During the last decade, awareness about dead wood conservation has grown among the environmentalists, the biologists and the forest policy makers. In Europe, a specific indicator of sustainability dedicated to deadwood (criteria 4.5) has been even created during the Ministerial Conference on the Protection of Forests (MCPFE) in Vienna in 2003. Despite this official recognition, forest owners' attitudes towards deadwood preservation are contrasted and controversial. Many forest owners still maintain the utilitarian notion of fauna and flora ; they often classify some animal and plants associated to dead wood as noxious for forestry even if they are useful for the ecosystem. More over, for a decade now, forests are becoming increasingly important for supplying wood for renewable energy production. The European union aims at raising the share from renewable energy in energy consumption to 20% by 2020 (Verkerk et al., 2011). Forests are considered an important resource to meet these renewable energy targets, because woods and wood waste represent currently about half of all the renewable energy production (Eurostat 2010). the old-fashioned image of firewood has been modernized and its use is encouraged as a means to prevent global warning, to save fossil fuels, to increase the security of energy supply, to create jobs and new incomes in rural areas, and to reduce forest fire risks. In their daily practices, forest owners are confronted with these two environmentally-friendly but contradictory discourses about dead wood. But their attitudes towards increased use of forest biomass are rather unclear and difficult to quantify. The purpose of our research is to answer the following questions: -Do foresters integrate or not biodiversity associated with deadwood into their forest management practices? -How do they choose between deadwood conservation or deadwood harvesting?