Conserve and Enhance Feedstocks for Bioenergy

Two recent issues have reinvigorated bioenergy research activity within the Northern Research Station. One is the groundswell of interest in mitigating global climate change by reducing atmospheric carbon dioxide (CO₂) accumulation. Bioenergy from harvested wood results in “no net accumulation” because the CO₂ released is re-cycled back into the new forests that grows back to replace the harvested one. Second is the increasing cost and threats to national security associated with crude oil imports. The Northern Research Station (NRS) has worked with the U.S. Department of Energy since the first OPEC oil embargo in 1973.

Research Studies

Genetics and Genotype × Environment Interactions Affecting Adventitious Rooting and Early Establishment of Poplar Energy Crops
Gaining knowledge about the genetics and genotype × environment interactions affecting adventitious rooting is important for energy crop production. First, rapid and extensive rooting reduces establishment costs by permitting the use of unrooted cuttings as commercial stock rather than rooted cuttings. Second, assuming concomitant and well-balanced shoot development, rapid and extensive rooting promotes early growth, reducing vegetation management costs and the time period to crown closure. Third, rapid and extensive rooting that is stable in the face of varying environmental conditions can increase the period of time during which successful planting can occur, increasing operational flexibility.  

Using Low Energy X-ray Radiography to Evaluate Adventitious Rooting of Poplar Energy Crops
Adventitious roots of poplars have been studied less than aboveground tissues. However, there is an overwhelming need to evaluate root initiation and growth in order to understand the genetics and physiology of rooting, along with genotype × environment interactions. The Plant Root Visualization and Characterization System (PRVCS; Phenotype Screening Corporation, Seymour, TN, USA) is a novel imaging technique for non-destructive rooting studies using low energy x-rays to characterize roots as the plants develop.

Using Spatial Analysis and Genotypic Screening to Optimize Testing, Siting, and Productivity of Poplar Energy Crops at a Regional Scale
Establishing poplar genotypes that are adapted to local environmental conditions substantially increases establishment success and subsequent productivity. But, it is difficult to design plant domestication field trials in landscapes where the crop has not been previously deployed.

Impacts of harvesting forest residues for bioenergy on nutrient cycling and community assemblages in northern hardwood forests
The increasing demand to utilize slash for bioenergy purposes will compete with other ecological services forests provide.  Current site-level guidelines emphasize retaining large diameter coarse woody debris (CWD) based on many studies documenting the important role it plays in managing biodiversity and contributing to nutrient cycling.   However, little information exists to help guide land managers on appropriate levels of fine woody debris (<6 inch diameter) retention for biodiversity and nutrient cycling concerns. 

Breeding and Selecting Poplar for Biofuels, Bioenergy, and Bioproducts
Hybridization of poplars occurs naturally among certain taxonomic sections, as well as from planned breeding efforts. Given that most of the variability of poplars is at the species level, both intra- and inter-specific hybridization have been vital tools for producing progeny that outperform either or both parents for biologically and economically important traits. It is important to refine breeding, testing, and selection protocols so that new, superior poplar genotypes can replace their underperforming counterparts.

Advanced Tree Gene Discovery for Carbon Sequestration
We are studying physiogical traits, including gas exchange properties and growth analysis parameters, of clones of the poplar backcross population sequenced by DOE.

Enhanced Adaptation to Climate Change of Conifer Species and Provenances in Northern Forest Ecosystems
Over 12 million trees were distributed from Wisconsin state forest nurseries in 2007. The success of such regeneration programs depends upon the development of adaptation strategies for enhanced ecosystem sustainability under changing climates. There is a need to identify species and seed sources with enhanced adaptation to climate change pressures to ensure biologically and economically sustainable reforestation, afforestation, and gene conservation.

Salt Tolerance and Salinity Thresholds of Woody Energy Crops Irrigated with High-salinity Waste Waters
There is a need for environmental practices that merge intensive forestry with waste management. Producing short rotation woody crops for energy, fiber, and environmental benefits requires adequate irrigation and fertilization, which can be supplied via waste waters including landfill leachate. Yet, leachate often contains elevated levels of salts such as chloride and sodium that cause leaf chlorosis and necrosis, decreased biomass accumulation, and increased mortality. Therefore, there is a pressing need to learn about the response of poplar energy crops when salts are taken up into root, leaf, and woody (stem + branch) tissues, as well as identifying thresholds of salt concentrations and salinity that can be recommended for these crops in both field testing and production plantations.

Technical Innovations to Reduce Impacts of Invasive Species
Technology that is available to manage invasive species and increase productivity of short rotation woody crops (SRWC) is often too expensive, difficult to operate, cumbersome, and/or impractical. There is a need for technical innovations that help to achieve these objectives while meeting specific experimental needs.

Biofuels, Bioenergy, and Bioproducts from Short Rotation Woody Crops
We are testing the genetics, physiology, and silviculture of poplar crops. Specific areas of interest include quantitative genetic analyses of biomass, rooting, and other important traits from hundreds of genotypes grown throughout the North Central United States, as well as analyses of tree growth regulating mechanisms in the face of varying environments and changing climate. Our silviculture research includes a range of studies from vegetation management to yield trials.

Sustainable Production of Woody Energy Crops with Associated Environmental Benefits
Increasing human population levels at regional, national, and global scales have heightened the need for proper management of residential and industrial waste. Contaminants from this waste stream have polluted water, air, and soil much faster than traditional technologies could remediate the problem. Therefore, we are combining intensive forestry and waste management methods to increase the potential for producing woody crops for energy and fiber, along with decreasing the environmental degradation associated with waste disposal and subsequent waste water production.