<p>Tree microhabitats associated with decay are rare in forests managed for timber because trees are often felled before reaching the age at which they naturally develop. Non-lethal tree management, such as harvesting non-timber forest products (NTFPs), can accelerate microhabitat formation in young trees. Cork bark is an important NTFP in Iberia that is harvested from cork oak trees (<i>Quercus suber</i>) every 9–14 years. Here we investigate the effect of bark harvesting coefficient (HC, harvest height/stem circumference) on the formation of cavities and other microhabitats in cork oaks in Los Alcornocales Natural Park, Spain. We surveyed 301 cork oaks and detected 1033 microhabitats (3.4 per tree), including 46 cavities. The number of unique microhabitats per tree significantly increased from 2.5 (± 0.25) at low intensity (0 &lt; HC ≤ 1) to 3.7 (± 0.15) at moderate intensity (1 &lt; HC ≤ 2, <i>p</i> = 0.003), but further increase to high intensity (2 &lt; HC ≤ 3), yielded no additional microhabitats. The probability of a tree having cavities exhibited a significant non-linear increase with harvest intensity. Cavities were low (&lt; 5&#xa0;m) and large (median entrance area 267cm²) and probably originated from wounds sustained during cork harvesting. A total of 57 cavities were identified in the study area, including an additional 3 in dead or unharvested cork oak and 8 in co-occurring gall oaks (<i>Q. faginea</i>). 11% (<i>n</i> = 6, 0.18 cavities ha^− 1) had a suitable volume and entrance size for honey bee (<i>Apis mellifera</i>) colonies and other cavity-nesters with similar requirements. Our results indicate that bark harvesting, at moderate intensity, can be beneficial to wildlife in cork oak woodlands by increasing the supply of cavities and other microhabitats. However, even at moderate intensity, temporary benefits to wildlife might be offset by reduction in tree vigour and increased mortality.</p>