Tree Hollows Research Articles

Species identification of Late Pleistocene bat bones using collagen fingerprinting

AbstractBats form the second most diverse mammalian order (Chiroptera), after rodents, and vary widely in their physiology and ecology. Those species that live in temperate climates are generally insectivorous and nocturnal or crepuscular, sheltering in tree hollows, caves, or buildings during the day. They are potentially valuable ecological indicators, due to their dependence on suitable roosting sites and arthropod food, both of which are commonly affected by human activities. Identification of bats from ancient assemblages that are found in caves could therefore provide useful data for palaeoenvironmental reconstructions and show the effect of habitat loss. Here, we apply the recently developed approach of collagen fingerprinting by soft ionisation mass spectrometry to the identification of ancient bat remains in an archaeological assemblage from Pin Hole Cave (Derbyshire, England). Our results show that a simple set of markers can distinguish all seven genera of bats known to be present in either modern or ancient Britain (Myotis, Nyctalus, Pipistrellus, Barbastella, Plecotus, Eptesicus, and Rhinolophus). Further analysis indicates that species‐level determination is possible in some of these taxa, but it would more readily be achieved using the more advanced methods of collagen sequence analysis by liquid chromatography coupled with tandem mass spectrometry. Within our assemblage yielding ~6,800 ancient bone collagen fingerprints, we identified only ~1% that derived from chiropterans, and these were predominantly derived from Myotis (two apparent Brandt's bat fingerprints but the majority indistinguishable between the whiskered, Daubenton's and Natterer's bats), Barbastella (the western barbastelle being the only member of this genus known within Europe), and Rhinolophus (identified as the lesser horsehoe bat R. hipposideros rather than the rare greater horseshoe bat R. ferrumequinum). We infer that the site was likely used by roosting bats throughout the year, and the accumulation of these remains was probably not the result of predator activity. More importantly, the peptide biomarkers provided here could proove valuable in the more systematic analysis of microfaunal remains across many European archaeological and palaeontological sites, preferably those that are collected with well curated stratigraphical information and chronological frameworks.

Biologi Sarang Rayap Subfamili Nasutitermitinae di Stasiun Penelitian Suaq Balimbing Taman Nasional Gunung Leuser

A study had been carried out from May 2017 to February 2018 at Suaq Balimbing Research Center, Gunung Leuser National Park to determine the biology of termite nests of Nasutitermitinae subfamily. The termites were collected with Finding Colony method, while the identification of the termite types and data analysis was conducted in Zoology Laboratory, Department of Biology, Faculty of Mathematics and Natural Sciences, Syiah Kuala University. The results found 3 types of termite nests, i.e., (1) arboreal mounds type (N. roboratus, N. matangensis, H. bicolor and N. neoparvus) as an attempt to disguise themselves and protect their colonies from predators; (2) wood nesting type (N. havilandi, N. proatripennis, H. hospitalis, B. neopusillus, L. leucops, and Aciculitermes sp.1) that is built using drywood to form ventilation space between nests, so the nests become sturdier; and (3) subterraneannest type (L. longipes) that has a stronger construction than arborealmounds and wood nesting since it is made of soil attached by saliva liquid. Shapes of termite nest found namely a rounded shape, a cone shape, a shape that fills in hollow trees, a shape that forms a mound on the ground, and rectangular shape. Some of the termites activities were searching for food outside the nest, consuming remaining food in the nest, and making an attack. The identification results showed that there were 18 termites species from 6 genera of Nasutitermitinae subfamily namely Nasutitermes, Hospitalitermes, Leucopitermes, Longipeditermes, Bulbitermes and Aciculitermes.

First Isolation, Antifungal Susceptibility, and Molecular Characterization of Cryptococcus neoformans from the Environment in Croatia.

The purpose of this study was to investigate the presence of Cryptococcus neoformans species complex isolates from environmental sources in Croatia and to determine their molecular types and antifungal susceptibility. Swab samples of tree hollows and bird excreta in the soil beneath trees were collected. Samples included 472 (92.73%) samples obtained from tree hollows and 37 (7.27%) samples from bird excreta. Four C. neoformans species complex isolates were recovered from tree hollow swabs along the Mediterranean coast, while there were no isolates recovered from bird excreta or from the continental area. Three isolates were identified as molecular types VNI and one as VNIV. All tested antifungals showed high in vitro activity against the four isolates. This is the first report proving the presence of C. neoformans species complex in the environment of Croatia. The results of the study suggest a major risk of exposure for inhabitants living along the Croatian coast and that both VNI and VNIV molecular types can be expected in clinical cases of cryptococcosis. Susceptibility to antifungals confirmed that no resistance should be expected in patients with cryptococcosis at the present time.

Saproxylic beetles (Insecta: Coleoptera) on an old beech (Fagus sylvatica L.) in Madonie Mountains (Sicily, Italy)

Saproxylic insects associated with old trees are seriously threatened in Europe and their habitat is severely decreased. Usually, old trees harbour a very diverse fauna of beetles with many rare species and red-listed saproxylic insect species. These insects live in the dead wood outside the tree (in branches or parts of the trunk), inside the tree hollows, in the debris, and in fungal fruit bodies. During 2019 we collected saproxylic beetles near Monte Carbonara (Madonie Mountains, Sicily, Italy) at 1800 meters above sea level. Particularly, we studied a very old still standing beech (Fagus sylvatica L.), t with numerous cavities and parts of the trunk fallen to the ground. Samples were collected by visually looking for beetles, on the ground and under leaves near the old beech, in its cavities and sifting the debris in the laboratory. Up to date the results include interesting beetle species such as Osmoderma cristinae Sparacio, 1994 (Cetoniidae), Byrrhus numidicus Normand, 1935 (Byrrhidae), Rosalia alpina (Linnaeus, 1758) and Morimus asper Sulzer, 1776 (Cerambycidae).

Molossops temminckii (Chiroptera: Molossidae)

AbstractThe dwarf dog-faced bat, Molossops temminckii (Burmeister, 1854), is a small molossid bat that occurs from Colombia, Venezuela, and Guyana, southwestward through Ecuador, Peru, Bolivia, Paraguay, Brazil, Uruguay, and Argentina. It is one of two species in the genus Molossops and usually roosts in man-made structures, rock crevices, and hollow trees. The species is insectivorous, inhabits a variety of habitats, and is typically found in low altitude zones. Diagnostic characters include triangular ears separated by a wide space, one lower incisor in each ramus, and a last upper molar with three clearly marked commissures. Molossops temminckii is listed as “Least Concern” by the International Union for Conservation of Nature and Natural Resources.

The mycobiome of Australian tree hollows in relation to the Cryptococcus gattii and C.neoformans species complexes.

Cryptococcosis is a fungal infection caused by members of the Cryptococcus gattii and C. neoformans species complexes. The C. gattii species complex has a strong environmental association with eucalypt hollows (particularly Eucalyptus camaldulensis), which may present a source of infection. It remains unclear whether a specific mycobiome is required to support its environmental survival and growth. Conventional detection of environmental Cryptococcus spp. involves culture on differential media, such as Guizotia abyssinica seed agar. Next‐generation sequencing (NGS)‐based culture‐independent identification aids in contextualising these species in the environmental mycobiome. Samples from 23 Australian tree hollows were subjected to both culture‐ and amplicon‐based metagenomic analysis to characterize the mycobiome and assess relationships between Cryptococcus spp. and other fungal taxa. The most abundant genera detected were Coniochaeta, Aspergillus, and Penicillium, all being commonly isolated from decaying wood. There was no correlation between the presence of Cryptococcus spp. in a tree hollow and the presence of any other fungal genus. Some differences in the abundance of numerous taxa were noted in a differential heat tree comparing samples with or without Cryptococcus‐NGS reads. The study expanded the known environmental niche of the C. gattii and C. neoformans species complexes in Australia with detections from a further five tree species. Discrepancies between the detection of Cryptococcus spp. using culture or NGS suggest that neither is superior per se and that, rather, these methodologies are complementary. The inherent biases of amplicon‐based metagenomics require cautious interpretation of data through consideration of its biological relevance.

Hábitats de cría de Aedes aegypti (Diptera: Culicidae) en Jutiapa, Guatemala

Las enfermedades vectoriales constituyen un gran reto para la salud global por su diversidad genética y evolutiva, así como por su potencialidad para causar infecciones graves. Entre estas, merecen especial atención las enfermedades transmitidas por mosquitos (Diptera: Culicidae), con especial énfasis en las arbovirosis. Con el objetivo de profundizar en los hábitats preferenciales de cría de Aedes aegypti (Linnaeus, 1762), se realizó un estudio descriptivo y retrospectivo mediante la revisión documental del registro de muestras del Laboratorio de Entomología Departamental (LED) de Jutiapa, en la región suroriental de Guatemala. Como resultado de las inspecciones periódicas trimestrales, intra y peridomicialiares, realizadas en el universo urbano y rural, se reportaron 56 tipos de depósitos positivos a formas preimaginales de Ae. aegypti, de los cuales 17 fueron útiles (30.35 %) y aunaron el 90.00 % de los depósitos con presencia del mosquito. Se destacó la pila estándar, que aportó el 36.26 % de los casos positivos, y de los cuales el 88 % estuvieron ubicados en el exterior. Ante la variedad de tipos de depósitos artificiales que la población jutiapaneca utiliza en el entorno domiciliario, las hembras de Ae. aegypti no mostraron preferencia por oviponer en depósitos naturales, reportándose la presencia del vector en siete jícaras de coco y 11 oquedades en árboles, fuentes de infestación que oscilaron entre el 0.16 % y el 0.25 %, respectivamente.

Relationship between the common brushtail possum (Trichosurus vulpecula) and tuart (Eucalyptus gomphocephala) tree decline in Western Australia

Forest canopy loss due to plant pathogens, insect or abiotic factors significantly alters habitat and resource availability for animals, which has flow-on effects for whole ecosystems. The tuart (Eucalyptus gomphocephala) has been in decline throughout its geographic range; this is likely associated with watertable and salinity changes, although a plant pathogen (Phytophthora multivora) has also been implicated. We examined the relative abundance of common brushtail possums (Trichosurus vulpecula) across 12 sites (each 0.72 ha) selected on the basis of the health of dominant tuart trees (six ‘healthy’ and six ‘declining’ sites). Habitat variables (understorey, tuart dimensions and density, tree hollows, tree-to-trap distance) and tuart tree health (crown loss, epicormic regrowth) were compared with possum abundance. Possums were detected at most sites. There was no significant difference between brushtail possum numbers at ‘healthy’ or ‘declining’ sites, although marginally more possums were recorded at declining sites (5.7 ± 1.5 (s.e.), n = 6 sites) compared with healthy sites (3.3 ± 0.7; Cohen’s effect size d = 0.80). Slightly higher abundance of possums was associated with sites that had a greater density of smaller-diameter but taller tuart trees. ‘Declining’ sites, with more epicormic regrowth and greater tree densities, may provide more palatable food resources for possums.

Does temperature variation influence nest box use by the eastern pygmy-possum?

Cavity-using birds and mammals reliant on nest boxes may be negatively affected by the poor thermal buffering of nest boxes. I investigated whether nest box use by the eastern pygmy-possum (Cercartetus nanus) over a 4-year period was influenced by maximum ambient temperature, which ranged from 15.6 to 34.9°C during survey occasions. Occupancy modelling of 144 site detections over 30 survey occasions suggested that a model that included maximum temperature had little support whereas a model involving time-varying detection (i.e. detection differed across sample occasions) was the most plausible. I also investigated how temperatures in nest boxes and tree hollows varied over the four hottest days of summer, including one day when the temperature reached 40.6°C. Maximum temperatures were 3–4°C cooler in plywood nest boxes and 5–8°C cooler in tree hollows compared with ambient temperatures. Together, these results suggest that eastern pygmy-possums using nest boxes in coastal areas are unlikely to experience heat stress. Cavity-using species are a heterogeneous group such that empirical studies are required to identify those that may be vulnerable to heat stress if nest boxes are used to provide population support.

The interrelationship between torpor expression and nest site use of western and eastern pygmy-possums (Cercartetus spp.)

Physiology and behaviour are closely linked, making knowledge of the interaction between species’ energetics and activities important when attempting to understand how animals function in the wild. I examined torpor use by western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) in relation to nest site characteristics and movement patterns. In coastal mallee heath in winter, C. concinnus nested beneath leaf litter at the base of dead Banksia ornata, where they employed torpor on 69% of observed days. In warm temperate sclerophyll forest, C. nanus nested in tree hollows of Eucalyptus spp. and used torpor on 64% of days in winter and 10% in summer. Torpor was used in nest sites that were buffered from outside temperature extremes. Both species frequently reused nest sites and while C. nanus was more likely to employ torpor in a previously used site, site familiarity did not influence torpor use for C. concinnus. Additionally, C. nanus was more likely to use torpor in hollows with a higher relative thickness in both seasons. No relationship was found between range size and the number of tracking days or capture body mass, though sample sizes were small. I suggest that the thermal attributes of nest sites influence torpor use for both species and this is likely vital for maintaining a positive energy balance, stressing the importance of preserving habitat with ample potential nest sites for conservation management.

Isolation of Cryptococcus species from the external environments of hospital and academic areas.

Fungi of the genus Cryptococcus are cosmopolitan and may be agents of opportunistic mycoses in immunocompromised and sometimes immunocompetent individuals. Cryptococcus species are frequently isolated from trees and bird excreta in the environment and infection occurs by inhalation of propagules dispersed in the air. The aim was to investigate Cryptococcus species in bird excreta and tree hollows located in a university hospital area and in an academic area of a university campus. A total of 40 samples of bird excreta and 41 samples of tree hollows were collected. The identification of the isolates was done by classical methodology and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Twenty (62.5%) isolates of Cryptococcus were found in bird excreta and 12 (37.5%) in tree hollows. C. laurentii (currently Papiliotrema laurentii) was the most frequent species in both samples, being found in 5 samples of excreta and in 8 tree hollows. The diversity of species found in excreta (C. laurentii, C. albidus [currently Naganishia albida], C. liquefaciens [currently N. liquefaciens], C. friedmanii [currently N. friedmannii] and others) was higher than in tree hollows (C. laurentii, C. flavescens [currently Papiliotrema flavescens], and other yeasts). Many Cryptococcus species were isolated from excreta and tree hollows, and this fact is important for understanding the environmental epidemiology of those emerging pathogens for public health, as a way to implement surveillance actions and control of cryptococcosis.

Bat flies aggregation on Artibeus planirostris hosts in the Pantanal floodplain and surrounding plateaus.

For parasites in natural systems, the most common pattern of spatial distribution is aggregation among hosts. The main causes of such aggregation are variable exposure of hosts to parasites and heterogeneity in host susceptibility. The objective of this study was to determine if there are differences in the aggregation pattern of two species of ectoparasitic flies between the Pantanal and Cerrado regions of Brazil on the bat Artibeus planirostris. We collected the ectoparasites from bats captured between 2002 and 2017 with mist nets in 21 sites in the Pantanal and 15 sites in the surrounding plateaus. The results showed that the aggregation of ectoparasitic flies in Pantanal was more pronounced than in Cerrado. The discrepancy aggregation index (D) of the bat fly Megistopoda aranea was 0.877 in Pantanal and 0.724 in Cerrado. The D values of Aspidoptera phyllostomatis was even higher, with 0.916 and 0.848 in the Pantanal and Cerrado, respectively. Differences in the shelters used may be the main factor shaping variation in aggregation, since the Pantanal does not have rock formations, with only foliage, crowns and hollow tree trunks. These differences likely affect host exposure to the parasites, leading to an increase in parasite aggregation.

Breeding biology of three large, sympatric rainforest parrots in New Guinea: Palm Cockatoo, Pesquet’s Parrot and Eclectus Parrot

ABSTRACT In New Guinea Palm Cockatoos, Pesquet’s Parrots and Eclectus Parrots are potentially threatened by deforestation and hunting. In a 28-month study, we found 51 Palm Cockatoo, 34 Pesquet’s Parrot and 71 Eclectus Parrot nests. Eclectus Parrots used taller, larger, live trees. Palm Cockatoos preferred hollows in broken trunks having deeper hollows with larger entrances. Pesquet’s Parrots excavated their nest hollows in dead trees. Palm Cockatoos nested at lower density (0.008 nests/ha) than Pesquet’s (0.022 nests/ha) and Eclectus Parrots (0.069 nests/ha). Palm Cockatoos and Pesquet’s Parrots appeared to breed seasonally; Eclectus Parrots bred at higher frequency year-round. Palm Cockatoo clutch size was one; Pesquet’s and Eclectus Parrots clutches had one to two eggs. Eclectus Parrots had higher fledging success: 54%, compared with 40% of Palm Cockatoo and 17% of Pesquet’s Parrot eggs. Predation caused most nest failures for Palm Cockatoos and Eclectus Parrots; starvation caused most loss in Pesquet’s Parrots. Humans hunted Palm Cockatoos and Pesquet’s Parrots, not Eclectus Parrots. Higher nest tree density, breeding success, and more generalised feeding habits may make Eclectus Parrots the least vulnerable of the three species. Low population density and breeding frequency of Palm Cockatoos and Pesquet’s Parrots may make them more vulnerable.

Competition drives the decline of a dominant midstorey tree species. Habitat implications for an endangered marsupial

ContextMulti-species native forests are an important source of habitat for many plant and animal species. The dynamics of these forests are shaped by species-specific differences in growth, shade tolerance, life span, and other life-history traits, which lead to complex development patterns. Whether a particular forest stand is suitable habitat for a specific animal species may depend on various stand structural elements, which may vary in abundance due to stand dynamics, thereby generating temporal variability in habitat suitability. In the Central Highlands of Victoria, Australia, the critically endangered Leadbeater’s possum (LBP) requires both a dense lower storey of Acacia spp.for foraging and suitable hollow-bearing trees (HBTs; primarily large eucalypts) for nesting. While most LBP habitat research has focused on the dynamics of HBTs, there are uncertainties about the extent to which the occurrence and abundance of Acacia spp.are affected by competition with eucalypts. Material and methodsWe used 230 forest inventory plots to quantify how the abundance of Acacia dealbata, the most abundant of the Acacia species in these forests, varies with stand age and the abundance of overstorey eucalypts. We also took tree cores from 92 A. dealbata growing in either pure stands or stands mixed with eucalypts to test for the effects of tree age and eucalypt suppression on Acacia growth and decay patterns. ResultsThe frequency and abundance of A. dealbata decreased as stand age increased, but was strongly influenced by eucalypt basal area. When eucalypt basal area was >50m2/ha, Acacia was almost never present. In multi-species stands, Acacia grew more slowly (by a factor of 0.66, 95% credible interval 0.51–0.86) and was more likely to have internal decay (probability increased by 0.25; 0.07–0.48) than when grown in pure stands. DiscussionAcacia dealbata is a native pioneer species regenerating following fires. Eucalyptus overtop the Acacia after 8–10 years. The ensuing stand stratification leads to the decline and loss of the Acacia. We propose silvicultural approaches to slow Acacia decline and prolong the suitability of regrowth Eucalyptus stands as potential LBP habitat.

Characterization of the Beekeeping Value Chain: Challenges, Perceptions, Limitations, and Opportunities for Beekeepers in Kayonza District, Rwanda

A survey was undertaken to characterize the honey production value chain and identify the challenges, limitations, and opportunities for beekeepers in Kayonza District, Eastern Rwanda, in light of the stagnation of the apiculture industry. The majority (86%, n = 100) of the beekeepers were adult males. Most of the respondents (71%) lacked primary level education. The majority of the hives were made from hollow tree logs (40%), tree barks (12%), banana leaves/bark (11%), cow dung (8%), mud (7%), grass (6%), tree leaves (6%), and the rest (20%) were improved beehives, particularly Langstroth hives. The hive pests encountered were hive beetles (25%), small black ants (19%), wax moths (12%), lizards (8%), termites (7%), birds (6%), mites (3%), and mice (2%). Fifty-five percent of the respondents hung their hives on trees to prevent pest invasion with 95% effectiveness, 25% frequently smoked their hives with 85% effectiveness, 16% cleared the bushes around apiaries with 55% effectiveness, and 4% used traditional plant insect repellents with 35% effectiveness. Forty-one percent of the respondents lacked adequate information on beekeeping, 25% had inadequate time to work on apiaries, 24% had inadequate technical knowledge and implements, and 10% needed additional labour for managing apiaries. Based on the results of this study, beekeeping in Kayonza is still largely traditional, characterized by the use of antiquated production methods and underutilization of available marketing channels. Perceptions in the district are that beekeeping is for the poor and illiterate. Challenges and limitations of beekeeping in Kayonza District include lack of education, gender bias, pests and diseases, absconding and swarming of bees, high costs, and lack of modern apicultural equipment. However, the potential for developing beekeeping enterprise (opportunities) is immense given the abundance of wild bee populations, possibility of women participation, abundance of honey collection centres (market), and availability of technical support from Government and development agencies. In conclusion, this study advocates the need for intervention measures to educate and promote production and marketing of quality honey, tackle pest and disease for beekeepers and boost Rwanda’s apiculture industry.

Characteristics of hollows and hollow‐bearing trees in semi‐arid river red gum woodland and potential limitations for hollow‐dependent wildlife

AbstractUp to 37 species of the birds and microbats inhabiting inland Australia are dependent on tree cavities for breeding or roosting. The river red gum (Eucalyptus camaldulensis), a well‐known hollow‐bearing tree species, occurs in linear semi‐arid woodland along thousands of kilometres of ephemeral river channels and is the only tree species that provides widespread, aggregated hollow resources across a landscape otherwise dominated by shrublands. Here we assess the type and quantity of hollows available along ephemeral rivers of the MacDonnell Ranges bioregion in central Australia and determine which characteristics of river red gums best predict the abundance and characteristics of different tree hollows, as first steps towards assessing the current availability of hollows in the region. Approximately a third of all river red gums sampled were hollow‐bearing, but individual trees with abundant hollows were rare. Further, 36% of hollows had an entrance ≤ 5 cm, and 37% had entrances which were 6–10 cm in diameter, whereas only 13% of hollows had an entrance diameter > 20 cm suitable for larger hollow‐using species. Large and high hollows only occurred on trees that did not display post‐disturbance resprouting. Trees with multiple and diverse hollows were rare and tended to be in advanced stages of senescence and had larger stems (82.3 ± 3.33 cm) and were taller (14.4 ± 0.53 m) compared to non‐hollow‐bearing trees (23.44 ± 1.68 cm, 8.0 ± 0.34 m). Further research is required to establish whether the current abundance of hollows and diversity of hollow types are limiting to cavity‐dependent wildlife, and to identify any threats to availability of hollows.

A Scientific Note on a Stingless Bee Hive Model for Ecological and Behavioral Studies and for Environmental Education

Stingless bees (Apidae; Meliponini) occupy a great diversity of habitats in tropical and subtropical regions. They are eusocial and live in sessile colonies. Most meliponini species build nests in pre-existing cavities, such as tree hollows and stingless bee hive models imitate the conditions of natural nests. However, they are unwieldy for scientific studies, especially those focused on ecological and behavioral characteristics. We developed and tested a hive model that ensures clear visibility of the interior of the hive and facilitates ecological and behavioral studies and for environmental education. It successfully housed ten stingless bee species and one semi-social orchid bee species.

都市屋外のゴキブリ生息調査 : XI 超高層ビルの公開空地と都市公園の樹木の樹洞におけるゴキブリ捕獲結果

都市屋外のゴキブリ生息調査 : XI 超高層ビルの公開空地と都市公園の樹木の樹洞におけるゴキブリ捕獲結果

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.