Modified foragers represent a cost-effective option for harvesting high-density short-rotation energy plantations. However, new energy plantations grown in Brazil far exceed the stocking and the stem size characterizing plantations in the Northern hemisphere, which raises the question about the ability of modified foragers to perform effectively. A study was conducted on five eucalyptus plantations, located in different Brazilian States and spanning over a wide range of work conditions in terms of clone, age, planting density and row system (e.g. single or twin rows). Field stocking varied between 90 and 157 t ha À1 , and breast-height diameter between 5 and 8 cm. The tests were conducted with a New Holland 9060 forager, equipped with a 130 FB energy wood header. This machine was capable of negotiating all test fields, and reached a productivity on these sites between 39 and 65 t h À1 , which was comparable with the productivity values recorded in Europe and North America. The machine coped well with the high field stocking and stem size levels encountered in Brazil. Blockages accounted for a very small proportion of total harvesting time, which was similar to that recorded in studies conducted on poplar and willow in the Northern hemisphere. Productivity was directly proportional to field stocking and target chip length. Changing target chip length from 30 to 20 mm resulted in a 20e30% reduction in productivity. These figures reflect work conditions in uncoppiced first-rotation plantations, and they should be applied with some caution to following rotations.

Single-pass cut-and-chipping with modified foragers currently represents the most efficient technique for harvesting fuel chips from short rotation forestry (SRF). Modified foragers are designed to produce small chips, in the 25-30-mm length range. However, chip length settings can be adjusted for obtaining different commercial products. In that regard, it is important to determine the trade-offs of chip length manipulation, which may affect machine performance. This study tested the same modified forager designed for producing 30-mm chips, under variable chip length settings. In particular, chip length setting was adjusted both downwards to a minimum length of 5 mm (microchips), and upwards to a maximum length of 90 mm (billets). As expected, any setting adjustments that deviated from optimum values resulted in performance decline. Downward alterations of chip length setting resulted in a steady performance decline, which peaked at the shortest length setting (5 mm). Under that setting, productivity was 56% lower and diesel fuel consumption was 183% higher than under the optimum 30-mm setting. In contrast, upward alterations of chip length setting resulted in an immediate and moderate decay of machine performance at the very first increment, followed by the absence of further significant decline as additional increments were introduced. Reducing target chip length below 30 mm doubled or even quadrupled the proportion of fine particles (<3 mm) in the total chip mass, which detracted from chip quality.

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In this paper, the drying of whole-tree chip (WTC) storage from young Eucalyptus plantation managed at short-rotation coppice in Brazil was studies. The biomass was converted from high-density energy plantations of Eucalyptus grandis at 2 years old into four piles. Wood chip particles had 5, 15, and 30 mm length were disposed on a paved surface to evaluate the effect on the chip drying. An additional covered pile (30-mm wood chip) was installed to evaluate the effect of coverage condition. The non-ventilated and uncovered piles were not affected by WTC length, and the final moisture content (MC) was 48.4 e53.5% and temperature inside the piles (storage temperature) was approximately 36 C. However, the coverage showed beneficial effect on drying wood chip process, collaborating to keep the MC lower than 35%, conventionally recommended for energy purposes. Among storage systems studied, the higher daily moisture content was assigned to covered pile, about 0.197% day À1 during the first 30 days. This paper can be used as a reference for further studies with wood chip pile storage at tropical conditions.

The increasing demand for renewable energy feedstock has raised interest in growing eucalypts for fuel wood production, which is achieved by establishing very dense plantations cut every 18-24 months. The high moisture content of fresh Eucalyptus may handicap cut-and-chip operations, and offers a unique opportunity for supply chains based on baling. Therefore, the Canadian-made BioBaler was tested in Brazil on a eucalypt energy plantation, as well as on the resprouts generated by a conventional pulpwood plantation after severe frost damage. The BioBaler coped well with both crops, achieving high productivity levels: 7.1 and 3.3 t h −1 in the energy plantation and the failed crop treatments, respectively. Harvesting cost was estimated at €13 t −1 and €26 t −1 for the energy plantation and the failed crop, respectively. Productivity and harvesting cost were comparable with those reported in previous studies conducted in other countries on similar crops. Productivity was directly proportional to field stocking. Future studies should test the machine on a wider range of work conditions and include bale extraction, storage, processing and transportation, in order to estimate an overall supply chain cost and allow direct comparison with alternative options.