1. Since the biodiversity of saproxylic beetles has been proposed to be used as a management tool in forestry, more explicit knowledge about the efficiency and selective properties of beetle sampling methods is needed. 2. We compared saproxylic beetle assemblages caught by alcohol-baited or unbaited window traps in different forest contexts. Considering that trap attractiveness depends on kairomone concentrations, we appraised whether the trap efficiency was influenced by trap environment (openness and local supply of fresh dead wood). 3. Saproxylic beetles were sampled using 48 cross-vane window flight traps, arranged in paired designs (alcohol-baited/unbaited), in 8 ancient and 8 recent gaps (open stands), and 8 closed-canopy control stands in an upland beech forest in the French Pyrenees. 4. Baited traps were more efficient than unbaited traps in terms of abundance and richness in our deciduous forests. The ethanol lure did not have any repellent effect on the individual response of saproxylic taxa. 5. The influence of local environmental conditions on trap attractiveness was observed. The effects of variations in openness were actually moderate but significant on species richness. Besides trap attractiveness appeared to be slightly reduced in the alcohol-saturated environment of recent gaps due to a disruption by local fresh dead-wood concentrations of the kairomonal response of saproxylic beetles to baited traps (alcohol disruption'). 6. Since the ethanol lure globally enhances species detection probability (no repellent effect, many individual attractive effects), it may be extensively used in programs of early-warning surveillance, monitoring and control of wood borers. We recommend to account for the slight influences of local conditions on baited trap efficiency while using them for beetle biodiversity monitoring.