Short Rotation Forestry (SRF) in a Mediterranean Environment Under Limited Energy Inputs

摘要

The aim of this work is comparing the two year performance (diameter, total height and mortality) of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF) have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter). Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa), Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis) were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing). Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima) were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants). Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row). Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed good performances in terms of diameter and total height of R. pseudoacacia, E. camaldulensis and E. angustifolia. The highest mortality percentage was recorded for S. nigra, P. nigra, P. alba both in “collection” and “experimental” plots. All other species showed mortality percentage lower than 20%.