Some metals in aboveground biomass of Scots pine in Lithuania

The stocks of iron (Fe), manganese (Mn), zinc (Zn) and aluminium (Al) in different compartments of the aboveground tree biomass were estimated in Scots pine (Pinus sylvestris L.) stands in Lithuania. Simulated removals of metals due to the forest biomass extraction in a model Scots pine stands during a 100-year-long rotation period were compared with metals pools in sandy soil and the fluxes through atmospheric deposition. Applying whole tree harvesting, total removal comprised about 20 kg ha⁻¹ of each Al and Mn, and 5 times lower amount of each Zn and Fe. The metals were mainly removed with stemwood and living branches. However, metal export with aboveground biomass represented relatively small proportion of metals in mineral sandy soil. The annual inputs of Fe and Zn with atmospheric deposition were over 10 times higher than the mean annual removals with total aboveground biomass. The content of metals in forest biomass fuel ash was relatively small to compare with their total removals. The findings of this study have an important implications for future practice, i.e. the recommended maximum forest biomass fuel ash dose for the compensating fertilising could be increased with respect to balanced output – input in Lithuania.     

Estimates of technically available woody biomass feedstock from natural forests and willow biomass crops for two locations in New York State

A Geographic Information System (GIS) was used to estimate the technically available woody biomass from forests and willow biomass crops within a 40 km radius of Syracuse and Tupper Lake, NY. Land cover and land use data were used to identify the available land base and restrictions were applied for slope, parcel size and designated wetlands. Approximately 222,984 oven-dry tonnes (odt) of forest biomass are technically available annually around Syracuse, from 165,848 hectares (ha) of timberland. There are 67,880 ha of agricultural land technically available for growing willow biomass crops, which could produce 38,181 odt yr^?1 if 5% of this land was used and yields were 11.25 odt ha^?1 yr^?1. There are approximately 215,300 odt of forest biomass technically available annually around Tupper Lake from 211,500 ha of timberland. There are 781 ha of technically available agricultural land in this area so willow biomass production would be minimal. While these two areas have different land cover and land use characteristics, both have the potential to produce significant amounts of woody biomass.     

Geneti|c diversity of superior Salix clones selected for intensive forestry plantations

A number of willow clones are today in use in short rotation intensive culture plantations. The clonal nature of this crop makes it an easy target for pests and pathogens when grown in monocultures. This is a major concern as plantations of coppice must remain viable for up to 20 years to be profitable. In this paper the genetic diversity of 114 selected willow clones was examined and the possible solution of growing willows in multiclonal plantations is discussed. Forty five Salix eriocephala clones, 53 S. exigua clones and 16 clones of their inter-specific hybrid (12 S. eriocephala×exigua clones and 4 S. exigua×eriocephala clones), were evaluated. Starch gel electrophoresis was employed and 12 enzyme systems were used for the assessment of the genetic variation in the clonal material. A total of 29 loci and 57 alleles were revealed. Three measures of genetic diversity were used in order to evaluate the genetic base of the clonal set: average number of alleles per locus, percentage of polymorphic loci and mean heterozygosity. Results indicated that the genetic diversity within a species, is generally lower than the genetic diversity observed in natural populations or full-sib families of the same species. These results, however, are within the limits obtained from natural populations of the Salicaceae family. Heterozygosity values were found to be greater than similar values from poplar clonal material. In contrast to the results within species, inter-specific hybrid clones presented relatively high amounts of genetic diversity. The significance of these results in the management of clonal plantations is discussed from both the operational and conservation points of view.     

Biomass and nutrient removal by willow clones in experimental bioenergy plantations in New York State

The development of short-rotation intensive cultural (SRIC) willow systems as a source of bioenergy and bioproducts is growing in the northeastern and midwestern United States. Important data for sustainable management such as nutrient removal and nutrient use efficiency in willow bioenergy plantations is lacking. This study reports wood biomass production, annual removal of nutrients, and nutrient use efficiency in experimental plantings of SRIC willow and poplar at Tully, New York. Effects of clone, fertilization, irrigation, planting density, and harvest cycle were analyzed.

Annual biomass production of 15–22 dryMg/ha removed 75–86, 10–11, 27–32, 52–79 and 4–5 kg/ha/year of N, P, K, Ca and Mg, respectively. For all the variables studied, the responses depended on clone. Fertilization and irrigation increased rates of nutrient removal by means of increased biomass production. Unlike planting density, harvest cycle significantly affected rates of nutrient removal and nutrient use efficiency. For clone SV1 (Salix dasyclados), an irrigated and fertilized planting with a density of 36,960 trees/ha harvested on a 3-year rotation had the highest biomass production and nutrient use efficiency, and the lowest rates of nutrient removal. The annual harvest cycle had the lowest nutrient use efficiency and the highest annual removal of nutrients suggesting that this choice would be most appropriate for biomass crops that are to be used as buffer strips to manage nutrient runoff from agricultural fields. An appropriate choice of clone, planting density, and harvest cycle could tailor the rates of nutrient removal and nutrient use efficiency to match the objective of the planting.     

Cumulative continuous predictions for bole and aboveground woody biomass in Eucalyptus globulus plantations in northwestern Spain

At present there is increasing interest in modelling biomass to estimate carbon sequestration or the availability of forest products for use as bioenergy. The biomass of different tree components can be estimated to provide more detailed information. However, the different components have not been clearly defined. Moreover, the greater the number of components considered, the more difficult it is to fit the system of equations with any guarantee of statistical robustness. To overcome these limitations, we developed a continuous function that predicts cumulative biomass from the stump until any top diameter (including the biomass of branches). We also used two different methods to predict bole biomass: a cumulative continuous biomass function and conversion from volume to biomass by use of a taper equation and average wood density. We used a mixed-effects modelling framework to account for correlated errors in developing the taper equation. We developed a separate equation to estimate the foliar biomass for use in estimating total aboveground tree biomass. The cumulative aboveground woody biomass equation is implicitly additive, and no heteroscedasticity was observed, thereby resolving two of the main modelling goals in the development of biomass equations. For predicting cumulative bole biomass, estimation from volume generated less error, after bias correction, than direct estimation. Moreover, the indirect method also yields useful variables such as volume and height limits. Other variables such as carbon and nutrient contents, calorific power, ash content, etc. can be estimated by multiplying the mean contents by the predicted biomass or, for more accurate predictions, by using equations based on the relative diameter.     

High yielding biomass genotypes of willow (Salix spp.) show differences in below ground biomass allocation

Willows (Salix spp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation.     

Effects of burning of biomass on satellite estimations of solar irradiation in Brazil

Atmospheric combustion products from forest fires in the Brazilian Amazon and ‘Cerrado’ regions during the dry season (July–October) induce systematic deviations on the routine satellite techniques for the assessment of solar energy resource information. This study, based on clear-sky days, has shown model overestimations of the incoming solar radiation as high as 44%. On the average, clear-sky model overestimation was four times larger than that found for clear-sky days in regions outside the biomass-burning season. A positive correlation between the combustion products of black carbon, total aerosols, CO, N₂O, CH₄, and the number of fire spots counted by the AVHRR sensor from the NOAA series satellites suggests a possible mechanism for the parameterization of these effects on the radiation transfer methods.     

Biomass production,water use and photosynthesis of Salix clones grown in a wastewater purification system

An objective of the study was to identify leaf morphophysiological characteristics indicative of high aboveground woody biomass production of Salix clones growing in the vegetation filter of a wastewater purification system. It was hypothesized, that in these extra irrigated stands, the characteristics of photosynthesis are stronger determinants of the production than the characteristics of leaf water relations. The biomass production of the clones was correlated with numerous characteristics of leaf water relations and photosynthesis. Significant correlation was found between the biomass production and the following characteristics of top foliage leaves: daily decrease in water potential, stomatal conductance, stomatal sensitivity to increase in light intensity, and hydraulic conductance (positive); daily minimum and maximum water potentials, instantaneous water use efficiency, and stomatal sensitivity to decrease in leaf water potential (negative); maximum rate of photosynthetic electron transport, chlorophyll content, and the partitioning coefficient for leaf nitrogen into bioenergetics associated with electron transport (positive). In the most productive clones, the vertical gradient (through foliage) of values of almost all the characteristics was the smallest. The biomass correlated more strongly with the characteristics of photosynthesis light stage than with the characteristics of water relations. We conclude that the characteristics of photosynthesis light stage – high maximum rate of photosynthetic electron transport, high chlorophyll content, and also flat vertical gradient (through foliage) in values of the characteristics could be the strongest indicators of high biomass production of Salix clones growing in vegetation filter.     

Evaluation of sorghum hybrids for biomass production in central Italy

Two field experiments were carried out in 2005 and 2006 in central Italy in order to evaluate the biomass production and quality in eight sorghum hybrids, to define their biomass partitioning among leaves, panicles and stems and to identify which were the most adapted at early harvest. Sorghum showed a high potential in terms of biomass production in central Italy, with biomass dry yield of 25 t ha⁻¹ in average, adopting low input in terms of irrigation and fertilization. The most productive hybrids were H133 (26.3 t ha⁻¹) and H952 (25.9 t ha⁻¹) among the biomass hybrids and SS506 (27.3 t ha⁻¹) among the forage hybrids. The trends of dry weight and moisture content of biomass during the different hybrids growth cycles allowed to estimate the biomass production of each hybrids, hypothesizing an early harvest at 20 August with in-field drying of biomass. Early harvest reduced dry weight of biomass from 4.6% to 21.7%, depending of hybrids; SS506 and H128 showed to be the most adapted at early harvest. HHV and LHV of biomass showed average values higher in biomass hybrids (18.4 and 17.5 MJ kg⁻¹ d.m.) than in forage hybrids (17.7 and 16.8 MJ kg⁻¹ d.m.); while, ash content average values were lower in biomass hybrids (6.8% d.m.) than in forage hybrids (7.7% d.m.). The highest values of leaves + panicles partitioning in the forage hybrids increased ash content, reducing the quality of their biomass for thermal utilization; the biomass hybrids should be therefore preferable.     

Evaluating sampling designs and deriving biomass equations for young plantations of poplar and willow clones

Short-rotation intensive culture (SRIC) for bioenergy production is at its pre-commercial stage in Canada. To be economically viable, these types of plantations need an accurate examination of actual yields, which requires precise and efficient estimation methods (i.e., specific allometric equations and sampling methods). At six SRIC plantations from three Canadian provinces (Quebec, Ontario and Alberta), 6 willow and 10 poplar clones were sampled and clone allometric equations were developed to estimate plant biomass. A stem selection approach was successfully used to develop plant allometric equations, reducing the number of stems to be measured by up to 81% in coppiced plantations relative to traditional stem equations. Clone-specific equations were more accurate than equations for groups of clones, but the difference in terms of RMSE% was generally small (less than 5%). Using extensive measurements of all the plants inside a plantation and a simulation approach, we also compared five sampling methods (simple random sampling, stratified sampling, systematic sampling, random and systematic cluster sampling) to estimate total biomass inside the plantation. Simple random sampling and stratified random sampling were the most efficient methods (i.e., increased precision for equal sample size) for the estimation of average plant biomass, survival and total plantation biomass. Stratified random sampling (based on the position inside the plantation) made it possible to reduce the sample size as compared to simple random sampling, but only at higher levels of precision (e.g., 25 less plants at 5% precision). Applications of sampling using remote sensing techniques and GIS are briefly discussed.     

Cob biomass supply for combined heat and power and biofuel in the north central USA

Corn (Zea mays L.) cobs are being evaluated as a potential bioenergy feedstock for combined heat and power generation (CHP) and conversion into a biofuel. The objective of this study was to determine corn cob availability in north central United States (Minnesota, North Dakota, and South Dakota) using existing corn grain ethanol plants as a proxy for possible future co-located cellulosic ethanol plants. Cob production estimates averaged 6.04 Tg and 8.87 Tg using a 40 km radius area and 80 km radius area, respectively, from existing corn grain ethanol plants. The use of CHP from cobs reduces overall GHG emissions by 60%–65% from existing dry mill ethanol plants. An integrated biorefinery further reduces corn grain ethanol GHG emissions with estimated ranges from 13.9 g CO₂ equiv MJ⁻¹ to 17.4 g CO₂ equiv MJ⁻¹. Significant radius area overlap (53% overlap for 40 km radius and 86% overlap for 80 km radius) exists for cob availability between current corn grain ethanol plants in this region suggesting possible cob supply constraints for a mature biofuel industry. A multi-feedstock approach will likely be required to meet multiple end user renewable energy requirements for the north central United States. Economic and feedstock logistics models need to account for possible supply constraints under a mature biofuel industry.     

我国生物质资源化利用新技术及其进展

针对生物质传统利用方式的不足与弊端 ,提出生物质资源化利用新技术是生物质最终处置的根本方式 ,并就目前研究的生物质高温空气气化、生物质制氢、生物质液化、生物质固体成型等多种利用方式进行了综述     

Rapid biomass estimation using optical stem density of willow (Salix spp.) grown in short rotation

Quick and accurate biomass estimation of willow (Salix spp.) grown under short rotation intensive culture (SRIC) is essential for carbon accounting and management decisions. Currently, most estimates of tree biomass, including willow, rely on measurement of stem diameter. This is a suitable approach for single-stem species but for measurements of multi-stem species such as willow, there is an increase in the time and effort required as well as the need to include site, clone and age specific information. Therefore, we developed a new method which calculates optical stem density from digital photographs taken at predetermined locations and angles within a plantation during the fall or winter when the willow is without leaves. We then calibrated a mathematical model using destructive sampling to convert the measurements of optical stem density into estimates of biomass. The method produced very strong relationships (adjusted r² = 0.97) between the predicted and actual harvested biomass for the plots studied. Being new, the method still requires further testing and possibly adjustments for different planting designs and clones.     

Determination of biomass accumulation in mixed belts of Salix,Corylus and Alnus species in combined food and energy production system

Given the energetic, demographic and the climatic challenges faced today, we designed a combined food and energy (CFE) production system integrating food, fodder and mixed belts of Salix, Alnus and Corylus sp. as bioenergy belts. The objective was to assess the shoot dry weight-stem diameter allometric relationship based on stem diameter at 10 (SD₁₀) and 55 cm (SD₅₅) from the shoot base in the mixed bioenergy belts. Allometric relations based on SD₁₀ and SD₅₅ explained 90–96% and 90–98% of the variation in shoot dry weights respectively with no differences between the destructive and the non-destructive methods. The individual stool yields varied widely among the species and within willow species with biomass yield range of 37.60–92.00 oven dry tons (ODT) ha⁻¹ in 4-year growth cycle. The biomass yield of the bioenergy belt, predicted by allometric relations was 48.84 ODT ha⁻¹ in 4-year growth cycle corresponding to 12.21 ODT ha⁻¹ year⁻¹. The relatively high biomass yield is attributed to the border effects and the ‘fertilizing effect’ of alder due to nitrogen fixation, benefitting other SWRC components. On termination of 4-year growth cycle, the bioenergy belts were harvested and the biomass yield recorded was 12.54 ODT ha⁻¹ year⁻¹, in close proximity to the biomass yield predicted by the allometric equations, lending confidence and robustness of the model for biomass yield determination in such integrated agro-ecosystem.     

Use of harmonized equations to estimate above-ground woody biomass for two hybrid poplar clones in the Pacific Northwest

Equations were developed to estimate components of above-ground woody biomass, as a function of diameter, height, spacing and age for two hybrid poplar clones in western Washington. Independent and harmonized fitting techniques are compared. With the small sample sizes that are unavoidable in such experiments, harmonized equations provided more useful and consistent estimates of biomass increment than did independent equations by age and spacing. They were also better suited to interpolation and extrapolation of long-term trends of biomass increment than those based on the independent fits.     

Surface energy balance and 24-h evapotranspiration on an agricultural landscape with SRF willow in central New York

Surface energy balance and 24-h evapotranspiration were mapped on an agricultural landscape with SRF willows using a remote sensing-based model to provide information on the water use by different land cover types. The results demonstrate the influence of land cover and vegetation type on surface energy balance and water losses. The evapotranspiration from forests was much higher than for other land cover types, corresponding to the significant cooling of the land surface. The SRF willow plantings were on average 3.6 °C cooler than the surrounding grassy areas; the 24-hour evapotranspiration from willows was 1.6 times higher than the evapotranspiration from surrounding grass, but lower than evapotranspiration from the forests. The possibility of changes in evapotranspiration patterns, local climate, and regional water balance with increasing acreage in SRF crop are discussed.     

Evaluating the impact of three incentive programs on the economics of cofiring willow biomass with coal in New York State

Plantations of fast-growing willow shrubs are being promoted as a source quality biomass feedstock for bioenergy and bioproducts in New York State (NY). In the near-term, cofiring of the feedstock—in combination with other woody biomass—with coal in existing utility power boilers is considered to be the most promising conversion method for energy generation. Despite the clear technological viability and associated environmental benefits, cofiring of willow has not been widely adopted. The relatively high production cost of the willow feedstock, which is over twice that of coal, is the primary reason for this lack of interest. Taxes that account for some of the social costs of using coal and/or incentives that appropriate value for some of the social benefits of using willow are essential for eliminating most or the entire current price differential. This paper presents an integrated analysis of the economics of power generation from cofiring willow biomass feedstock with coal, from the perspective of the grower, aggregator and the power plant. Emphasis is placed on analyzing the relative impact of a green premium price, a closed-loop biomass tax credit, and payments to growers under the proposed Conservation Reserve Program (CRP) harvesting exemption policy. The CRP payments reduced the delivered cost of willow by 36–35%, to $1.90 GJ⁻¹ and $1.70 GJ⁻¹, under current and increased yield conditions, respectively. These prices are still high, relative to coal. Other incentives are required to ensure commercial viability. The required levels of green premium price (0.4–1.0 cents kWh⁻¹) and biomass tax credit (0.75–2.4 cents kWh⁻¹) vary depending on whether the incentives were being applied by themselves or in combination, and whether current yield or potential increased yields were being considered. In the near term, cofiring willow biomass and coal can be an economically viable option for power generation in NY if the expected overall beneficial effects associated with the production and use of the biomass is accounted for.     

生物质气化工程在村级集中供气系统中的设计

按照生物质燃气物理特性,根据流体力学对输气管道、排水器等进行水力计算,优化设计出自动排水器等各部分结构和尺寸,并在生物质气化集中供气系统工程中得到很好的应用。     

Assessment of coal and biomass to liquid fuels in central Appalachia,USA

Liquid fuels from coal and biomass have the potential to reduce petroleum fuel consumption and CO₂ emissions. A multi‐equation model was developed to assess the economics of a potential coal/biomass‐to‐liquids (CBTL) fuel plant in the central Appalachian hardwood region, USA. The model minimizes the total annual production cost subject to a series of regional supply, demand, and other constraints. Model inputs include coal and biomass availability, biomass handling system, plant investment, production capacity, transportation logistics, and project financing. The outputs include the required selling price (RSP) and the optimal logistical decision‐making associated with feedstock requirement, collection, delivery, and liquid fuel production. Results showed that the RSP of Fischer–Tropsch (FT) diesel for a 40 000 barrel‐per‐day CBTL plant with coal/biomass ratio (by weight) of 85/15 was $86.45–87.25 bbl^?1 using different biomass handling systems. The RSP would vary between $86.45 and $89.81 per barrel according to different coal/biomass mix ratios. In consideration of the carbon offset credits due to the addition of biomass, the RSP was adjusted to $84.19–86.74 with respect to four levels of carbon prices. Sensitivity analyses indicated that the RSP of FT diesel was mostly affected by plant capacity, capital cost, coal price, and liquid fuel yield. The crude‐oil‐equivalent price of FT fuels must be above $66 bbl^?1 for a CBTL plant to be profitable in central Appalachia for the long run. These results can help investors/decision‐makers evaluate future CBTL developments in the region. Copyright © 2011 John Wiley & Sons, Ltd.     

生物质热解液化反应塔中最小携带流速的可视化试验验证

生物质颗粒的最小流化速度是生物质快速热解液化工艺最重要的控制参数之一,准确掌握各种因素对最小携带流速的影响规律,对于保证充足的热解时间、提高生物质热解液化率是十分关键的,文章提出了生物质循环流化床快速热解反应塔中最小携带流速的预测方法;揭示了最小流化速度随生物质粒径和颗粒密度的变化规律,并通过可视化试验对预测结果进行了初步验证。