Softwood Forest Research Articles

Drivers of truffle biomass, community composition, and richness among forest types in the northeastern US

Abstract Truffle-producing fungi (hypogeous sporocarps) are important mycorrhizal symbionts and provide a key food source for many animals, including small mammals. To better understand truffle diversity and associations in the northeastern US, we surveyed for truffles and analyzed spores in eastern chipmunk (Tamias striatus) scat across hardwood (angiosperm-dominated), softwood (gymnosperm-dominated), and mixed forest at Bartlett Experimental Forest, New Hampshire. Truffle biomass ranged from 3.8 kg/ha in hardwood forest to 31.4 kg/ha in softwood forest and was up to 35 times greater than mushroom (epigeous sporocarp) production in softwood forest. Elaphomyces species were the most common truffle taxa in both field surveys and chipmunk scat. Scat analysis indicated that truffle richness increased over the summer and accurately reflected fruiting time, providing greater resolution of richness than field surveys alone. Basal area of eastern hemlock (Tsuga canadensis) was the primary driver of Elaphomyces biomass and was the best explanatory variable of truffle community composition. We discuss implications of hemlock loss, due to the introduced hemlock woolly adelgid (Adelges tsugae), on forest mycorrhizal communities and food webs.

Equivalence among three alternative approaches to estimating live tree carbon stocks in the eastern United States

Assessments of forest carbon are available via multiple alternate tools or applications and are in use to address various regulatory and reporting requirements. The various approaches to making such estimates may or may not be entirely comparable. Knowing how the estimates produced by some commonly used approaches vary across forest types and regions allows users of carbon stock estimates to make informed comparisons. Here, we focus on equivalence of alternate estimates of aboveground live tree carbon in eastern U.S. forests derived from the carbon reports output by the Fire and Fuels Extension (FFE) to the Forest Vegetation Simulator (FVS). Three approaches to estimating individual-tree carbon are compared by FVS variant and forest type. There are two approaches available in the FVS Fire and Fuels Extension (labeled FFE and Jenkins) and a third based on the U.S. Forest Service’s forest inventory (component ratio method, labeled CRM).We found that the two volume-based approaches, CRM and FFE, are most often identified as equivalent within forest type group or whole-variant relative to the other two pairs of approaches. Equivalence is common in the Northeast and Southern variants, but relatively infrequent in the Central States and Lake States variants. The underlying volume equations of the FFE and CRM approaches influence the carbon equivalence patterns as indicated by differences in volume estimates between FVS and the U.S. Forest Service’s forest inventory. Aggregation, or expanding forest estimates to include increasingly larger areas, tends to reduce apparent differences between approaches – that is, they become more equivalent. This result is most evident with the CRM-FFE pair or in softwood forest type groups.

New tool for improved control of sub-process interactions in rotating ring die pelletizing of torrefied biomass

A new concept was developed for feed layer formation control and to obtain continuous pellet production when pelletizing torrefied biomass. The materials pelletized were softwood forest residues and a hardwood species which both had been torrefied at 308°C for 9min. The torrefied wood chips were milled over a screen size of 6mm and the torrefied feedstock moisture content was adjusted to about 9% before pelletizing. Two types of pelletizers were used; one with a stationary ring die and one with a rotating ring die. With a traditional, non-cooled die configuration, the die temperature increased to 75–78°C. During temperature increment, pellet production deteriorated and finally ceased at approximately 80°C. This phenomenon was caused by a breakdown of the feed-layer formation between the free rolling rollers and the die. However, continuous production could be sustained when the die was cooled. A new tool was developed based on nozzle injection of water directly onto the feed layer. By this course of action pellet production was sustained at temperatures well above 80°C. This proof-of-concept for a new tool to control sub-process interactions in ring die pelletizing also includes use of low initial moisture content to utilize the flowability of torrefied particulates and, thus, avoid problems connected to feeding, conveying and silo discharging which frequently occurs at higher feedstock moisture contents.

Evaluation of the two model biocorridors in South-West part of Slovakia in agricultural landscape

Evaluation of the two model biocorridors in South-West part of Slovakia in agricultural landscape

Genetic structure of remnant black poplar (Populus nigra L.) populations along biggest rivers in Serbia assessed by SSR markers

AbstractBlack poplar (Populus nigra L.) is a keystone species of riparian softwood forests along riversides in vast areas of Europe, Western Asia and Northern Africa. Since the end of the 20thcentury, black poplar has been recognized as an endangered species throughout Europe due to the loss of its natural habitat and possible crossbreeding with hybrid poplars. Using twelve nuclear SSR loci, we analysed the genetic structure of four native populations from three river valleys in the northern part of Serbia. All tested loci were highly polymorphic, displaying 8 to 25 alleles per locus, overall 179 detected alleles and an average effective number of alleles 5.87. Observed heterozygosity (overall Ho = 0.703) has been lower than the expected (overallHe= 0.808) in each population, which indicates positive mean of fixation index values (overallFis> 0 (0.132)). An AMOVA analysis revealed that the highest degree of genetic variation occurred within populations (95.33 %) while the genetic variation between populations was really low (4.67 %). High gene flow and no significant loss of allelic diversity have been recorded in the studied populations in Serbia.

White willow sexual regeneration capacity under estuarine conditions in times of climate change

Tidal wetlands provide both habitats for coastal populations and wildlife, and ecosystem services for human welfare. Building with nature regarding cost-effective coastal protection is of increasing interest. Much research has been carried out on plant reproduction capacities in mangroves and salt marshes, but less is known on this issue in tidal freshwater wetlands. Willows are being successfully used for bank stabilization in riverine habitats, however, today white willow softwood forests in tidal wetlands are highly fragmented, and restoration is required e.g. by the European Habitats Directive. Recently, tolerance to increasing salinity and tidal flooding was found for vegetative propagules of floodplain willows. However, the establishment of autochthonous sexual recruits is necessary to conserve the genetic diversity of local populations, and thus may be preferable in restoration. The germination and early seedling establishment of Salix alba (white willow) was experimentally studied under simulated estuarine conditions. The species tolerance to increasing salinity (0, 0.5, 1, 1.5, and 2) was tested in a climate chamber, and its tolerance to flooding at different tidal treatments (control, spring tide, daily tide 15 min and 2 h flooding) in the greenhouse. Germination was neither affected by increasing salinity nor by tidal flooding. Salix seedlings established up to salinity 1.5, but cotyledon performance and radicle growth was largely reduced at salinity 2. Under tidal flooding, seedling growth was similar in all treatments. However, in the treatments with daily tides seedling anchorage in the substrate took more than two weeks, and fewer seedlings reached a suitable length to approach the high water line. We assess S. alba sexual regeneration under estuarine conditions as generally possible. Further studies are needed on the effects of sedimentation-erosion processes on willow establishment in the field, especially on feedbacks between Salix survival and tidal wetland evolution.

Nitrogen and phosphorus regulation of soil enzyme activities in acid forest soils

The activities of soil extracellular enzymes are important in governing rates of organic matter decomposition and nutrient cycling in forest ecosystems. Measurements of soil enzyme activities can provide insights on microbial function, in terms of how much energy microbial communities are investing to acquire particular nutrients from OM substrates. In ecosystems enriched with nitrogen (N), phosphorus (P) supply may play an important role in regulating microbial activity, enzyme production, and organic matter decomposition. The response of extracellular enzyme activity to chronic N-enrichment was assessed at a long-term paired watershed N-enrichment experiment, the Bear Brook Watershed in Maine (BBWM) in hardwood and softwood forest types. Specifically, we measured the ambient (extant) activity of C hydrolyzing β-glucosidase (BG) and xylosidase (XYLO), N hydrolyzing N-acetylglucosaminidase (NAG), and P hydrolyzing acid phosphatase (AP) in the watershed subjected to chronic N-enrichment, and in the reference watershed. Secondly, in a series of soil incubations, we characterized the extent to which microbial C and P acquisition were regulated by N and P availability. In these incubations, we measured BG and AP activity response to acute (high-dose fertilizer) nutrient amendments. We hypothesized that soil enzyme activities would respond more to enhanced P availability than N, particularly in the N-enriched watershed. Our results from extant enzyme activity measurements suggest that chronic N-enrichment inhibited rather than stimulated extant soil hydrolytic enzyme activities, which could reflect suppression of microbial biomass and activity. In the acute nutrient amendment incubations, our data indicate that inorganic P was more important than N in regulating soil microbial C and P acquisition in soils from both the N-enriched and reference watersheds. Our results also indicate that the extent to which P availability regulated microbial acquisition of P in O horizon soils was greatest in softwood soils subjected to chronic N-enrichment. Findings from this study suggest that both forest type and soil inorganic P availability could be more important in influencing soil biological response to N pollution than previously recognized.

Land use and general equilibrium implications of a forest-based carbon sequestration policy in the United States

A comparative static Computable General Equilibrium model was used to assess the impacts of forest-based carbon payments on sequestration, land use, and agricultural commodity prices in the U.S. A modified 2008 regional Social Accounting Matrix, considering land as a heterogeneous factor, was used as the model's main input. The matrix was projected to its 2050 counterpart using capital and labour growth projections. The forest-generated carbon offset sources considered were afforested set-asides, commercial forestry intensification and harvested wood products. A new dataset on regional afforestation carbon uptake rates and costs was used to include afforested set-asides as latent activities. For a carbon offset price of $20/MT CO2, 12% of U.S. annual emissions could be sequestered in 2050. More than half of the additional carbon sequestered (611millionMT CO2), compared to the 2050 baseline, would be attributed to set-asides and composed mainly of softwood forests. High carbon prices would increase land prices resulting in the diversion of 15% and 8% of pasture and cropland to carbon set-asides, respectively, mainly in the Central Plains. The high agricultural land diversion would force activities to intensify production systems driving the prices of beef up by 14% as well as oilseeds and grains by 3% and 4%, respectively.

Spatial ecology and resource selection of a high-elevation American marten (Martes americana) population in the northeastern United States

High-elevation forests that contain mature, closed canopy stands are considered important habitat for American martens (Martes americana (Turton, 1806)) in the northeastern United States. To investigate this hypothesis, we monitored 15 radio-collared martens over a 2-year period and measured spatial use, as well as second- and third-order resource selection, from 33 seasonal home ranges and 889 telemetry locations. The population was composed primarily of adults that had small home-range size with average seasonal fidelity. During leaf-off seasons, martens selected against regenerating forest at both scales and selected for mixedwood and softwood forests and areas with rugged terrain within home ranges. Second-order selection was less pronounced during leaf-on seasons, yet martens exhibited greater selection for hardwood forest and areas with rugged terrain within home ranges. Home-range size was correlated positively with the amount of regenerating forest and body-condition index scores were lower during winter, indicating that these spatial and temporal attributes were influential. Although martens utilized low-elevation forest with extensive timber harvesting, contiguous, mature, and rugged high-elevation forest was used preferentially during winter. Land managers should minimize disturbance of montane ecosystems to ensure population viability for martens and other boreal forest species along distributional edges.

Global trade impacts of increasing Europe's bioenergy demand

Abstract European governments are rapidly turning to biomass to comply with the EU's legislated renewable energy targets for 2020 and 2030. To do so, EU member states will likely have to increase imports of biomass from timber rich regions, which will undoubtedly disrupt international wood product markets. In this study, a static global forest trade model of coniferous wood products is used to examine the effects of expanded demand for wood pellets in Europe to generate reliable electricity. Positive mathematical programming (PMP) is used to calibrate the model to 2012 bilateral trade flows. To assess the impact of increased wood-pellet demand on global forest products, we consider a scenario where EU demand for wood pellets doubles. Model results suggest increases in the world prices of industrial roundwood (1%), particleboard ($34/m 3 ), fibreboard ($30/m 3 ), pulp ($65/t) and pellets (71% to 128%), while the prices of sawnwood and plywood & veneer are projected to fall by $12/m 3 and $4/m 3 , respectively. The gains and losses are unevenly distributed between timber rich and timber poor regions; Russia, Canada and the U.S. experience large net welfare gains of $706 million, $544 million and $416 million, respectively, while Asia loses $1.8 billion. In the forest products sector, the gains outweigh losses with economic benefits increasing by some $4.9 billion, but this is a cost to the consumers of electricity and/or taxpayers in the regions implementing these renewable energy policies. The price of wood pellets is projected to rise between $107 and $154 per tonne. The findings highlight the need to account for the interconnections among softwood forest products globally.

Habitat and Time Are More Important Predictors of Weed Seed Predation than Space on a Diversified Vegetable Farm in Maine, USA

Postdispersal weed seed predation is a significant source of weed mortality in agroecosystems. The magnitude of seed predation, however, is variable. Understanding the relative importance of factors driving variability in seed predation rates will increase the potential utility of seed predation to farmers. We conducted landscape-scale field experiments to quantify and compare the effects of space, time of sampling, and habitat on weed seed predation. Seed predation assays, with and without vertebrate exclosures, measured seed predation rates at spatially explicit sample sites across 8.5 ha of crop and noncrop habitats on a diversified organic vegetable farm in Maine. Total and invertebrate seed predation averaged 8% and 3% d−1, respectively. Vertebrate seed predators detected by motion-sensing cameras included small mammals and birds. A ground beetle,Harpalus rufipes, was highly dominant in pitfall traps, comprising 66% of invertebrate seed predators captured within crop fields. Seed predation was randomly distributed in space. However, time of sampling and habitat were highly significant predictors of seed predation. Variance partitioning indicated that habitat factors explained more variation than did time of sampling. Total seed predation was greater in crop and riparian forest habitats than in mowed grass, meadow, or softwood forest. Generally, invertebrate seed predation was greatest at sites with an intermediate degree of vegetative cover, whereas habitat type was the chief biotic determinant of vertebrate seed predation rates. These results suggest cover cropping and wetland conservation as practices that may bolster seed predation rates.

Case studies on sugar production from underutilized woody biomass using sulfite chemistry

We examined two case studies to demonstrate the advantages of sulfite chemistry for pretreating underutilized woody biomass to produce sugars through enzymatic saccharification. In the first case study, we evaluated knot rejects from a magnesium-based sulfite mill for direct enzymatic sugar production. We found that the sulfite mill rejects are an excellent feedstock for sugar production. In the second study, we presented SPORL (sulfite pretreatment to overcome the recalcitrance of lignocelluloses), a sulfite pretreatment process based on modified sulfite pulping for robust bioconversion of softwood forest residues. Sulfite pulping technology is well developed, with proven commercial scalability, and sulfite pretreatment is a strong contender for commercial adoption.

River dynamics and invasion: distribution patterns of native and invasive woody vegetation at the Río Negro, Argentina

AbstractSalicaceae are typical invaders of riparian ecosystems throughout the world and they have the potential to change much of the invaded habitats. Along Patagonian streams, riparian softwood forests composed of non-native Salicaceae are increasing in abundance, area and tree species diversity. Especially in the last decades, dense floodplain forests dominated by invasive willows and poplars and additionally Russian olive and tamarisk spread almost explosively e.g. along the Río Negro in northern Patagonia. This study focuses on the identification of ecological niches and niche overlaps of the native and invasive woody species in order to assess the impact on the native Salix humboldtiana Willd. Data on species (presence/ absence) and explanatory variables were gathered in the field using a grid-based, stratified-randomized sampling design. Different environmental variables were then related to species occurrence in different life stages (adult, juvenile, seedling) using habitat distribution models. In the final models, flood duration, the amount of gravel and the location (upper or middle river valley) were included to describe the probability of occurrence of native and invasive taxa. For all life stages, a strong niche overlap could be observed for S. humboldtiana and the invasive taxa with no remaining exclusive habitats indicating a potential threat to the native willow. The study contributes to a better understanding of Salicaceae invasion and its consequences for riparian ecosystems.

하천의 생태적 복원을 위한 자연하천변의 목본성 식물군락에 대한 연구

하천의 복원을 위한 기초자료로 사용하고자 인간의 간섭에 의한 훼손이 없거나 적은 10개의 자연하천을 군집생태학적 방법으로 조사하여 통계적으로 분석하였다. 그 결과 신갈나무군락과 소나무군락, 사시나무군락, 굴참나무군락, 산벚나무군락 등 총 29개의 식물군락으로 확인되었다. 하천식생은 계곡 계반림과 하변림으로 나누어졌다. 계곡 계반림은 경사가 급하고 물에 의한 영향이 적어 경목림이 우점하였고, 하변 연목림은 버드나무류로 대변되었다. 하천 선택시 자연성이 기준이 되어 인간의 간섭이 많은 하류보다 중 상류에 위치한 조사지가 많았고, 그에 따라 출현군락의 92%(44 plot)는 경목림이었고, 8%(4 plot)는 연목림이었다. 전층을 이용한 PCA 분석에서는 신갈나무군락 그룹과 산벚나무군락 그룹, 소나무군락 그룹, 산벚나무군락과 소나무군락 혼합 그룹, 기타군락 그룹으로 크게 5개의 그룹으로 나누어졌다. 교목층을 이용한 PCA 분석은 신갈나무군락 그룹, 산벚나무군락 그룹, 기타군락 그룹으로 크게 3개의 그룹으로 나누어졌다. 하천변에 출현한 식물군락은 경목림과 연목림으로 나누어졌으며, 이를 통해 하천제방권 및 고수위권은 신갈나무, 소나무, 사시나무, 굴참나무와 산벚나무 등의 종을 식재하는 것이 적합하고, 고수부지권 및 저수위권은 버드나무속 식물을 식재하는 것이 적합할 것으로 판단된다. 식재될 목본에 따른 초본의 선택은 통계분석에서 같은 그룹에 속해있고, 높은 빈도로 출현하는 종으로 하는 것이 적합하다고 판단된다. In order to get as ecological basic data for river restoration, vegetation investigation was conducted in natural river and analysed it synecological methods, such as ordination cluster. 29 plant communities units were identified and the major dominant plant communites were Quercus mongolica community, Pinus densiflora community, Populus davidiana community, Q. variabilis community and Prunus sargentii community. River vegetations were classified into ravine and gorge forest type and riverine softwood forest type. Ravine and gorge forest was dominanted by hardwood which located in steep slope and in high elevation, and riverine softwood forest by softwood, salix spp. Naturality was an important criterion for the selection of rivers, so many of the selected rivers are located in the upper stream and mid stream rather than the lower stream, where more human intervention is involved. Plant communities were consisted of hardwood forest(44 plots, 92%) and softwood forest(4 plot, 8%), respectively. PCA with total layer data showed 5 groups of communities: Q. mongolica community group, Prunus sargentii community group, Pinus densiflora community group, Prunus sargentii community - Pinus densiflora community group and the rest communities group. PCA with tree layer showed 3 groups: Q. mongolica community group, Prunus sargentii community group, and the rest community group. Cluster analysis also a showed a similar communities group to PCA ordination, but Magnolia sieboldii community and Prunus sargentii community were distinguished from the PCA result. From the result, it can be concluded that the plant communities of riparian be divided into hardwood and softwood forest by statistical techniques. It was appropriate to plant species such as Quercus mongolica, Pinus densiflora, Populus davidiana, Quercus variabilis and Prunus sargentii, at levee zone and high water level. And Sliax spp. were appropriate for planted plants at waterfront and low water level. The herb species to be planted on the floodplain were recommanded in the species composition co-occurred with the woody species.

Characteristics of species richness and diversity of woody vegetation in the natural rivers in Korea and its meaning to restoration design in flood plains

In order to get basic data for flood plain restoration, we surveyed the woody vegetation in Korean natural rivers and analyzed the species`` characteristics with regards to patterns of richness and diversity. These characteristics were higher in hard wood forests than those in soft wood forests, such as Salix spp. community. Futhermore, they were the highest in the Prunus sargentii-Pinus densiflora community(H`` 1.095), and the lowest in the Carpinus laxiflora community(H`` 0.118) among the hard wood forests. Species`` richness diversity were the highest in the Salix gracilistyla community, but the lowest in the S. koriyangi community or S. koreensis community among the soft wood forests. With regards to the dominant index, just one community is over 0.9, 13 communities are between 0.3-0.7 and 15 communities are less than 0.3. The Salix koreensis community was the highest at 0.931, and Prunus sargentii-Pinus densiflora community was the lowest at 0.13. Species`` richness and diversity was significantly correlated with tree layer coverages and degree of slope. These results mean that in order to increase plant species diversity in flood plains planted hard woody trees, such as oaks and fir, are needed to suit environmental conditions with steeper slope and lower canopy coverage.

Land snail diversity and composition in relation to ecological variations in Central European floodplain forests and their history

We explored patterns of land snail assemblages using 93 alluvial forest sites in six river floodplains of the Elbe drainage basin (northwestern Bohemia, Czech Republic). Differences in species richness and composition across the four floodplain forest types (i.e., alder carrs, ash-alder forests, willow-poplar softwood forests, and hardwood forests) were analysed using generalized linear models, multidimensional scaling and redundancy analysis with the Monte Carlo permutation test. The studied floodplain forest types did not differ in species richness, except for the alder carrs which were significantly poorer. The number of species expressed a significant unimodal response along with elevation and Ellenberg nutrients, and further significantly decreased towards the most humid sites. Contrary to species richness, the main forest types clearly differed based on land snail species composition, with the exception of the ash-alder and willow-poplar forest sites which became completely overlapped in the ordination space. The main changes in species composition were mostly associated with elevation and Ellenberg moisture on the first MDS axis: Ellenberg nutrients and light were fitted on the second and the third axes, respectively. These variables, along with calcium content estimated using Ellenberg indicator values for soil reaction, had significant effects on the variation and snail species composition in the final RDA model. No response of either species richness or compositional changes was found for the measured content of topsoil calcium, most likely due to the higher importance of other variables. On the basis of some recently published data we can conclude that historical development and long-term human activities on the succession of floodplain assemblages have resulted in a sharp impoverishment of strictly land snail species of several hardwood forest sites in the majority of lower river stretches. Whilst in most areas there are no exact palaeoecological data available, these historical influences were closely correlated with the site elevation in our dataset as the main difference in species composition was hard to explain solely using environmental predictors.

Non-wood Forest Products Based on Extractives- A New Opportunity for Canadian Forest Industry Part 2- Softwood Forest Species

<p>Forest resources are among the most important of Canada (in the case of Quebec, nearly 90% of the territory). Innovation represents an essential challenge for the Canadian forest industry, which is presently undergoing major changes towards finding new solutions for recovery. The processing of forest biomass has become increasingly relevant along with the popular concept of biorefineries. This concept should include the development of novel technologies based on forest extractives. Bioactive molecules are readily available through eco-friendly extraction processes using various types of forest residues including barks which are generated in significant quantities by the industry. This literature review offers a glimpse into the softwood boreal forest with a particular focus on industrial species. We are adopting an ethno-pharmacological approach prior to presenting existing data on bioactive molecules from various sources, along with results from our own laboratory. In conclusion, this paper clearly demonstrates the need for further research on bioactive molecules from Canadian forest species since there remains an important lack of reliable data.</p>

Landscape-scale modeling of water quality in Lake Superior and Lake Michigan watersheds: How useful are forest-based indicators?

The Great Lakes watersheds have an important influence on the water quality of the nearshore environment, therefore, watershed characteristics can be used to predict what will be observed in the streams. We used novel landscape information describing the forest cover change, along with forest census data and established land cover data to predict total phosphorus and turbidity in Great Lakes streams. In Lake Superior, we modeled increased phosphorus as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, and agricultural land, and we modeled increased turbidity as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, agricultural land, and urban land. In Lake Michigan, we modeled increased phosphorus as a function of ecoregion, decrease in the proportion of forest disturbed during 1984–1999 and watershed storage, and increase in the proportion of urban land, and we modeled increased turbidity as a function of ecoregion, increase in the proportion of forest disturbed during 2000–2009, and decrease in the proportion softwood forest. We used these relationships to identify priority areas for restoration in the Lake Superior basin in the southwestern watersheds, and in west central and southwest watersheds of the Lake Michigan basin. We then used the models to estimate water quality in watersheds without observed instream data to prioritize those areas for management. Prioritizing watersheds will aid effective management of the Great Lakes watershed and result in efficient use of restoration funds, which will lead to improved nearshore water quality.

Changes in forest biomass carbon stock in Northern Turkey between 1973 and 2006

New forest management and planning approaches are designed to optimize forest structure. Optimal forest structure was determined using newly established growth models while considering primary timber production objectives as well as non-timber objectives for inaccessible areas and social and political pressures on land management. With currently planned management the forests of the Ormanüstü Planning Unit (OPU) in the Black Sea region of northern Turkey are likely to become an important C sink. To quantify this potential C sink and understand its implication to the regional carbon budget and future forest management, we estimated the changes in the OPU between 1973 and 2006. Based on four periods of data for the OPU forests obtained from the Forest Management and Planning Office of Turkey, we used allometric biomass and C regression equations along with biomass expansion factors to estimate the forest biomass carbon pool for each of four inventory years 1973, 1984, 1997, and 2006. Since 1973, OPU forests have accumulated 110.2 × 10(3)tons of C as a result of forest expansion and the growth of extant forests, increasing by 50.8% from 217 × 10(3)tons in 1973 to 327.2 × 10(3)tons C in 2006. Hardwood and softwood forests accounted for 44 and 56% of carbon accumulation during this period, respectively. From 1973 through 2006, forest C accumulated at a rate of 3.3 × 10(3)tons Cyear(-1). Carbon density of the OPU forests in the Black Sea region increased by 48.2% from 5,679 to 8,419tons/ha.

Saccharification of recalcitrant biomass and integration options for lignocellulosic sugars from Catchlight Energy’s sugar process (CLE Sugar)

BackgroundWoody biomass is one of the most abundant biomass feedstocks, besides agriculture residuals in the United States. The sustainable harvest residuals and thinnings alone are estimated at about 75 million tons/year. These forest residuals and thinnings could produce the equivalent of 5 billion gallons of lignocellulosic ethanol annually. Softwood biomass is the most recalcitrant biomass in pretreatment before an enzymatic hydrolysis. To utilize the most recalcitrant lignocellulosic materials, an efficient, industrially scalable and cost effective pretreatment method is needed.ResultsObtaining a high yield of sugar from recalcitrant biomass generally requires a high severity of pretreatment with aggressive chemistry, followed by extensive conditioning, and large doses of enzymes. Catchlight Energy’s Sugar process, CLE Sugar, uses a low intensity, high throughput variation of bisulfite pulping to pretreat recalcitrant biomass, such as softwood forest residuals. By leveraging well-proven bisulfite technology and the rapid progress of enzyme suppliers, CLE Sugar can achieve a high yield of total biomass carbohydrate conversion to monomeric lignocellulosic sugars. For example, 85.8% of biomass carbohydrates are saccharified for un-debarked Loblolly pine chips (softwood), and 94.0% for debarked maple chips (hardwood). Furan compound formation was 1.29% of biomass feedstock for Loblolly pine and 1.10% for maple. At 17% solids hydrolysis of pretreated softwood, an enzyme dose of 0.075 g Sigma enzyme mixture/g dry pretreated (unwashed) biomass was needed to achieve 8.1% total sugar titer in the hydrolysate and an overall prehydrolysate liquor plus enzymatic hydrolysis conversion yield of 76.6%. At a much lower enzyme dosage of 0.044 g CTec2 enzyme product/g dry (unwashed) pretreated softwood, hydrolysis at 17% solids achieved 9.2% total sugar titer in the hydrolysate with an overall sugar yield of 85.0% in the combined prehydrolysate liquor and enzymatic hydrolysate. CLE Sugar has been demonstrated to be effective on hardwood and herbaceous biomass, making it truly feedstock flexible.ConclusionsDifferent options exist for integrating lignocellulosic sugar into sugar-using operations. A sugar conversion plant may be adjacent to a CLE Sugar plant, and the CLE Sugar can be concentrated from the initial 10% sugar as needed. Concentrated sugars, however, can be shipped to remote sites such as ethanol plants or other sugar users. In such cases, options for shipping a dense form of sugars include (1) pretreated biomass with enzyme addition, (2) lignocellulosic sugar syrup, and (3) lignocellulosic sugar solid. These could provide the advantage of maximizing the use of existing assets.