Anyone involved in timber production needs some knowledge of autecology. With the renewed interest in hardwoods in the last 20 years, they are increasingly being introduced by planting or encouraged in natural stands. The results in terms of growth have not always met foresters’ expectations, due to technical problems and especially because the species are not always suited to the different sites. While the principle of establishing hardwoods is not in question, it is important to be aware of the conditions they need for their growth. This is why the first component of the Pirinoble programme is about improving knowledge on the ecology and adaptation of valuable hardwood species. To support this, a wide-ranging bibliographic analysis was made of scientific publications in French, English, Spanish and Italian on the main hardwood species that can be established as plantations: - Wild Cherry (Prunus avium l.), - Common Ash (Fraxinus SSP.), - Wild service tree (Sorbus torminalis l.), service tree (Sorbus domestica L.) and other sorbus species. - Walnut (Juglans SSP.), - Common pear tree (Pyrus pyraster (l.) Du ROI) and the European Wild Apple tree (Malus sylvestris Mill.). - Lime (Tilia ssp.), - Maple (Acer SSP.). Favourable site conditions for hardwood trees are now better understood thanks to numerous observations carried out in stands and a number of scientific studies. Some species have been studied in more depth, including the wild cherry, wild service tree, common ash, maple and walnut. This guide is based on the results of these studies, supplemented by the expertise of the authors. It includes a series of autecology factsheets that describe the site conditions in which hardwoods will thrive and the minimum conditions required for rapid timber production. The factsheets were published on a regular basis in Forêt-entreprise in 2012 and 2013 (see footnote at the end of each of factsheet), and are now published together in this guide along with the bibliographical references consulted.