Abstract:Eucalyptus species are native to Australia but grown extensively worldwide as short rotation hardwoods for a variety of products and as ornamentals. We describe their general importance with specific emphasis on existing and emerging markets as energy products and the potential to maximize their productivity as short rotation woody crops. Using experience in Florida USA and similar locations, we document their current energy applications and assess their productivity as short-term and likely long-term energy and related products.

This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180 degrees C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0-4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU beta-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus.

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Florida citrus and vegetable crops generate billions of dollars in revenue every year. However, wind, freezing temperatures, hurricanes, and diseases negatively impact production. Windbreaks located perpendicular to the prevailing wind can increase farm production simply by reducing wind and modifying microclimate. Windbreaks can also help in managing pathogens such as citrus canker (Xanthomonas campestris pv. citri). To study the modification of wind speed, temperature, and relative humidity on the leeside of single-row tree windbreaks in southern Florida, automated weather stations were installed in 2007/2008 at 2 m above the ground along transects perpendicular to a eastern redcedar (Juniperus virginiana) and three cadaghi (Corymbia torelliana) (WB1-WB3) windbreaks. All windbreaks reduced wind speed, with minimum wind speed (*5% of the open wind speed) at two times the distance of windbreak height (2H, where H = windbreak height in m) on the leeside of a E. redcedar (*17% porosity) and at 4H (*3-30% of the open wind speed) and 6H (\50% of the open wind speed) on the leeside of cadaghi windbreaks WB1 (*22% porosity) and WB2 (*36% porosity), respectively, when the wind direction was nearly perpendicular to the windbreaks. Wind speed reduction was observed up to 31 times the windbreak height (31H). Cadaghi windbreaks reduced wind speed on the leeside even during a tropical storm event. Temperatures on the leeside of the windbreaks were warmer during the day and cooler near the windbreaks at night compared to temperature in the open fields. This study demonstrates that single-row tree windbreaks can reduce wind and modify the microclimate to enhance crop production for Florida growers.

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Realized gains from selection of the first-generation breeding population of slash pine (Pinus elliottii Engelm. var. elliottii) were estimated using data from 38 field trials planted in large rectangular plots in the southeastern United States. The trials consisted of material selected for volume growth and planted by the Cooperative Forest Genetics Research Program at the University of Florida (19 trials) and by the Plantation Management Research Cooperative at the University of Georgia (19 trials). All trials contained slash pine seedlots collected from unrogued or lightly rogued first-generation seed orchards. Analyses of variance detected, on average, moderate gains in rust resistance (I50 = 43.1%) and site index (4.3%) and important gains in individual tree volume (7.7%) and stand yield (10.2%). Silvicultural treatments and age by realized gains interactions were never significant, but significant interactions between seedlots and trials showed that realized gains are not consistent at all sites. Overall results were highly consistent with predicted breeding values for rust resistance, but lower than expected for volume. On average, realized gain in stand yield for first-generation material was approximately 10%, or an extra inside-bark volume of 25 m 3 ·ha -1 (357 feet 3 ·acre -1 ) at 25 years.Résumé : Les gains réalisés par la sélection dans la population de première génération de pin d'Elliott typique (Pinus elliottii Engelm. var. elliottii) ont été estimés à l'aide de données provenant de 38 essais au champ plantés dans de grandes parcelles rectangulaires dans le sud-est des États-Unis. Les essais étaient constitués de matériel sélectionné pour la croissance en volume et planté dans le cadre du programme coopératif de recherche en génétique forestière de l'Université de Floride (19 essais) et par la Coopérative de recherche sur l'aménagement des plantations de l'Université de Georgie (19 essais). Tous les essais contenaient des lots de pin d'Elliott typique collectés dans des vergers à graines de première génération légèrement ou non éclaircis. Les analyses de variance ont détecté en moyenne des gains modérés pour la résistance à la rouille (I50 = 43,1 %) et l'indice de station (4,3 %) ainsi que des gains importants dans le volume des arbres (7,7 %) et le rendement des peuplements (10,2 %). Les interactions entre les gains réalisés et les traitements sylvicoles ou l'âge n'étaient jamais significatives mais il y avait des interactions significatives entre les lots de graines et les essais indiquant que les gains réalisés ne sont pas les mêmes dans tous les sites. Dans l'ensemble, les gains réa-lisés sont très consistants avec les valeurs en croisement prédites pour la résistance à la rouille mais plus faibles que prévu pour le volume. En moyenne, les gains réalisés dans le rendement des peuplements avec le matériel de première génération étaient approximativement de 10%, ou un volume sans écorce supplémentaire de 25 m 3 ·ha -1 (357 pieds 3 ·acre -1 ) à 25 ans.[Traduit par la Rédaction] Vergara et al. 2600