Restoration of former pine plantations in Australia: revegetation techniques, pine wildling control and the importance of land use history.

Le résumé fourni par la source

Within Australia, pine plantations were first revegetated with native species in the 1980s with the number and size of restoration projects growing each year. Sites span a wide range of environments including alpine areas within the Australian Capital Territory and New South Wales (NSW), the coastal sands of NSW and Western Australia; and both low and high elevation sites across Victoria. Sites were restored for four reasons: (i) a plantation of introduced species was considered incompatible with National Park objectives; (ii) plantations were failed species’ trials; (iii) a second rotation pine plantation was not economically viable; and (iv) for protection of natural resources. Associated objectives ranged from the re-establishment of eucalypts for conservation or commercial purposes, to the reestablishment of whole vegetation communities for conservation and recreation. The re-establishment of indigenous communities on a 2 000 ha Pinus radiata plantation along the Delatite Arm of Lake Eildon in northeast Victoria is the largest of these projects. The restoration process includes an intensive annual planting program returning 100 000 eucalypt seedlings to harvested sites, supplemented by aerial and hand seeding. Major challenges include the limited opportunity for the use of fire, pine wildling invasion with densities reaching 3 000 stems ha -1 , limited propagule availability (through past agricultural land uses), and mammal browsing. For the Delatite, this paper reports on: (i) experimental treatments investigating the effects of site preparation (ripping vs pitting, cable vs ground-based logging) and planting treatments (guarding/fertiliser/seedlings/seed) on plant survival and growth; (ii) the effect of land use history on the potential contribution of natural successional processes to the restoration process through broad-scale vegetation surveys of harvested sites and an investigation of the soil seed bank; and (iii) the effectiveness of pine wilding control techniques. Further, owing to the paucity of information concerning restoration of pine plantation sites, this paper provides a synthesis of the major restoration techniques employed across Australia, and provides recommendations on the most suitable techniques under a range of conditions.

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