Photo: BMLFUW / Schima
Forest health
Only healthy forests can fulfil their functions - the economic, social, recreational, and beneficial functions. But how do forests respond to stressors?
Impacts like air pollution, forest pasturing, excessive game populations, disturbance of game by tourism, traffic and settlement activities lead to regional stresses of the forest ecosystem.The mass propagation of forest pests like, for example, bark beetles, as well as storm, snow and other weather-related disasters cause significant, usually regionally limited, economic damage and impairment of the forest functions.
How is the status of forests surveyed Austria-wide?
The monitoring, a long-term survey of the forest condition, is conducted by the Federal Forest Office (BFW). The BFW is an agency of the Ministry of Life.
For more than 40 years the Austrian Forest Inventory has been carried out, an Austria-wide large-scale monitoring of the condition of Austria's forests. Its objective is to provide information about the resources of the raw material timber as well as about the status and changes of the forest ecosystem.
Another monitoring programme is the Forest Damage Monitoring System.
The crown condition inventory shows the crown thinning of coniferous and broad-leaved trees according to ECE criteria in the European area. So in 2005 50.5 percent of the trees were not thinned in Austria; 34.7 percent were slightly thinned; 11.7 percent were subject to moderate thinning, and 3.1 percent were severely thinned or dead.
To sum up it can be said that problems arise above all where several stressors act together. In sensitive forest areas air pollutants, wind breakage, bark beetles, over-mature stands due to poor utilisation and insufficient regeneration as a result of browsing by game and forest pasturing often complicate the efforts for stable forest stands.
The most severe danger for the forest is the bark beetle; in addition, a higher incidence of infestation with the procession moth, the nun moth, pine-shoot dieback, the European spruce saw-fly, and the fungus phytophthora is recorded.
In the case of a hot and dry summer we have to reckon with an increase in pest infestation and, above all, with a higher risk of forest fire. So which effects would a long-term climate change have?
Global warming will have a tremendous impact on the host-parasite interaction. There will be changes in the range and aggressiveness of pests. Host plants will be subjected to the climate changes, too. Both increases, but also restrictions of the effects would be possible.
Damage to forests by pests and certain kinds of fungi will increase. This might cause problems especially in hardly accessible high-mountain stands with a key protective forest function.
New pests and diseases will be able to establish more easily, as, following the climate change, they will find more favourable conditions for development and survival and, due to the disturbance of the ecological balance, natural control mechanisms will become effective either not at all or only slowly.
The sensitive protection forest is subject to higher infestation pressure and, thus, greater risk.
Which forest protection measures have been taken?
To identify the impact of hoofed game on regeneration in an objective way, a nation-wide uniform game impact monitoring has been established. However, attention focuses on fighting the mass propagation of the bark beetle species printer beetle (Ips typographus) and copper engraver (Pityogenes chalcographus).
Priorities comprise the quick removal of the infested trees, preventive control as well as the promotion of re-afforestation with mixed forest species in accordance with the natural forest communities. All Federal Provinces have launched effective control measures which comprise for example the placing of trap stems, a monitoring using pheromone traps, the salvage-logging and removal or the chipping and mulching of infested material.
As detecting new infestation is of great importance, specifically trained staff is used to observe infestation on the standing tree.
15.02.2008,