Western Australia’s jarrah forest may be far more resilient to long\u2011term drought than previously claimed \u2014 and more at risk from fire than from drought \u2014 according to new analysis drawing on more than 50 years of monitoring in one of the state\u2019s most closely studied forest catchments.<\/p>\n\n\n\n
The findings come from professional forester Frank Batini, a retired environmental consultant and former Adjunct Professor of Environmental Sciences at Murdoch University, who has reviewed long\u2011term hydrological and ecological data for a soon\u2011to\u2011be\u2011published journal article. His analysis focuses on a 2,000\u2011hectare research catchment in the state\u2019s south\u2011west \u2014 the same region the WA Government cited when it decided to cease native forestry in 2023.<\/p>\n\n\n\n
Batini says the jarrah forest covers two million hectares in the extreme south\u2011west of the state, growing in a Mediterranean\u2011type climate with \u201chot, dry summers and cooler, wetter winters.\u201d The forest, he told Wood Central, carries high biomass but grows slowly on ancient, nutrient\u2011poor lateritic soils. Individual trees may live for 350 years and tolerate moderate bushfire.<\/p>\n\n\n\n
Since 1965, rainfall across the region has fallen by about 20 per cent, water tables have dropped more than 10 metres, and inflows into Perth\u2019s water\u2011supply dams have reduced by 80 per cent. Batini said that \u201csuch a large change in hydrology over a period of 60 years should have had a substantial effect on biodiversity and tree health.\u201d<\/p>\n\n\n\n
The research catchment \u2014 monitored since 1972 and containing 500 vegetation plots \u2014 provides one of the most complete long\u2011term records in the region.<\/p>\n\n\n\n
Batini said studies conducted between 2006 and 2012 found that \u201crainfall had declined by 15%, streamflow by 75%, flow days by 50%, and water tables had fallen by several metres.\u201d At the same time, streamflow was \u201cabout 5% of rainfall, mostly coming from storage,\u201d he said, adding that a model \u201caccurately matched these trends\u201d and was used to assess thinning effects on soil storage and streamflow. \u201cEvapotranspiration (Et) matched the rainfall,\u201d with interception and evaporation from bare areas forming significant components.<\/p>\n\n\n\n
Despite these shifts, Batini says the forest remained in strong condition.<\/p>\n\n\n\n
\u201cIn 2025, the trees and understorey vegetation were healthy,\u201d he writes. As a result, \u201cthe populations of birds, mammals and insects that depend on this vegetation for food and shelter were unaffected.\u201d Only \u201ca few aquatic invertebrates with longer life cycles were no longer represented.\u201d<\/p>\n\n\n\n
And even after the extremely dry years of 2010 and 2024, impacts were minimal and highly localised. Batini reports \u201cscorch, canopy loss and some tree deaths\u201d confined to shallow soils over clay or near basement rock \u2014 less than 10 hectares, or 0.5 per cent of the monitored area. Two eucalypt species that favour swamp margins showed a slight shift toward wetter sites.<\/p>\n\n\n\n
Batini disputes claims that the forest is in an unprecedented state of collapse. \u201cDespite the statements from politicians, government agencies, academia, environmental NGO\u2019s, IUCN and the press that the current dry spell is \u2018unprecedented\u2019 and that the forest is in \u2018imminent threat of collapse\u2019 due to human\u2011induced Climate Change, the resilience shown by this ecosystem to date is very encouraging,\u201d Batini said, arguing that this is \u201cprobably due to the fact that similar or even worse droughts have occurred many times before.\u201d<\/p>\n\n\n\n
Three independent tree\u2011ring studies support that view, showing \u201cmany multi\u2011decadal pluvials and droughts\u201d over the past 650 years. All studies record that \u201cthe 19th Century (when carbon dioxide levels were low) was extremely dry and that the 1911 to 1965 period was the wettest on record.\u201d The current dry spell, Batini writes, \u201cis considered to be neither \u2018unprecedented\u2019 nor \u2018exceptional\u2019.\u201d<\/p>\n\n\n\n
He said that \u201cthe data do not support the widely\u2011held hypothesis that the current dry spell is caused by human\u2011induced climate change.\u201d Instead, \u201cthe minor ecological shifts that were observed are simply the result of natural variability in climate.\u201d Batini warns that \u201ca severe bushfire would have a far greater negative effect on water, forest and biodiversity values.\u201d<\/p>\n\n\n\n
His assessment contrasts sharply with the WA Government\u2019s position, which has repeatedly cited climate\u2011driven forest decline as a key factor in its decision to end commercial harvesting.<\/p>\n","protected":false},"excerpt":{"rendered":"
Western Australia’s jarrah forest may be far more resilient to long\u2011term drought than previously claimed \u2014 and more at risk from fire than from drought \u2014 according to new analysis drawing on more than 50 years of monitoring in one of the state\u2019s most closely studied forest catchments. The findings come from professional forester Frank […]<\/p>\n","protected":false},"author":2,"featured_media":31844,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_wpscppro_dont_share_socialmedia":false,"_wpscppro_custom_social_share_image":0,"_facebook_share_type":"default","_twitter_share_type":"default","_linkedin_share_type":"default","_pinterest_share_type":"default","_linkedin_share_type_page":"default","_instagram_share_type":"default","_medium_share_type":"default","_threads_share_type":"default","_google_business_share_type":"default","_selected_social_profile":[],"_wpsp_enable_custom_social_template":false,"_wpsp_social_scheduling":{"enabled":false,"datetime":null,"platforms":[],"status":"template_only","dateOption":"today","timeOption":"now","customDays":"","customHours":"","customDate":"","customTime":"","schedulingType":"absolute"},"_wpsp_active_default_template":true},"categories":[50,45,44,82],"tags":[],"ppma_author":[70],"class_list":{"0":"post-31843","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-australia","8":"category-sustainability","9":"category-sustainable-forest-management","10":"category-western-australia"},"authors":[{"term_id":70,"user_id":2,"is_guest":0,"slug":"jason","display_name":"Jason Ross","avatar_url":{"url":"https:\/\/woodcentral.com.au\/wp-content\/uploads\/2023\/01\/J-Ross-headshot.jpeg","url2x":"https:\/\/woodcentral.com.au\/wp-content\/uploads\/2023\/01\/J-Ross-headshot.jpeg"},"0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/posts\/31843","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/comments?post=31843"}],"version-history":[{"count":1,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/posts\/31843\/revisions"}],"predecessor-version":[{"id":31845,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/posts\/31843\/revisions\/31845"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/media\/31844"}],"wp:attachment":[{"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/media?parent=31843"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/categories?post=31843"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/tags?post=31843"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/woodcentral.com.au\/wp-json\/wp\/v2\/ppma_author?post=31843"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}