The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of “potential” biomass within the contiguous United States based on numerous assumptions about current and
future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable manner—enough to displace approximately
30% of the country’s present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available.
In addition to updating the 2005 study, this report attempts to address a number of its shortcomings

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U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

Polluted soil and water impact the quality of food and nutrients of human and animal biota. Soil and water are mainly polluted by effluent discharges from industries, which are broadly classified into metallic and nonmetallic pollutant-bearing effluents. In order to tackle this problem, a plant-based technology called phytoremediation is used to clean contaminated lands. Phytoremediation is based upon several processes such as phytodegradation, phytovolatilization, phytoaccumulation and phytoextraction. These methods are efficient, eco-friendly and economic. This paper reviews the methods and mechanisms involved in phytoremediation of heavy metals, and enhancement processes.

Phytoremediation of heavy metals: mechanisms, methods and enhancements

To evaluate the phytoremediation capability of some poplar and willow clones a hydroponic screening for cadmium tolerance, accumulation and translocation was performed Rooted cuttings were exposed for 3 weeks to 50 μM cadmium sulphate in a growth chamber and morpho-physiological parameters and cadmium content distribution in various parts of the plant were evaluated Total leaf area and root characteristics in clones and species were affected by cadmium treatment in different ways Poplar clones showed a remarkable variability whereas willow clones were observed to be more homogeneous in cadmium accumulation and distribution This behaviour was further confirmed by the calculation of the bio-concentration factor (BCF) and the translocation factor (Tf) Mean values of all the clones of the two Salicaceae species showed that willows had a far greater ability to tolerate cadmium than poplars, as indicated by the tolerance index (Ti), calculated on the dry weight of roots and shoots of plants As far as the mean values of Tf was concerned, the capacity of willows to translocate was double that of poplars On the contrary, the mean values of total BCF in poplar clones was far higher with respect to those in willows The implications of these results in the selection of Salicaceae clones for phytoremediation purposes were discussed

Metal Tolerance, Accumulation and Translocation in Poplar and Willow Clones Treated with Cadmium in Hydroponics

The ecological principles that define the competitive and complementary interactions among trees, crops, and fauna in agroforestry systems have received considerable research attention during the recent past. These principles have not yet, however, been adequately integrated and synthesized into an operational approach. This paper reviews the ecological and ecophysiological bases for interspecific interactions based on data from site-specific research and demonstration trials from temperate agroforestry systems, primarily from temperate North America. The review shows that information on ecological interactions in several temperate agroforestry systems is inadequate. It is recommended that the future research should focus on exploring new species and systems that have received little attention in the past. Priority research areas should include cultural practices and system designs to minimize interspecific competition and maximize environmental benefits such as improved water quality. Potential for genetic modification of components to increase productivity and reduce competition also needs to be explored. Process-oriented models may be used increasingly to predict resource-allocation patterns and possible benefits for a suite of site and species combinations.

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Interspecific interactions in temperate agroforestry

https://estudogeral.sib.uc.pt/bitstream/10316/3916/1/filef8d0c75233134b6ea3d6c22a09cc05ef.pdf

Influence of metal resistant-plant growth-promoting bacteria on the growth of Ricinus communis in soil contaminated with heavy metals.

Worldwide, fuelwood demands, soil and groundwater contamination, and agriculture's impact on nature are growing concerns. Fast growing trees in short rotation woody crop (SRWC) systems may increasingly meet societal needs ranging from renewable energy to environmental mitigation and remediation. Phytoremediation, the use of plants for environmental cleanup, systems utilizing SRWCs have potential to remediate contaminated soil and groundwater. Non-hyperaccumulating, i.e., relatively low contaminant concentrating, species such as eucalypts (Eucalypts spp.), poplars (Populus spp.), and willows (Salix spp.) may phytoremediate while providing revenue from fuelwood and other timber products. Effective phytoremediation of contaminated sites by SRWCs depends on tree-contaminant interactions and on tree growth as influenced by silvicultural, genetic, and environmental factors. Locally adapted trees are essential for phytoremediation success. Among the different agroforestry practices, riparian buffers have the greatest opportunity for realizing the SRWC and phytoremediation potentials of fast growing trees. Agroforestry that combines SRWC and phytoremediation could be an emerging holistic approach for sustainable energy, agricultural development, and environmental mitigation globally.

G.R. Alker

Papers

Short-rotation woody crops and phytoremediation: Opportunities for agroforestry?