Application of a life cycle assessment to walnut tree (Juglans regia L.) high quality wood production: a case study in southern Italy

Although Italy is one of the most important exporters of furniture in Europe, it is also a great importer of foreign timber. We decided to focus our study on Walnut tree (Juglans regia L.) as it can be considered one of the most important species for high quality timber production in Italy. Our goal is to examine the production of high quality timber deriving from a dedicated walnut tree plantation with the intent of evaluating the environmental impact from the LCA prospective (ISO 14040). The functional unit adopted here was 1 m3 of dry solid under bark wood (u = 12%). Tillage and N-based fertilisers had the heaviest environmental impact, respectively through diesel consumption and a high NH3 volatilization rate. The emissions produced by urea may be reduced by switching to other N-fertilisers with a lower NH3 volatilization rate, or by choosing biofuels that can also represent an alternative to traditional diesel. Plant protection systems against animals such as metallic fences represent an unexpected hot spot because of the steel production and galvanizing processes related to them. Biodegradable protection systems might be adopted instead of metallic fences, even though this choice depends on the size of the animals. When considering the lack of data in industrial tree plantations literature with regard to the production of high quality wood, the present LCA study can be considered a useful tool in providing a deeper understanding of the key environmental impact issues related to high quality timber production.