Lawrence P. Abrahamson

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 e8ciency in willow bioenergy plantations is lacking. This study reports wood biomass production, annual removal of nutrients, and nutrient use e8ciency in experimental plantings of SRIC willow and poplar at Tully, New York. E9ects of clone, fertilization, irrigation, planting density, and harvest cycle were analyzed. Annual biomass production of 15 –22 dry Mg=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 signiBcantly a9ected rates of nutrient removal and nutrient use e8ciency. 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 e8ciency, and the lowest rates of nutrient removal. The annual harvest cycle had the lowest nutrient use e8ciency and the highest annual removal of nutrients suggesting that this choice would be most appropriate for biomass crops that are to be used as bu9er strips to manage nutrient runo9 from agricultural Belds. An appropriate choice of clone, planting density, and harvest cycle could tailor the rates of nutrient removal and nutrient use e8ciency to match the objective of the planting. c 2001 Elsevier Science Ltd. All rights reserved.

Growing fuel: a sustainability assessment of willow biomass crops

2to the atmosphere. The implementation of good management practices will maintain productivity over multiple rotations. Rural development and environmental benefits associated with deployment and use will accrue to the local community because of the willow system’s short supply chain. The economic valuation of these benefits are necessary for the deployment of woody crops, which in turn can help society become more sustainable.

Energy feedstock characteristics of willow and hybrid poplar clones at harvest age

Abstract Woody biomass feedstock produced from willow and hybrid poplar can be converted into bioenergy via thermochemical and biochemical processes. Variation in key properties that relate to the quality of biomass feedstock and determine its value for energy conversion were determined at rotation age (3 years), in 30 willow and seven hybrid poplar clones, grown in a short-rotation intensive culture (SRIC) system in central NY. Substantial clonal variation in the concentrations of nitrogen (2.9– 5.0 g kg −1 ), phosphorus (0.4– 0.8 g kg −1 ) potassium (1.2– 2.4 g kg −1 ), sodium (0.09– 0.20 g kg −1 ), calcium (3.9– 8.9 g kg −1 ), magnesium (0.2– 0.6 g kg −1 ), ash (13.2– 27.2 g kg −1 ) and bark percentage (3.6–8.1%) was found in stem (bark+wood) samples. A lower amount of variation was documented for specific gravity (0.33– 0.48 g cm −3 ) and percent moisture (49–56%). Bark had a higher concentration of inorganic elements and ash, relative to wood. Willow clones as a group had a higher specific gravity, bark percentage and calcium concentration relative to hybrid poplar clones, which had a higher potassium concentration. The two groups were similar in terms of the concentrations of other elements and ash. Clonal variation in these characteristics present opportunities for manipulating feedstock quality through selection, breeding and plantation management.

Willow biomass production during ten successive annual harvests

Abstract Five willow clones and one hybrid poplar clone were planted during 1987 at 0.3×0.3 m spacing and harvested annually for 10 years. Half of the trees were fertilized annually with N, P and K and all trees were irrigated beginning in the third growing season. Annual biomass production fit the logistic growth curve well for four of the clones with r 2 values ranging from 0.91 to 0.54, suggesting that well-adapted willow clones can be consistently productive for at least 10 years with annual harvesting. Fertilizer did not increase the maximum biomass production level attained, but it reduced the time required to reach maximum production by 1 year. The correlation between annual biomass production and the number of growing degree days during years 4–10 was high, ranging from 0.95 to 0.66.

Effect of organic amendments and slow-release nitrogen fertilizer on willow biomass production and soil chemical characteristics

Abstract Lime-stabilized sewage sludge and composted poultry manure, at a rate of 250 m 3 ha −1 each, and slow-release N fertilizer (Scotts Osmocote) at 100, 200 and 300 kg N ha −1 , were applied to plots of willow biomass crops during the first season of a three-year growth cycle. Stem biomass production was measured annually and soil chemical characteristics were assessed at the end of the growth cycle. Average annual stem biomass production was 8– 11 Mg ha −1 in slow-release N fertilized plots corresponding to a yield increase of 7–33% relative to control plots. In organically amended plots, annual stem biomass production increased by 30–38% relative to control plots. The study suggests that organically amended willows grew at a slightly faster rate than slow-release N fertilized willows. Statistically, the relationship between slow-release N application rate and stem biomass production was not highly significant; applications of slow-release N in excess of 100 kg N ha −1 provided no additional yield benefits. Differences in soil characteristics were most strongly expressed in surface soil. The pH at 0– 10 cm depth was 1 and 2 units higher on lime-stabilized sludge and composted poultry manure plots, respectively. Concentrations of soil K, P and Mg were dramatically higher in the composted poultry manure soils. The highest soil organic matter and N levels were observed in the surface horizons of organically amended soils. Utilization of organic residuals increases biomass production, provides beneficial use for wastes, reducing production costs and contributing to the sustainability of biomass production systems.

Sustainability and environmental issues associated with willow bioenergy development in New York (U.S.A.).

Abstract Biomass-for-bioenergy cropping and production systems based on willow (and poplar) planted and managed at high densities and short (3–4 year) coppice harvest cycles, providing fuel for co-firing with coal (or other types of energy conversion) must be ecologically and environmentally sustainable to be commercially successful. Current knowledge and ongoing research and development indicate that the production and utilization systems involved are environmentally and ecologically sustainable. Therefore two primary constraints to commercialization are being met. The remaining constraint is economic viability based on cost of production and use, the value of environmental externalities (such as atmospheric emissions), and potential government/public policy actions to promote this system of providing a locally produced and renewable farm crop and fuel. The environmental and ecological benefits of the system should act as a catalyst for developments needed to overcome the economic constraints of the system.

Cutting cycle and spacing effects on biomass production by a willow clone in New York.

An experiment was established in central New York State in 1990 to determine cutting cycle and spacing effects on willow biomass production. Cutting cycles were annual, biennial and triennial, and spacings were 0.3 × 0.3, 0.3 × 0.9, and 0.6 × 1.1 m; biomass production and survival by willow clone SV1 (Salix dasyclados) were measured. Beginning in the second growing season, trees were fertilized with N, P and K, and irrigated. Willow clone SV1 harvested triennially with 0.3 × 0.9 m spacing yielded 71.3 odt ha−1, an average annual production of 23.8 odt ha−1 year−1. Spacing of 0.3 × 0.9 m yielded the most biomass, but spacing differences were not significant for biomass production. Triennial harvesting was significantly more productive than cumulative production after 3 years with annual harvesting (64.5 versus 39.2 odt ha−1). Cumulative production from two biennial harvests was significantly larger than cumulative production from four annual harvests (64.3 versus 50.1 odt ha−1). Tree survival was similar among cutting cycles after five growing seasons, averaging 75%. Statistically significant differences in survival were detected among spacings, averaging 88, 80 and 57% at 0.60 by 1.1, 0.3 × 0.9 and 0.3 × 0.3 m spacings, respectively during 1994.

Multivariate approach for integrated evaluation of clonal biomass production potential

Abstract Evaluating the performance of clones to be used in short rotation intensive culture (SRIC) plantations for biomass production is critical for identifying superior clones and matching them with sites on which they will perform best. This will lead to increased production and a strengthening of the commercial prospects of these plantations. The primary objective of this study was to use a multivariate approach to evaluate the relative clonal performance of 38 willow and hybrid poplar clones, deployed in a genetic selection trial based on a coppice rotation system established in central New York State (NY) in 1997. Cluster analysis was conducted using survival, several individual plant growth attributes, and insect defoliation, all measured during or at the end of 1998. Two linear functions developed using discriminant analysis, comprising primarily of attributes related to tree vigor and site adaptability; tree volume index and length of growing period, explained most of the variation (98.5%) among the clusters. Eight of the 38 clones evaluated are expected to be high biomass producers, and are recommended for more extensive clone-site trials and commercial scale plantations across central NY and the northeastern United States (US). The results of this study indicate a possible approach to more effective juvenile selection in tree improvement programs, and insights for a refinement of the current SRIC tree ideotype.

Principal component analysis to evaluate the relative performance of nine year old hybrid poplar clones

Abstract Previous studies have identified particular hybrid poplar parentage lines associated with a certain level of growth or disease resistance. This study used principal component analysis (PCA) to evaluate the relative performance of 54 hybrid poplar clones based on nine year old measures of growth and canker disease. Growth was characterized by percentage survival and total basal area per clone, while disease was characterized by the number of cankers per living tree and canker appearance. The first principal component which accounted for 85% of the variation in the data set was used to rank the clones. In general, clones which exhibited high growth and low disease measures were ranked at the top of the list. One exception, clone GA88 (ranked near the top), was uncankered and despite having low survival, produced a relatively high basal area. PCA provided an ordering of clones based upon growth and disease which can be used to select clones for larger scale testing. Future applications of multivariate techniques can incorporate additional variables considered important for biomass, wood pulp, or veneer production.

Evaluating hybrid poplar clonal growth potential in a three-year-old genetic selection field trial

Abstract Survival, growth, and insect and disease damage of 54 hybrid poplar clones were compared in a three-year-old genetic selection field trial located in the St Lawrence River Valley, near Massena, New York, USA. Clones were grouped into growth potential classes using cluster analysis and indices of total growth and canker severity. Statistical significance of growth potential classes was tested using discriminant analysis. Seven of the 54 clones examined (DN16, NM6, NE17, D51, DN38, DN55 and NE21) were recommended for additional evaluations in larger scale clone-site trials. The technique presented in this report facilitates hardwood clone performance evaluation for a wide variety of desired products.