Genetic and environmental effects on rooting ability of dormant unrooted hybrid poplar cuttings

Genotypes with enhanced rooting ability are crucial for deployment of intensively cultured Populus plantations. Rooting of dormant, unrooted cuttings is the first biological prerequisite to stand establishment. The primary objective was evaluating three developmental systems affected by site conditions: lateral and adventitious root ontogenies, root/shoot growth rates, and temperature dependent physiologies. The study tested rooting ability of 21 clones from five taxonomic backgrounds ((Populus deltoides x Populus trichocarpa) x P. deltoides \u27BC1\u27; P. deltoides \u27D\u27; P. deltoides x Populus maximowiczii \u27DM\u27; P. deltoides x Populus nigra \u27DN\u27; P. nigra x P. maximowiczii \u27NM\u27) at Ames, Iowa; Waseca, Minnesota; and Westport, Minnesota, across three planting dates during 2001 and 2002. The experimental design was randomized complete blocks with 12 blocks per planting date and a single 20 cm cutting per clone per block. Spacing was 1.2 x 2.4 m, with two border rows of unrooted cuttings. Trees were harvested 14 days after planting. Dry weights, dimensions, and counts were determined for lateral roots, callus roots, callus, shoots, leaves, and cuttings. Height following establishment was also determined. Growing degree days (GDD) were estimated from aboveground and belowground temperatures. Precipitation data were compiled. Tree growth and environmental data were analyzed using univariate and multivariate approaches according to the Statistical Analysis System. The percentage of cuttings rooted among clones ranged from 21.8--86.1%. Broad-sense heritabilities for root and top dry weight ranged from 0.09--0.11 and 0.31--0.38, respectively. BC1 clones exhibited the highest root dry weight, while NM and DM clones produced the highest top dry weight. Clonal and taxonomic group shoot:root ratios ranged from 5--77 and 11--71, respectively. Clonal performance was stable over all year x site combinations, except for Westport 2002 where root growth was relatively poor. Rooting increased with increasing belowground GDD for all taxonomic groups. Least-squares regression models indicated very similar taxonomic group responses for each rooting trait. A minimum of four days with at least four GDD per day, along with precipitation dispersed throughout the growing period, were needed for above-average rooting. Clone NM6 performed well relative to others, while clone DN34 performed poorly

Using Phytotechnologies to Remediate Brownfields, Landfills, and Other Urban Areas

Urban areas requiring remedial work has prompted the use of phytotechnologies to improve water quality, soil health, and biodiversity, as well as to achieve sustainable social and economic goals. Phytotechnologies directly use plants to clean up contaminated groundwater, soil, and sediment. While woody and herbaceous crops are candidates for such remediation systems, trees within the genera Populus (poplars, cottonwoods, aspens) and Salix (willows) are ideal given their fast growth, extensive root systems, and elevated rates of photosynthesis and transpiration. The genetic diversity within these genera substantially increases the establishment and growth potential across heterogeneous sites. We have tested these trees for more than a decade across various sites and contaminants, which has resulted in developing phyto-recurrent selection, a method utilizing multiple testing cycles to evaluate, identify, and select favorable varieties with adequate genetic variation to guard against insect/disease outbreaks and changing edaphic conditions (especially those induced by contaminated soil and water) in the field. We will present information from our studies involving the selection and growth of trees performing well across variable site conditions (generalists) or sites with specific contaminant concerns (specialists) in order to enhance the success of phytotechnologies at brownfields, landfills, and other urban areas. This effort supports scientists and resource managers to acquire information that contributes to the deployment of systems that are ecologically and economically more sustainable versus traditional technologies, while the general public maintains environmental quality and protection of the natural resource base on which local and regional recreation, agriculture, and forestry depend

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

Biofuels, Bioenergy, and Bioproducts from Sustainable Agricultural and Forest Crops

This issue of BioEnergy Research highlights the Short Rotation Crops International Conference held in Bloomington, Minnesota in August 2008. This is the first special issue of BioEnergy Research, with several additional special issues planned in the next year, focused on the three U.S. Department of Energy Bioenergy Research Centers (Great Lakes Bioenergy Research Center, BioEnergy Science Center, and Joint BioEnergy Institute), and emerging technologies for biodiesel production. The purpose of these special issues is to highlight emerging research efforts in the areas of biomass, biofuels, and bioenergy. The Short Rotation Crops International Conference represented a unique opportunity for communication and interaction between researchers working on herbaceous and woody bioenergy feedstocks, one that we hope will continue to stimulate new interactions and creative solutions for bioenergy and bioproducts. We invite other groups to submit ideas for future special issues to one of the three co-Editors-in-Chief of BioEnergy Research

Biofuels, Bioenergy, and Bioproducts from Sustainable Agricultural and Forest Crops

This issue of BioEnergy Research highlights the Short Rotation Crops International Conference held in Bloomington, Minnesota in August 2008. This is the first special issue of BioEnergy Research, with several additional special issues planned in the next year, focused on the three U.S. Department of Energy Bioenergy Research Centers (Great Lakes Bioenergy Research Center, BioEnergy Science Center, and Joint BioEnergy Institute), and emerging technologies for biodiesel production. The purpose of these special issues is to highlight emerging research efforts in the areas of biomass, biofuels, and bioenergy. The Short Rotation Crops International Conference represented a unique opportunity for communication and interaction between researchers working on herbaceous and woody bioenergy feedstocks, one that we hope will continue to stimulate new interactions and creative solutions for bioenergy and bioproducts. We invite other groups to submit ideas for future special issues to one of the three co-Editors-in-Chief of BioEnergy Research

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

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 shortcoming

Dendroclimatic analysis of white pine (Pinus strobus L.) using long-term provenance test sites across eastern North America

Background: The main objective of this study was to examine the climatic sensitivity of the radial growth response of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the northern part of the species’ native distribution in eastern North America. Methods: The test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in the early 1960s in the eastern United States and Canada. Principal components analysis (PCA) was used to examine the main modes of variation [first (PC1) and second (PC2) principal component axes] in the standardized radial growth indices of the provenances at each test site. The year scores for PC1 and PC2 were examined in relation to an array of test site climate variables using multiple regression analysis to examine the commonality of growth response across all provenances to the climate of each test site. Provenance loadings on PC1 and PC2 were correlated with geographic parameters (i.e., latitude, longitude, elevation) and a suite of biophysical parameters associated with provenance origin location. Results: The amount of variation in radial growth explained by PC1 and PC2 ranged from 43.4% to 89.6%. Dendroclimatic models revealed that white pine radial growth responses to climate were complex and differed among sites. The key dendroclimatic relationships observed included sensitivity to high temperature in winter and summer, cold temperature in the spring and fall (i.e., beginning and end of the growing season), summer moisture stress, potential sensitivity to storm- induced damage in spring and fall, and both positive and negative effects of higher winter snowfall. Separation of the loadings of provenances on principal component axes was mainly associated with temperature-related bioclimatic parameters of provenance origin at 5 of the 7 test sites close to the climate influence of the Great Lakes (i.e., Wabeno, Manistique, Pine River, Newaygo, and Turkey Point). In contrast, differences in radial growth response to climate at the Ganaraska test site, were driven more by precipitation-related bioclimatic parameters of the provenance origin location while radial growth at the easternmost Orono test site was independent of bioclimate at the provenance origin location. Conclusions: Study results suggest that genetic adaptation to temperature and precipitation regime may significantly influence radial growth performance of white pine populations selected for use in assisted migration programs to better adapt white pine to a future climate