Journal articles on the topic 'Tree trunk hollows'

Many hundreds of species of wildlife worldwide are dependent on tree hollows (cavities) for their survival. I reviewed the published literature for hollow-using Australian birds and microbats to document their tree-hollow requirements and to guide future research and management. Such information is vital to the conservation of these species. The hollow requirements of only 35 of 114 hollow-using bird species and 15 of 42 hollow-using microbat species were documented in some detail. This overall paucity of information limits the ability to manage for the future requirements of species. However, some generalisations can guide management until further studies are conducted. Most species used a variety of available tree species, and the extensive use of dead trees probably reflects the high likelihood of these trees containing hollows. Birds (other than large parrots) and bats chose hollow entrances of a size close to body width. Large parrots require large hollows, with a preference for large vertical spouts and trunk hollows. Few birds or bats demonstrated an absolute requirement for high (>10 m) tree hollows, with most (70%) using some hollows with entrances ≤5 m above ground. Temperature has been postulated to influence roost selection among microbats because it enables passive rewarming from torpor and there is some evidence from Australian bats to support this. Many studies suggest a future shortage of hollow-bearing trees. Currently, artificial hollows appear to be the most likely interim solution to address this. Knowledge of the natural hollow requirements of species can be used to refine artificial-hollow designs. An increase in research effort is needed to address the many gaps in knowledge that currently exist. Priorities for research include (1) many additional studies to document the characteristics of the hollow-bearing trees used by species of microbat, (2) the need to conduct long-term bioregional studies of hollow-bearing tree attrition to help identify where management responses are most needed and (3) investigating whether fire plays a significant role in the creation of tree hollows of a range of size classes and therefore may have a management use. Such information has broad relevance because it will provide ecological insight that can be applied to the management of hollow-using birds and bats elsewhere in the world.

The oil palm trees in Southeast Asia face a great challenge due to voids within tree trunks. Besides, both plantations and the palm oil industry suffered considerable losses due to ineffective inspection of defective trees. Several techniques such as ultrasound, X-ray, capacitive volume, gamma computed tomography, and microwave tomography were applied to detect and control the decay of a trunk. However, all the techniques showed substantial drawbacks (such as limited resolution, tedious processing time, and use of bulky equipment with limited mobility) except for microwave tomography which overtook the other techniques by using a method that distinguishes the dielectric properties of healthy and diseased trunks. This work proposes ultra-wide-band (UWB) signal transmission and reception using antenna sensor arrays that record reflections from affected regions in the trunk. Various factors have been considered, such as different cylindrical arrays of 4, 8, 12, and 16 antennas; different positions of hollows; a heterogeneous trunk; multiple targets; and larger trunk samples (16–30 cm). To validate the system’s capabilities, two cylindrical wood samples with different diameters of 100 mm and 140 mm and with one hollow and three hollows within are 3D-printed, investigated, and then measured. The authors recommended a robust time-reversal algorithm (RTR) to reconstruct 2D images that successfully identified and localized cavities with the smallest diameter of 3.5 mm. Furthermore, reconstructed images of measured data verified a practical and reliable oil palm trunk imaging and sensing system with a high structural similarity index and resolution.

The occurrence of hollows in eucalypts and Ironwood Erythrophleum chlorostachys was examined in different habitats in Limmen National Park in the Gulf Falls and Uplands bioregion of the Northern Territory. For each tree sampled, the diameter of the trunk at breast height (DBH) and numbers of hollows in three size categories were recorded. It was found that the riparian zone had the highest density of hollows per unit land area, followed by the rocky hill zone, and then the sandy flat zone. The relationship between hollows per tree and DSH was compared for four species: Eucalyptus camaldulensis (the dominant riparian tree), Eucalyptus leucophloia (the dominant tree on rocky hills), Eucalyptus miniata (the dominant tree on sandy flats), and Ironwood. E. miniata and Ironwood were found to have fewer hollows for a given DBH. It is suggested that the low incidence of hollows in Ironwood is a result of the species' know resistance to termites. The low number of hollows per Ironwood tree, the scarcity of Ironwood in the study area, and the small size of Ironwood trees relative to most of the eucalypts resulted in very few Ironwood hollows overall. This considered, harvesting of Ironwood (a preferred timber species) in this area is unlikely to have an impact on the availability of hollows to fauna. Further research is required to clarify discrepancies with other studies, and assess whether these results apply more broadly, for instance to wetter areas with larger Ironwood trees.

Effective management of tree-hollow-dependent wildlife requires a sound knowledge of the characteristics of the trees used for shelter or breeding. We used radio-tracking to identify the den trees of squirrel gliders (Petaurus norfolcensis) in south-east Queensland (Qld) and north-east New South Wales (NSW). Squirrel gliders used dead trees as well as 13 species of living tree for dens across the two locations. Dead trees accounted for a large percentage of dens (54% of 48 dens in Qld, and 50% of 18 dens in NSW) despite comprising only 3–10% of the forest (trees >20 cm diameter at breast height (dbh)) at each location. This preference is largely due to dead trees being more likely to contain hollows, accounting for 26–44% of available hollow-bearing trees. Mean den tree size (dbh) was 48.9 ± 2.4 cm in Qld and 62.8 ± 5.6 cm in NSW. Den entrance height averaged 6.8 ± 1.2 m in Qld and 11.9 ± 1.3 m in NSW. Fissures in the trunk and holes in branches were the most common of six hollow types used. At one location branch end hollows were ignored relative to their availability. Den entrances varied in size (2.5–12 cm wide) but most were ≤5 cm in diameter. Entrance size of hollows appears to be the hollow attribute of most importance to squirrel gliders. Monitoring of these den trees over several years revealed the collapse of three dead den trees at each location, which is equivalent to an annual loss of 3% of den trees. Further research is needed to determine whether this will lead to a future shortage of den trees.

Abstract The studies to determine the qualitative and quantitative characteristics of pathologies on trees have carried out as a part of a survey of plantations along the Big Voronezh ecological trail. These characteristics are not taken into account in the guidance documents, but in fact they define these trees as emergency ones. In addition to stem rot and dangerous trunk slope, recommended by the instructions, trees with butt hollows, cancerous tumors on the trunk, splitting of the trunk and shriveled skeletal branches were taken into account. The collected material and its analysis showed that (in case of accounting for trees with such pathologies) the number of trees classified as emergency can increase by 62%. Among additional pathologies, butt hollows take the leading position. It is indicated that there is a number of pathologies fatal for trees found in other types of plantations (in addition to these pathologies characteristic of oak stands). It is concluded that the modern technique for identifying emergency trees is not perfect, since it does not take into account a significant number of tree pathologies that increase the likelihood of tree breaking off or falling out, which definitely makes such trees extremely dangerous.

The trees growing in urban environments are exposed to the highest pressure of negative exogenous factors and, consequently, many tree species come to the critical age and become hazardous. A complex approach to evaluate the condition of green plantings under the technogenous load using visual, instrumental, biomechanical etc. methods allows timely and reliable identification of hazardous trees. For this purpose, we developed a new methodology of determining the hazardous degree of trees in residential areas. This method is based on the accounts of tree mechanical hardiness evaluation and up-to-date instrumental research data to be used by municipal services employed in plantings monitoring and care. The main parameters are: age, diameter of the base, diameter at height, trunk girth at the base, trunk girth at a height of 1,3 m, the height of the tree, the angle of inclination of the trunk, the vital status score for Saveleva, morphological damage to the trunk, the description of the crown architectonics, the presence of morphogenetic and exogenous damage to the leaf blade, the population of the trunk pests, the presence of hollows, the wind feature and the loading of this site, the mode of visiting the territory (recreational load), the direction of possible fall, percentage of sound rot, modulus of elasticity of wood, density of wood, the ratio of biomass to critical mass, mechanical resistance to static and dynamic loads according to calculations on biomechanics. In the case study of a model tree (London plane) the applicability of this approach to landscaping practices is shown.

There are rather ubiquitous relief forms on the Ukrainian territory, which are created by strong winds within the forest lands and other areas where woody vegetation is represented. This article analyzes peculiarities of the emergence of such windthrow relief forms as windthrow hills, hollows, microstrands, microcaves, percussive microcraters and root blocks. By size, they predominantly have a rank of nano- and microrelief while their surface is often complicated by picoforms of relief. According to the materials of our own field research in different regions of Ukraine and based on the analysis of available publications on the subject, morphological and morphometric features as well as the density of the location of such relief forms within the territories with domination of woody vegetation were described. On the grounds of the field research, it can be concluded that hollows, hills (“earth hills’) and microstrands are the most widespread windthrow relief forms. The mechanism of their formation can be described in the following way: the root system of the tree breaks out under the influence of the wind, captures a certain amount of soil and forms a windthrow hollow on the place where the tree used to grow, a windthrow hill (“earth hill’) appears on the edge of the windthrow hollow from which the windthrow microstrand branches out. The dimensions of the windthrow hills and hollows depend mainly on the structure and condition of the root system and the composition of the soil. Meanwhile, the dimensions of microstrands depend on the length and diameter of the tree trunk and the height of the windthrow hill. As a result of falling of mature trees up to 1m deep hollows are often formed. Only occasionally, they have a rounded shape with a diameter of about 2m. In most cases, these relief forms are oval, 2-3 m in length and 1-2 m in width. Smaller windthrow forms occur when relatively small trees fall. The density of the windthrow hills, hollows and microstrands in the forest lands of different regions of Ukraine can range from several items to several dozen per 1 hectare. In some cases, during strong winds, windthrow “microcaves” (the result of incomplete root canal deformation) and percussive “microcraters” (the result of hitting the earth’s surface by broken trunks and large branches) are formed. On the slopes, as a result of the interaction of eolian activity, gravity, phytogenic factor and sometimes erosion, the formation of such a kind of windthrows as “root blocks” might take place. The study of such relief forms enables to assess the role and extent of the influence of the eolian factor and biota on the formation of morphosculptural characteristics of the surface of particular regions of Ukraine.

Trees and shrubs grown in ordinary plantings along city streets play a role of barrier between residential developments and highway, protecting residential area from adverse impact of motor vehicles. Different varieties of poplar have received large spread in the greening of cities. This unpretentious, resistant to dust and gases, fast growing species is able to successfully protect living space from harmful emissions. In Bratsk, with harsh, sharply continental climate and adverse environmental conditions, balsam poplar (Populus balsamifera L.) is dominant variety of species. The age of trees currently close to critical one (40-50 years), therefore there is a need of gradual replacement of plantations of Populus balsamifera L. in urban plantings. In one of the residential areas of the city a study on plantations of poplars was conducted. Samples of 653 tree were studied in a visual way: damage of different nature are fixed: thinning of branches, thinning of crown, frost cracks, side-dry tree, mechanical damage, curvature of trunk, presence of rot, hollows, exfoliation, contaminants. We compared the trees subjected to pruning of the crown and trees without pruning. It was discovered that beheading trees are damaged more. 102 trees were examined using Resistograph 4450 device. This method, which is less traumatic for the tree, allows to accurately determine the presence of rot in the trunk. Central rot was detected in different degrees of spread in all trees. There are trees, which state is normal in visual inspection, but the results of instrumental evaluation show internal damage to the trunk by more than 80 %. The greatest danger is the trees with inclination of the trunk, asymmetry of crown. In the presence of the central rot, such trees are considered hazardous ones. 17 of 102 trees were considered hazardous and they are recommended for cutting. A significant part of plantations are planted with violation of the rules: distance from the edge of the roadway to the axis of tree does not comply with the regulatory, which affects traffic safety and condition of plantations. On the basis of conducted research, conclusions are formulated and recommendations on the improvement of urban spaces are proposed, restoration of their environmental and aesthetic functions: to gradually replace old plantings of poplars to other dust - and gas resistant species, expanding the range of vegetation; to comply with the rules in cutting of poplars; to carry out agricultural activities, to remove damaged trees on time.

AbstractThis study investigated the effect of environmental variables such as soil class, soil water availability, topography and slope on spatial distribution patterns of tree species in a Brazilian Seasonal Semideciduous Forest area. Floristic and structural data for a tree community were obtained by sampling 100 plots 10 × 10 m in which every tree with trunk diameter (dbh) ⩾ 4.77 cm at 130 cm above ground level was sampled. The area under study showed a marked soil gradient, directly associated with the topography: flat hilltops with Al3+-rich Dystric Latosols give way to steep colluvial slopes with shallower and more Dystric Cambic Latosols without Al3+, changing over, at the bottom of the hollows, to Epieutrophic Cambisols richer in nutrients. The floristic-sociological parameters analysed for the soil habitats did not differ statistically from each other. The diversity and equability indices were 3.6 and 0.84, 3.48 and 0.85, 3.49 and 0.84 for the Dystric Latosol, Dystric Cambic Latosol and Epieutrophic Cambisol, respectively. The soil variables (related to the fertility and texture) and the soil water regime (drainage) were probably the principal factors determining the spatial distribution patterns of tree species in the forest.

Failure of hollow trees in urban areas is a worldwide concern, and it can be caused by different mechanisms, i.e. bending stresses or flattening-related failures. Here we derive a new analytical expression for predicting the bending moment for tangential cracking, and compare the breaking moment of various failure modes, including Brazier buckling, tangential cracking, shear failure and conventional bending failure, as a function of t / R ratio, where t and R are the trunk wall thickness and trunk radius, respectively, of a hollow tree. We use Taiwan red cypress as an example and show that its failure modes and the corresponding t / R ratios are: Brazier buckling (Mode I), tangential cracking followed by longitudinal splitting (Mode II) and conventional bending failure (Mode III) for 0 < t / R < 0.06, 0.06 < t / R < 0.27 and 0.27 < t / R < 1, respectively. The exact values of those ratios may vary within and among species, but the variation is much smaller than individual mechanical properties. Also, shear failure, another type of cracking due to maximum shear stress near the neutral axis of the tree trunk, is unlikely to occur since it requires much larger bending moments. Hence, we conclude that tangential cracking due to cross-sectional flattening, followed by longitudinal splitting, is dominant for hollow trunks. Our equations are applicable to analyse straight hollow tree trunks and plant stems, but are not applicable to those with side openings or those with only heart decay. Our findings provide insights for those managing trees in urban situations and those managing for conservation of hollow-dependent fauna in both urban and rural settings.

Palm trees, like all other tree species, are living entities that may be subject to the attack of several natural agents which affect the strength of the trunk. The most serious of these damaging agents are parasites and rot fungi, which proliferate in the substance of the stem, destroying its cells and fibers and weakening it. Consequently, this decay affects the physical characteristics of the modes of vibration in the tree trunk regarding resonance frequency, shape, and damping. Advanced stages of rot infection in a tree trunk may reach such an extreme level that substantial amounts of its solid mass are removed, ultimately leading to a hollow trunk rather than one of substance. In cases like these, the trunk presents less resistance to forced vibrations, and the active modes affecting the cross section of the trunk exhibit decreased resonance frequency values. This paper aims to present a method based on vibrations which might be employed for tracking a specific mode of radial vibrations known as the ovalling mode. To achieve this goal, the trunk of a palm tree was set into vibration via mechanical excitation in the radial direction and its response at some specific point on the trunk was examined. This method uses a single concentrated source of excitation and two vibration sensors, which are diametrically positioned and fastened to the surface of the tree trunk. The ovalling mode might be extracted from the frequency response by adding the signals recorded by the two sensors, which are in phase for a test specimen with a perfectly circular, cylindrical shape made of homogeneous, isotropic material. This study provides a preliminary investigation into the feasibility and reliability of this nondestructive method when applied for the identification of rot hosting by the trunks of standing trees, wooden poles, and logs, as well as the level of severity of rot attack.

Abstract:Two main types of hollow tree are frequently found in savannas: trees with external splits (externally damaged trees), and trees with no or little visible external damage, but with their entire core removed (internally damaged or ‘piped’ trees). As this may affect trunk mechanical resistance and tree survivorship, we studied the incidence of these two types of cavity in relation to two possible causal agents, fire and termites, in a West African savanna. Overall, the proportion of damaged adult trees (height &gt;2 m) reached 36%, and up to 84% forCrossopteryx febrifuga. In this species, almost all (93%) damaged individuals showed signs of digging by fungus-grower and wood-feeder termites. External damage was more frequent in the more fire-prone shrubby savanna, suggesting that while termites are responsible for the piping, fire is responsible for the later opening of the trunk. Trees growing in the more fire-prone savanna tended to reach significantly smaller sizes, both in height and basal diameter, than in the less intensely burnt woody savanna. There was also evidence that piped trees were taller than externally damaged trees. This strongly suggests that fire causes an increased mortality of adult trees through lateral opening of the trunks causing later breakage.

Understanding the failure modes of curved hollow tree trunks is essential from both safety and conservation perspectives. Despite extensive research, the underlying mechanism that determines the cracking failure of curved hollow tree trunks remains unclear due to the lack of theoretical analysis that considers both the initial curvature and orthotropic material properties. Here we derive new mathematical expressions for predicting the bending moment, M crack , at which the cracking failure occurs. The failure mode of a tree species is then determined, as a function of t / R and cR , by comparing M crack with M bend , where t , R and c are, respectively, the trunk wall thickness, outer radius and initial curvature; M bend is the bending moment for conventional bending failure. Our equation shows that M crack is proportional to the tangential tensile strength of wood σ T , increases with t / R , and decreases with the final cR . We analyse 11 tree species and find that hardwoods are more likely to fail in conventional bending, whereas softwoods tend to break due to cracking. This is due to the softwoods' much smaller tangential tensile strength, as observed from the data of 66 hardwoods and 43 softwoods. For larger cR , cracking failure is easier to occur in curvature-decreasing bending than curvature-increasing due to additional normal tensile force F acting on the neutral cross-section; on the other hand, for smaller cR , bending failure is easier to occur due to decreased final curvature. Our formulae are applicable to other natural and man-made curved hollow beams with orthotropic material properties. Our findings provide insights for those managing trees in urban situations and those managing for conservation of hollow-dependent fauna in both urban and rural settings.

In many living trees, much of the interior of the trunk can be rotten or even hollowed out. Previously, this has been suggested to be adaptive, with microbial or animal consumption of interior wood producing a rain of nutrients to the soil beneath the tree that allows recycling of those nutrients into new growth via the trees roots. Here I propose an alternative (non-exclusive) explanation: such loss of wood comes at very little cost to the tree and so investment in costly chemical defence of this wood is not economic. I discuss how this theory can be tested empirically.

AbstractIn the Czech Republic and Slovakia, the term “hollow tree fire“ was first used in a publication in 1956 without being well defined and was then uncritically used in other publications. The term refers to fires occurring in the rotted, inner trunks of trees. The main aim of the current study was to determine whether the term should be considered a useful category for the statistical analysis of forest fires. The nature and causes of fires from 2006–2015 were assessed by performing a detailed analysis of the Fire Rescue Service of the Czech Republic (FRS CR) database. The database included a total of 7,256 fires in the natural environment, but only 18 of these were hollow tree fires. Most hollow tree fires were initiated by human carelessness, and only three were initiated by lightning. Based on our critical consideration of fire attributes, hollow tree fires should not be considered a category of forest fire. The presence of rotten trees is, however, a serious problem because such trees represent long-lasting sources of fire in forest stands and because they complicate firefighting. The numbers of rotten trees in forests is increasing, and firefighters should be made aware of the complications of extinguishing fires involving rotten trees in forests.

Abstract Adult ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) bore into ornamental nursery trees resulting in trunk vascular tissue damage, which can potentially kill trees. Ambrosia beetle exposure to surface-applied insecticides is minimal after internal trunk galleries are formed, so effective management requires insecticide treatments to be applied near the time of infestation or to have residual activity on the bark. Tree trunk sections (bolts) were used to determine the effect of field aging or irrigation (i.e., simulated rainfall weathering) on permethrin residual activity against ambrosia beetles. In all experiments, 30-cm-long bolts from Liriodendron tulipifera L. (Magnoliales: Magnoliaceae) were hollowed and filled with 70% ethanol at field deployment to induce ambrosia beetle attacks over a 2-wk period. To evaluate insecticide residual activity, permethrin was sprayed onto tree bolts at 0, 8, 17, or 24 d before ethanol addition, and then bolts were deployed along a wooded border in fall 2017 and spring 2018. Tree bolts with permethrin residues ≤17 d old had significantly fewer ambrosia beetle attacks than bolts with 24-d-old residues or the non-permethrin-treated control bolts. To evaluate simulated rainfall weathering, permethrin was applied to tree bolts 8 or 22 d before ethanol (spring 2018) or 10 or 24 d before ethanol (fall 2018) with half of the bolts receiving regular irrigation events. Irrigation had no significant effect on permethrin residual activity against ambrosia beetles during either test. This study determined ambrosia beetle control was affected by permethrin residue age more than simulated rainfall weathering, and a reapplication interval of ≤17 d maximized beetle control.

AbstractHoney bees (Apis mellifera L.) inhabiting trees in forests are not managed by humans or treated for pathogens; therefore, many researchers and beekeepers believe that viral, bacterial, and parasitic diseases may lead to their decline. The aim of the study was to evaluate the prevalence of L. passim and Nosema spp. in feral colonies by real-time PCR. This study was performed on twenty-six samples of honey bees inhabiting tree trunks in north-eastern Poland. One sample consisted of sixty worker bee abdomens collected from hollow trees. Honey bees were sampled only from naturally colonized sites. Amplicons of the three evaluated pathogens were detected in twenty of the twenty-six tested samples. A significant correlation was observed between infection with three pathogens (N. apis, N. ceranae, L. passim) (r = 0.84) compared to infection with only two pathogens (N. apis and N. ceranae) (r = 0.49). N. ceranae was the predominant pathogen, but infections with various severity caused by L. passim were also noted in fourteen of the twenty-six tested samples. In view of the general scarcity of epidemiological data concerning coinfections with Nosema spp. and L. passim in honey bees in tree trunks in other countries, further research is needed to confirm the effect of concurrent pathogenic infections on the decline of bee colonies.

To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Ilex spp. (holly) trees are endemic to Central Florida and among the most popular landscape trees for their hardness, bright colors and go-anywhere size. To provide a basis for irrigation allocations both during production and in landscapes, daily actual evapotranspiration (ETA) for three holly trees were measured with weighing lysimeters over 5.75 years, beginning with rooted cuttings and continuing until trees averaged 4.3 meters in height. Empirical models were derived to calculate ETA based on crown horizontal projected area or trunk caliper, adjusted daily by changes in evapotranspiration (ETo). Average ETA to produce these hollies was 20 432 L cumulative over 5.75 years.

The new testate amoeba species Meisterfeldia bitsevi is described from the linden-tree trunk hollow in the urban park in Moscow (Russia). New species is characterized by elongated ovoid bilaterally symmetrical shell, which is laterally not compressed. The shell is composed of proteinaceous material without mineral particles. Almost circular subterminal aperture is placed on ventral side. The key to the species of the genus Meisterfeldia is developed.

Abstract Trunk growth rates one year after transplanting 5 cm (2 in) caliper laurel oak (Quercus laurifolia Michx.) from above-ground plastic containers, from in-ground fabric containers or from the field (B&B) matched or exceeded growth rates before transplanting. Growth rates for all three treatments were similar seven months after transplanting. Shoots on field-grown trees grew more in the first year after transplanting than those from fabric or plastic containers. Roots removed at the time of digging were completely replaced on field and fabric container trees six months after transplanting. One year after transplanting, roots occupied the same soil volume as just prior to transplanting. Trees from plastic containers regenerated roots slower than B&B trees or those from fabric containers. When irrigation frequency was reduced 14 weeks after transplanting (WAT), trees from plastic containers were water stressed more (had more negative xylem potential) than B&B or fabric container trees. Growth rates of East Palatka holly (Ilex × attenuata Ashe. ‘East Palatka’) responded similarly to laurel oak; however hollies took longer to establish roots into landscape soil and took longer for the trunk growth rate to match that on trees prior to transplanting.

Modes of area searching and exploratory behaviour of the sympatric pine marten, Martes martes (L., 1758), and stone marten, Martes foina (Erxleben, 1777), were studied by snow-tracking in two regions of Poland. The accuracy of identifications of the two species on the basis of their snow tracks was assessed by DNA analysis of their faeces, as collected on the tracks; identifications were found to be correct in 88% of cases. Although most activities of the two species were concentrated on the forest floor, pine martens climbed trees, moved in tree crowns, and searched the bases of tree trunks and tree hollows more frequently than stone martens. In contrast, stone martens were more inclined to search for food in brushwood and piles of wood, and visited logged areas and garbage dumps more frequently. Pine martens avoided man-made objects and barriers such as roads and passed through open areas with reluctance. Such behavioural traits make this species particularly vulnerable to forest fragmentation and human activity in forests. Stone martens often explored woodless areas and inhabited buildings, which allowed them to use habitats substantially transformed and intensively explored by humans. The future coexistence and relative numbers of the two martens in forest habitats will depend on the mode of forest management and on the existence of effective migratory corridors connecting forest patches.

The recent report of ancient trees in the Amazon region (Chambers et al. 1998) with a maximum radiocarbon dated age of about 1400 years for the long-living pioneer species Cariniana micrantha is discussed in the light of dendrochronological age determinations from Africa and South America together with the results of indirect age estimations from other sources. There is a tendency in the literature to considerably overestimate the maximum ages of tropical trees. Age determination by the direct counting of annual rings and making estimations for hollow trees by measuring growth rates and diameters result in ages between 400 and 500 years for the largest trunk dimensions, e.g. in Cariniana legalis.

The objective of this study was to evaluate the presence of epiphyte species in trees that compose the urban trees of four avenues of Goiânia city – state of Goiás. All individuals from the avenue median and sidewalks were quantified, all epiphyte host individuals were inventoried and the epiphytes found were evaluated qualitatively and quantitatively. The species Ficus rubiginosa was present in 68.63% of the cases, followed by Ficus luschnathiana (15.69%), Ficus insipida (5.88%) and Ficus guaranitica (5.88%). A total of 84.62% of the hosts are Poincianella pluviosa, 51.92% are individuals of height between 14 and 16 meters and 35.29% have a diameter between 46.00 and 61.99 cm. The hemiepiphytes occurred on Libidibia ferrea, Ceiba speciosa, Albizia lebbeck and Pachira aquatica. The occurrence of hemiepiphytes prevailed on trunk bifurcations (44.23%), branch bifurcation (19.23%), branch hollows (17.31%) and on branches and roots (3.85%). About 15.65% of each adult arboreal in Goiânia city is inferred to hold at least one epiphyte.

A catastrophic frost in the Bonang valley, Victoria (alt. 660 m), during Aug. 1982 caused severe damage to naturally occurring trees growing within a contour-related inversion layer. All eucalypts and acacias on the valley floor and up to 6 m above it on the lowest slopes were either killed outright or suffered complete crown loss. Between 6 and 25 m above the valley floor, tall Eucalyptus viminalis. trees escaped damage if their crowns were positioned well above the inversion layer. Neighbouring trees of the slightly shorter original codominant E. radiata were so severely damaged that they were either killed or survived crown destruction only by production of trunk epicormics. Despite being wholly positioned within the inversion layer, the shorter trees of E. pauciflora generally survived without much damage, although leaf injury continued to develop for several years in some trees. Results of the final assessment 5 yr after the frost indicate that the lowest surviving E. viminalis trees, together with severely damaged E. radiata. trees, now constitute an inverted treeline separating forest above from dead trees and grassland below. This treeline is related to the 666 m contour, 6 m above the valley floor, and forms a very abrupt boundary because of the predominance of large undamaged trees of E. viminalis. The consequences of this rare catastrophic frost have implications for subalpine ecology in south-eastern Australia, especially the genesis and stability of inverted treelines.

Resumo. A temperatura é o agente climático que afeta mais diretamente o metabolismo das abelhas, influenciando no desenvolvimento das crias, podendo acarretar resultados negativos para produção de mel. O objetivo deste estudo foi conhecer a diferença da termorregulação de colônias de Melipona eburnea Friese. As observações foram realizadas en­tre 09 de junho e 09 de julho de 2016, 24 horas por dia, utilizando-se dois ninhos de M. eburnea, um em caixa racional e outro em troncode árvore. Utilizou-se Data Logger(modelo HOBO U12 – 012), com exatidão de ±0,35 °C. Verificou-se que o ninho de M. eburnea em oco de árvore manteve uma temperatura média de 31,7 ºC, enquanto que o ninho em caixa racional apresentou temperatura média de 27,8 ºC. A temperatura ambiente variou de 16,6 a 34,2 °C, com média de 23,8 ºC. A espécie M. eburnea em caixa racional apresentou termorregulação inferior à colônia em oco de árvore e também maior oscilação de temperatura. Concluiu-se que M. eburnea mantém sua colônia em homeostase, mesmo quando há variações na temperatura ambiente (ninho em oco de árvore). M. eburnea apresentou termorregulação insatisfatória, quando mantida em caixa racional.Thermoregulation in colonies of Melipona eburnea Friese(Apidae: Meliponina) rationally bred in Rio Branco, AcreAbstract. Temperature is the climatic agent that most directly affects the metabolism of bees, influencing at the development of the young being able lead to negative results for honey production. The objective of this study was to know the difference of thermoregulation of Melipona eburnea Friese colonies. The observations were made between June 9 and July 9, 2016, 24 hours a day, using two nests of M. eburnea, one in rational box and the other in tree trunk. Was used Data Logger (model HOBO U12-012) was used, with accuracy of ± 0.35 °C. Was verified that the nest of M. eburnea in tree hollow maintained an average temperature of 31.7 ºC, whereas the that nest in rational box presented average temperature of 27.8 ºC. The ambient temperature ranged from 16.6 to 34.2 ºC, with a mean of 23.8 °C. The species M. eburnea in rational box presented inferior thermoregulation to the colony in tree hollow and also greater temperature oscillation. It was concluded that M. eburnea maintains its colony in homeostasis, even when there are variations in the ambient temperature (nest in hollow tree). M. eburnea presented unsatisfactory thermoregulation when kept in rational box.

Panstrongylus lutzi is generally restricted to the "caatinga" areas of north-eastern Brazil. Adult insects are frequently found in local houses, but colonies have not previously been registered in the statistics of the Control Programme of Chagas Disease. In Ceará State, our study revealed increasing occurrence of this species, usually with high infection rates for Trypanosoma cruzi, and always represented by adults that invaded the artificial environment. We also found nymphs in the peridomicile and inside the houses. In silvatic habitats we collected two adult females from hollow tree trunks, which may represent an alternative natural ecotope for the species in this state. Panstrongylus lutzi entomological collections from Sobral and Crateús, studied by morphology and morphometrics, showed great variability; those from Crateús were larger smaller and paler in colour, with individuals showing genital features consistent with those described for Panstrongylus lutzi or Panstrongylus sherlocki, whereas those from Sobral were darker and with genitalia compatible with P. sherlocki, nevertheless, all were considered to be Panstrongylus lutzi.

Aim. The main aim of the research is to study the conditions of existence and the timing of the development of the preimaginal and imaginal phases of blood-sucking mosquitoes, depending on the natural and climatic conditions. Methods. Adult species were collected at the roost sites and at the time of swarming with the use of scoop net every five days throughout the season. The larval phases of bloodsucking mosquitoes were taken into account in all given reservoirs of various types using a photocell. Discussion. The results of the study showed that in the study area, the largest region where mosquitoes are reproduced is mainly artificial reservoirs accounting for approximately 65%, natural water bodies (25%) and hollows of tree trunks (10%). The saturation of the larvae of the malarial mosquito of the genus Anopheles was 82 species/m2, non malaria mosquitoes of the genus Culex – 234 species/m2, while Aedes genus made up 105 species/m2. Conclusion. There are 19 species of mosquitoes inhabiting Dagestan. The development of preimaginal and imaginal phases of blood-sucking mosquitoes on the territory of Dagestan is ecologically diverse.

In Europe, insects represent approximately ¾ of the forest animal species. Thanks to their appreciable numbers and their varied diets, they render numerous services to the forest. By accelerating the recycling of organic material they contribute to the fertility of the soil. A rich and diversified entomological fauna reduces the risk of a proliferation of pests, thanks to predation and competition. Last but not least, many forest insects are in addition active pollinators. Many very specialized forest insects lacking a great mobility have become exceedingly rare and survive only in a few isolated reservoirs. The forest entomological biodiversity must be preserved, quite as much for ethical reasons as for the services which it provides. In order to do this, it is necessary to conserve a structurally diversified forest with many old trees, hollow trunks and snags, clearings and multi-storeyed forest edges.

AbstractFor 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 batArtibeus 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 flyMegistopoda araneawas 0.877 in Pantanal and 0.724 in Cerrado. The D values ofAspidoptera phyllostomatiswas 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.

This study aimed to investigate the patterns of diameter distribution of residual wood pieces found on the forest ground (e.g. tree branches, sound and hollowed trunks, log trimmings) of an unlogged and of a logged forest area one year after logging operations with impact reduction techniques (EIR), by setting up a mathematical model. Diameters were field measured of wood residue pieces in 48 sampling units systematically distributed across the experimental area, 24 units for each situation, that is, unlogged (FNE) and logged forest (FE), with sampling errors of 8.32% and 7.58% respectively for the variable volume (m³.ha-1), applying the line intercept sampling method proposed by Wagner (1968). In both situations, the diameter distribution of the wood residue pieces was decreasing and reverse J-shaped, similarly to the DBH distribution occurring in native forests of the Amazon. A highly significant linear correlation exists between the diameter class midpoints and the number of wood residue pieces. Distributions were modeled using the exponential equation proposed by Meyer (1952), whose adjusted coefficients of determination (r²aj.) were 98.6% and 94.8%, for unlogged and logged forest areas respectively.

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).

AbstractWe radio-tracked fifteen reproductive females (5 pregnant, 5 lactating, 5 in post-lactation) of the Daubenton’s bat in summer 2005 in order to reveal the effect of reproductive state on their foraging and roosting activity. Spatial activity of females decreased from pregnancy to lactation and increased again in the post-lactation period. Overall time spent foraging did not differ among the three study periods. However, while pregnant and lactating females spent similar proportion of the night length foraging, females in the post-lactation period were foraging for shorter part of night. The frequency of nightly visits to roosts was highest during lactation but there was a trend towards shortening of particular visits during that period. All but one roost were in tree hollows excavated by woodpeckers in spatially restricted area of ca 0.7 km2. Tree cavities used during pregnancy were located higher on a tree trunk and had larger entrance area than the cavities used in the two later periods. Bats switched roosts every 2–3 days (range 1–8) and moved to a new roost up to 800 m apart. Pregnant females tended to switch roosts more frequently than females in the two later periods. We did not observe a significant effect of minimum nightly temperature on the activity of radio-tracked Daubenton’s bats. Therefore, we suggest that observed seasonal changes in the pattern of behaviour of Daubenton’s bat females were driven by their changing energetic demands rather than by some extrinsic factors (e.g. weather conditions).

Приведены результаты изучения фитопатологического состояния березы повислой в насаждениях Санкт-Петербурга, которое в целом оценивается как удовлетворительное с преобладанием ослабленных и сильно ослабленных деревьев. Даны качественная и количественная оценки деревьев-угроз. Проанализированы причины падения деревьев березы в Санкт-Петербурге. Выявлены прямые и косвенные признаки, указывающие на наличие корневых и стволовых гнилей. Сделан вывод, что наиболее часто в городских условиях древесина поражается белой волокнистой и бурой трещиноватой гнилями, возбудителями которых являются дереворазрушающие грибы. При поражении древесины гнилью происходит резкое снижение плотности и прочности, и при значительном ее развитии прочность практически утрачивается. Предел прочности древесины березы с белой волокнистой гнилью III стадии при сжатии вдоль волокон в 6–7 раз, а при статическом изгибе – в 14–16 раз меньше соответствующих показателей неповрежденной древесины. Падение деревьев и их частей часто связано не только с развитием гнили, но и с различными аномалиями в строении древесины, которые приводят к резкому снижению прочности древесины в этих зонах и падению частей дерева. При оценке аварийности деревьев березы следует особое внимание уделять осмотру нижней и средней частей ствола, а при оценке поражения древесины гнилью – не только наличию плодовых тел грибов, но и косвенным признакам – дуплам, сухобокостям, морозным трещинам. The results of the study on phytopathological condition of silver birch trees in St. Petersburg are presented. The condition is assessed generally as satisfactory with a predominance of weak and strongly weakened trees. A qualitative and quantitative assessment of trees that represent topple threat was performed. The reasons for the fall of birch in St. Petersburg were analyzed. Direct and indirect signs indicating the presence of root and stem rots were identified. It was concluded that the most often in urban areas wood is affected by white wood pulp and fissured brown rot caused by wood-destroying fungi. During rotting fungal attacks, sharp decrease in wood density and durability occurs, and with intense rot development durability is almost lost. Comparing to healthy wood, compressive strength of birch wood with white fibrous rot in stage III is 6–7 times lower along the fibers and 14–16 times lower in a static bend. Falling of trees and their parts is often associated not only with the development of rot, but also with various abnormalities in wood structure that lead to a sharp decrease in wood durability in these areas and cause tree parts to fall. In birch trees topple risk assessment special attention should be paid to examination of lower and middle parts of the trunk. In assessment of wood decay extent, not only the presence of fungi fruiting bodies should be considered, but also circumstantial evidence such as hollows, stem scars, and frost cracks.

Allometric models embedding independent variables such as diameter at breast height (d) and total height (h) are useful tools to predict the biomass of individual trees. Models for tropical forests are often constructed based on datasets composed of species with different morphological features and architectural models. It is reasonable to expect, however, that species-specific models may reduce uncertainties in biomass predictions, especially for palms, tree ferns, and trees with peculiar morphological features, such as stilt roots and hollow trunks. In this sense, three species with wide geographical distribution in the Brazilian Atlantic Forest were sampled, namely Euterpe edulis Mart., Cyathea delgadii Sternb., and Cecropia glaziovii Snethl., with the aim to (i) quantify their aboveground biomass (AGB), (ii) evaluate the AGB distribution in different plant compartments, (iii) fit species-specific models for predicting AGB at the individual level, and (iv) assess the performance of specific and generic models available in the literature to predict the AGB of individuals of these species. The compartment stem represented, on average, ∼74% of the total AGB of E. edulis individuals; in turn, the caudex compartment of C. delgadii represented, on average, ∼87% of the total AGB, while the trunk compartment of C. glaziovii represented, on average, ∼74%. Among the fitted models, the power model [Formula: see text] showed the best performance for E. edulis and C. delgadii. In turn, the asymptotic logistic model [Formula: see text], where dc is the diameter above the upper stilt root, presented the best performance for C. glaziovii. The variable h appeared as the most important predictor of AGB of E. edulis and C. delgadii; in contrast, the stem and caudex mean basic specific gravities were not suitable predictors. The fitted species-specific models outperformed the specific and generic models selected from the literature. They may, therefore, contribute to the reduction of uncertainties in AGB estimates. In addition, the results support evidence that specific models may be necessary for species with different growth forms and (or) peculiar morphological features, especially those with great abundance and wide geographic distribution.

Abstract Stingless bees constitute an important group of bee diversity providing a vital ecological service i.e. pollination. From India, nine species of stingless bees have been reported out of which Tetragonula iridipennis Smith is widely distributed. Studies revealed that the majority (86.67%) of these bees’ nests were present in brick walls and the remaining (13.33%) were in cavities of hollow tree trunks. Most of the colonies nested at a height of 3.50 m from the ground. Most of the nests (56.67%) had entrances oriented to the east. No distinct entrance tube was observed in 26.92 per cent of the colonies. Overall average entrance tube dimensions (longer side diameter x shorter side diameter x tube length) were 11.62 x 11.73 x 14.04 mm. In all the nests, brood area was surrounded by pollen pots and a few honey pots. The mean dimensions (depth x width) of brood cells, honey pots and pollen pots were 2.79 x 2.62 mm, 5.33 x 4.52 mm and 6.93 x 5.19 mm, respectively. All of the sixty colonies whether in brick/stone walls or in hollow tree trunks overwintered successfully. Our results can be useful for developing conservation measures for T. iridipennis and its augmentation for crop pollination.

The goal of this article is to inform community regarding porcupines damage, and deliver guidelines for their harmless, real and liable elimination. The utmost apparent attribute of porcupines is their extensive, piercing and shakable quills, which shelter backs of the physiques that make them hit, as a threatening to probable raiders. In general, porcupines occur the maximum in mountainous and gravelly states, however these may adjust in many territories like extremely wet plantations and somewhat territory comprising of prairies, foothills, deserts and tropical forests. Porcupines can become a pest by eating of carrots and other root vegetables, clovers, roots, fruits as well as foraging on the farm crops. A definite indication of porcupine burrow is a mound of feces at entering site of cave or hollow tree. In this global region, Hystrix indica Kerr is most plentiful and scattered species, and has been familiarized as a severe pest of fruit orchards, vegetables, flowering plants, forage grasses in pastures or rangelands and traditional as well as non-traditional crops. When porcupines inflict optimum damage, then their control actions must be adopted. A pest controlling expert can provide skill to recognize the porcupines problematic and decide the superlative promising way out to decide the pest annoyance. Prior to executing a loss managing method, evaluate the porcupines incidence by means of watching for shattered quills, fecal masses beneath nourishing and sleeping plants, or distinctive injury marks to trees in a region. Manipulate habitat to attract more natural predators to control porcupine populations, place aluminum flashing around mature tree trunks and enclose small trees with wire baskets, and enclosure areas with electric or nonelectric fencing, to stop porcupines from gnawing at their bark. Implement forest management practices to reduce food supply and some wood preservatives applied to trees, and use of poison baits may provide partial damage relief. During late spring and summer activity periods, shooting of pest is most effective option, and use steel leg-hold traps lured by salt-soaked ingredients and placing proximate to alive burrows or else frequently used tracks.

AbstractIncreasing efficiency and productivity in the field of agriculture is important to provide sufficient food to the world’s increasing population. It is important to monitor crops using image processing in order to realize these increases in efficiency and productivity. In order to monitor crops with high quality and accuracy, high resolution images are needed. In this research, a crop monitoring method for pecan nut trees was developed using high-resolution video taken from the side of a vehicle. First, trees were extracted by applying an object detection model to the video data. Second, the extracted trees were divided into canopy and trunk areas. Finally, using labels made by experts and the canopy image as input, the convolutional neural network (CNN) model was trained to classify unhealthy and healthy trees. The model achieved an area under the curve for classification over 0.95. Gradient-weighted Class Activation Mapping (Grad-CAM) was also applied to the model for the purpose of evaluation, and it clarified that the model is focusing on the hollow features of the canopy when performing its classification.

PurposeWood is one of the materials that is used for building construction either as structural member or as finishes from ages past to contemporary generation. It is composed of elongated, hollow spindle shaped cells that are arranged parallel to each other along the trunk of a tree. The resistance to water, chemicals, strength properties, appearance and decay rate is dictated by the fibrous cells. The purpose of this paper was to examine the application and use of wooden floor finish (an extract from wood) in residential buildings in Lagos, Nigeria, with a view to determine its effectiveness.Design/methodology/approachThe study adopted a dual stage survey approach before the administration of questionnaire on 100 respondents that were selected through purposive sampling after the initial inquiry on the use of the material from 384 randomly selected samples from the entire population.FindingsThe study shows that the material is applied in all interior spaces except bathrooms and toilets. Minimal adoption is also seen in the kitchen area. Users indicate that wooden floor finish requires little maintenance, has low impact on users' health, considered safe-minimal occurrence of home accidents is recorded, has moderate thermal insulation and affordable.Practical implicationsThe usage has impact on the environment due to continuous lumbering activities and lack of adequate plan for reforestation. This suggests that its sustainability depends on afforestation programmes. Its poor performance in sound insulation, water and fire resistance requires further attention. The maintenance is relatively easy and affordable.Originality/valueThe author made a new foray into investigating the performance of wooden floor finish due to its resurgence in the area bearing in mind the unseasoned condition of wood in circulation in the area. Previous adoptions were done by a less aggressive generation of well-trained artisans. Best places for its usage within the interior spaces are identified.

The article presents the preliminary results of the interdisciplinary research (geological and geospatial studies, archaeological excavations, salt production experiments, and ethnographic survey) carried out during 2016-2019, in the site and hybrid saltscape of Băile Figa, well known for its remarkable environmental, ancient and current salt exploitation evidence. Besides, the article aims to evaluate the contribution of the recent research to a better understanding of the environmental context of the site and ancient salt production technology in the Inner Carpathian region. Also, it focuses on the hybrid character of the site and its potential to the transdisciplinary and holistic study. Environmental context. The site is rich in environmental, archaeological and ethnographic evidence. It is positioned in the salt-rich area of the Someșul Mare Basin at the northern edge of the Transylvanian Plain (Fig. 1/2; 2/1). The site is part of the landscape that was and is strongly affected by the dynamics of a salt diapir (Fig. 2/2) and deposits of salt mud, brine and halo-biotic factors, as well as by the intense human activity. Excavation. The excavation was carried out in Trench S.XV (16 m x 14 m), located in the central-southern sector of the site. The trench cut through the stream-bed and steep and high banks of the salt stream that crosses the site from south to north (Fig. 4; 5, 10). Its profile sections show four major stratigraphic units: a blackish topsoil, yellow clay mixed with gravel, salty mud, and the rock salt massif. The excavation was conducted in the mud layer, in the central sector of the trench, and in the clay-and-gravel layer found in its lateral sectors. In the area of ca. 60 square meters of the central sector, the excavation has reached the rock salt massif (Fig. 7-11). The excavation in the trench has uncovered rich evidence for Late Bronze Age salt production: seven interconnected features and around one hundred artifacts. The vast majority of the finds have been uncovered in the mud layer. The uncovered features included five timber structures surviving in the salt mud layer, as well as a ditch and a pit dug in the rock salt massif. Feature 1-XV-2013 (Fig. 12; 14/1) is a structure that includes a cone-shaped wattle-lined pit surrounded by a roundish wattle-made fence. The pit cuts through the mud up to the rock salt massif. Its rock salt bottom was sectioned by a ditch, 0.4-0.5 m wide and over 0.9 m deep. It seems that first, by rather extensive digging, the soil and mud were removed down to the salt massif. Then, a ditch, about 5 m long, 0.4 m wide and over 0.9 m deep (see below), was dug in the rock, from east to west. After that, a cone-shaped outer framework made of wattle (D maximal: 1.2 m, D minimal: 0.4 m, H: 1.8 m) was placed over the ditch, narrow end down. After that, the empty space around the framework was filled with mud. Then the pit was surrounded by a roundish wattle fence. A 1.6 m long massive rope made of three twisted threads (Clematis vitalba) has been found in the ditch (Fig. 41). Four samples taken from the wattle framework have produced five dates which fall between 2821±24 and 2778±26 BP. Feature 2-XV-2013 (Fig. 13) was uncovered in the northern part of the trench, on the right side of the stream, between feature 1-XV-2013 (see above) and the north edge of the trench. It was a rectilinear fence, 3.6 m long, built of vertical planks, split troughs, and channelled pieces, pushed into the mud down to the rock salt massif. Three fragments of the troughs from the fence were dendrochronologically dated to the period between 996 and 980 BC. Feature 1-XV-2015 (Fig. 14) was uncovered in the central-southern part of the trench. It was a corridor, 2.5 m long and 1 m wide, oriented E – W, made of two parallel rectilinear alignments of massive upright poles driven into the mud. One of its poles was at the same time part of the fence of the Feature 1-XV-2013. The corridor, on the base of three samples, has been radiocarbon-dated between 2870±32 and 2718±30 BP. Feature 1-XV-2018 (Fig. 15-17) was partially uncovered in the north-west part of the trench, about 3.5 m west of the stream. It is a 5 m long fence, oriented S – N, made of vertical planks, stakes (Fig. 17/2), and a split trough (Fig. 17/1), stuck into the mud, and four horizontal planks linking them to each other (Fig.17/2). Not dated. Feature 2-XV-2018 (Fig. 18; 19/1) was partially uncovered in the western part of the trench, in the rock salt massif. It is a roundish pit (over 2.5 x 1.8 m) with irregular edges, ca. 1.7 m deep below the salt massif surface. Not dated. Feature 3-XV-2018 (Fig. 19; 20) was uncovered in the central part of the trench. It was a ditch dug in the salt massif, 0.4 to 0.8 m wide, over 0.9 m deep, and about 4 m long. It cuts through the bottom of feature 1-XV-2013 (Fig. 12/2) and links it to the feature 2-XV-2018. Not dated. Feature 4-XV-2018 (Fig. 19/1; 20-22) was uncovered in the south-east corner of the trench, covering about 4 x 4 m, and consisted of a cluster of parallel beams laying on the salt massif, and a few vertical poles. The feature continues eastwards and southwards beyond the sides of the trench. On the base of three samples, it was radiocarbon-dated between 2856±31 and 2817±30 BP. Artifacts. We found some 100 artifacts in Trench S.XV during the excavation seasons, between 2016 and 2019. Most of them were made of wood, 1 of hemp (?), and 3 of stone (basalt). The wooden artifacts include 31 component pieces and fragments of trough bodies (Fig. 24-27), 17 channelled pieces (Fig. 28-30), 2 shovels (Fig. 33), 12 paddles (Fig. 31; 32), 4 mallets (Fig. 34/2,3), an L-shaped haft for a socketedaxe (Fig. 34/1), 2 pans (Fig. 35), a bowl (Fig. 36), fragments of 2 ladders (Fig. 37), 3 knife-shaped tools (Fig. 38/2,3), 11 rods with pointed end (Fig. 38/4), 4 loops made of twisted twigs (Fig. 40), a massive rope made of three twisted threads (Clematis vitalba) (Fig. 41), and 5 wedges. One of the artifacts found was made of plant material, possibly hemp: a small twisted cord (it may come from a peg inserted in the trough hole). Stone (basalt) artifacts include 2 mining hammers (mining tools) with engraved grooves aimed to fix the bindings (Fig. 44/1,3), an ovoid-shaped object with many percussion marks at its thicker end (Fig. 44/2). The chronology of the finds. In 2018 4 samples (wattle) from the Feature 1-XV-2013 were dated at Oxford University Research Laboratory for Archaeology and the History of Art / Radiocarbon Accelerator Unit. In 2019 some of the timber features (1-XV-2015 and 4-XV-2018) and wooden artifacts (the ladder, the troughs nos. 4 and 5 and some others) were radiocarbon dated by “Horia Hulubei” National Institute for Research and Development in Physics and Nuclear Engineering. Most of the dates fall between 1000 – 900 cal BC. Just one date (a wooden bowl) falls between ca. 1419-1262 cal BC (Tabels 1, 2, 3). The structures and most of the artifacts uncovered in S.XV date to ca. XI-IX centuries cal BC and seem to have been part of a complex production system aimed at brine and rock salt processing. Differential distribution of finds across the site. The research has revealed differential distribution of finds across the site. Thus, the evidence dating to ca. 2300 – 2000 cal BC (a pit dug in the rock massif and pottery), 1600 – 1400 cal BC (a wattle-built structure and wooden troughs), and 400 – 180 cal BC (timber-lined shaft, a wooden ladder and pottery) is mainly concentrated in the southern sector of the site. In exchange, the finds dating to ca. 1400 – 1100 cal BC have mainly been uncovered in the south-central part of the site (timber structures) and northern part of the site (pottery). The evidence dating to about 1050 – 850 cal BC covers two distinct areas: the south-central and northern sectors of the site. While about thirty fragmented troughs have been found in the south-central sector, no one object of this kind has been found in the northern sector. There are also differences concerning the timber structures between these sectors of the site. These strongly suggest that in XI – IX centuries cal BC, at least two different and complementary production areas were active in the site. Salt production experiments. The experiments on salt production, using faithful replicas of Late Bronze Age artifacts uncovered in trenches S.I and S.XV – troughs, channelled pieces, mallets, wedges, stone mining hammers, etc. – aimed to obtain from the different source material – rock salt massif, brine, and mud – various forms of salt: lumps of rock salt, fine salt, and highly concentrated and pure brine. The experiments showed the technical validity of several techniques. The most effective were as follows: 1. Detaching lumps of rock salt from the massif. By means of jets of fresh water directed with the troughs (along the twisted cords fitted in the perforations of the sticks that went through the pegs which were fixed in the holes at the base of the trough) depressions were simultaneously created in the rock salt at ten to twenty spots, 10 to 15 cm apart and 7 to 12 cm deep. This process took few hours (Fig. 45/1). It was noticed that each hole generated one to three cracks in the salt massif, around 1 m long and 5 to 10 cm deep. The holes and cracks allowed the insertion of wooden wedges. By hitting them with heavy wooden mallets, the wedges were pushed down to ca. 20 cm deep. Finally, using hooked sticks, many blocks of rock salt could be detached from the massif. The larger blocks were easily broken by stone hammers (mining tools). 2. Producing small pieces of salt and fine salt from the rock salt massif. The first stages of the process were identical to the previously described. After the holes and cracks were created, the rock salt mass was beaten with stone hammers (mining tools) along the cracks and holes, so that small pieces of salt, as well as wet and soft fine salt, were easily separated from the mass. Thus, about 50 kilograms of fine salt were collected in 30 minutes during the experiment (Fig. 45/2). 3. Boiling brine in the troughs with hot stones and drawing off the brine. Stones heated as much as possible in a fire were immersed in the brine with which the trough was filled, thus bringing it to the boil (Fig. 46). The boiling continued until the salt begun to crystallize. After that, the trough, full of highly concentrated brine, was left motionless for several hours. The insoluble impurities of the brine sedimented according to their specific weight: the lightest of them floated to the top, while the heaviest (metals and minerals) settled on the bottom. Above the sediment lying on the bottom of the trough and under that at the top remained a rather thick layer of fairly clean brine. During the experiments, the lower sediment has never reached 3 cm in thickness. The wider tops of the plugs that were inserted into the holes found at the bottom of the trough, were at least 3 cm high. Because of this, the upper edges of the plugs remained above the sediment on the bottom of the trough. We then slightly raised the long sticks that were tightly inserted into the axial holes of the plugs, which in turn tightly closed the holes in the trough’s bottom. The sticks were fixed and maintained in a slightly raised position by a kind of pliers – half split twigs – set transversely over the trough opening. In this way, the brine was allowed to drain easily into channelled pieces set under the trough. The brine then flowed through the channelled pieces to the next trough(s). The process could be repeated in the next trough(s) until the salt makers would get a fairly clean and highly concentrated brine. Ethnographic survey. Băile Figa and its surroundings are places where the evidence for ethnographic research, of what is commonly called ‘the traditional salt civilization’, can still be found. In every ancient salt production archaeological site known in Romania, without any exception, the current folk salt exploitation is still in progress. The latter offers to these sites a valuable research potential, almost unique in Europe, for the ethnoarchaeological research. The ethnographic survey has attested a number of aspects of the present-day folk ways of exploiting brine, rock salt, salt mud, and halophytic vegetation, as well as other traditional practices and customs related to these resources. Brine folk exploitation. The most exploited saline occurrence at Băile Figa is currently brine. Brine is taken directly from the numerous springs filling the central salty stream valley (Fig. 48/1). Then, it is loaded into plastic drums of 50 to 200 litres and transported by carts to the neighbouring villages (Fig. 48/2). The locals told us that, in the past, the brine was transported in large, cone-shaped barrels, called “bote mari”, of 60 litres, made of softwood boards connected to each other with circles of hazel twigs (Fig. 49/5), in smaller containers, of approx. 20 litres, called “barbânțe” (Fig. 49/3), as well as in smaller containers hollowed out of tree trunks and called “bote” (Fig. 49/2). The most remote localities, to which the brine from Băile Figa is transported, are situated at a distance of 11 km. But most people that currently get brine from Băile Figa live within a maximum perimeter of 6 km. Brine is mainly used for preserving meat, bacon (especially around the winter holidays), and vegetables. Sometimes the brine is used for health care purposes, mainly against colds, rheumatic pains, skin diseases or circulatory deficiencies, either on the spot or at home. In the 1960s and 1970s, the locals built two brine ponds and used them for health cure baths. Rock salt folk exploitation. According to some elderly locals, until 1989, the rock salt was periodically extracted at Băile Figa, by manual or mechanized digging of vertical pits. It was mainly used to supplement the feed of domestic animals in the individual households, sheepfolds (Fig. 50) and collective farms or state agricultural enterprises. Sometimes, the locals crushed and grinded salt lumps. In some households in the village of Figa, we have identified and documented some primitive millstones used in salt grinding (Fig. 49/1). Ground salt is added to animal feed and very rarely in human food, people being sure that this kind of salt can harm their health. Sapropelic mud folk exploitation. The ethnographic surveys have documented the traditional exploitation of sapropelic mud at Băile Figa. It is found only in some limited spots of the salt stream valley. The spots with small deposits of sapropelic mud are known only by “connoisseurs” who, among the clues, are guided by a specific smell. The sapropelic mud is used for health care purposes, especially for the treatment of rheumatic diseases. The mud is applied, either on most of the body or only on the parts affected by pain. Sometimes, the mud is applied to animal wounds, for disinfection and drying. Mud-based treatments are done both on-site and at home. Shepherding. Until the building, during 2007 – 2011, of the leisure resort, Băile Figa was the favourite place for grazing for the local domestic animals (sheep, cows, buffaloes, and horses). The animals, according to the information delivered by the shepherds, loved salt grass and brine (Fig. 49/2). Shepherds tried to prevent the animals from drinking brine from the springs because their fondness of the salty taste made them to drink it in unhealthy quantities, so that they could “swell” and die. Beekeeping. In the northern sector of the salt stream valley, at the surface of the soil, in the summer of 2018, a primitive beehive made of a hollowed-out oak trunk was discovered (Fig. 48/4). So far, as we can know, it is a unique find of this sort in a saline context.