In an old-growth forest you are surrounded by death and dying. More than likely, you’re tripping over it, you’re marveling at the weird growths on trees, you’re listening to the hammering of woodpeckers, without knowing how much death you’re actually witnessing. In its undisturbed state, a forest offers standing dead trees, live trees decaying because of various fungal infections or insect attack, and a cornucopia of logs.
“The truth is, the system depends on it, depends on the death of trees,” says Torolf Torgersen. “The more we learn, the better we understand that the connections in the life and death cycle from trees to logs are not only wonderfully complex but also quite confounding. What is clear is that the forest absolutely requires death to survive.”
Torgersen is an entomologist who worked with wildlife biologist Evelyn Bull and plant pathologist Catherine Parks, all from the Pacific Northwest Research Station’s Forestry and Range Sciences Laboratory in La Grande, Oregon.
Living trees with internal pockets of decay, top dieback, or broken tops can all serve as wildlife habitat; many species of wildlife use hollow living trees and the hollow snags and logs that result from them. The decay process that hollows trees can occur only in living trees. Witches’ brooms caused by dwarf mistletoes, rust fungi, or a needle cast fungus provide unique, largely unappreciated habitat for a host of wildlife. In a forest setting, standing dead trees (known as snags) and logs are colonized by organisms representing a broad array of plants, invertebrates, and vertebrates. Snags also are important structural components, and logs ultimately contribute to the nutrient reserves and chemical and physical characteristics or forest soils.
We’re often asked, for good, solid health and safety reasons, to take action on dead and dying trees, and there will always be a good case for such action when a tree is assessed as potentially unsafe. But where the risk is managed, as in the case of this decaying stump, covered in hoof-like ganoderma fungus we found recently amongst the beautiful trees in the arboretum at Bute Park in Cardiff, it’s also good to know that they’re providing such a rich environment for life in future.
Are you concerned about a dead or dying tree? Call Andrew on 01256 817369, 07771 883061 or email him at Andrew@primarytreesurgeons.co.uk for advice or a quote.