regions: southern Western Australia; the Green Triangle in South Australia and Victoria; eastern Victoria and southern New South Wales; and northern New South Wales for both E. globulus and P. radiata (only P. radiata in northern New South Wales). These regions and the scope of the modelling were determined after consulting closely with plantation growers.
The research team was led by Dr Libby Pinkard, Senior Research Scientist in CSIRO Land and Water, based in Tasmania. The team was grateful to be able to use plantation management and silviculture data that had been collected by growers for the last 20 years in the case of E. globulus and slightly longer for P. radiata. Such a wealth of information enabled the computer models to be calibrated and refined so as to have the best chance of predicting how climate change may affect different sites that have different characteristics (such as soil depth, rainfall etc.).
The researchers used three models to look at climate risks and impacts: CABALA—CSIRO’s plantation growth and water use model for analysis of productivity and the impacts of drought on stand mortality; e-Cambium, which uses information about site, management regime and daily weather data to predict variation in wood density and stiffness; and Climex, which predicts changes in the distribution and abundance of invasive insect pests related to climate.
‘The important thing to remember about models is that they need interpretation. We need to make sure that what they’re telling us makes sense ‘biologically’, that is, will the trees actually thrive in a particular scenario or will something else come into play,’ says Libby. ‘Rules of thumb are difficult to develop when looking at climate change impacts. Site-level assessments will be required in many cases because of the complex interactions between site conditions, climate changes and hazards such as pests.’
Five climate scenarios that spanned the worst, most likely and best case climate outcomes were used for the analyses. The research suggests productivity for plantations currently in well performing areas may be only slightly affected (positively or negatively), with modelling showing little change by 2030 or even 2050. However, plantations growing in the drier areas of existing plantation regions are vulnerable to reduced productivity and increasing mortality, and in the worst instances may be highly likely to fail.
The project also developed a series of regional reports to help industry understand and mitigate potential hazards that might exist in the next 15 years, no matter which climate pattern ultimately occurs. Indeed, up to 2030 good silvicultural management has the potential to mitigate the negative impacts of climate change for both P. radiata and E. globulus within the core of the plantation estate.
