This book presents a selection of peer reviewed-papers that were prepared after the communications given to ECOWOOD 2010 - 4th International Conference on Environment-Friendly Forest Products, that was held at Fernando Pessoa University, Porto, Portugal, from 8 to 10 September 2010. Topics covered are related to recent research developments in order to have forest products and manufacturing processes with lower negative environmental impact, namely: sustainable wood construction, wood protection and preservation with environment-friendly methods and chemicals, adhesives from renewable sources, wood recycling, utilization of low-grade wood, etc.