Tree Hollows Research Articles

A four-point electrical resistivity method for detecting wood decay and hollows in living trees

An accurate method of detecting wood decay and hollows or cavities in living trees is useful for risk assessment and maintenance of both forest and urban trees. This study presents the implementation of the four-point electrical resistivity method for the early detection of the presence, location and extent of wood decay and hollows in living acacia trees (Senna alata L.). Electrical resistivity measurement of randomly selected living acacia trees and a freshly-cut acacia tree with decay and hollows were taken to obtain electrical resistivity profiles for sound, decayed and hollowed trees. A laboratory experiment was set up to replicate the resistivity profiles. Wood decay and hollows were replicated at different depths in the laboratory prototype using good electrical conductors and insulators respectively. Resistivity profiles for the sound, decayed and hollowed trees were obtained from the experimental and field results. The resistivity profiles were applied to detect decay and hollows of similar dimensions in living trees through resistivity curve matching. The electrical resistivity of the decayed acacia tree was markedly lowered by an average factor of 5 compared to that of the sound acacia tree. Likewise, the electrical resistivity of the hollowed acacia tree was noticeably greater than that of the sound acacia tree by an average factor of 4. Wood decay and hollows modelled into the laboratory prototype were detected with relatively lower and higher resistivity anomalies respectively. The method indicated that 80% of the randomly selected living trees were sound, healthy trees, whilst 20% had decay and hollow at the time of measurements. This method is suitable for early detection of decay and hollows in hardwood trees.

Carbon emissions and potential emissions reductions from low-intensity selective logging in southwestern Amazonia

Forests in southwestern Amazonia are increasingly being converted for agriculture, mining, and infrastructure development; subjected to low-intensity selective logging of high value timber species; and designated as conservation areas and indigenous reserves. To understand the impacts of forestry in this region, we evaluated carbon emissions from felling, skidding, and hauling in five FSC-certified concessions where workers were trained in reduced-impact logging (RIL) and in four non-certified concessions where workers were not trained in RIL in Madre de Dios, Peru. Emissions estimates did not differ by certification status, so we established a single baseline for selective logging emissions. Total carbon emissions from selective logging were low per hectare (4.9–11.6 Mg ha−1) due to low logging intensities (2.9–8.1 m3 ha−1). Despite the unique architecture of trees in the southwestern Amazon (short stems and large crowns), emissions per volume and per ton carbon in the extracted timber were also relatively low (1.55 Mg m−3 and 4.04 Mg Mg−1, respectively). Only emissions per area scaled with logging intensity. Emissions were dominated by the felled tree itself (in extracted logs and residuals), whereas hauling infrastructure (roads and log landings) contributed comparatively little. Unintended emissions could be reduced by 46% if concessions were able to achieve the best demonstrated outcomes in each source category and by 54% with additional improvements. Less than 5% of timber was lost due to hollow sections. We determined that it would be overly cautious to avoid cutting all trees with any hollow sections, and it would actually increase emissions per unit timber extracted if no other trees were cut in place of the hollow trees. At the tree level, certified concessions had higher log recovery and damaged fewer commercial species during felling, which should increase their current and future timber yields. It is important to both understand and improve carbon dynamics in managed forests in this emerging hotspot for greenhouse gas emissions from deforestation and forest degradation.

Видове різноманіття та особливості поширення дереворуйнівних грибів у парку культури і відпочинку імені Михайла Чекмана міста Хмельницького

Наведено результати дослідження видового складу дереворуйнівних грибів у Парку культури і відпочинку ім. Михайла Чекмана міста Хмельницького та біоекологічні особливості їх поширення. У Парку культури і відпочинку ім. Михайла Чекмана виявлено 29 видів дереворуйнівних грибів, які поширені на 14 видах деревних порід. Найпоширенішими виявилися таки види дереворуйнівних грибів: трутовик облямований, б'єркандера обвуглена, б'єркандера димчаста, трутовик несправжній та стереум жорстковолосистий. Ці види дереворуйнівних грибів трапляються майже на всіх деревних видах парку, які пошкоджені дереворуйнівними грибами. Ці гриби трапляються поодиноко на видах дерев I та ІІ стадій деструкції, дуже рідко – на III стадії. Встановлено деревні породи, які найбільше піддаються ураженню дереворуйнівними грибами, це такі види: береза повисла, ясен звичайний, верба біла, тополя чорна та дуб звичайний. Доведено, що роль дереворуйнівних грибів у міських насадженнях негативна. Більшість видів дереворуйнівних грибів спричиняють різноманітну гниль. Такі дерева довгий час не мають зовнішніх ознак ослаблення. Встановити вражені дерева дереворуйнівними грибами можна тільки за наявністю плодових тіл. Запропоновано основні методи боротьби з дереворуйнівними грибами у парку.

KEANEKARAGAMAN JENIS KELELAWAR (Chiroptera) DI HUTAN KOTA TELUK AKAR BERGANTUNG KABUPATEN KETAPANG

Bats (Chiroptera) are the only mammals that can fly. Bat habitats are in caves, large trees in the forest, hollow trees, coconut trees, banana trees and roofs of buildings. Bats are nocturnal, they forage at night and sleep during the day by hanging upside down. Teluk Akar Bergantung has a generally flat and swampy topography, with a small portion submerged in water. Various types of trees have grown, one of them is Beringin/Kayu Are, which is where bats live. Bats play a role in the balance of ecosystems as seed dispersers, flower pollinators, insect controllers and guano producers. Based on the potential in this area, the research aims to collect data on various types of bats in Teluk Akar Bergantung, Ketapang regency, West Kalimantan. The method used is catch and release method using mist nest. Data analysis of the research used bats identification guide written by Suyanto (2001) entitled “Kelelawar di Indonesia” and “Panduan Lapangan Mamalia di Kalimantan, Sabah, Sarawak dan Brunei Darussalam” by Payne et. al (2000), diversity index (H’), equitability index (e), dominance index and species richness (d). The result of research obtained 14 individuals consist of 6 species (Vampir palsu (Megaderma spasma), Codot mini (Cynopterus minutus), Codot krawar (Cynopterus bracyothis), Codot horsfield (Cynopterus horsfieldii), Codot kecil kelabu (Pentethor lucasii) and Codot pisang-coklat (Macroglossus minimus), belonging to 2 families (Pteropodidae and Megadermatidae). Diversity index is in the medium category (1,47), the equitability index is in the high category (0,82), no type of bats that dominates (0,31) and the species richness is in medium category (2,79). Keywords: bats, diversity, Teluk Akar Bergantung, urban forest

Mortality and morbidity in wild Taiwanese pangolin (Manis pentadactyla pentadactyla).

Globally, pangolins are threatened by poaching and illegal trade. Taiwan presents a contrary situation, where the wild pangolin population has stabilized and even begun to increase in the last two decades. This paper illustrates the factors responsible for causing mortality and morbidity in the wild Taiwanese pangolin (Manis pentadactyla pentadactyla) based on radio-tracking data of wild pangolins and records of sick or injured pangolins admitted to a Taiwanese wildlife rehabilitation center. Despite being proficient burrowers, results from radio-tracking show that Taiwanese pangolins are highly susceptible to getting trapped in tree hollows or ground burrows. Data from Pingtung Rescue Center for Endangered Wild Animals showed that trauma (73.0%) was the major reason for morbidity in the Taiwanese pangolin with trauma from gin traps being the leading cause (77.8%), especially during the dry season, followed by tail injuries caused by dog attacks (20.4%). Despite these threats, Taiwan has had substantial success in rehabilitating and releasing injured pangolins, primarily due to the close collaboration of Taiwanese wildlife rehabilitation centers over the last twenty years.

The influence of different restoration thinning treatments on tree growth in a depleted forest system

Land managers increasingly are interested in the means by which degraded or alienated forest ecosystems can be restored, typically for biodiversity gains. Indeed, there is some urgency to restore the integrity of dwindling intact forests across the globe, in part to halt an accelerating biodiversity crisis and also achieve sustainability goals. Restoration thinning can be an effective management tool where there is excessive stem density by utilising the selective removal of trees to return an ecologically more-desirable ecosystem structure and processes. A key objective of such thinning has typically been the hastened growth of retained stems and associated environmental attributes (e.g. tree hollows, coarse woody debris, understorey structure and other habitat) that provide benefits for forest flora and fauna. The Box-Ironbark forests of south-eastern Australia have been extensively exploited since European settlement and lost many of the ecological attributes considered beneficial for effective function and biodiversity conservation, especially large trees. Three thinning treatments, differing in their density and pattern of retained trees, were compared with controls to determine the most effective approach for restoring these systems and increasing the rate of recovery for biodiversity benefits. The thinning treatments applied different retention levels of stems, one which reflected conventional silvicultural practice and two designed to reflect a patchy forest structure. The response of tree diameter growth to thinning treatments, for multiple tree species, was examined approximately a decade after thinning. All three thinning treatments increased tree growth-rates similarly (0.32–0.57 cm/yr), compared with the controls (0.2–0.27 cm/yr). These data suggest that the choice of thinning treatment may not be critical for accelerating tree growth, and land managers can focus more strongly on the treatment that provides the best overall outcomes for biodiversity.

Isolation of Cryptococcus neoformans from a Chesnut Tree (Castanea sativa), Denizli, Turkey

Cryptococcus neoformans is a basidiomycetous encapsulated yeast that can cause life-threatening infections in immunosuppressed humans and animals. C.neoformans/Cryptococcus gattii infections are considered to be acquired via inhalation of aerosolized particles from the environment. Avian guano, decaying tree hollows and soil are known as environmental niches. In recent years, colonization of the woody structures of different trees such as Eucalyptus camaldulensis, Tamarix hispida, Platanus orientalis and Punica granatum has been reported in the environmental study of the western Anatolian region. Based on the results of previous studies, our country may have intensive Cryptococcus colonization niches in the western regions. The aim of this study was to investigate the presence of the colonization of C.neoformans niche in chestnut (Castanea spp.) trees on higher altitudes. In the study, the colonization of C.neoformans was screened on chestnut trees (Castanea spp.) in Aydın-Ödemiş-Denizli geographical area. This area consists of mountainous terrain between the fertile plain formed by two major rivers.This region is one of the widespreading areas of chestnut farming in Anatolia. Two hundred and fourteen chestnut trees that had deep fissures or trunk hollows were screened during mid-summer 2017. A swabbing technique was used, and all samples were cultured on Staib agar medium containing biphenyl and antibiotics. Cultures were checked for ten days for suspicious brown colonies. Suspicious yeast colonies were tested for the identification of pathogenic Cryptococcus by conventional methods and canavanine-glycine-bromothymol agar reactions. ITS 1-4 primers were used for strain PCR tests. We determined the mating type and serotypes by PCR analysis of the STE20 genes using STE20 (Aa), STE20 (Aα), STE20 (Da), and STE20 (Dα) primers. V8 agar medium was used for mating cultivation. Only one (0.47%) strain of C.neoformans was isolated from 214 screened trees. This strain was confirmed by ITS 1-4 sequencing. The serotype A MATα mating type was observed. Basidium, basidiospores and clamp connections in hyphal structure were noted with MATα mating on V8 agar medium. In this study, the first C.neoformans isolate from a chestnut tree (Castanea sativa) was determined from Denizli region. Further studies of distribution of human pathogenic Cryptococcus will be helpful to determine the risk areas for the living organisms in our region.

Limited use of bat boxes in a rural landscape: implications for offsetting the clearing of hollow‐bearing trees

Bat boxes frequently form part of hollow‐bearing tree offsets; however, their effectiveness is poorly documented. We investigated the effectiveness of a bat box program designed to partially offset tree hollow loss from clearing for a coal mine. During the first year of monitoring, we detected bats in 5% of 1,308 box checks. Only 3 of 13 local tree cavity‐roosting bat species/species groups used boxes and occupancy was not strongly associated with modeled box and site attributes. In the second year, we tested two hypotheses that may explain the relatively low box use: (1) solar exposure of boxes was inadequate for heterothermic bats and (2) available box designs were of low suitability. Relocating boxes to increase solar exposure did not increase use, or enhance the temperature profiles of relocated boxes. Introduction of a new box design led to 11 times higher use compared with existing designs forNyctophilusspp. (long‐eared bat). Overall, our data suggest that the bat box program was ineffective due to few bat species using boxes, infrequent box use by three species, and rarity of maternity roosting. The knowledge gap of species‐specific box designs and roosting ecology limits the effectiveness of boxes to offset cleared hollow‐bearing trees. Lack of knowledge and the widespread use of bat boxes to offset lost tree hollows highlights the need to (1) rigorously protect hollow‐bearing trees and (2) advance our understanding of species‐specific roost ecology, box design preferences and mechanical hollow creation into trees, before artificial hollows can be considered a meaningful offset measure.

Roost selection in concrete culverts by the large-footed myotis (Myotis macropus) is limited by the availability of microhabitat

The large-footed myotis (Myotis macropus) is a specialist trawling bat with flexible roosting behaviour, being able to switch between caves, tree hollows and artificial roosts such as bridges, tunnels and culverts. However, little is known about how this species selects culvert roost sites in urban landscapes where hollows may be limited or absent. We surveyed 57 concrete culverts and found 21 M. macropus roosts comprising day and maternity roost sites; 305 bats were captured. Colony sizes averaged 20.6 ± 17.7 (range = 4–49) for maternity roosts and 2.0 ± 0.8 (range = 1–3) for day roosts. Roost culverts differed significantly from available culverts predominantly in terms of availability of microhabitat (lift holes and crevices). Roost culverts had lift holes that had greater cavity dimensions than available culverts and crevices were found only at roost culverts. Culverts containing microhabitat were a limited resource in this urban landscape and so increasing their availability may provide more urban roost sites for this specialist species.

Les puits de l’âge du Bronze du Parc d’Activités du Pays d’Erstein (Bas-Rhin, Alsace) : des analyses dendroarchéologiques à l’ étude de l’occupation du sol

Les puits de l’âge du Bronze du Parc d’Activités du Pays d’Erstein (Bas-Rhin, Alsace) : des analyses dendroarchéologiques à l’ étude de l’occupation du sol

Comparison of three trap types in sampling saproxylic beetles living in hollow urban trees

Hollow trees are an important habitat for a large number of saproxylic invertebrates, many of which are rare or threatened. Large old trees occur frequently in cities, but the saproxylic fauna inhabiting these trees has been poorly studied. Sampling in urban areas includes the risk of trap failure due to human interference, which needs to be considered when designing sampling. The aim of our study was to find an efficient trap type for sampling saproxylic beetles in hollow urban trees. We compared the species richness and species composition of saproxylic beetle assemblages between trunk window, aluminium foil tray and pitfall traps placed inside hollow trees in the Helsinki metropolitan area, Finland. A total of 30 traps of each trap type were set in 15 trees. The traps caught a total of 4004 saproxylic beetle individuals belonging to 131 species. Trunk window and aluminium foil traps had similar assemblage and trapping efficiency, and were significantly more efficient than pitfall traps. However, pitfall traps caught certain species more efficiently than the other two trap types. Time spent separating insects from samples was the most laborious work stage. The time increased with increasing sample weight, i.e. the amount of wood mould in the trap. Trunk windows were the most efficient trap type also in terms of saproxylic species and individuals per handling time. We conclude that saproxylic beetle fauna living in hollow urban trees can be efficiently sampled with small trunk window traps or containers placed on the inner walls of hollows.

Diet of boreal owl (Aegolius funereus) in lowlands of north-eastern Poland

Abstract Although studies on many owl species diets are common, there are only scarce data on the diet of the boreal owl from the lowlands of Eastern Europe. We have therefore studied its diet in one of the most important Polish population areas, the Knyszyńska Forest (north-eastern Poland). Pellets were gathered between February and June in 2006, 2012–2016 from tree hollows and the ground underneath. Altogether 178 pellets and six sets of pellet fragments were collected from 19 different sites. Eight mammal and eight bird species were identified among the 213 prey items found in the gathered material. Small mammals dominated, both in prey number (88.3%) and biomass (85.1%). Bank vole proved to be the main prey (over 40% of prey numbers), while Microtus voles (27.3%), small passerine birds (11.7%) and shrews (7.5%) were important alternative prey. Diet range proved to be similar to other sites in Europe.

Effectiveness of vole control by owls in apple orchards

Abstract Biological pest control is gaining greater acceptance as an important part of integrated pest management for sustainable agriculture. However, knowledge regarding biological control of rodent pests is limited, and its effectiveness in temperate areas has not been quantified. In traditional Japanese apple orchards, the Ural owl Strix uralensis breeds in tree hollows and preys on the Japanese field vole Microtus montebelli, a native pest species that can harm fruit production. In this study, we hypothesised that the Ural owl, a generalist predator, can act as a biological control agent by reducing vole densities in temperate orchards. To quantify the pest control effects of breeding Ural owls, we first analysed the diet of individual owls nesting in apple tree hollows. Second, we installed nest boxes in orchards to attract breeding owl pairs and collected data on vole population changes around owl nests to compare with control areas. The population changes were analysed using a generalised linear mixed model to assess the effect of breeding owls within their breeding territory. The model considered seasonal fluctuations in vole population size as well as surrounding land‐use. We also examined vole populations around the owl nests in April, and the distance between nests and forested areas, to determine if these variables influenced nest site selection. Voles were the primary prey of Ural owls breeding in orchards and the owls reduced vole populations within their estimated breeding territories by 63% (±SE: 53%–70%) compared with the predicted density without owls. Owls preferred to nest in orchards with higher vole population densities in April. Our findings also indicate that higher occupancy rates are possible by distributing nest boxes based on Ural owl breeding territory size (306 m radius circle in our study). Synthesis and applications. As breeding Ural owls provide significant pest control effects within their breeding territories, the reintroduction of breeding Ural owl pairs within orchards would contribute to rodent pest control. Promoting the reproduction of native raptors in agricultural areas can be an option for developing integrated pest management while simultaneously maintaining regional biodiversity.

Detection of decay and hollows in living almond trees (Terminalia catappa L. Roxb.) using electrical resistivity method

A precise and cost-efficient diagnostic technique for detecting decay and other structural defects in living trees is indispensable for the risk assessment and conservation of urban and forest trees. A study was carried out to detect the location and extent of decay and hollows (or cavities) in almond trees (Terminalia catappa L. Roxb.) using the four-point electrical resistivity method. Electrical resistivity measurements (ERm) of randomly selected living almond trees were taken using an earth resistivity meter, four probes and a modified form of Schlumberger electrode configuration. The ERm were used to obtain resistivity profiles (RP) of the trees. The RP of freshly cut healthy, decayed and hollowed trees were also obtained. A laboratory experiment was set up to replicate the RP of healthy, decayed and hollowed trees. Wood decay and cavities in trees were detected through RP matching. In comparison to healthy trees, wood decay and cavities in tree stems were detected with relatively sharp decrease and increase in electrical resistivity values, respectively. The extent of the resistivity anomalies corresponds to the extent of wood decay and cavities in trees. This method is applicable to early detection of decay and cavities in hardwood trees.

Identifying regrowth forests with advanced mature forest values

In this study, we examined the associations between field-assessed floristic and structural habitat values for mature forest and GIS-derived variables to assess whether high conservation value forests could be predicted for strategic reservation at a landscape scale. We investigated the Eucalyptus regnans forests of the Victorian Central Highlands in south-eastern Australia, where several extensive wildfires in the last century have left little mature forest. We assessed the extent to which the floristic composition and a suite of habitat-related structural variables could be explained by two forest inventory GIS variables (percentage senescence and site productivity) and whether explanatory capacity improved from inclusion of additional environmental variables (climate, soils, topography, structure and spatial location). Results showed that the floristic composition was weakly related to productivity, but not to percentage senescence. Four habitat-related structural variables were positively related to percentage senescence (density of old-growth eucalypts, the quadratic mean diameter (QMD) of both live and dead eucalypts, and the maximum eucalypt form class (a proxy for tree hollows)) while the volume of CWD had a marginally significant positive relationship. Three structural variables were related to productivity (the maximum eucalypt form class, the QMD of dead understorey trees and of dead eucalypts). However, in all cases the explanatory power of percentage senescence and productivity was weak (proportion of deviance explained by the models <0.3). Inclusion of the other environmental variables did not substantially improve explanatory power in any case. Our results suggest that there is a high degree of stochasticity driving floristic and structural composition within these forests, making the detection of most mature forest values difficult without site visits. There may be some limited capacity for the presence of senescent trees visible in aerial photographs to highlight stands more likely to contain habitat trees, but there was no relationship with floristic maturity. Our results also suggest that more productive sites do not have substantially greater habitat values, indicating that the current timber harvesting approach of prioritising the harvest of stands on more productive sites is unlikely to have negative consequences for biodiversity.

Isolation of &lt;i&gt;Cryptococcus&lt;/i&gt;-Like Yeast From Natural Environments

Background: Cryptococcus (C. gatti and C. neoformans) causes meningitis and pneumonia in immunocompromised and immunocompetent hosts, and several cases are diagnosed at Aurora Health Care each year. Cryptococcus is infrequently isolated from the environment, despite being the presumed infection source, with no known isolations in Wisconsin since 1964. C. gatti-endemic areas are expanding worldwide, and it is commonly isolated from tree hollows.

New species of Pseudoscorpiones (Arachnida) from tree hollows in a Mediterranean oak forest in Spain.

Pseudoscorpions inhabiting mature Quercus pyrenaica Willd. trees have been surveyed using hollow emergence traps and window traps in Salamanca, Spain. Three new species are described: Neobisium (N.) hispanicum Zaragoza Hernández-Corral, n. sp., Rhacochelifer gaeli Zaragoza Hernández-Corral, n. sp. and Rhacochelifer nonidezi Zaragoza Hernández-Corral, n. sp. The genera Amblyolpium Simon, 1898 and Beierochelifer Mahnert, 1977 and the species Amblyolpium dollfusi Simon, 1898 and Beierochelifer peloponnesiacus (Beier, 1929) are new records for the Iberian Peninsula. Beierochelifer peloponnesiacus jonicus (Beier, 1932) is shown to be a junior subjective synonym of B. peloponnesiacus n. syn. New regional records of five other species belonging to the families Cheliferidae, Chernetidae and Withiidae are given. Keys are given for the species of the genera Pseudorhacochelifer Beier, 1976 and Rhacochelifer Beier, 1932 with elongated keels on posterolateral corners of carapace and anterior tergites in males, and for the Rhacochelifer species of the Iberian Peninsula. Complementary data to the description of the female syntypes from Caravaca (Murcia, mainland Spain) and males from the Canary Islands of Rhacochelifer pinicola (Nonídez, 1917) are given. Brief redescriptions of the female of Neobisium (N.) maroccanum Beier, 1930 and the male of Rhacochelifer euboicus Mahnert, 1977 are provided. The previous record of R. disjunctus from Slovakia is shown to be an error for R. euboicus. New data on the distribution and habitats of species of Cheliferidae, Chernetidae and Withiidae are given.

Saproxylic biodiversity and decomposition rate decrease with small-scale isolation of tree hollows

Biodiversity is fundamental for ecosystem functioning, but little is known about how function responds to biodiversity loss following habitat disturbance in natural systems. Due to the global decay of veteran trees, many associated saproxylic (i.e. deadwood-dependent) insects are considered threatened. Nevertheless, the role of habitat spatial configuration on saproxylic insect biodiversity and dead wood decomposition is poorly understood. We performed a six-year landscape-scale colonization experiment on saproxylic beetles inhabiting hollow oaks, using boxes filled with wood mould as standardized habitat patches. We placed boxes either on a hollow tree or on another tree 61–324 m from the hollows, thereby creating two habitat isolation levels. We quantified wood mould decay and biodiversity in the boxes, measuring species richness, total abundances and community-weighted mean of body mass (CWM) as an index of community functional composition. Isolation had a persistent negative effect on primary consumer biodiversity, but it only impaired decay at the beginning of the experiment. All effects were independent of landscape-level (500-m radius) habitat amount surrounding the boxes. Wood mould decay was mediated by CWM of primary consumers. Therefore function was driven by the body masses of the dominant primary consumer species but not by species numbers (richness) or individual numbers (abundance). Our experiment shows that small-scale habitat isolation leads to biodiversity loss and reduced function and indicates that habitats created by conservation efforts will be used by more saproxylic species if located within sites with a high density of veteran trees.

Managing mature forest features: The production, accuracy and ecological relevance of a landscape‐scale map

SummaryMature 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.

The road to oblivion – Quantifying pathways in the decline of large old trees

Large old hollow-bearing trees have a wide range of key ecological roles in forest and other ecosystems globally. Patterns and rates of mortality and decay of these trees had profound effects on the size and composition of their populations. Using an 18-year empirical study of large old trees in the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, we sought to determine if there are particular patterns of decline that are shared by a proportion of the trees in a tree population. We also sought to identify drivers of decline of these trees by quantifying relationships between the condition state of trees (viz: tree form) and a range of covariates.We found that time, stand age and fire can individually and in combination, strongly affect the decay (and eventual collapse) of large old trees. In particular, we found compelling evidence that patterns of tree decline were markedly different in old growth forest (stands dating from ∼1850) relative to three other younger age classes examined. Trees in older forest decayed less rapidly than trees of equivalent tree form in younger forest. Old growth stands also were characterized by trees in an overall much lower (more intact) form category than the other age classes of forest. A key pattern in our study was the rapid deterioration of large old trees in the youngest aged stands (viz: those regenerating after fires in 1939 and following disturbance between 1960 and 1990). In these forests, a very high proportion of large old trees were either in the most advanced state of tree decay (form 8) or had collapsed (form 9). This is a major concern given that 98.8% of the Mountain Ash forest ecosystem supports forest belonging to these (or even younger) age cohorts. Our investigation highlights the need for forest management to: (1) increase levels of protection for all existing large old hollow-bearing trees, (2) expand the protection of existing regrowth forest so there is the potential to significantly expand the currently very limited areas of remaining old growth forest.