Why Deadwood Is Dead Good

NatWest International Environmental Education Initiative 2024-25

Benefits of Deadwood

Deadwood in all its many forms – standing dead trees and stumps, fallen trunks, branches and twigs – is one of nature’s most important habitats and has a hugely positive impact on biodiversity.

The loss of trees and damage caused by Storm Ciarán is deeply saddening, but there might be a silver lining: a windfall of deadwood.

Deadwood is rich in benefits as well as nutrients:

  • There are over 70,000 known species in the UK, 13% of which depend on deadwood. These species include fungi, lichens, mosses, birds, bats, mammals, and thousands of invertebrates.
  • Many more species depend on the above as sources of food and even habitats. Some deadwood invertebrates parasitise and predate species considered to be pests.
  • Of the 1,700 species of invertebrates associated with deadwood in the UK, 330 are Red Data Book-listed, because they are rare or endangered.
  • Deadwood provides nutrients and habitats for the largest single group of threatened species in Europe.
  • It is a key indicator of naturalness in forest ecosystems, stabilising woodlands and sustaining forest productivity. 
  • Deadwood acts as a long-term storage of carbon, taking hundreds of years for its constituents to decay and recycle.
  • Its contribution to soil formation is vital, as well as nutrient recycling.
  • In waterways, deadwood has a vital role in freshwater ecosystems, stabilising banks, creating habitats, and improving water quality by removal and oxygenation of silts.

Our Impact

Naturally, deadwood accumulates in healthy woodlands with a good proportion of veteran trees. But Jersey is lacking old trees and our woodlands have very low levels of deadwood, as do most of the forests of Europe.

Storm Ciarán wreaked havoc and devastation, but by preserving as much of the fallen, deadwood as possible, some good may come from it:

  • Where it is safe and practical to do so, fallen trees should be left. Leaving nature in its messy and disrupted state is the most effective and cheapest way to restore biodiversity associated with deadwood.
  • If fallen trees or overhanging branches must be cleared, as much of the timber as possible should be left. If it needs to be moved then creating log piles and deadwood hedges, barriers or wind breaks are a preferable alternative to taking it away to be chipped or burnt.
  • Tree stumps should be left, and if safe to do so, standing dead trees too.
  • Deadwood in all its various forms creates many different microhabitats which are diversified further by different processes of decomposition.
  • Embracing all the forms of deadwood enhances the quantity and diversity of species that use it.
  • The more deadwood the better, but the WWF has identified that in woodlands, we want at least 20-30 m3/hectare.

The UK, including Jersey, has seen its species diversity plummet in the last 50 years. We are ranked as the twelfth worst nation out of 240, for loss of biodiversity and the worst of the G7 nations. Our damaged and fallen trees are a heartbreaking loss but they present us with an opportunity to address some of those biodiversity losses.

An Opportunity

Around the island, the fallen trees and branches are a sad sight and look rather messy. Is it not best to “clear them away”? A lack of understanding about the importance of dead wood results in much of it being removed by people who don’t realise what a fantastic opportunity they are missing to enhance biodiversity and support threatened species.

In his Woodland Survey of Jersey (2022), John Pinel identified that Jersey’s woodlands were depleted in deadwood and made specific recommendations to increase it alongside protecting veteran trees.

Governments have made commitments and have obligations under the international treaty, the Convention on Biological Diversity, including to:

To conserve their biodiversity and maintain the ecological integrity of ecosystems.

Use their biological resources in a sustainable manner, ensuring that their use does not lead to the decline of biodiversity.

Raise public awareness about biodiversity and its importance as well as promoting education and training on biodiversity conservation.

Deadwood is one of the most threatened habitats in forests and the species it supports make up the largest single group of threatened species in Europe. There is a strong imperative and a wonderful opportunity to embrace the obligations outlined above and address the shortfall identified by John Pinel, by preserving as much storm damaged, fallen, and felled wood as possible.

Myths & Issues

  • A clean forest is a healthy forest: FALSE.
  • Old, aged trees are a problem: FALSE.
  • Deadwood harbours disease: FALSE.
  • Deadwood is a risk to visitors: FALSE.
  • Deadwood and old trees are unattractive: Hmmm!

While “beauty is in the eye of the beholder”, our perception of normal and healthy is based on forests where the oldest trees are around 100 years. Not many generations ago, most European forests had many trees that were 300 years old, with significantly more deadwood and the many associated fungi, bugs, mosses and lichens.

As we learn how important the kingdom of fungi are to the world and humanity, the multitude of ecosytem services provided by bugs and the vital role all of these species play in creating healthy soils, we will hopefully all come to appreciate the importance and beauty of deadwood and its many dependent species.

There is still so much to learn about the interdependence of humanity and the multitude of ecosystems that we live among; however it is beyond doubt that biodiversity is the very foundation of our existence. Let’s engage with every opportunity to nurture it and help it flourish.

Supporting Biodiversity

Saproxylic organisms are species that depend on decaying and dead wood for part of their life cycle. Even as a tree approaches death, saproxylic species are attracted to it; 115 species of hoverfly are attracted to dying wood rather than dead wood.

The process of wood decay and nutrient recycling can take hundreds of years and involves three main phases:

  • A short colonisation phase when primary saproxylic organisms invade. These include longhorn beetles, fungi such as shelf fungi and bacteria. They produce enzymes that are able to break down lignin, opening up the wood to other invaders and colonisers.
  • A long decomposition phase, when numerous plant and animal species start to eat the exposed organic matter and each other. A study in Sweden identified 2500 species of saproxylic fungi and in the Czech Republic a study found 389 saproxylic beetle species.
  • A long humification phase (formation of humus). Scavenging organisms such as millipedes and springtails incorporate wood residues into the ground.

Many species of birds and other invertebrates feed on the saproxylic organisms, for example the great spotted woodpecker relies on saproxylic species for 97% of its food. The decomposing wood also enables nesting holes and cavities to be created, including 10 out of 11 species of European woodpeckers, 10 European owl species, flycatchers, treecreepers, nuthatches, tits and even some ducks (e.g. Goldeneye duck). Also numerous bat species and larger mammals such as bears (although not in Jersey).

A study in the Pyrenees found that a quarter of all mammals and over a sixth of all bird species are associated with deadwood.

Deadwood creates a multitude of different habitats depending on numerous factors that include: the species of dead tree, age at death, how long has been decaying, cause of death, position-fallen/still standing, size, climatic conditions. The WWF report descibes 16 different habitats each attracting a different range of species.

Sources & Further Reading

WWF Report on Deadwood-living forests. The importance of veteran trees and deadwood to diodiversity. October 2004

https://wwfint.awsassets.panda.org/
downloads/deadwoodwithnotes.pdf

The importance of deadwood for wildlife. July 2021

https://heartofenglandforest.org/news/
importance-deadwood-wildlife

Deadwood. Buglife, Scottish Invertebrate Habitat Management. 2011

https://cdn.buglife.org.uk/2019/07/
Deadwood_1.pdf

The Woodland Trust. Deadwood.

https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/habitats/deadwood/

Woodland Report 2022 by John Pinel for Jersey Trees for Life.

What is the state of biodiversity in the UK? Royal Society

https://royalsociety.org/topics-policy/projects/biodiversity/biodiversity-in-the-uk/

What is the Biodiversity Intactness Index, The Natural History Museum.

https://www.nhm.ac.uk/our-science/data/biodiversity-indicators/what-is-the-biodiversity-intactness-index.html

Why is biodiversity important? Conservation International 2021

https://www.conservation.org/blog/why-is-biodiversity-important

Diversity from Decay-Why Deadwood is Great. RSPB

https://community.rspb.org.uk/ourwork/b
/natureshomemagazine/posts/diversity-from-decay-why-deadwood-is-great