HYDROLOGIC IMPACTS AND TRADE-OFFS ASSOCIATED WITH FOREST-BASED BIOENERGY DEVELOPMENT ACROSS THE AMERICAS

A simulation-based framework for studying hydrologic impacts and associated tradeoffs for existing and proposed biofuel projects in the US (poplar), Argentina (eucalyptus) and Mexico (oil palm) is developed. For each case study, a representative watershed is selected and a SWAT model is set up and calibrated for an improved simulation of hydrologic processes and plant growth cycles. Potential bioenergy scenarios are developed that represent various planting densities, harvest cycles, fertilization and irrigation rates, land cover types being converted, slope, and locations across the watershed. Simulations indicate that growth and biomass production are significantly dependent on nitrogen availability, making fertilization a necessary management practice. However, there is a threshold beyond which further fertilization has no impact on yield and only increases the potential for non-point source pollution from contaminated runoff and leaching of nutrients. In contrast to fertilization, irrigation is not an impactful parameter due to the high average annual precipitation amounts in the case study watersheds. All the studies show significantly higher water use (evapotranspiration, ET) by the bioenergy feedstock due to fertilization, high planting density and/or morphology of the trees compared to the land cover that they replace. Simulation results indicate that average annual ET rates are 24%, 24% and 45% higher for poplar, eucalyptus and oil palm, respectively. The higher water use leads to a decrease in streamflow, especially during the low-flow months and dry years. The timing and degree of change in the streamflow is dependent on the crop, area of the plantation, and climate. On a watershed scale, the average annual decreases in streamflow as a result of planting poplar (on 70% of the watershed), eucalyptus (63% of the watershed) and oil palm (62% of the watershed) are found to be 21%, 28% and 9%, respectively. In all case studies, management practices are demonstrated to be significantly sensitive parameters for improving yield and mitigating negative environmental impacts. Water-energy tradeoff curves are plotted for each case to evaluate the most efficient management practices in terms of water and fertilizer use. The most productive scenarios can produce up to 6.5, 12.8 and 12.9 ton/ha/year biomass for poplar, eucalyptus and oil palm, respectively. Farm gate-level water footprints to produce bioenergy are estimated for all the case studies, indicating a lower water requirement for biodiesel production from eucalyptus compared to other case studies and reported values in literature. The green water footprint estimates indicate 98, 57 and 87 m3 water/GJ for poplar, eucalyptus and oil palm, respectively

Trees and water: smallholder agroforestry on irrigated lands in Northern India

Trees / Populus deltoids / Agroforestry / Afforestation / Reforestation / Models / Water use / Water balance / Evapotranspiration / Precipitation / Remote sensing / Irrigation requirements / India

The examination of the profitability and competitiveness regarding the energy plantations of woody plants in the region of Észak-Alföld

Due to the decrease in the quantity of traditional energy sources, in the future an alternative energy production should be sought which provides minimum environmental burden and offers an opportunity to generate energy. The use of biomass provides another option to resolve this problem. The most important features of the biomass are that the quantity doesn’t decrease during conversions and are reproduced by natural processes. The main raw materials of the biomass are considered to be the energy plantations, which are economic in areas where the farmer, during the traditional production, can’t or with difficulties can cover the expenses, so that profitably sustainable cultivation branches can come to the forefront with less material and energy input. Those cases in which the cultivation of agricultural areas are not economically feasible, there is a possible utilization in our country which is the installation of plantations with energetic aim

Modelled agroforestry outputs at field and farm scale to support biophysical and environmental assessments

This report, comprising Deliverable 6.17, in the AGFORWARD project brings together examples of modelled outputs at field and farm scale to support the biophysical, social, and environmental assessment of the innovations selected from work-packages 2 to 5.N/

Short Rotation Woody Crop Production Systems for Ecosystem Services and Phytotechnologies

While international efforts in the development of short rotation woody crops (SRWCs) have historically focused on the production of biomass for bioenergy, biofuels, and bioproducts, research and deployment over the past decade has expanded to include broader objectives of achieving multiple ecosystem services. In particular, silvicultural prescriptions developed for SRWCs have been refined to include woody crop production systems for environmental benefits such as carbon sequestration, water quality and quantity, and soil health. In addition, current systems have been expanded beyond traditional fiber production to other environmental technologies that incorporate SRWCs as vital components for phytotechnologies, urban afforestation, ecological restoration, and mine reclamation. In this Special Issue of the journal Forests, we explore the broad range of current research dedicated to our topic: International Short Rotation Woody Crop Production Systems for Ecosystem Services and Phytotechnologie

Evaluation of Markov chains for projecting diameter distributions

Fifteen years of the University of Tennessee\u27s Continuous Forest Inventory data were used to determine if Markov chains could be used to make accurate predictions of future diameter distributions for pulpwood size trees in natural hardwood stands. Distributions projected five and ten years were compared to actual data by means of the Kolmogorov - Smirnoff Test for Goodness of Fit. Projections were made for all hardwood species on each of three forest tracts and for several individual species that were abundant. Markov chain theory is based on the assumption that transition probabilities remain constant through time. To determine if this assumption was met when projecting forest stands, two initial probability matrices were constructed from data at five year intervals. If transition probabilities had not changed, differences between the two matrices would have been minimal. The two matrices were constructed and compared for all hardwoods on each tract and for the individual species. Markov chains and matrix algebra were employed to predict the average number of periods expected to pass before trees in each diameter class reach sawtimber size. Also, the number of periods spent in each diameter class before reaching sawtimber size was predicted. The results of the analysis of projected and actual diameter distributions indicated that Markov chains could be used as a reliable technique to determine future stand conditions. The only significant differences found between actual and projected data were because of the underestimation of the number of trees in upper diameter classes or, more often, the underestimation of mortality. In each of these cases actual mortality was unusually high as a result of an initial high proportion of intolerant trees in the stand which possibly succombed to suppression or competition; unprojected harvest or timber stand improvement; or catastrophic mortality caused by fire, insects or disease. Comparison of the probability matrices constructed at five year intervals indicated that, for each of the forest tracts studied, overall growth rates were not steady. Differences were not large, though, showing that short term projections were reliable. If longer time periods were projected, it would be expected that the differences between actual and projected data would increase. The other Markov chain calculations, average time to reach sawtimber size and average time spent in each diameter class, provided useful information about the growth and productivity of each tract. These predictions may be used in planning and timing various management activities

Growth and Development of Short Rotation Woody Crops for Rural and Urban Applications

Integrating biomass production of short rotation woody crops (SRWCs), with their use in environmental applications to produce income, sequester carbon, and clean the environment, provides an opportunity to enhance livelihoods and increase ecosystem services in rural and urban communities. This book consists of 20 papers from the special issue on the Growth and Development of SRWCs for Rural and Urban Applications highlighting four genera (Phalaris L., Populus L., Robinia L., Salix L.) from 13 countries. In addition to the development and management of a Salix cultivar database, rural and urban applications represented in the book included: a) forest buffers, b) forest health screening, c) phytoremediation, d) short rotation coppice, e) volume production, and f) wastewater reuse