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Summary: Mature forests have structural habitat features that can take hundreds of years to develop, and large reserves alone are unlikely to ensure conservation of the species that rely on these features. This paper outlines a proposed new approach to managing mature forest features, the ‘mature habitat management approach’, in areas outside of reserves. The objective was to maintain a network of current and future mature forest habitat distributed across the landscape. The approach is designed to complement the existing reserve network and management actions and is tenure‐blind. Spatial information on the availability of mature forest habitat at the local (1‐km radius) and landscape (5‐km radius) scales is used for decisions on retention within a 1‐km radius of a harvest area, to reach the minimum target of 20% and 30% retention of mature forest at the local and landscape spatial scales, respectively. We believe this approach could contribute to meeting the conservation needs of many species that require mature forest features for refuge and breeding in Tasmania and elsewhere. [ABSTRACT FROM AUTHOR]

Summary: Mature trees and forests contain structural features such as tree hollows, large coarse woody debris and large spreading crowns that provide critical habitat for a wide range of species. These features can take hundreds of years to develop and require careful management to ensure their continued availability. Managing these features requires spatial mapping layers to facilitate landscape‐scale management. This paper outlines how a map of mature forest habitat was developed for Tasmania, Australia. The map was produced using spatial data on vegetation type, mature crown density and senescence, a global layer of forest loss data derived from satellite imagery, a database on timber harvest plans and a spatial layer on the extent of fire. The relationship between mapped mature habitat availability (high, medium, low or negligible) and tree hollow availability in wet forest areas was explored, complementing a similar published study in dry forests. The number of large trees likely to have hollows significantly increased with mapped mature habitat availability, although there was considerable variation and overlap between map categories. Data from a fauna locality database and two radio‐tracking studies showed that three of the vertebrate hollow‐using species examined (Swift Parrot, Common Brushtail Possum and the Tasmanian Long‐eared Bat) and nest records of a species reliant on large tree crowns (the Wedge‐tailed Eagle) were all more likely to occur in areas of higher mapped mature habitat availability. It is concluded that this map reflects the relative availability of tree hollows, is ecologically meaningful and will be useful when managing mature forest habitat at large spatial scales, but the variable accuracy of the map at fine scales needs to be taken into account. [ABSTRACT FROM AUTHOR]

Hollow-using fauna are thought to be particularly vulnerable to timber harvesting, and habitat for these species is often managed by retaining single hollow-bearing trees or patches of hollow-bearing trees within the harvested area. This study examined tree retention, survival and use by arboreal mammals in 27 small clumps of trees (0.04–0.21 ha) retained at ten partial harvest sites and 24 clumps of trees in nearby unharvested sites in Tasmania, Australia. Harvested sites were assessed on three occasions (1999, 2005–06 and 2014) and unharvested sites on two occasions (2005–06 and 2014). Of the retained clumps in harvested areas, 96% contained at least two habitat trees at the time of first survey (one year after harvest) which is the minimum required under the Tasmanian Forest Practices Code. Loss of retained trees in clumps between 2005–06 and 2014 was higher in harvested sites (average of 11.7% of all trees and 1.5% of habitat trees per clump) than unharvested sites (average of 2.8% of all trees and 0.3% of habitat trees per clump), but was comparable to or lower than rates of loss in many other studies. Trees were more likely to fall if they were dead and had little burn damage at the time of last survey. Factors found to influence tree death included the interaction between burn damage and the size of the tree, with the likelihood of a heavily burnt, average sized tree dying being twice that of an unburnt tree. Scratch marks from arboreal mammals were more prevalent in large trees with visible hollows, particularly in the clumps in harvested areas. In conclusion, the Tasmanian Forest Practices Code provisions were generally implemented as required and the evidence suggests the retained clumps of trees survive and are effective to some degree at providing habitat and promoting recolonisation by fauna in partial harvest coupes. However, further work is required to assess the adequacy of the clump provisions, when combined with management for other values in production forests, for maintaining hollow-using fauna throughout their range. [ABSTRACT FROM AUTHOR]

Abstract: A useful theoretical approach in the literature for those trying to conserve forest biodiversity involves a number of strategies to achieve maintenance of habitat for different species across multiple spatial and temporal scales. This approach emphasises the importance of implementing measures in off-reserve areas to complement reserve systems. This contrasts with both the traditional ‘set-aside’ approach to conservation and the primary aim of production forestry. Translating this risk-spreading approach into on-ground practice is often a difficult task. Using the conservation management of habitat for hollow-using fauna in Tasmania''s production forests as a case study, we explore the issues associated with adopting the theory and applying it to on-ground practice. The approach that has evolved is evaluated in terms of the strategies proposed in the literature. The inadequacy of the existing reserve system in Tasmania to fully cater for the conservation of threatened hollow-users, problems associated with the current ‘off-reserve’ measures, impediments to effective implementation and the use of an adaptive management framework are highlighted. We provide some practical considerations to guide more effective implementation. This includes the development of measurable objectives, integration of conservation goals with silvicultural goals, development of clear and practical guidelines, effective training and communication programs and the development of a monitoring and an adaptive management process agreed to by all stakeholders. The ongoing success of such an approach depends on a high level of commitment by all involved to the overall goal of ecologically sustainable forestry. [Copyright &y& Elsevier]

Abstract: The distribution of hollow-using fauna is frequently related to forest type. If hollow occurrence varies with forest type, the use of generic prescriptions for managing the hollow resource may be inappropriate. This study examined the relationship between the occurrence and abundance of tree hollows and site and tree attributes in wet and dry Eucalyptus obliqua forest in Tasmania, Australia. A total of 388 trees at 39 sites were examined before and after being felled. Evidence of invertebrate damage contributing to hollow formation was more common in wet forest than either dry or damp forest. Evidence of hollow formation by fire and fungi was more prevalent in drier than wetter forest. There was no difference among forest types in the proportion of hollows showing evidence of limb breakage. Examination of the site and tree factors related to hollow presence and abundance was done using Classification Trees, Random Forests and generalised linear models. The variables found to be most practical for predicting hollow occurrence were the number of hollows observed before the tree was felled, tree diameter and the amount of dead wood in the canopy. Tree age, an important variable to consider when planning harvest rotations, was strongly associated with hollow presence but had less bearing on hollow abundance. The size of hollows that were found in a tree was related to greater senescence. Although significantly more hollows of all sizes were found in wet forest than either dry or damp forest, the age at which trees began to produce hollows was similar among the different forest types. The models predicted that trees needed to be at least 100 years old before they are likely to contain a hollow and that medium-sized hollows rarely occur in trees younger than 140 years old. Trees grow slightly more slowly in dry forest than wet which means that smaller diameter trees were found to contain hollows in dry forest than wet and that even the largest trees may not contain large hollows in wet forest. Despite this, no differentiation between the forest types was found in the predictive models. It is recommended that trees retained for faunal habitat be at least 100cm in diameter. [Copyright &y& Elsevier]

• Large, old trees with hollows provide important habitat for hollow-using species. • Retention forestry can help retain habitat trees in harvested areas. • Aggregated retention retained more habitat trees than other silvicultural systems. • Aerial and ground-based surveys gave similar estimates of habitat tree abundance. • Helicopter surveys are a rapid, cost-effective approach for post-harvest assessment. Habitat trees (mature live and dead trees with hollows) are a keystone habitat in Australian eucalypt forests where tree hollows typically occur in large, old trees. These trees provide potential habitat for hollow-using birds, bats and arboreal marsupials, including many threatened species. Habitat trees may be felled during forest harvesting and can also be negatively affected by wildfires. Shortages of habitat trees in harvesting landscapes can be a limiting factor for populations of hollow-using vertebrates. Retention forestry systems are expected to retain a greater number of habitat trees within sites than traditional clearcutting silviculture, but there is a need to quantify how the pattern of retention (dispersed trees vs. retained clumps) will affect the numbers and types of trees retained. The method of assessment (ground-based vs. aerial surveys) may influence the estimated numbers of habitat trees. We investigated habitat tree retention at the Warra Silvicultural Systems Trial in Southern Tasmania, Australia. This trial was instrumental in developing alternatives to clearcutting in tall, wet, old-growth eucalypt forests. Our research has two objectives. Objective 1 is to assess the numbers of habitat trees retained in various alternatives to clearcutting by comparing: unlogged control areas, 0.5–1 ha clumps retained within a harvested matrix (aggregated retention), trees scattered throughout the harvested area (dispersed retention), and small ~0.08 ha machinery exclusion zones where trees were retained if they were not of commercial value (clearcutting with understorey islands). Objective 2 is to compare ground-based to aerial, helicopter-based, assessment of large live and dead trees. Although low replication of harvest treatments precluded statistical comparison of silvicultural systems, the results, based on 1,260 trees, were clear. Of the various alternatives to clearcutting, aggregated retention retained the greatest proportion of all classes of habitat trees, primarily because of higher retention targets, but possibly also because of greater survival with reduced wind exposure in aggregates. Substantially fewer habitat trees were retained with dispersed retention, and virtually none with understorey islands in clearcutting. Aerial and ground-based assessment methods provided similar estimates of numbers of trees with visible hollows in aggregates and understorey islands (R2 = 0.95). Choice of method for future studies should consider available resources and objectives, since there were advantages and disadvantages of each approach. In conclusion, aggregated retention was found to be the preferred silvicultural system for retaining habitat trees within sites for hollow-using vertebrates, and helicopter surveys provide a rapid alternative to traditional ground-based assessment. [ABSTRACT FROM AUTHOR]