I'm delighted to present a guest blog from RSPB Reserves Ecologist Kelly Thomas who reveals the importance to wildlife of our often-neglected dead wood. As the leaves start to come out on the trees, spare a thought for this vital habitat and maybe have a think about what you can do to leave more of it on your patch. Here's Kelly.
What do you imagine when someone mentions dead wood? Perhaps a tree that has declined through neglect or old age, or something static and no longer useful? Even in human societies we consider dead wood to be a negative term to describe those who’ve had their day. But life abounds in our dead wood if you look for it. From death springs a world of wood digesters, fungi eaters, predators and parasites. For instance, in the UK around 2,000 species of invertebrates are considered to be saproxylic (reliant on dead or decaying wood in part or all of their lifecycle), including many rare and threatened species. Beetles and flies dominate the UK’s saproxylic fauna. And of course, many of the woodland birds we are concerned about such as lesser spotted woodpeckers, pied flycatchers and willow tits are reliant on the holes that appear or are created in dead parts of trees.
The diminutive, and declining, lesser spotted woodpecker needs dead wood (Mike Langman rspb-images)
The key to understanding the importance of dead wood is decay. Decaying wood is a dynamic habitat constantly changing with new species coming and going as the available resources change. And fungi are the big daddies when it comes to decaying wood. While a small handful of fungi can be pathogenic (cause death) to our trees the vast majority are in fact beneficial and are the equivalent of the green bin in our neighbourhoods, recycling the nutrients locked up in dead wood and converting it into more easily accessed forms. Few other organisms have the ability to digest wood (although some harbour microbes in their guts that can do so), so without fungi the world would quickly become engulfed in a 'sea' of dead wood.
Willow tits excavate nest holes each year, often using standing stumps of soft rotting deadwood. So, at RSPB Dearne Valley and Middleton Lakes, we have been attaching deadwood to trees to provide them with breeding habitat (Heather Bennett)
Decaying wood habitat comes in many forms from dead standing trees (snags), living trees with dead branches, fallen limbs, hollow tree trunks, rot holes, even cut logs on the floor. Each can host a different group of species, and these species change over time as the wood decomposes. When it comes to decaying wood, variety truly is the spice of life!
The willow tit is one of the species benfiting from the fabulous Back from the Brink project (Mike Langman rspb-images.com)
But like any resource, decaying wood declines over time and disappears if it is not replaced. In many of our wooded (and non-wooded) habitats today fallen trees and limbs are cleaned away or gathered up for fire wood. Trees are grown and cut down for timber before the decay processes are able to start. Old trees are one of the best sources of decaying habitat because they are continually laying down new wood which will eventually die and decay. Without a steady supply of new decaying wood many of the species reliant on it are at risk of being lost.
Ring barking is creating vital standing dead wood at RSPB Corrimony (photo by Chris Bingham)
Seven ways to create more dead wood
But there are things we can all do to help support our decaying wood species, and here are just some of the things we do to maintain the supply of decaying wood: