Bark Removal Research Articles

Bark wounding triggers gradual embolism spreading in two diffuse-porous tree species.

Xylem transport is essential for the growth, development and survival of vascular plants. Bark wounding may increase the risk of xylem transport failure by tension-driven embolism. However, the consequences of bark wounding for xylem transport are poorly understood. Here, we examined the impacts of the bark wounding on embolism formation, leaf water potential and gas exchange in the terminal branches of two diffuse-porous tree species (Acer platanoides L. and Prunus avium L.). The effects of bark removal were examined on field-grown mature trees exposed to increased evaporative demands on a short-term and longer-term basis (6h vs 6 days after bark wounding). Bark removal of 30% of branch circumference had a limited effect on the xylem hydraulic conductivity when embolized vessels were typically restricted to the last annual ring near the bark wound. Over the 6-day exposure, the non-conductive xylem area had significantly increased in the xylem tissue underneath the bark wound (from 22-29% to 51-52% of the last annual ring area in the bark wound zone), pointing to gradual yet relatively limited embolism spreading to deeper xylem layers over time. In both species, the bark removal tended to result in a small but non-significant increase in the percent loss of hydraulic conductivity compared with control intact branches 6 days after bark wounding (from 6 to 8-10% in both species). The bark wounding had no significant effects on midday leaf water potential, CO2 assimilation rates, stomatal conductance and water-use efficiency of the leaves of the current-year shoot, possibly due to limited impacts on xylem transport. The results of this study demonstrate that bark wounding induces limited but gradual embolism spreading. However, the impacts of bark wounding may not significantly limit water delivery to distal organs and leaf gas exchange at the scale of several days.

Low accuracy bark gouging controls Ips typographus outbreaks while conserving non-target beetle diversity

Natural disturbances and subsequent outbreaks of forest insects led to unprecedented amounts of damaged timber. In Eurasia, the European Spruce Bark Beetle (Ips typographus) breeding in Norway spruce (Picea abies) is creating the main share of infested trees in recent years. As alternative to salvage logging, different technics of mechanical and manual methods of bark removal for pest control are frequently applied in areas with conservation status or in protective forests that mitigate or prevent the impact of a natural hazard. To test the field applicability of bark removal technics, we compare work productivity mirroring economic costs between the widely used manual debarking and the new technique of bark gouging. Additionally, we evaluate how pest control and non-target biodiversity are affected from bark gouging if the phloem is cut with decreasing accuracy mirroring practical application by forest enterprises. Based on data of an experimental design we show, that bark gouging is twice as fast as manual debarking. From complete debarked P. abies logs no I. typographus emerged (pest control efficiency of 100%) but diversity of other emerging beetle species is reduced near zero. If bark gouging is conducted with high accuracy (phloem sufficiently cut in more than half of stripes) pest control efficiency is 99.9% and for low accuracy (below 50%) pest control efficiency is still 95.7%. Non-target beetle diversity increases with reduced accuracy. Bark gouging combines sufficed pest control with biodiversity conservation at lower work productivity than manual debarking and can thus be recommended for protected areas and protective forests, in particular.

Influence of Anthropogenic Factors on Reforestation Activities in the Ecosystems of the Teaching and Research Forest (FER) of the National School of Water and Forests (ENEF) Mbalmayo in Cameroon

Aims: This study, carried out in the Teaching and Research Forest (FER) of the national school of water and forests (ENEF) Mbalmayo, is part of the maintenance and protection of its biodiversity. The general objective is to identify the anthropogenic threats to the ENEF's FER. Specifically, to take stock of the reforestation, and to propose a restoration strategy corresponding to the ecological and social context of the RFM’s reforestation.
 Study Design: Forestry Department of the Mbalmayo National Forestry School. More precisely, in the school's teaching and research forest, commonly known as the "forest school". Between May 2021 and March 2022.
 Methodology: To achieve this, four plots of 1 hectare each were set up according to the level of degradation caused by the type of human activity. The data collected included an inventory of degraded areas, identification of the threats caused by human activities to FER ecosystems through direct observations in the field, and botanical inventories in the degraded plots. Given that the information on past floristic potential (before the threat) is known, the current inventory data made it possible to assess the threats. Bush fires, the removal of bark by local residents and agricultural plantations are the main threats to the RMF.
 Results: The Krustal Wallis test was used to compare the different plots, where a P-value of 0.00 for the Moabi and Bamboo plots means that there is no significant difference between these two sites at the 5% threshold with regard to the threats they face. On the other hand, this test shows that there is a significant difference between the plots in the inaugurated zone (ZI) and the burnt zone (ZB) at the 5% threshold with regard to their significant anthropogenic impacts, with respective P-values of 47% and 88%. These values show, following the determination of importance value indices (IVI), that threats are more severe on polyspecific sites such as inaugurated and burnt sites, as these are more coveted by local populations.
 Conclusion: The anthropogenic activities detected in the course of this study were the debarking observed in the Moabi plots, the bush fires encountered in the ZB site and the field activities (agricultural plantations) encountered in the Bamboo site. However, 3,174 trees survived the anthropogenic threats, compared with 1,036 that barely survived. 181 trees miraculously regenerated naturally.

Visualization of the initial radiocesium dynamics after penetration in living apple trees with bark removal using a positron-emitting 127Cs tracer

Following the Fukushima nuclear accident in March 2011, radiocesium (rCs) contamination in deciduous trees remains over 10 years later even though the trees were leafless at the time of the accident. This phenomenon is considered to be the result of repeated retranslocation of rCs that initially penetrated the bark into the internal tissues. To implement effective measures after a possible accident in the future, it is necessary to clarify how rCs is translocated in the tree after penetration. In this study, rCs translocation was dynamically visualized using a positron-emitting tracer imaging system (PETIS) and autoradiography after the bark of apple branches was removed. The PETIS results showed the translocation of 127Cs from the branch to young shoots and the main stem in apple trees under controlled spring growing conditions. The transport velocity of rCs in the branch was faster than that in the main stem. The transport of rCs, which was either acropetal or basipetal, in the main stem through the branch junction favored basipetal movement. Autoradiography of transverse sections of the main stem indicated that basipetal translocation was due to transport in the phloem. This study demonstrated the initial translocation responses of rCs similar to previous field research, which indicates that rCs transport to the young shoots tends to be higher under controlled conditions. Our laboratory-based experimental system may be useful to gain an improved understanding of rCs dynamics in deciduous trees.

The Potential Value of Debarking Water as a Source of Polyphenolic Compounds for the Specialty Chemicals Sector.

Forest-based industries produce huge quantities of bark during their primary processing activities. In Nordic pulp and paper industries, where a wet debarking process is used for bark removal, toxic debarking water and bark press water are produced as a by-product. However, polyphenols represent an important fraction of the debarking water and bark press water. These polyphenolic compounds are of commercial interest in chemical specialty sectors since polyphenols have been proven to have diverse health benefits, and after collecting them from waste sources, they can act as alternatives to oil-based chemicals. Determining the economic potential of polyphenolic compounds, identifying their molecular structure, and determining the antioxidant capacity of these compounds present in debarking water and bark can support the identification of their potential applications. The results show that water extractions from bark have a lower efficiency than (partial) alcoholic extractions. Nevertheless, a considerable amount of low-molecular polyphenolic compounds, which are of interest for high-end applications, was found in all extracts. Bark press water has a highly versatile range of polyphenolic compounds and showed some antioxidant activity, making it a great source for the collection of polyphenolic compounds, in contrast to debarking water, which had a much lower polyphenolic content and low antioxidant activity.

Shifting patch dynamics of floodplain woodlands in an arid savanna region: effects of soil form, flooding and large herbivores

• Monospecific woodland groves were associated with soil forms and flooding regimes in a floodplain. • Extreme floods removed trees and created substrates for woodland regeneration. • Damage by elephants and meso-browsers affected regeneration dynamics. • Flooding and herbivory interactively generated a shifting woodland mosaic anchored by soil. Our study addressed the regeneration dynamics of the patch mosaic of monospecific woodland groves in the floodplains of the Luvuvhu and Limpopo rivers following the removal of human settlements to create the Makuleke Contractual Park falling within the northern Kruger National Park. We anticipated that subsequent increases by elephants and meso-browsers like impalas would deflect or even prevent the re-establishment of these groves through the damage that they inflicted on plants. We compared the responses exhibited in groves of fever trees ( Vachellia xanthophloea ) associated with layered clay alluvium with those of ana trees ( Faidherbia albida ) associated with deep sandy deposits. Multi-decadal changes in the woodland mosaic were identified using aerial photographs and Google Earth imagery supported by onsite inspections and related to flood events and soil features. Woodland regeneration following recent major floods was tracked using onsite inspections over five years recording sapling growth and disappearance along with the breakage, bark removal and defoliation imposed by elephants, medium-sized browsing ruminants and porcupines. Fever trees were concentrated near the confluence of the two rivers where floodwaters inundated this region. Extreme floods carried away flanking ana trees while leaving sandy deposits open for recolonization. Elephants pushed over tall fever trees but not the ana trees, while regenerating saplings of both tree species were broken or uprooted. Browsing impalas defoliated juvenile trees contributing to their demise. These impacts contributed to the contraction or even disappearance of some fever tree groves and suppressed the growth and establishment of ana tree saplings. While these herbivores contributed to the shifting patch mosaic of these monospecific woodlands, the local distribution of these woodlands was associated with the soil features that they favoured.

Reciprocal bark exchange helps to disentangle tree species‐dependent bark and wood trait effects on invertebrate diversity

Abstract Previous studies showed that bark cover at early‐decay stage had profound control on the invertebrate assemblages of bark and wood, with possible consequence for the decomposition process. However, previous experimental designs could not disentangle how bark versus wood traits affect the invertebrate assemblage process in bark and/or wood separately because wood traits of different tree species may vary independently from bark traits. Furthermore, we do not know whether such tree species‐specific bark trait effects are still influential at mid‐decay stage. To unravel whether and how bark and wood traits influence invertebrate communities in tree logs at mid‐decay stage, we introduce reciprocal bark transplantation within pairs of different tree species as a new method. We applied this method to two pairs of phylogenetically contrasting species of gymnosperms (pair I: Araucaria araucana and Cryptomeria japonica, pair II: Picea abies and Thuja plicata) and another gymnosperm (Chamaecyparis lawsoniana) set as disturbance control to test for potential bark manipulation artefacts on invertebrate community composition. Our bark exchange experiment revealed that both bark and wood host abundant and divergent subsets of invertebrates on mid‐decay logs of different tree species. We further documented that the invertebrate community composition was predominantly shaped by the traits of host tissue per se, while also being significantly but less strongly affected by the traits of the other tissue, that is, the adjacent bark or wood. Our results indicated that bark trait effects faded with time and how long bark trait effects persist greatly depends on bark thickness. Synthesis. Our study suggests that maintaining deadwood heterogeneity related to variation between tree species and bark versus wood, is important for nursing a large biodiversity of invertebrates. Combined with bark removal methodology, our bark exchange method can be further extended to more decay stages and more forest biomes to track bark trait effects and bark induced priority effects on deadwood decomposition, and its associated invertebrate and microbial communities.

Nondestructive Techniques for Determination of Wood Mechanical Properties of Urban Trees in Madrid

The aim of this paper is to analyze the mechanical properties of Robinia pseudoacacia L. (black locust), Platanus × hybrida Brot. (London plane), Ulmus pumila L. (Siberian elm), and Populus alba L. (white poplar), estimated using ultrasound wave equipment (USLab y Sylvatest Duo) and impact wave equipment (Microsecond Timer) on standing trees, felled logs and on specimens obtained from different parts of the trees. Bending strength, axial compression strength and tension parallel to grain were determined for each specimen, in order to subsequently correlate the strength and stiffness with the acoustic properties determined in the standing tree. For the relationship between the static modulus of elasticity of the specimens and the dynamic modulus of elasticity determined in standing trees using the USLab, coefficients of determination were found to be between 0.30–0.92, between 0.52 and 0.80 using the Sylvatest Duo and between 0.60 and 0.94 with the Microsecond Timer. It would be necessary to determine whether the removal of bark for the correct coupling of the ultrasonic sensors would provide an entry route for pests or diseases that could affect the health of the tree.

Post-exploitation bark recovery rates of some medicinal tree species in Ghana

Unregulated harvest of tree bark for medicinal purposes has led to overexploitation and extinction of some valuable tree species. The study assessed bark recovery rates of four medicinal tree species and determined their regenerative abilities, stress shoot production and susceptibility to wood borers. A total of 192 trees of Bombax buonopozense, Mangifera indica, Azadirachta indica and Blighia sapida were randomly selected outside protected forests in the Moist Semi-deciduous (MSD) and Guinea Savannah (GS) ecological zones of Ghana. The trees were harvested using three harvesting intensities, 25%, 50%, and 75% bark removal. Edge and sheet re-growth, stress shoot production and wood borer attack were recorded for each tree in twelfth months. Our results show that the bark of B. buonopozense (29.4% at MSD and 21.4% at GS), M. indica (22.3% at MSD and 16.1% at GS) and A. indica (13.5% at MSD and 12.8% at GS) showed higher regeneration percentage compared to B. sapida (3.8% at MSD and 3.7% at GS), while stress shoot growth percentage was limited to only B. buonopozense (4.7% at MSD and 25% at GS). Though no tree died during the study period, borer attack was recorded for all the species except A. indica. We recommend that forest managers should allow minimum harvesting of B. sapida as they showed slow recovery, while rotation period for repeated harvest can also be prescribed for B. buonopozense and M. indica. Moreover, the coppicing ability of B. buonopozense needs to be examined since it produced a higher number of stress shoots.

Trunk spines of trees: a physical defence against bark removal and climbing by mammals?

Background and Aims The defensive role of spines has previously been related to leaves, young shoots and reproductive organs. However, some woody species harbour spines on their trunks where none of those organs are present. Several explanations are plausible: they could be (1) climbing aids, (2) remnants from defence of leaves or reproductive organs during an earlier development phase, or (3) an as-yet undescribed defence. Here we investigate whether they could play a role against either bark feeding or preventing climbing animals accessing food resources in the tree canopy.MethodsWe described 31 woody species with spines on their trunk, growing in a botanical garden, to test whether morphological strategies could be identified and suggest what could be their most likely function. As testing their function is difficult experimentally for large pools of species, we performed virtual experiments to evaluate the potential roles of trunk spines against bark removal and climbing animals of different sizes. We then compared for each species and their confamilial non-spiny species the nutritional profiles of leaf, bark and reproductive organs to test whether trunk spines were associated with a nutritious organ (more likely targeted by herbivores).Key ResultsWe identified four morphological syndromes of trunk spines. Two corresponded to already known functions (anchorage for lianas and crown defence against large ground mammals), and two strategies are newly described trait syndromes with traits suggesting a defence against bark feeding and climbing mammals. By simulation, we show how each strategy could translate into defence against debarking and prevent herbivores from climbing.ConclusionsWe identified trunk spine strategies and the criteria to classify them, their most likely function and the likely feeding mode and size of animal against which different trunk spine strategies may be effective. We discuss further perspectives for testing their function and their ecological significance.

Effects of Indole-3-Butyric Acid (IBA) and rooting media on rooting and survival of air layered wax apple (Syzygium samarangense) CV Jambu Madu.

The wax apple or jambu madu, is a non-climacteric tropical fruit from Myrtaceae family and widely cultivated in South East Asia. The limited availability of good quality seedlings of wax apple is the main problem to development of flourish it's market share in the current fruit industry. Therefore, in order to produce good quality planting materials, a study aimed at optimizing propagation and adventitious rooting technique and survivability of wax apple air layer was conducted. In this study, four different levels of Indole-3-Butyric Acid (IBA) concentration (0, 1000, 1500 and 2000 mg L-1) and three rooting media (sphagnum moss, vermicompost and garden soil) were applied after removal of bark (phloem) on the shoot to determine the effect on rooting and survivability of the wax apple air layer under field conditions. The results showed that the wax apple shoots treated with 2000 mg L-1 IBA produced the significantly higher number of roots, increased length of root, diameter of branch, length of branch, number of leaf and leaf area of air layers. In addition, the highest chlorophyll content and stomatal aperture were recorded in 2000 mg L-1 IBA treatment compared to other treatments including control. Vermicompost medium was better than garden soil and sphagnum moss in respect of rooting and survivability of air layers. The results showed that the combination of 2000 mg L-1 IBA and vermicompost as rooting media give the best combination to root initiation, root number, root length and survival rate (100%) of wax apple air layers. From this study, it can be concluded that 2000 mg L-1 IBA and vermicompost treatment enhance the root initiation, early establishment and survivability of wax apple air layered under field conditions.

Кора ильма лопастного Ulmus laciniata (Trautv.) в питании изюбря Cervus elaphus xanthopygos (Milne-Edwards)

Bark stripping by red deer has a significant impact on the state of forest ecosystems throughout the range of this ungulate species. Range-wide, red deer eat the bark of more than 20 species of trees, often causing significant damage to forestry. In the south of the Russian Far East, Manchurian red deer Cervus elaphus xanthopygus feed on the bark of elms Ulmus sp. in autumn and spring. However, prior research on the ecology of Manchurian red deer contains no quantitative estimates of the removal of elm bark by this ungulate. This article presents, for the first time, quantitative data on the influence of such deer feeding behavior on the forest stand of Primorsky Region. Manchurian red deer mainly damage undergrowth and young trees up to 40 years old with diameters of 0.5–7.4 cm at breast height (M = 3.75 ± 0.069, n = 249). In Ulmus laciniata undergrowth, the damaged bark area was 0.01–0.45 m2 (M = 0.11 ± 0.096, n = 249). At the same time, the deer scraped more bark from large trees by area on average when converted to one tree.

Fumigation of Insect-Infested Wooden Logs by EDN Using Two Scenarios of Plastic Tent-Tarpaulin Sealing: Wooden Logs Stacks Placed on Bottom Plastic Sheets or Directly on Underlying Soil

Recently, the largest bark beetle calamity (Ips typographus) of the last 100 years has erupted in Central Europe, including the Czech Republic. This calamity may threaten the sustainability of growing large areas of monoculture Norway spruce (Picea abies) in this area. Limited economically feasible physical and chemical pest control options are available to prevent the bark beetle spread. However, from these options, only mechanical bark removal or gas-insecticide fumigation result in instant deactivation of all pest stages throughout the entire stack of stored logs. Due to the ban on the use of methyl bromide (MeBr) for the fumigation of log piles under tarpaulin, the adaptation of the phyto-quarantine method EDN to the destruction of I. typographus bark beetles in harvested wood directly in forests was newly proposed in the Czech Republic. The methodical experience with fumigation of the harvested logs, however, was only available for wood fumigation in chambers or in tent-tarps fumigation placed on paved (concrete/asphalt) surfaces mainly in ship harbors. Prior to the introduction of the new EDN fumigation method of bark beetle infested wood stored directly in the forests, it was initially unclear whether it was necessary to use or neglect bottom sheets to optimize exposure and maximize Ct products for the permitted fixed initial dose (50 g·m−3). Therefore, the initial validation pilot trials were aimed at the estimation and comparison of EDN temporal dynamics and Ct products under real forest conditions and two fumigation scenarios: Wooden log pile placed on bottom plastic sheets or directly on soil without the bottom sheets. Field trials were performed under both identical as well as different environmental conditions. In addition, they revealed that the concentration decrease was significantly faster and Ct products were significantly lower in the case of trials without the bottom sheets. The experiments indicated high EDN sorption by the uncovered soil under the tent. Quantitatively, the average Ct product was 4.8 (identical conditions) and 3.7 (different conditions) times lower in EDN trials without the bottom sheets when compared to the use of bottom sheets. The initial field-forest fumigation validation trials indicated a necessity to carry out EDN fumigation under tent-tarps also using bottom sheets, although this fumigation procedure increases the labor-demands to some extent. Based on the presented results and additional data, the Czech authority issued for the EDN plant protection product an authorization for the limited and controlled use of wooden logs. Therefore, this work became the basis of the historically and first officially authorized use of any fumigant for pest control under commercial forest conditions.

Assessment and Distribution of Damages Caused by the Trunk-Boring Insects Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in Mediterranean Restored Cork-Oak Forests

This work assesses damage caused by Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in managed cork oak forests from the southern Iberian Peninsula. Lesions were diagnosed and quantified in relation to the following features: height and orientation in the trunk, diameter at breast height, solar exposure, understory presence and orography. The distribution patterns of lesions in the study area across 12 plots and in the trunk of the trees were also analyzed. The study was performed in “Sa de Hornachuelos” Natural Park (Córdoba, Spain) and the research area encompassed 12 environmentally-restored sampling plots. Data were recorded from 2007 to 2014, with yearly sampling from late June to mid-September, corresponding to the cork extraction period, since lesions caused by these insects are well distinguishable promptly after bark removal. The results reveal that C. undatus has low population levels and a non-uniform distribution pattern in the study area as well as in the trunk of the tree. It shows preference for medium height but not by any trunk orientation. R. grassei also shows low infestation levels and a preference to affect the trunk’s base. Comparatively, C. undatus showed higher infestation levels than R. grassei. The location of damage was also different, since galleries made by C. undatus predominated at intermediate trunk heights while those of R. grassei were more frequent at lower heights. Our results further showed a low co-occurrence of both species in the same tree trunks, which could be explained in terms of overlapping in the distribution areas of both species. These results provide background information that will enable natural resources managers to detect changes and trends of these species and inform future management decisions.

<p><strong>Observations on <em>Phassus n-signatus </em>Weymer (Lepidoptera: Hepialidae) feeding on <em>Ligustrum lucidum</em> in a suburban habitat of Heredia, Costa Rica</strong></p>

Larval feeding by the Central American ghost moth Phassus n-signatus is recorded in the Asian tree Ligustrum lucidum for the first time. Larval feeding and feeding damage was observed on 15 plants in a suburban environment where L. lucidum is widely used as a residential hedge. Larvae feed under a web of silk and frass on callus wound tissue that grows back following removal of bark around the entrance to a short (less than 42 cm) tunnel where the larva resides when at rest. The diameter of host plant stems at the tunnel site ranged between 4–32 cm and most larval tunnels were found less than 1.5 m from the ground. The presence of P. n-signatus within a suburban residential area shows that this species can persist within human modified urbanized environments where there are sufficient host plants available, and ground conditions include decaying plant debris that would be necessary to support growth of early instars that are presumed to occupy this microhabitat as documented for other stem boring Hepialidae. Key words: callus feeding, Central America, ecology, host plant, larva, phytophagy, stem borer

Retaining eucalyptus harvest residues promotes different pathways for particulate and mineral‐associated organic matter

AbstractEucalyptus plantations have replaced other (agro)ecosystems over 5.6 Mha in Brazil. While these plantations rapidly accumulate carbon (C) in their biomass, the C storage in living forest biomass is transient, and thus, longer‐term sustainability relies on sustaining soil organic matter (SOM) stocks. A significant amount of harvest residues (HR) is generated every rotation and can yield SOM if retained in the field. Yet, there is little information on how managing eucalyptus HR changes SOM dynamics. We used isotopic and molecular approaches in a 3‐yr field decomposition experiment where a native grassland has been replaced by eucalyptus plantations to assess how HR management practices influence content and chemistry of two distinct SOM fractions [particulate (POM) and mineral‐associated organic matter (MAOM)] at two soil depths (0–1 and 1–5 cm). The management practices investigated were HR removal (−R), only bark removal (−B), and retention of all HR (including bark, +B), combined with two levels of nitrogen (N) fertilization [0 (−N) and 200 (+N) kg/ha]. N fertilization inhibited HR decomposition (P = 0.0409), while bark retention had little effect (P = 0.1164). Retaining HR, especially with bark, increased POM‐C and MAOM‐C content (2.1‐ and 1.2‐fold, respectively), decreased POM‐δ13C (1.2‐fold), and increased inorganic N retention (1.7‐fold) compared with plots where HR had been removed. Inorganic N applications, however, diminished the positive impacts of bark retention. Although the influence of HR management was most pronounced in POM, retaining HR reduced potential soil C mineralization by up to 20%. POM and MAOM chemistry shifted over time and revealed distinct influence of HR on the formation of these fractions. We demonstrate that HR management alters SOM dynamics and that retaining HR, particularly including bark, enhances SOM retention. With continuing conversion of native grassland ecosystems to eucalyptus, long‐term sustainability will require careful HR and fertilizer management to balance total biomass harvest with sustaining belowground SOM concentrations.

Wood Products for Cultural Uses: Sustaining Native Resilience and Vital Lifeways in Southeast Alaska, USA

Ongoing revitalization of the >5000-year-old tradition of using trees for vital culture and heritage activities including carving and weaving affirms Alaska Native resilience. However, support for these sustained cultural practices is complicated by environmental and political factors. Carving projects typically require western redcedar (Thuja plicata) or yellow cedar (Callitropsis nootkatensis) trees more than 450 years of age—a tree life stage and growth rate inconsistent with current even-aged forest management strategies. Herein, we qualitatively assess the significance of wood products to rural communities and Indigenous cultures with implications for natural heritage sustainability. In partnership with Alaska Native Tribes, we engaged local youth programs to lead community discussions throughout southeast Alaska to provide specificity to the suite of cultural activities linked to regional forest lands. Results from 58 discussions across 11 southeast Alaska communities (primarily Alaska Native participants) highlighted the cultural importance of forest products including totem poles, dugout canoes, longhouses, woven hats, and woven baskets. Findings indicated spiritual well-being, health, education, tourism, and livelihood significance attributed to these products. Participant-suggested management strategies for increasing supply and expanding access to trees on public lands included: engaging local artisans in forest planning, selecting and delivering specific trees to roads as part of ongoing timber sales, allowing bark removal prior to forest-timber sales, simplifying the tree-acquisition permit process, and setting aside cultural forest groves to sustain trees seven generations into the future. By facilitating discussions, this study fostered relevant place-based youth and community engagement, benefiting youth and enhancing community knowledge transfer while simultaneously summarizing the significance of forest products for resilient culture and heritage activities. Forest management plans aiming to support Alaska Native lifeways may benefit from improved understanding of Indigenous perspectives and worldviews; designation of “culture market values” and “culture targets” can help deliver a broad array of ecosystem services.

<p><strong>New rearing method, life cycle, tunneling behavior and ecological notes on the splendid ghost moth <em>Aenetus djernaesae</em> Simonsen, 2018 from Western Australia (Lepidoptera: Hepialidae)</strong></p>

This study successfully documents, for the first time, the entire life cycle of Aenetus djernaesae Simonsen, 2018 and confirms the efficacy of using supplemental sources of fungi to feed the early instar larvae. Fresh cut pieces of the commercial mushroom Agaricus bisporus (J.E. Lange) and sections of Eucalyptus L’Her. bark were placed around the base of potted host plants –Myoporum insulare R.Br. (Scrophulariaceae) and the potential host plant Dodonea hackettiana W.Fitz. (Sapindaceae). First instar larvae were added to this matrix where they fed on the mushroom and bark. The life cycle comprised egg development of 20 days, fungal feeding of ~36 days, and host plant development (including pupal) of ~300 days. Adult emergence of reared and field collected samples occurred within a 22 day period. Larvae transferring from fungi to host plants transitioned during the night by constructing a web of silk and plant tissues within two hours and proceeding to excavate a tunnel from within. The mature larval tunnel is relatively short, up to 220 mm in length and usually extending below the entrance around which the larvae grazes on callus tissue forming after bark removal. Most adults emerged within an hour of dusk with the pupa protruding from the top of the vestibule. The rearing method described here demonstrates the feasibility of laboratory based studies of larval development in Aenetus Herrrich-Schäffer and other callus-feeding stem boring Hepialidae. Key words: Hepialidae, Aenetus, life cycle, artificial diet, Myoporum, Dodonea, larval foodplant

Potential contribution of eucalypt harvest residues to soil organic carbon in Brazil

The extent by which the contribution of eucalypt harvest residues (HR) to soil organic carbon (SOC) is impacted by soil disturbance during and/or after harvesting is unclear. We addressed this question by following the decomposition of HR in microplots (15-cm diameter, 15-cm height) and determining their contribution to SOC in 10 sites across southeastern Brazil. The experiment was set up according to a complete randomized block design arranged into a 3 × 2 factorial scheme including: HR removal (HR0), only bark removal (HR − B) and HR including bark (HR + B) applied to: undisturbed soil (US) with HR left on the soil surface or disturbed soil with HR mixed into the first 5 cm of the topsoil. We had eight blocks as replicates. Following a 12-month field decomposition, soil samples were fractionated to isolate SOC within the particle-size fractions (PSF) greater and lower than 53 µm. Subsequently, we used 13C to quantify the effects of the treatments in C3-derived SOC content (C3-SOC) within each PSF. For both PSF, their C3-SOC content increased in response to HR − B or HR + B relative to HR0, depending on soil disturbance and HR half-life time (t0.5). For HR − B, net increments in C3-SOC within the PSF > 53 µm increased significantly with HR t0.5, regardless of soil disturbance. Otherwise, the C3-SOC content within the PSF < 53 µm increased with HR t0.5 in response to both HR types, but only for US treatments. Overall, in regions where climate drives fast decomposition rates, on-site disturbance during and/or after harvesting should be minimized to favor the contribution of HR to SOC, particularly within the PSF < 53 µm.

A REVIEW OF WOOD-BARK ADHESION: METHODS AND MECHANICS OF DEBARKING FOR WOODY BIOMASS

Debarking systems and strategies are used to increase the value of woody biomass by separating wood and bark into two value-added product streams. Several debarking methods have been used for the removal of bark from wood. The selection of a debarking method is often based on the wood type and its end use. Debarking methods discussed briefly in this review include drum debarking, ring debarking, cradle debarking, chain flail debarking, high-pressure water jet debarking, compression debarking, and biodebarking. The performance of these debarking methods is highly dependent on operational parameters of machines, properties and type of woody biomass, and pretreatments. A universal applicable mechanistic model of the debarking process would be especially valuable for the development and optimization of debarking systems. In this respect, the competing objectives of high bark removal, low wood damage, high throughput, and low energy must be balanced against one another to arrive at a truly optimized approach. Wood-bark bond strength plays a vital role in impacting the effectiveness and efficiency of debarking technology. Thus, it is important to understand how mechanical properties of the wood-bark interface are influenced by different factors. Key factors that affect the wood-bark bond strength include MC, harvest season, wood species, temperature, and direction of applied load. The likely reason why MC affects the wood-bark adhesion strength is that the constituent elements of primary plant cell walls (cellulose, hemicellulose, and pectin) behave differently when they are exposed to water molecules. For example, there is negligible change in the length if cellulose microfibrils when exposed to water molecules. However, characteristics of hemicellulose and pectin behave differently than cellulose when they contact with water molecules. Also, the difference in the adhesion strength of wood-bark bond among varieties of woody plants is possibly due to the difference in density of cross linkages of homogalacturonan pectin by Ca2., and arabinan and galactan side chains of pectin. The relevance of this information to the debarking process is discussed.