To increase the understanding of poplar and willow perennial woody crops and facilitate their deployment for the production of biofuels, bioproducts, and bioenergy, there is a need for broadscale yield maps. For national analysis of woody and herbaceous crops production potential, biomass feedstock yield maps should be developed using a common framework. This study developed willow and poplar potential yield maps by combining data from a network of willow and poplar field trials and the modeling power of PRISM-ELM. Yields of the top three willow cultivars across 17 sites ranged from 3.60 to 14.6 Mg ha À1 yr À1 dry weight, while the yields from 17 poplar trials ranged from 7.5 to 15.2 Mg ha À1 yr À1. Relationships between the environmental suitability estimates from the PRISM-ELM model and results from field trials had an R 2 of 0.60 for poplar and 0.81 for willow. The resulting potential yield maps reflected the range of poplar and willow yields that have been reported in the literature. Poplar covered a larger geographic range than willow, which likely reflects the poplar breeding efforts that have occurred for many more decades using genotypes from a broader range of environments than willow. While the field trial data sets used to develop these models represent the most complete information at the time, there is a need to expand and improve the model by monitoring trials over multiple cutting cycles and across a broader range of environmental gradients. Despite some limitations, the results of these models represent a dramatic improvement in projections of potential yield of poplar and willow crops across the United States.

Seventy-five eastern Cottonwood (Populusdeltoides Bartr.) clones, selected from tests representing the top one-third of clones tested throughout the Lower Mississippi River Valley, were analyzed for alpha cellulose content, specific gravity, and volume after three growing seasons. All traits were found to differ significantly among clones. Mean clonal alpha cellulose content ranged from 48.2 to 55.8% of oven-dry, extractive-free wood with an average of 51.1%. Specific gravity averaged 0.33, with clones ranging from 0.27 to 0.39. Specific gravity was highly inherited, while alpha cellulose content was found to be moderately heritable. Negative genetic correlations between volume and both wood properties indicate that using a selection index to simultaneously improve all three traits is currently not possible. Two other selection methods were discussed. These selections showed substantial gain differentials in volume, but either a small loss or improvement in specific gravity and alpha cellulose content. This indicates that at age 3 years only volume should be considered in a selection program.

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A 14‐wk greenhouse study was conducted to assess how varying application rates of biomass‐derived black carbon (biochar) and N fertilizer affect soil properties, plant N status, and switchgrass (Panicum virgatum L.) productivity. Biochar derived from a southern pine species was mixed with a silty clay loam at rates of 0, 0.4, 1.9, and 3.9% (w/w) and two rates of N fertilizer (0 and 56 kg ha−1 of N as urea) were applied in a randomized complete block design. Biochar provided increases in the volumetric water content (VWC, %) of the soil during the study period. At study completion, soil pH and total C were increased. Foliar N concentration and content did not differ among treatments despite significant increases in soil C/N ratios due to biochar. Switchgrass yields were reduced at the highest biochar application rate but were unaffected when rates were moderate. Nitrogen fertilization had few effects on measured soil and plant properties, and no interactive effects were found when applied in conjunction with biochar. Overall, moderate rates of biochar application increased soil pH, soil C content, and VWC but had negligible effects on plant N status or switchgrass yields. Our results demonstrate a potential function of biochar for improving temperate soil properties.

In 1987, an open-pollinated test of cherrybark oak (Quercus pagodae Raf.) was established on a loess site in Carlisle County, Kentucky. The test contained 37 half-sib families representing eight provenances from Louisiana, Mississippi, Tennessee, and Virginia. Height measurements were taken at ages one, three, five, ten, and fifteen, and diameter at ages five, ten, and fifteen. Significant differences existed among provenances and among families within provenances. Seed sources from the west-central Mississippi area performed better for both diameter and height, yet no overall geographic trend was apparent. The top three families were all from the Warren Co., Mississippi source while two of the top three diameter families were from Washington Co., MS and the third was from Warren Co., Mississippi. Survival among the eight provenances was constant from age one to ten. A drop in survival was shown between ages 10 and 15, probably a result of inter-tree competition. Height and diameter growth between ages five and 10 was nearly double that prior to age five and between ages 10 and 15. Family heritabilities for height and diameter were calculated for each measurement year. Family heritabilities for diameter ranged from 0.55 to 0.70 while height ranged from 0.50 to 0.70. Strong age-age correlations for height, diameter, and volume were found indicating good trait predictability from early measurements. Genetic gain equations were used to identify the optimum selection age and trait for maximizing age 15 volume. Early selection of families within provenances should yield gains in height, diameter, and volume.