Vulnerability of Tasmanian giant trees

Abstract

SummaryTasmania's giant trees are among the world's tallest flowering plants and Australia's greatest eucalypts. However, they are not well protected in National Parks or extensive reserves.Of the 69 known trees that meet the official criteria for protection as giants, almost 90% are in State forests managed for wood harvesting. Several of the giants are within coupes that were scheduled for clearfelling under the Tasmanian 2004–2007 three-year wood production plan, and recent harvesting operations have threatened or killed several others.Fifty-five per cent (38) of the known Tasmanian giants, including the tallest trees, the tallest stand, the tallest stringybark, and the second most massive stringybark, exist in the middle of the Styx Valley. Harvesting and regeneration burning operations indirectly threaten most of these trees, because they stand close to scheduled or recently clearfelled coupes. More importantly, increasing the proportion of young, dense, highly flammable eucalypt regrowth forest, at the expense and fragmentation of less flammable old—growth forest, seriously exacerbates the risk of wildfire, and invites annihilation of all the Styx Valley giants.Nominal protection of individual giant trees in small (100-m radius) management decision classification zones, or stands of trees in reserves of a few hundred hectares surrounded by production forest, does not provide effective protection in the long term. Numerous historic and recent examples in Tasmania and Victoria show the failures of these well-intentioned small-scale conservation efforts. Giant tree conservation requires very long-term preservation of large areas of forest in which the frequency of wildfire is very low; it is incompatible with current Tasmanian forest harvesting and regeneration practices.The Styx Valley contains the greatest number of, and many of the finest, giants existing in Tasmania. It also has high potential to produce another generation of great trees to stimulate wonder and admiration for the next half millennium. The best plan to ensure their long-term survival is to desist from forest harvesting and regeneration by fire, and to transform the entire valley into Australia's first large reserve dedicated to giant tree conservation.