Contents

3. life after death

   3.1. Stages and consequences of dying of trees

   3.2. How do dead trees revive? Colonisation of dead trees and dead wood 4. Dying and dead wood in living forest

 appendices................................

8. resume

 

Dead wood in forests, i.e. standing dead trees and shrubs, snags, stumps, old trees with dying boughs and cavities, lying logs, branches, etc. are, in consequence:

-         great species richness of fungi, plants and animals,

-         higher landscape diversity and tourist appeal,

-         positive influence on site (soil, forest litter),

-         better water retention in the ecosystem,

-         protection against erosion,

-         source of indispensable in the forest elements (carbon, nitrogen, calcium, etc.) and energy,

-         facilitating and conditioning the regeneration of trees,

In the light of the listed above functions, dead wood in forests, contrary to current opinions, is not “an incubator” where “pests” and diseases are hatching. It is primarily an indispensable element of the ecosystem, conditioning its natural, biological resistance and securing a natural dynamic equilibrium of the forest (fig. 39). Wood should not be extracted from the forests revealing primeval characteristics (e.g. in old-growth stands), since they are irreplaceable as a bank of biological diversity and a model, where we can observe and investigate natural processes, learn from nature so as to mimic her in managed forests. Wood extraction in protected areas – national parks and nature reserves – should be banned. As the managed forests are concerned, a portion of stands should be left without harvesting as well as a certain amount of dead wood should not be removed in order to perpetuate the suitable conditions for saproxylic organisms.

            Below, we present all our postulates in the following conclusions and the table of quantitative and qualitative norms related to dead wood in various types of forest.

 

Conclusions:

1.      The quantity of wood left in forests should be as large as possible. In the ecosystem dead wood is not less important than living trees or shrubs. Utilising CWD, e.g. as a fuel, can bring a bigger damage to the forest ecosystem than felling a living tree.

2.      The CWD resources should reflect the diversity of living stand, considering species composition and size structure. Securing continuity of CWD supply, especially of large size debris is a very important matter. In particular, dead trees larger than 40 cm of DBH should be left for they play a key role in preservation of numerous endangered species.

3.      In the close-to-natural forests, especially in national parks and in nature reserves, no dead or dying trees (shrubs) should be removed and the quantity of CWD should entirely depend on the course of natural processes.

4.      All remnants of natural or semi-natural forests in Poland should be maintained without human intervention. Natural processes do not threaten the durability of forests!

5.      One should stop felling dead trees and removing dead wood in the forest reserves under a partial protection regime. In case of necessity of intervention, trees should be killed e.g. by girdling, but left without further manipulation such as barking.

6.      In wet forests, such as marshy coniferous forests, alder swamps and riparian forests, as well as in high elevation spruce forests, even if not designated legal protection, all DWM (logs, uprooted trees, etc.) should be left for they condition efficient regeneration of trees and in the mountains, additionally, they prevent erosion.

7.      Wood harvest in commercial forests should not take place during the growing season. Wood that has not been removed in time should be left in the forest until its complete decomposition; trees or snags left in the forest should not be felled, barked or sawed into sections.

8.      Regardless the felling system* [Felling system – complex of regulations related to timber harvesting, aimed to establish optimal conditions for tree regeneration and achieve a demanded stand composition and structure; we distinguish clearcut, shelterwood, group cutting and selective cutting systems.], 5-30% of trees on every forestry felling area should be retained until natural death and complete decomposition. Selected for preservation trees should well represent species composition and DBH diversity of the felled stand. In the case of a large scale clearcut (simultaneous felling of all trees on the surface up to 4 hectares, usually followed by planting new trees), selected trees should be retained in clusters, covering undisturbed ground layer.

9.      In case of sanitary cutting, trees with bracket fungi, potential places of future hollows – so important for fauna conservation, should not be removed.

10.  It is recommended to retain as much organic matter as it is possible; during improvement cutting (thinning), extraction of wood should take place only if economically justifiable.

11.  The slash residues should not be burned or piled up. It should be retained randomly scattered on the forest floor.

12.  Stumps should not be barked. It can be exceptionally tolerated in coniferous monocultures, threatened by the massive outbreaks of cambio- and xylophages.

13.  In the case of cutting off the trunk of an uprooted tree, the root plate should be prevented from falling back to the crater.

14.  The volume of dead wood in all managed stands older than 50 years should not be lower than 5-10% of the living trees volume and CWD should reflect the stand’s species composition and size structure.

15.  One should secure the presence of the flowering forest plants, especially representing umbellifers, Rosaceae and Compositae, in the neighbourhood of stands with dead wood (e.g. through retention of inner-forest meadows, suitable mowing, keeping roadsides open, etc.). Such plants provide food to imagines of numerous saproxylic species.

16.  It is very important to retain all hollow trees in plantings and parks. The hollows of such trees should never be cleaned from mould being an environment to rare stenotopic species of invertebrates. “Curing” old trees should be constrained to few trees of a cultural significance, but it should exclude any interference in rotted wood microhabitats.

17.  In the designs of parks one should secure the presence of lying logs and, at a certain safe distance from alleys, also standing dead trees.

18.  An aggressive educational campaign showing the role and significance of dead wood should target broad society, in particular children and youth as well as the conservation service and forestry administration.

19.  Further studies of multiple unknown aspects of dead wood and its role in ecosystems are badly needed.