Timber Species Research Articles

Resistance to Bark Beetle Outbreak in Norway Spruce: Population Structure Analysis and Comparative Genomic Assessment of Surviving (LTS) and Randomly Selected Reference Trees

Norway Spruce (Picea abies (L.) H. Karst.), a timber species of significant economic and ecological importance in the Northern Hemisphere, faces increasing threats imposed by drought and bark beetle infestation intensified by ongoing climate change. Despite the extensive mortality within stands, a small proportion of mature trees remarkably survive during severe bark beetle outbreaks. Hypothesizing that bark beetle resilience is genetically determined and thus is under natural selection, we anticipated that there is a genetic variation in genome regions linked to the respective resistance in surviving trees. In the Bohemian Forest, restricted to the area of the Czech–Austrian–German border, we identified those resistant individuals, referred to as the “Last Trees Standing” (LTS). Concurrently, we collected reference samples from randomly selected individuals from natural regeneration within concerned sites (seedlings, young trees) and in adjacent unaffected stands (mature trees). Genomic data were generated on a 50K SNPs genotyping array. We conducted a population genetic study based on the Discriminant Analysis of Principal Components (DAPC) method as well as the Genome-Wide Association Study (GWAS). We identified 12 markers (SNPs) significantly associated with tree survival using this approach. Three of those SNPs are located within the genes with the known function in Arabidopsis thaliana orthologs. After further confirmation, we argue that the identified SNPs can be instrumental in identifying trees of higher resistance to bark beetle infestation.

Evaluation of dowel bearing strength of fungal-decayed cross-laminated timber

ABSTRACT Dowel bearing strength of three cross-laminated timber (CLT) species (Douglas-fir, Norway spruce, spruce pine fir) were periodically assessed through 40 weeks of exposure to two brown rot fungi species (Gloeophyllum trabeum and Rhodonia placenta). Time-dependent regression models were developed to describe the relationship between level of fungal exposure and dowel bearing strength of CLT. Obtained dowel bearing strength values were used to predict the capacity of floor-to-wall CLT connection systems. Predicted strength values were compared with capacity of actual connection systems which were subjected to similar biodeterioration treatments. Significant reductions in the dowel bearing strength of CLT were observed 30 weeks after fungal inoculation. Similar patterns of degradation were observed for both fungi in all three CLT species, but R. placenta was slightly more aggressive than G. trabeum, causing a 16.2 MPa reduction in dowel bearing strength of Douglas-fir after 40 weeks of exposure. Connection capacities estimated using National Design Specification yield models for dowel type fasteners and the dowel bearing strength of fungal-damaged CLT were consistent with observed properties and were within 85% of actual capacity of connections tested, especially in early stages of decay.

Indigenous knowledge in agroforestry promotion: a case from Bandegaun, Indrawati Rural Municipality, Sindhupalchok District, Nepal

This research presents the role of indigenous traditional knowledge on agroforestry promotion in Bandegaun of Sindhupalchok district. Both primary and secondary information was collected through a household survey, key informant discussion, focus group discussion, direct observation, and review of agroforestry-related literature, papers, and reports. Agriculture was the main occupation of the respondents with the majority (62%) of the total respondents having a small landholding of less than 0.75 ha. However, about 91% of the total had practiced both agri-silviculture and home gardening, 55% of the total respondents had a Silvi-pastoral system and 27% of the total respondents had a small wood lot of trees. The main indigenous traditional knowledge used by the respondents for the promotion of these agroforestry practices in their farms were knowledge on the palatability of fodder species, knowledge on timber quality, knowledge on propagation by cutting, knowledge on NTFP value, knowledge on cash earning, and knowledge on religious value of tree species. A total of 39 tree species were included in the agroforestry practices of the study areas. Among them were 10 fodder species, 12 timber and fuelwood species, 6 NTFPs, and 11 fruit trees. Each study household on average have grown 4 fruit trees, 47 fodder tree, 19 fuelwood, and timber trees, and an NTFP in their farmlands, which have provided a great contribution to fodder, fuelwood, and timber supply for household use reported by 91% of the total respondents and some respondents (76%) had also generated income from the sale of timber, fuelwood, and NTFPs. Finally, it is recommended that indigenous knowledge-based agroforestry awareness and training programs along with preferred seedlings of good quality should be provided to promote agroforestry in study areas.

Advantages and limitations of tree mixtures in enhancing avian diversity in commercial timber plantations: Early insights from southern China

Commercial timber plantations, particularly monocultures, have limited capacity to support biodiversity. A widely promoted approach to enhance this capacity is the diversification of monocultures into tree mixtures, by adding “secondary” timber species while retaining the production focus on the monoculture species. However, the presumed biodiversity benefits of tree mixtures are yet to be robustly tested, because current evidence predominantly comes from mixed plantations in the general sense, which are often not under active production or differ from monocultures in other important ways. To address this gap, we assess the effectiveness of early-stage tree mixtures in enhancing the avian diversity of Eucalyptus monocultures in southern China, which is the country's most important timber production region and has been pioneering tree mixtures in large trials over the past decade. During the avian breeding and non-breeding seasons in 2021, we conducted rigorous surveys to compare the avian diversity of Eucalyptus monocultures and their tree mixtures involving slow-growing native species, against the reference baseline of mature native forests. We found that tree mixtures exhibited modest advantages over monocultures during the breeding season, and both plantation types had notable shortfalls relative to mature native forests. We additionally found that tree mixtures tended to benefit species that foraged in the medium–low strata, consumed diets of higher trophic levels, and depended more on mature forest habitat. We conclude that the biodiversity benefits of early-stage commercial tree mixtures were rather limited and more modest than typically assumed, highlighting the importance of studying tree mixtures in real-world production settings. Our study also underscores the conservation importance of protecting existing mature native forests.

Botanical Collection Patterns and Conservation Categories of the Most Traded Timber Species from the Ecuadorian Amazon: The Role of Protected Areas.

The Ecuadorian Amazon is home to a rich biodiversity of woody plant species. Nonetheless, their conservation remains difficult, as some areas remain poorly explored and lack georeferenced records. Therefore, the current study aims predominantly to analyze the collection patterns of timber species in the Amazon lowlands of Ecuador and to evaluate the conservation coverage of these species in protected areas. Furthermore, we try to determine the conservation category of the species according to the criteria of the IUCN Red List. We identified that one third of the timber species in the study area was concentrated in three provinces due to historical botanical expeditions. However, a worrying 22.0% of the species had less than five records of presence, and 29.9% had less than ten records, indicating a possible underestimation of their presence. In addition, almost half of the species evaluated were unprotected, exposing them to deforestation risks and threats. To improve knowledge and conservation of forest biodiversity in the Ecuadorian Amazon, it is recommended to perform new botanical samplings in little-explored areas and digitize data in national herbaria. It is critical to implement automated assessments of the conservation status of species with insufficient data. In addition, it is suggested to use species distribution models to identify optimal areas for forest restoration initiatives. Effective communication of results and collaboration between scientists, governments, and local communities are key to the protection and sustainable management of forest biodiversity in the Amazon region.

Traditional use of Polypores in Georgia (the Caucasus)

Background: The present work was intended to explore the quantitative ethnobotany and conservation status of flora of Koh-e-Suleman range, Razmak valley, North Waziristan, Pakistan. For the first time, significant traditional knowledge of the uses of reported flora was documented. Objective: The aim of the present study was to: (i) elucidate local populations' traditional knowledge of indigenous plants used for various purposes (ii) compile ethnomedicinal data using quantitative analyses for in-depth pharmacological evaluation of medicinal plants. (iii) evaluate the reported flora's conservation status. Methods: Ethnobotanical data were analyzed using quantitative tools, i.e., Relative frequency citation (RFC), use value (UV), and fidelity level (FL). Results: 102 participants including 75 men and 27 women were interviewed. The participants reported a total of 68 plant species, belonging to 57 genera and 19 families. There was 1 family of pteridophytes (1 species), 1 family of gymnosperms (4 species) and 63 species belonging to 17 families of angiosperms. Of the total reported plants, 38 were fodder species, 37 were medicinal species, 5 were timber species, 9 were fuel species, 8 were fruits species, 1 was vegetable species, 5 were condiment species, 2 were thatching species, 9 were ornamental species while none of the species was poisonous in nature. Conservation status revealed that 49 species (72.05 %) were vulnerable, 12 species (17.64 %) were rare, 6 species (8.82 %) were endangered, and 1 species (1.47 %) was found infrequent. Conclusion: The current study showed the majority of the species were used as fuel wood, medicines, and fodder. As most plant species have significant curative properties, a rotational and moderate grazing system is required to conserve the plants. Local residents must inculcate in their children the importance of floral diversity and conservation. Keywords: Anthropogenic activities, Conservation status, Endangered species, Quantitative ethnobotany, Razmak valley.

Transparent wood composite prepared from two commercially important tropical timber species

Transparent wood (TW) has garnered significant global attention due to its unique properties. In this study, TW composites were fabricated using two timber species of different density classes: Ailanthus triphysa (common name: Ailanthus wood) and Hevea brasiliensis (common name: Rubberwood). Sodium hydroxide (NaOH) and Hydrogen peroxide-based alkali method was used to modify the lignin in these veneer samples, producing a white cellulose template with a fully intact hierarchical cell structure. Subsequently, a cost-effective thermosetting unsaturated polyester resin (UPR) was infiltrated into the redesigned framework and polymerized to create rigid nanostructured transparent composites. High optical haze (of 94% and 89%) and favourable light transmittance of 59 and 55 percent were exhibited by the UPR-TW composites made from rubberwood and ailanthus wood, respectively. TW was characterised using Scanning electron microscopy and Fourier-transform infrared spectroscopy. The mechanical properties of TW were measured and compared with those of natural wood and pure-polymer. Furthermore, the anisotropic light diffusion behaviour displayed by TW in accordance with the fibre orientation indicates the utility of material as a potential light shaping device. Therefore, a cost-effective and commercially viable strategy to fabricate multipurpose TW composites using a combination of lesser-known timber species (LKTS) and UPR resin was successfully demonstrated.

Distribution and association pattern of Keruing (Dipterocarpus sp.) in Tangkahan, Gunung Leuser National Park

Keruing (Dipterocarpus sp.) is a commercially important timber and oil-producing species. Keruing’s wood is of high quality, and its oil is widely used for medicinal purposes. Because of the high price and demand for wood and oil, keruing has become a target for exploitation and causing the population to decrease. Understanding of the keruing population in natural habitats is important for conservation efforts, one of which is in the Gunung Leuser National Park (GLNP) area. The purpose of this study was to analyze the distribution patterns and associations of keruing in the Tangkahan area of GLNP. These are accomplished through the use of a vegetation analysis method with purposefully defined paths based on the presence of keruing. The Ochiai index (Oi), Dice index (Di), and Jackard index (Ji) were calculated for data analysis, while the Morisita index was used to determine the shape of the distribution pattern. The research reveals three keruing species, namely Dipterocarpus haseltii, Dipterocarpus constulatus, and Dipterocarpus elongataus Korth. The keruing distribution showed different patterns at different growth stages. At the seedling and tree stage, the distribution pattern was clustered, while at the sapling and pole stage were uniform. The three keruing species has weak associations with various surrounding species. The species that has the highest association value is Syzygium fastigiatum, which is 0.22.

Reproductive phenology of <i>Milicia excelsa</i>, <i>Antiaris toxicaria</i>, and <i>Pouteria adolfi-friedericii</i> in South West Ethiopia

Deforestation and degradation of natural forests pose a challenge for the forest sector in Ethiopia. Gathering scientific data on the reproductive biology of selected timber species has now become important to develop seed production areas and establish forest management regimes. In this regard, this study is aimed at determining the reproductive phenology of three indigenous tree species. The time of leafing, flowering, and fruiting in the three indigenous timber tree species has been recorded for three years in South West Ethiopia. This study was conducted in natural forests of the Benchi-Maji zone (Debub Bench district). We selected three prioritized species, Milicia excelsa, Antiaris toxicaria, and Pouteria adolfi-friedericii, based on the severity of their depletion and relative timber values in the area and in the country at large. Over 20 reproductively healthy, mature, and average mother trees 10 cm wide in diameter at breast height and with easily visible crowns, located at a distance of 100 m from one another, were selected out of each species and marked with marking ink. We conducted continuous observations and recorded data on leafing, flowering, and fruiting every 15 days (twice every month). The data was then analyzed using descriptive statistics. The result of this study indicates that the actual season when the seeds of Milicia excelsa are available for collection is once a year, from January to February. The results also showed that, for Antiaris toxicaria, the fruiting time is seasonal, and seeds become available for collection from early January up to the end of February. The fruiting time or the actual season when seeds of Pouteria adolfi-friedericii become available for collection is from May to June. Low-cost technologies (to establish seed production areas and domesticate the species) are recommended to be used for seed/seedling acquisition and distribution and preferable to reduce the destruction of the selected indigenous tree species.

Propagation of a U16 hybid Eucalyptus line by plant cell tissue culture

Eucalyptus is one of the important plant species for paper pulp, fuel wood, and timber. In this study, a hybrid Eucalyptus, U16 line, was investigated for rapid in vitro propagation. The apical and adventitious shoots served as initial explants. These were free-disease symptoms that were collected for surface sterilization. Different disinfectants including mercuric and Javel solutions at different concentrations and treated times were performed. The results showed that explants were cleaned under taping water with soap, rinsed in 70oEtOH for 1 minute, and then immersed in 10% Javen solution for 15 minutes and 0.1% HgCl2 for 10 minutes gave the highest disinfection rate that was 46.5%. The modified MS medium included basal MS, 30 g/L sucrose, and 7 g/L agar supplemented with 20 ml/L of coconut water (MS medium*) was the most suitable for the rapid multiplication of Eucalyptus lines U16, the shoot multiplication coefficient reached 1.56. In vitro multiplication of eucalyptus U16 was carried out by culturing disinfected shoot segments on the MS* medium supplemented with BAP 1.5 mg/L and kinetin 1.0 mg/L which gave the highest shoot multiplication coefficient (3.24 shoot per explant). The in vitro rooting medium of the U16 line was basal MS supplemented with 1.0 mg NAA/L, the rooting rate was 90.49%, the number of roots was 8.3, and the roots expressed strong growth

SOIL QUALITY AND HEIGHT DIAMETER MODEL ASSESSMENT IN THE MANAGEMENT OF GMELINA ARBOREA PLANTATION IN NASARAWA STATE UNIVERSITY, NIGERIA

Gmelina arborea is a very important timber species as it provides wood for furniture, serves as carbon sink and creates micro-climate with decrease soil temperatures enabling smaller niches to be formed within the forest ecosystem. Also, the nutrients composition of forest soil determines its stand structure and composition, growth rate and dominance, including other silvicultural practices. The study assessed soil quality and height-diameter (H-D) models in the management of Gmelina arborea plantation in Nasarawa State University. Thirty (30) temporary sample plots of 0.01 ha size were randomly selected from the sampling frame with 30% sampling intensity. Thereafter, the total height and the Dbh of each tree within the selected plots was measured for height-diameter model assessment. Also, ten (10) soil samples were randomly collected from the thirty (30) selected plots for H-D modeling in order to assess the soil properties of the plantation. Soil samples obtained were analyzed in the Faculty of Agriculture Laboratory to obtain data and further subjected to statistical analysis. The results of height-diameter models revealed that model one (1) with Akaike Information Criterion (62.19), Bayesian Information Criterion (66.39) and Residual Standard Error (0.64) had the lowest model selection indices when compared with other four models applied. Therefore, model one (1) was selected as the best and grand model for Gmelina aborea plantation in the study area. Also, the result of soil quality showed a significant difference between the soil properties in the study area. The Least Significant Difference result also showed that...

Influence of wet-dry cycles on the withdrawal capacity and corrosion of zinc electroplated self-tapping screws in CCA-treated and untreated Southern pine

Fastener products are commonly exported to different continents, and it is important to understand their performance in local timber species and construction practices. This paper investigates the effects of cyclic moisture changes on the withdrawal performance of yellow-zinc and nickel-zinc coated European screws in Australian copper chrome arsenate (CCA) treated Southern Pine, up to a maximum of 24 cycles. A 68–78% loss of the initial withdrawal strength was observed after three cycles, but this was recovered after twelve cycles. Overall, screws lost at least 50% of their initial strength after 24 cycles, regardless of the treatment or fastener coating. The corrosion resistance of nickel-zinc screws in CCA-treated timber was superior to that of yellow-zinc screws in the first three cycles, but the difference disappeared as the moisture cycle number increased. In CCA-treated timber, the corrosion rates of yellow-zinc screws were 40% higher than those in untreated timber. Although nickel-zinc screws were relatively more corrosion-resistant than yellow-zinc screws, the strength loss caused by corrosion confirms that the selected screws are best suited for indoor use. Finally, following a comparative analysis of test results, some recommendations were made in this paper for future research.

Integrated physiological and metabolomic analyses reveal changes during the natural senescence of Quercus mongolica leaves.

Quercus mongolica is a common landscape, afforestation, and construction timber species in northern China with high ecological, economic, and ornamental value. Leaf senescence is a complex process that has important implications for plant growth and development. To explore changes of metabolites during the ageing of Quercus mongolica leaves, we investigated physiological responses and metabolite composition in ageing leaves harvested from 15-20-year-old Quercus mongolica. Leaf samples of Q. mongolica were collected when they were still green (at maturity) (stage 1), during early senescence (stage 2), and during late senescence (stage 3). These leaves were then subjected to physiological index and metabolome sequencing analyses. The physiological analysis showed that the leaves of Q. mongolica changed from green to yellow during senescence, which induced significant accumulation of soluble sugar and significant reductions in the concentration of soluble protein and chlorophyll. Peroxidase and catalase were the main antioxidant enzymes mitigating leaf senescence. Metabolomic analysis identified 797 metabolites during leaf senescence. Compared to stage 1, 70 differential metabolites were screened in stage 2 and 72 were screened in stage 3. Differential metabolites in the two senescent stages were principally enriched in amino acid metabolism, lipid metabolism and secondary metabolite biosynthesis. The contents of N-oleoylethanolamine and N, N-dimethylglycine were significantly increased only in stage 2, while the contents of trifolin, astragalin, valine, isoleucine, leucine, and citric acid were significantly increased only in stage 3. Histidine, homoserine, tryptophan, tyrosine, phenylalanine, proline, norleucine, N-glycyl-L-leucine, linoleic acid, linolenic acid, gallic acid, 3-indoleacrylic acid, 3-amino-2-naphthoic acid, 3-hydroxy-3-methylpentane-1,5-dioic acid, 2,3,4-trihydroxybenzoic acid, trifolin, astragalin, DL-2-aminoadipic acid, pinoresinol dimethyl ether, dimethylmatairesinol, and lysophosphatidylcholine increased during both stage 2 and stage 3. Increasing contents of these metabolites may constitute the main mechanism by which Q. mongolica leaves adapt to senescence.

Development of an Advanced-Generation Multi-Objective Breeding Population for the 4th Cycle of Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook.)

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is an important timber species native to southern China. While the single, unstructured breeding strategy was employed in the past three cycles of breeding, it is no longer adequate for managing a more advanced breeding population. In this study, we utilized restriction-site-associated DNA-sequencing (RAD-seq) to estimate the genetic diversity of breeding populations and phenotypic values or breeding values to estimate the genetic gain of hundred-grain weight, diameter at breast height, and wood basic density. To achieve a balance between genetic gain and genetic diversity, we combined the multiple populations and core-main populations methods to construct the fourth cycle breeding population. Finally, the fourth cycle breeding population was made up of a core population of 50 individuals with an inbreeding coefficient of ~0, and an additional main population of 183 individuals, with an effective population size of 108. Crossings made within and/or between different trait-targeted subpopulations could facilitate bidirectional gene flow between the core and main populations, depending on the breeding objectives. This structured breeding population of Chinese fir could aim for both short- and long-term genetic gains and has the potential to support the preservation of germplasm resources for future climate change.

Potential geographical distribution and its multi-factor analysis of Pinus massoniana in China based on the maxent model

Pinus massoniana, an important timber, producing, and silvicultural species in southern China, exhibits high adaptability and wide distribution. This study utilizes the Maximum Entropy Model (MaxEnt), a species distribution model based on the theory of maximum entropy, to forecast the potential suitable distribution areas of P. massoniana in China under four climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) for both present and future (2080) conditions. The research integrates and analyzes the effects of various environmental factors, including topography, soil, and population, on the distribution of P. massoniana. Additionally, a geographical detector is employed to assess the interaction between different environmental factors and their contribution to the variation in suitability zones.The findings indicate that the MaxEnt model accurately predicts the potential distribution areas of P. massoniana, with AUC values exceeding 0.94. Precipitation in the driest month (BIO14), population density (POP), and annual precipitation (BIO12) emerge as the main factors influencing the current distribution of P. massoniana. Notably, BIO14 has the greatest impact on the species' distribution (43%), followed by POP (32.7%). Furthermore, lower BIO14 values correspond to higher probabilities of pine distribution, while higher POP values correlate with increased pine distribution probabilities. The potential distribution of P. massoniana is primarily concentrated in southern China under current climatic conditions, encompassing a total suitable survival zone of 25.24 × 105 km2, accounting for 26.29% of China's total area. Among the regions, Guangxi exhibits the largest suitable area for survival, reaching 28.9 × 104 km2, implying that the environmental characteristics of Guangxi are conducive to P. massoniana's survival. Under future climate scenarios, the overall distribution pattern of the potential range of P. massoniana remains similar to the present one, with an increasing trend in area. Notably, the SSP3-7.0 emissions scenario shows the most significant increase in area, totaling 4.71 × 104 km2, suggesting that this particular scenario is more favorable for the distribution of P. massoniana. This study provides valuable scientific insights for the management, conservation, and rational site selection of P. massoniana.

Effect of Particle Sizes on the Physio-Mechanical Properties of Bamboo Particleboard

The focus on timber species as the main source of raw material for wood based panel is alarming. This research work evaluated the effect of particle sizes on bamboo particleboard. The study was carried out in the Scientific Equipment Development Institution, Awkuke Enugu State. Laboratory tests were conducted both for physical and mechanical properties of the board at the Fredrick Research Centre, Agbani in Enugu state. Board density, moisture content and weight were variables measured for physical properties while internal bond, Modulus of elasticity (MOE), Modulus of rupture (MOR) were measured for mechanical properties using Shimadzu Universal Testing Machine. Data collected were analyzed using analysis of variance (ANOVA) and significant means separated with Duncan Multiple Range Test (DMRT) at 5% level of probability. Results recorded that T1 (fine particle) at 1.0 mm had higher values of MOR, MOE and internal bonding at 29.57, 1958.10 and 1.54 respectively followed by T3 (mixture of fine and coarse) and T2 (coarse particles). T2 had the highest moisture content of 8.22%, followed by T3 8.05% and T1 7.91% while T1 had the highest density (0.364g/cm3) and weight of 1.13 kg respectively. This study showed that particleboard made of fine particles (T1) of bamboo at 1.0 mm had better properties than T2and T3 in terms of their mechanical properties and physical properties with the exception of moisture content. It could be proposed that the finer the particles, the higher the strength of the board, thus recommends that smaller particles sizes like 0.5mm, 0.1mm and 0.3mm be used to increase the board strength.

Depth effect of tropical heavy hardwood of kekatong species towards EC5 using Weibull’s theory

The design practice has shifted from permissible stress design to limit state design using Eurocode 5 (EC5), which introduces design strength optimization. However, the adoption of EC5 in Malaysia cannot be done directly due to the absence of design strength data for Malaysian timber species. This paper presents a study that evaluates the bending strength properties, moisture content, and density of kekatong (Cynometra malaccensis) timber specimens using the Weibull theory to produce 1/k values for the local timber species. The depth impact adjustment factors for kekatong timber had a value of 0.23, which is not far from the well-established 1/k value of 0.2 for softwood and temperate hardwood with characteristic densities below 700 kg/m3 in EC5. The study shows that the bending strength of local timber is affected by its volume, and the variation of bending strength at several probabilities is in close agreement with theoretical predictions. Overall, the study provides important insights for the design of timber structures using Malaysian timber species, which can be used to improve the safety and sustainability of timber structures.

CARACTERIZACIÓN DE SISTEMAS AGROFORESTALES CON CACAO (Theobroma cacao L) EN TRES MUNICIPIOS DEL DEPARTAMENTO DE BOYACÁ, COLOMBIA

<p><strong>Background:</strong> In Colombia, most traditional cocoa crops are developed under agroforestry systems (SAF), associating shrubs and trees that provide shade for cocoa. They generate additional economic income and various ecosystem services. <strong>Objective:</strong> To characterize agroforestry systems with cocoa in three municipalities in eastern Boyacá (Miraflores, Berbeo, and Páez) belonging to the province of Lengupá. <strong>Methodology:</strong> A semi-structured interview was applied in 15 selected farms to learn about socioeconomic aspects, agronomic management of cocoa, and the use and management of trees. The botanical and structural composition and the Simpson (S), Shannon-Weaver (H´), and Jaccard (J) plant diversity indices were determined. <strong>Results:</strong> Cocoa producers in that region develop smallholder production under agroforestry systems with irregular tree species distribution, which are used for wood, firewood, shade, and food. At the regional level, 189 forest individuals accompanying cocoa were found, grouped into 18 families, 17 genera, and 28 species. The municipality of Berbeo presented the highest abundance (73 individuals), followed by Miraflores (67) and finally, Páez (49). In Berbeo, the species with a high importance value index (IVI) were <em>Ceiba pentandra</em> and <em>Cedrela odorata</em> (35 and 33, respectively), in Miraflores <em>Trichant<strong>h</strong>era gigantea </em>and <em>Persea americana</em> (44 and 42) and, in Páez <em>Cedrela odorata</em> (104). <strong>Implications:</strong> The selective felling of forests in SAF with cocoa, which intensifies the production of wood, has favored the loss of diversity; Therefore, the floristic composition studies serve as a basis to identify other potential forest species for the establishment of SAF to promote the diversification of the productive system and contribute to its resilience and sustainability. <strong>Conclusion:</strong> The agroforestry systems with cocoa in three municipalities in eastern Boyacá presented a differential composition and diversity, marked by a lower diversity in the municipality of Páez, where the species <em>C. odorata</em> had greater representation, related to the affinity of farmers for timber species of commercial interest.</p>

Study of mass transfer and hygroscopic properties of Australian mass-timber panels and species in hot and humid conditions- moisture sorption and desorption

ABSTRACT Wood is a commonly used building material with numerous advantages over other construction products. However, in engineered wood products such as cross-laminated-timber and laminated veneer lumber moisture absorption can lead to decay, swelling, deformation, and glue line failures, diminishing their properties. Understanding moisture intrusion processes in these materials can aid manufacturers, engineers, and architects in developing effective moisture management strategies during and after construction. The porosity of CLT 3P sections was 56.5%, higher than CLT 2P sections at 36.8%. True density varied among species, with radiata pine, southern pine, and shining gum measuring 1358, 1411, and 1031 kg/m3, respectively. True density values for CLT 3P, CLT 2P, and LVL were 1202, 837, and 1406 kg/m3, respectively. The species and sample type significantly influenced porosity and density values, crucial for future moisture modelling and predicting moisture gain/loss during wetting and drying processes. Moisture sorption and desorption properties were examined for Australian timber species, CLT, and LVL at different temperatures. LVL samples exhibited higher moisture content and dimensional changes, possibly due to improved moisture transfer facilitated by lathe checks. CLT samples demonstrated greater anisotropic behaviours than those of LVL samples. The product type and sample type had significant effects on equilibrium moisture content values.

Brown leaf spot of Cunninghamia lanceolata Caused by Colletotrichum kahawae in Sichuan province, China.

Chinese fir (Cunninghamia lanceolata) is an important timber species that has been widely cultivated in southern China. It is extensively applied in medicine, environmental monitoring, furniture, urban (e.g., street trees) and rural landscaping, windbreak forest, soil and water conservation. In January 2022, distinct leaf spot symptoms were observed in Chinese fir in Hongya Forestry (29°45'N, 103°11'E) Meishan City, Sichuan Province, China. Field surveys showed that the disease was widespread, with around 70% disease incidence. The typical symptoms initially appeared as yellowish-brown necrotic lesions on the margin of the leaves. Subsequently, lesions gradually expanded and developed into larger necrotic areas with red-brown irregular shape. The lesions later expanded throughout the leaf. Infected leaves turned dark brown and wilted, leading to seeding's death. Diseased leaves with typical symptoms were collected for pathogen isolation and identification. Infected tissues from ten samples were cut into small pieces of 2 × 2 mm. Infected tissues were surface disinfected with 3% sodium hypochlorite and 75% ethanol for 30s and 60s, respectively, and rinsed with sterile water 3 times. They were blotted dry with autoclaved paper towels and incubated on potato dextrose agar (PDA) with streptomycin sulfate (50 μg/mL) for 5 ~ 8 days at 25°C. and 12 h light/dark period. The diameter of the colonies reached 65.7 to 75.9 mm, with a gray to black center, and white edges while the reverse sides were gray to orange. Conidia were single-celled, colorless, straight, cylindrical, bluntly rounded at both ends, Conidia dimensions varied from, 7.3 μm to 15.7 μm in length and 3.3 μm to 6.1 μm in width (n = 100). For molecular identification, the genomic DNA of isolate SM2290708, SM229070801 and SM229070802 were extracted using a fungal genomic DNA extraction kit (Beijing Solarbio Science & Technology Co., Ltd., City, China). The internal transcribed spacers of the ribosomal RNA (ITS) [ITS1/ITS4 (White et al., 1990), calmodulin (CAL) (Weir et al., 2012), β-tubulin (TUB2) (O'Donnell et al., 1997), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (Templeton et al. 1992) were amplified. Sequences were deposited in GenBank (ITS: ON564877, OQ535027 and OQ535028; CAL: ON583827, OQ538101 and OQ538102; TUB2: ON583830, OQ538104 and OQ538105; and GAPDH: ON583831, OQ538108 and OQ538109). BLAST results showed that our ITS, CAL, TUB2 and GAPDH sequences were >99% identical to the corresponding sequences of Colletotrichum kahawae deposited at NCBI (GenBank JX010231, JX009642, JX010444, and JX010012). Identification was confirmed by Bayesian inference using MrBayes (Fig 2). The conidial suspension (1 × 106 conidia/ml) was used for inoculation by spraying leaves of ten 3-year-old Chinese fir plants for pathogenicity test. Fifteen leaves of each plant were inoculated. An equal number of control leaves was sprayed with sterilized distilled water as a control. Finally, all potted plants were placed in a greenhouse at 28°C under a 16 h/8 h photoperiod and in 73% to 79% relative humidity. After fifteen days, the symptoms observed on the inoculated plants were similar to those of the original diseased plants, but the controls remained asymptomatic. Colletotrichum kahawae was re-isolated from the infected leaves and identified by both morphological characteristics and DNA sequence analysis. The pathogenicity test was repeated three times, which showed similar results, confirming Koch's postulates. To our knowledge, this is the first report of brown leaf spot on C. lanceolata caused by C. kahawae in China. The results of this study provide basic information for diagnosis of the pathogen and developing prevention strategies to manage C. lanceolata leaf spot disease.