The carbon costs of global wood harvests.

After agriculture, wood harvest is the human activity that has most reduced the storage of carbon in vegetation and soils1,2. Although felled wood releases carbon to the atmosphere in various steps, the fact that growing trees absorb carbon has led to different carbon-accounting approaches for wood use, producing widely varying estimates of carbon costs. Many approaches give the impression of low, zero or even negative greenhouse gas emissions from wood harvests because, in different ways, they offset carbon losses from new harvests with carbon sequestration from growth of broad forest areas3,4. Attributing this sequestration to new harvests is inappropriate because this other forest growth would occur regardless of new harvests and typically results from agricultural abandonment, recovery from previous harvests and climate change itself. Nevertheless some papers count gross emissions annually, which assigns no value to the capacity of newly harvested forests to regrow and approach the carbon stocks of unharvested forests. Here we present results of a new model that uses time discounting to estimate the present and future carbon costs of global wood harvests under different scenarios. We find that forest harvests between 2010 and 2050 will probably have annualized carbon costs of 3.5-4.2 Gt CO2e yr-1, which approach common estimates of annual emissions from land-use change due to agricultural expansion. Our study suggests an underappreciated option to address climate change by reducing these costs.

Biometric assessment of early stem growth at a commercial stand of African mahogany (Khaya grandifoliola)

African mahogany species (Khaya spp.) have proven to be promising in the Brazilian forestry scenario, replacing native mahogany owing to their medium-fast growth and relevant timber value. This study aimed to carry out forest inventory and assessments of a Khaya grandifoliola plantation in the first years after planting, test hypsometric models to describe tree growth, and identify the maximum commercial stem yield (i.e., greater than 6 m in height). The stand was located in the municipality of Piracanjuba (GO), where seedlings of seed origin were used. Twenty random plots with a 15 m radius were allocated, and the total height (HT), stem height (HS), diameter at breast height (DBH), crown area, and forest canopy were measured. Four hypsometric models were employed in this study. The best equation was selected based on determination coefficients and standard errors. Further, the models were cross-validated to evaluate predictability and bias. At four years of planting, the largest class of HS was found to range from 3.1 to 4.1 m, and most trees had a DBH ranging from 0.084 to 0.126 m. The percentage of trees with stems > 6 m was 8.35%. The linear model ensured more consistent results for estimating HT, while the quadratic and Weibull models led to more consistent results for HS. By using models, stem measurements can be measured based on DBH, ultimately aiding the selection of stem management strategies for the growth of forests with greater commercial value.

Application of a simulation model to the prognosis of material loss in wood processing.

The article discusses the influence of a sample size on the credibility of a simulation model created for the estimation of material loss in the production of a middle layer of a wooden floorboard. The study was conducted in a production company operating in the wood processing industry. Geometric characteristics of input material were captured and used to derive statistical distributions, which were then included in the simulation model. The conducted experiments indicated that the quality of the simulation model was significantly affected by the quality and quantity of the sample, on the basis of which the stochastic model is estimated. It was shown that small sample for wood processing data was insufficient to capture process variability. On the other hand, excessive sample size (80 or more observations) for the material with high natural geometric variability, involves taking into account outliers, which may lower the overall prognostic quality of the simulation model. Based on the conducted simulation experiments, the recommended sample size which allows development of a reliable model for estimation of material loss in the analyzed manufacturing process, ranges from 40 to 60 measurements.

Abrupt increase in harvested forest area over Europe after 2015.

Forests provide a series of ecosystem services that are crucial to our society. In the European Union (EU), forests account for approximately 38% of the total land surface1. These forests are important carbon sinks, and their conservation efforts are vital for the EU's vision of achieving climate neutrality by 20502. However, the increasing demand for forest services and products, driven by the bioeconomy, poses challenges for sustainable forest management. Here we use fine-scale satellite data to observe an increase in the harvested forest area (49 per cent) and an increase in biomass loss (69 per cent) over Europe for the period of 2016-2018 relative to 2011-2015, with large losses occurring on the Iberian Peninsula and in the Nordic and Baltic countries. Satellite imagery further reveals that the average patch size of harvested area increased by 34 per cent across Europe, with potential effects on biodiversity, soil erosion and water regulation. The increase in the rate of forest harvest is the result of the recent expansion of wood markets, as suggested by econometric indicators on forestry, wood-based bioenergy and international trade. If such a high rate of forest harvest continues, the post-2020 EU vision of forest-based climate mitigation may be hampered, and the additional carbon losses from forests would require extra emission reductions in other sectors in order to reach climate neutrality by 20503.

Spatial characteristics and economic value of threatened species (Khaya ivorensis).

Khaya ivorensis (K. ivorensis), one of the most valuable tropical hardwood species indigenous to West and Central Africa, has been classified as a threatened tree species. However, information on its remaining population and distribution are limited. We mapped the current K. ivorensis spatial distribution, modelled the spatial autocorrelation and estimated its economic value using volume estimation and market pricing. The study was conducted in Odigbo and Irele local government areas (LGA), Ondo State, Nigeria. Spatially, localities of 97 K. ivorensis were identified across the study area and can be added into a wide range of datasets from local to global inventories. Large trees in diameter and height were statistically clustered in the north of Odigbo and assumed to relate with forest reserve management. Estimated median tree volumes were 0.39 m3 and 0.31 m3 in accordance with the allometric volume function and specific volume function, respectively. The economic values of wood varied approximately from US$111,208 to US$72,081. Findings from this study are a valuable resource for conserving this species and other threatened tree species.

Illegal logging as a disincentive to the establishment of a sustainable forest sector in the Amazon.

Brazil recently began granting timber concessions in public forests to promote sustainable forest use. The effectiveness of this strategy hinges on the design and implementation of the concessions themselves as well as their competitive position within the logging sector as a whole. There is, however, a lack of information on the competitive interaction between legal and illegal logging and its effects on concessions profits. We address this knowledge gap by using a spatially explicit simulation model of the Amazon timber industry to examine the potential impact of illegal logging on timber concessions allocation and profits in a 30-year harvest cycle. In a scenario in which illegal logging takes place outside concessions, including private and public "undesignated" lands, concession harvested area would decrease by 59% due to competition with illegal logging. Moreover, 29 out of 39 National Forests (≈74%) would experience a decrease in harvested area. This "leakage" effect could reduce concession net rents by up to USD 1.3 Billion after 30 years. Federal and State "undesignated" lands, if not adequately protected, could have 40% of their total volume illegally harvested in 30 years. Our results reinforce the need to invest in tackling illegal logging, if the government wants the forest concessions program to be successful.

EFO-LCI: A New Life Cycle Inventory Database of Forestry Operations in Europe.

Life cycle assessment (LCA) has become a common methodology to analyze environmental impacts of forestry systems. Although LCA has been widely applied to forestry since the 90s, the LCAs are still often based on generic Life Cycle Inventory (LCI). With the purpose of improving LCA practices in the forestry sector, we developed a European Life Cycle Inventory of Forestry Operations (EFO-LCI) and analyzed the available information to check if within the European forestry sector national differences really exist. We classified the European forests on the basis of "Forest Units" (combinations of tree species and silvicultural practices). For each Forest Unit, we constructed the LCI of their forest management practices on the basis of a questionnaire filled out by national silvicultural experts. We analyzed the data reported to evaluate how they vary over Europe and how they affect LCA results and made freely available the inventory data collected for future use. The study shows important variability in rotation length, type of regeneration, amount and assortments of wood products harvested, and machinery used due to the differences in management practices. The existing variability on these activities sensibly affect LCA results of forestry practices and raw wood production. Although it is practically unfeasible to collect site-specific data for all the LCAs involving forest-based products, the use of less generic LCI data of forestry practice is desirable to improve the reliability of the studies. With the release of EFO-LCI we made a step toward the construction of regionalized LCI for the European forestry sector.

Native species valuable timber plantations in Northern Guatemalan Humid Lowlands: ecological features and silvicultural feasibility / Plantaciones con especies nativas valiosas en Tierras Bajas del Norte de Guatemala: rasgos ecológicos y viabilidad silvícola

The Northern Humid Guatemalan Lowlands contains a significant diversity of tree species, including some valuable-timber producers; these species are threatened by commercial overexploitation and habitat loss due to deforestation. The cultivation of these species in forest and agroforest plantations is a potentially viable option for balancing their conservation and commercial harvesting, something that has been promoted with Government Incentives in Guatemala during the past two decades. However, these species have not been widely planted, among other constraints, because knowledge on their ecological requirements and silviculture is scarce. A characterization of monoculture and mixed plantations with 14 native valuable-timber species was made in the Humid Lowlands of Northern Guatemala, analyzing for each species frequency of association and accompanying species, planted area, the main ecological features and growth rates. To gather information, we combined field observation and measurements with interviews and literature review. Based on our survey, main management challenges for cultivation of the species were identified and described. Valuable-timber native trees could potentially be sustainably cultivated in the study zone in different types of forest plantations and agroforestry schemes of coffee, cacao, cardamom and cattle; considering their suitability to fit in diversified systems, growth performance and farmer's preferences, Swietenia macrophylla, Cedrela odorata, Tabebuia donnell-smithii, Calophyllum brasiliense and Cordia alliodora were the species with the higher potential for inclusion in plantations. However, several unsolved problems continue restricting the cultivation of these species in plantations; therefore, is essential a careful design and management.

Las Tierras Bajas y Húmedas del Norte de Guatemala contienen diversidad relevante de especies arbóreas, incluyendo algunas de madera valiosa; estas especies están amenazadas por sobre explotación comercial de su madera y deforestación. El cultivo de estas especies en plantaciones forestales y agroforestales es una opción potencialmente viable para equilibrar su conservación y aprovechamiento, lo cual ha sido promovido en Guatemala durante las dos décadas pasadas. Sin embargo, estas especies no se cultivan extensivamente, entre otras limitantes, debido al escaso conocimiento sobre su ecología y silvicultura. Se caracterizaron plantaciones puras y mixtas con 14 especies nativas maderables valiosas en Tierras Bajas y Húmedas del Norte de Guatemala, analizando para cada especie, presencia de especies, superficies plantadas, rasgos ecológicos y crecimiento. Para obtener información se combinó observaciones de campo, mediciones, entrevistas, consultas de archivo y revisión bibliográfica. Se identifican y describen los principales desafíos de manejo para cultivar las especies. Las especies nativas de madera valiosa podrían potencialmente ser cultivadas de manera sostenible, en diferentes tipos de plantación forestal y agroforestal con café, cacao, cardamomo y ganadería; considerando idoneidad para encajar en sistemas diversificados, tasas de crecimiento y preferencias de productores, Swietenia macrophylla, Cedrela odorata, Tabebuia donnell-smithii, Calophyllum brasiliense y Cordia alliodora fueron las especies que mostraron mayor potencialidad para ser incluidas en plantaciones en la zona. Sin embargo, aún persisten diferentes aspectos no resueltos que limitan el cultivo de estas especies en plantación, requiriéndose un cuidadoso diseño y manejo.

Expected Timber-Based Economic Impacts of a Wood-Boring Beetle (Acanthotomicus Sp.) That Kills American Sweetgum.

American sweetgum trees (Liquidambar styraciflua L. [Altingiaceae]) in China are being killed by a newly discovered wood-boring beetle "sweetgum inscriber" (Acanthotomicus sp.). It has not been detected in the United States yet, but given the extent of trade with Asian countries, eventual arrival of this beetle is a serious concern. The American sweetgum is one of the main hardwood species in the southern United States, and provides several economic and ecological benefits to society. We present the first economic analysis of the potential damage from sweetgum inscriber (SI) to timber-based land values in the southern United States. We modeled economic impacts for a range of feasible SI arrival rates that reflect policy interventions: 1) no efforts to prevent arrival (scenario A, once every 14 and 25 yr), 2) partial prevention by complying with ISPM 15 standards (scenario B, once every 33 and 100 yr), and 3) total prevention of arrival (scenario C, zero transmission of SI). Our results indicated much lower land values for sweetgum plantations without the prevention on SI establishment (scenario A, US$1,843-US$4,383 ha-1) compared with partial prevention (scenario B, US$5,426-US$8,050 ha-1) and total eradication of SI (scenario C, US$9,825). Across the region, upper bound timber-based economic losses to plantation owners is US$151.9 million (US$4.6 million annually)-an estimate that can help inform policy decisions.

Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood.

Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the pathway and planning measures for enhancing biosecurity.

Comparative economic and environmental assessment of four beech wood based biorefinery concepts.

The aim of this study was to analyze four conceptual beech wood based biorefineries generated during process design in terms of environmental and economic criteria. Biorefinery 1 annually converts 400,000 dry metric tons of beech wood into the primary products 41,600t/yr polymer-grade ethylene and 58,520tDM/yr organosolv lignin and the fuels 90,800tDM/yr hydrolysis lignin and 38,400t/yr biomethane. Biorefinery 2 is extended by the product of 58,400t/yr liquid "food-grade" carbon dioxide. Biorefinery 3 produces 69,600t/yr anhydrous ethanol instead of ethylene. Compared to biorefinery 3, biorefinery 4 additionally provides carbon dioxide as product. Biorefinery 3 and 4 seem most promising, since under basic assumptions both criteria, (i) economic effectiveness and (ii) reduction of potential environmental impacts, can be fulfilled. All four alternatives may reduce potential environmental impacts compared to reference systems using the ReCiPe methodology. Economic feasibilities of the analyzed biorefineries are highly sensitive.

DNA Barcoding of the Endangered Aquilaria (Thymelaeaceae) and Its Application in Species Authentication of Agarwood Products Traded in the Market.

The identification of Aquilaria species from their resinous non-wood product, the agarwood, is challenging as conventional techniques alone are unable to ascertain the species origin. Aquilaria is a highly protected species due to the excessive exploitation of its precious agarwood. Here, we applied the DNA barcoding technique to generate barcode sequences for Aquilaria species and later applied the barcodes to identify the source species of agarwood found in the market. We developed a reference DNA barcode library using eight candidate barcode loci (matK, rbcL, rpoB, rpoC1, psbA-trnH, trnL-trnF, ITS, and ITS2) amplified from 24 leaf accessions of seven Aquilaria species obtained from living trees. Our results indicated that all single barcodes can be easily amplified and sequenced with the selected primers. The combination of trnL-trnF+ITS and trnL-trnF+ITS2 yielded the greatest species resolution using the least number of loci combination, while matK+trnL-trnF+ITS showed potential in detecting the geographical origins of Aquilaria species. We propose trnL-trnF+ITS2 as the best candidate barcode for Aquilaria as ITS2 has a shorter sequence length compared to ITS, which eases PCR amplification especially when using degraded DNA samples such as those extracted from processed agarwood products. A blind test conducted on eight agarwood samples in different forms using the proposed barcode combination proved successful in their identification up to the species level. Such potential of DNA barcoding in identifying the source species of agarwood will contribute to the international timber trade control, by providing an effective method for species identification and product authentication.

Bactericidal Mechanism of Bio-oil Obtained from Fast Pyrolysis of Pinus densiflora Against Two Foodborne Pathogens, Bacillus cereus and Listeria monocytogenes.

Foodborne bacteria are the leading cause of food spoilage and other related diseases. In the present study, the antibacterial activity of bio-oil (BO) manufactured by fast pyrolysis of pinewood sawdust (Pinus densiflora Siebold and Zucc.) against two disease-causing foodborne pathogens (Bacillus cereus and Listeria monocytogenes) was evaluated. BO at a concentration of 1000 µg/disc was highly active against both B. cereus (10.0-10.6 mm-inhibition zone) and L. monocytogenes (10.6-12.0-mm inhibition zone). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values of BO were 500 and 1000 µg/mL, respectively, for both pathogens. At the MIC concentration, BO exhibited an inhibitory effect on the viability of the bacterial pathogens. The mechanism of action of BO revealed its strong impairing effect on the membrane integrity of bacterial cells, which was confirmed by a marked release of 260-nm absorbing material, leakage of electrolytes and K(+) ions, and reduced capacity for osmoregulation under high salt concentration. Scanning electron microscopy clearly showed morphological alteration of the cell membrane due to the effect of BO. Overall, the results of this study suggest that BO exerts effective antibacterial potential against foodborne pathogens and can therefore potentially be used in food processing and preservation.

Biomass logistics analysis for large scale biofuel production: case study of loblolly pine and switchgrass.

The objective of this study was to assess the costs, energy consumption and greenhouse gas (GHG) emissions throughout the biomass supply chain for large scale biofuel production. Two types of energy crop were considered, switchgrass and loblolly pine, as representative of herbaceous and woody biomass. A biomass logistics model has been developed to estimate the feedstock supply system from biomass production through transportation. Biomass in the form of woodchip, bale and pellet was investigated with road, railway and waterway transportation options. Our analysis indicated that the farm or forest gate cost is lowest for loblolly pine whole tree woodchip at $39.7/dry tonne and highest for switchgrass round bale at $72.3/dry tonne. Switchgrass farm gate GHG emissions is approximately 146kgCO2e/dry tonne, about 4 times higher than loblolly pine. The optimum biomass transportation mode and delivered form are determined by the tradeoff between fixed and variable costs for feedstock shipment.

Games of corruption: how to suppress illegal logging.

Corruption is one of the most serious obstacles for ecosystem management and biodiversity conservation. In particular, more than half of the loss of forested area in many tropical countries is due to illegal logging, with corruption implicated in a lack of enforcement. Here we study an evolutionary game model to analyze the illegal harvesting of forest trees, coupled with the corruption of rule enforcers. We consider several types of harvesters, who may or may not be committed towards supporting an enforcer service, and who may cooperate (log legally) or defect (log illegally). We also consider two types of rule enforcers, honest and corrupt: while honest enforcers fulfill their function, corrupt enforcers accept bribes from defecting harvesters and refrain from fining them. We report three key findings. First, in the absence of strategy exploration, the harvester-enforcer dynamics are bistable: one continuum of equilibria consists of defecting harvesters and a low fraction of honest enforcers, while another consists of cooperating harvesters and a high fraction of honest enforcers. Both continua attract nearby strategy mixtures. Second, even a small rate of strategy exploration removes this bistability, rendering one of the outcomes globally stable. It is the relative rate of exploration among enforcers that then determines whether most harvesters cooperate or defect and most enforcers are honest or corrupt, respectively. This suggests that the education of enforcers, causing their more frequent trialing of honest conduct, can be a potent means of curbing corruption. Third, if information on corrupt enforcers is available, and players react opportunistically to it, the domain of attraction of cooperative outcomes widens considerably. We conclude by discussing policy implications of our results.

Local wood demand, land cover change and the state of Albany Thicket on an urban commonage in the Eastern Cape, South Africa.

Understanding the rates and causes of land-use change is crucial in identifying solutions, especially in sensitive landscapes and ecosystems, as well as in places undergoing rapid political, socioeconomic or ecological change. Despite considerable concern at the rate of transformation and degradation of the biodiversity-rich Albany Thicket biome in South Africa, most knowledge is gleaned from private commercial lands and state conservation areas. In comparison, there is limited work in communal areas where land uses include biomass extraction, especially for firewood and construction timber. We used aerial photographs to analyze land use and cover change in the high- and low-use zones of an urban commonage and an adjacent protected area over almost six decades, which included a major political transition. Field sampling was undertaken to characterize the current state of the vegetation and soils of the commonage and protected area and to determine the supply and demand for firewood and construction timber. Between the 1950s and 1980s, there was a clear increase in woody vegetation cover, which was reversed after the political transition in the mid-1990s. However, current woody plant standing stocks and sustainable annual production rates are well above current firewood demand, suggesting other probable causes for the decline in woody plant cover. The fragmentation of woody plant cover is paralleled by increases in grassy areas and bare ground, an increase in soil compaction, and decreases in soil moisture, carbon, and nutrients.