A Tree-related Microhabitat (TreM) is a distinct, well-delineated morphological singularity occurring on living or standing dead trees, that constitutes a crucial substrate or life site for species. TreMs are widely recognized as key features for biodiversity. The current TreM typology identifies 47 TreM types according to both to their morphology and associated taxa. These 47 types have been pooled into 15 groups then 7 forms, in order to provide a range of accuracy and speed of use for different typology users. Thus, forest managers may identify forms during tree marking to promote a TreM diversity at the stand scale while researchers should use the type level for recording TreMs in biodiversity assessment. Another suggested approach to simplify TreM recording in day to day management may be co-occurrence patterns thus reducing the number of TreMs to be observed. From a large international standardized database, we evaluated the significance of TreM co-occurrence on living trees for 11 TreM groups. Bark Loss, Rot-Hole, Crack and Polypore showed the highest number of positive co-occurrences with the other TreMs for broadleaves (N=8) while BL (N=4) did for conifers. We found negative co-occurrences only for conifers: Exposed Heartwood (EH) with Dendrotelm (De) and Sap Run (SR).

02 - Tree-related microhabitat co-occurrences: towards easier monitoring?