Cavities in the heartwood in which water accumulates, usually within the main trunk (e.g. where lateral branches have died and broken off) but includes cavities in root bases or at branch forks.
Wet rot-holes tend to support the widest range of specialist invertebrates and so this fauna has been categorised under heartwood decay. However, some invertebrates also exploit other types of tree cavity involving natural pockets formed amongst tree root bases and/or in the top of the trunk amongst tight branch forks.
Diptera are perhaps more strongly associated with crown type wet decay than Coleoptera, and the money spider Midia midas is primarily known from accumulations of leaf litter this situation. The beetle Prionocyphon serricornis is largely confined to root base pools although does also develop in waterlogged white-rotten heartwood.