There are two different kinds of dead wood: coarse woody debris which includes fallen logs, branches and bark; and standing deadwood which includes snags and upright dead trees. Both types are important for forest health, more information about both types can be found below.
Course Woody Debris
Coarse woody debris (CWD) is any large fallen material from the forest canopy above. This includes large branches, fallen logs and bark material. CWD is crucial for maintaining soil health and provides a home to many species rich groups like insects, fungi, lichens and plants. Keeping as much dead wood within the forest is an easy way to boost overall forest healthy and biodiversity at the same time.
When large trees die and fall over they can become what is know as a ‘nurse log’. Because of their large size (12” or more) nurse logs decay slowly and provide a sustained source of nutrients for the soil below. Seedlings (particularly yellow birch) easily germinate on decaying nurse logs where they have access to the nutrients inside, this increases overall seedling recruitment and leads to faster forest regeneration times.
Steps you can take to maintain coarse woody debris are:
- Do nothing! Leave deadwood where it is
- Leave large fallen logs in the forest to become nurse logs. Scoring the outside with a chainsaw can make decay occur quicker
- Use a ‘safety first’ approach, and make sure that CWD is not going to cause injury to people or farm livestock
- Return branches and unused woody debris back to the forest after harvesting
For more information on nurse logs see Deadwood and Cavity Trees: A Forest Resource by Restelluris.ca
Interestingly deadwood, sometimes referred to as standing snags, is one of the most important parts of a healthy woodlot. For biodiversity, the life of a forest is found in the deadwood. Approximately a quarter of all the wildlife species found in Acadian forests depend on dead and dying wood for shelter. This included woodpeckers, owls, flying squirrels and many species of insects, fungi, and plants.
In healthy forests as much as 20% of the standing wood in the forest is deadwood. The standing deadwood provides important nesting sites for animals that live in tree cavities.
Increasing the amount of deadwood in your woodlot is easy and provides a huge boost to biodiversity on your farm.
Management tips for increasing deadwood
- Try not to think of dead trees as waste, leave them in the forest to provide habitat for all kinds of wildlife
- Leave trees with rotten portions; they are the least valuable at the saw mill and the most valuable to biodiversity
- Leave your biggest trees; they provide the healthiest seed bank and make the biggest nurse logs once they fall (see section on coarse woody debris)
- A reasonable goal for standing deadwood could be 5 big (greater than 12”) trees per acre, but the more the better
- Leave different species of deadwood; diversity is always better