Can we leave tree stump in ground?
QIs it safe to leave our bracket fungi-infected stump in place?
Betty Pedley, Halifax, West Yorkshire
ABracket fungi, unsurprisingly, produce horizontal, bracket-shaped, spore-producing structures on the trunks or main branches of trees. These structures are just the fruiting bodies of the fungus. The damage is done by the thread-like mycelium that cause decay and rot in the heartwood of trees, leading to branches falling or, where the roots are affected, for trees to topple. There’s often very extensive internal damage to the tree by the time brackets form. There’s no treatment once the fungi infect trees. Although the brackets release huge numbers of wind-blown spores, removing brackets will have little effect on possible infection. In the case of your small stump, you may just want to leave it in place and observe the activity of one of nature’s great ‘rotters’. Spores cannot penetrate healthy bark, with infection occurring via damaged branches. This can be from storm damage or poor pruning of large branches that exposes the heartwood. There are many different types of bracket fungi, many of which are specific to a particular host tree. They are notoriously difficult to identify without specialist knowledge. Two that commonly cause damage to broad-leaved garden trees are Inonotus hispidus (ash heart rot) and ganoderma species (beech heart rot).
Often, the first time you notice a problem is when the brackets form. These can easily be over 60cm (2ft) in diameter, either singly or in clumps. On closer inspection of the tree, you may notice thinning foliage cover and possibly some dieback of shoots, but not always. Trees may leaf up late in spring or drop leaves early in the autumn. There will already be extensive decay of the heartwood and branches may fall. Trees may eventually become hollow but remain stable, although they can be prone to damage in high winds. Even more serious than these ‘top rots’ up the trunk are ‘butt rots’, which affect roots and can lead to even apparently vigorous trees suddenly toppling.
Gardeners are legally responsible to seek professional inspection immediately. The Arboricultural Association (www.trees.org.uk; tel: 01242 522152) can provide details of suitably qualified consultants.