Even if a tree may appear healthy on the outside, it may already be rotting on the inside and therefore in danger of collapsing. For this reason, to avoid nasty surprises, you should check your trees regularly. Only then can you intervene in good time - which is particularly important if the tree is on public ground and can cause serious damage if it falls over.
Some mushrooms cause great damage to the tree
Warning sign for a diseased tree trunk
A sick tree is not necessarily recognizable by a layperson at first glance. Therefore, keep an eye out for specific changes that indicate a disease or pest infestation. These include, for example:
- birds nesting in trunk holes (especially woodpeckers, they prefer to look for rotten trees)
- bats living in trunk holes
- bleeding injuries of the tree trunk, gum flow, sap leakage
- damaged, cracked bark
- Boring and feeding holes in the wood
- rotting spots, cracks
- visible fungal growth
- fungi growing out of the stem or root area
- deadwood
The latter is often an indication of problems that lie below the surface of the earth, namely at the roots. If these can no longer provide the tree with sufficient nutrients, its above-ground parts gradually die off. There are a number of possible causes for this, such as an infection with viruses, bacteria or fungi. Voles can also cause significant damage.
Typical diseases of the tree trunk
The above symptoms often indicate one or more of the following diseases. Many diseases are species-specific, i.e. their specific manifestation and cause depend on the respective tree species.
Wood-destroying fungi
There are some types of fungus that destroy the wood from the inside - and cause the tree to rot, although nothing can be seen on the outside. An alarm signal is often the fruiting bodies that suddenly grow near the trunk or out of the trunk itself. But then the infection is already well advanced, because the actual fungus - the mycelium - is in the wood of the stem and/or in the roots.
white or brown rot
The wood-degrading fungi also include about 50 species that primarily feed on deadwood and cause either white or brown rot. You can recognize white rot on the fibrous wood, which often appears to be covered with a white-grey layer. In the case of brown or soft rot, on the other hand, the wood turns dark brown to black.
tree cancer
The so-called tree cancer is caused by bacteria or fungi and is characterized by strong growths on branches, twigs and trunk. In particular, growths that occur on the trunk (where wound tissue overflows a wound) can be problematic, since the tree's supply can be disrupted or even interrupted.
tips
Fruit trees in particular should be limed in autumn to prevent some of the diseases mentioned and pest infestation.