Eight years ago I cut down an Oak tree in the garden leaving a stump about 60 cm high and 55 cm wide; counting the annual rings revealed it to be about 30 years old. Standing beside a path, the gradual changes which subsequently took place were noticed on a daily basis.

Within two years the first signs of wood rotting fungi were seen when a Mottle Gill (Panellus spp.) appeared. (I have just discovered the British Mycological Society’s website of English names which adds a whole new dimension to naming fungi).

Go to http://www.britmycolsoc.org.uk/resources.asp
click on Recommended English names, the list is a downloadable Excel spreadsheet. (Web Editor)

This was soon followed by the Hairy Curtain Crust which persisted for two or three years and in October 2004 by another large, spectacular orange-capped gill fungus which escaped identification.

This year, however, has been outstanding; the stump is now in an advanced stage of decay and the bark has separated from the sapwood which, in wet weather, takes on the consistency of a wet sponge. One April morning, a song thrush was seen on top the stump, pecking away; to see a thrush in the garden is a noteworthy event, but this one was clearly finding something to eat. It was pulling out lumps of rotten sap wood from the stump, picking them to bits and selecting something from the fragments. This continued for half an hour or more; and while it was not possible to see what it was eating, it was clearly finding a good meal. After it had left, a lump was detached from where it had been busy. It was picked to pieces under a microscope and yielded four small slugs, two earthworms, three woodlice, one centipede, a multitude of springtails, mites and other tiny things, two pseudoscorpions, but the most frequent organism (12) was a millipede which was eating through the wood, making a long gallery, filled with frass, and which was the most likely food item.

I sent some of the millipedes to Paul Lee who identified them as Cylindroiulus punctatus a common species, typically found in rotting wood. My knowledge of the diet of the thrush does not extend beyond snails but Paul told me that millipedes have been recorded from the diet of song thrushes and that they appear unaffected by the noxious chemicals produced by the millipede’s defensive glands. Later, in July, what looked like three blobs of an oatmeal biscuit mix appeared overnight on the rim of the stump (see photo). The surface of these myxomycete plasmodia looked like a mass of random fibrils which darkened to a bay/tawny colour and within two days the ‘skin’ had disintegrated releasing a mass of chocolate coloured spores. An attempt to identify it and find out more about myxomycetes ended in defeat; their structure is so specialised and they are seen so infrequently (I have seen three in 12 years) that it is hard to develop any expertise. Perhaps the Society could find a Recorder?

The pièce de résistance, however, was an enormous bracket fungus which first appeared at the beginning of July at the base of the stump. This, a Giant Polypore (Meripillus giganteus), eventually grew to about 40 cm wide and deep with several overlapping brackets (photo, 25 July). Afterwards, this part of the fungus went into decline and by the end of August was no more than a black shapeless mass. As it died away further brackets sprang out from between the next pair of prop roots and by now (20 September) the stump is encircled by brackets at several stages of development.

All this does not exhaust the stump’s interest and fascination. ‘Sawdust’ dribbling down the bark indicates that some boring insects, yet to be seen, are busy and as the stump has aged, its lichen and moss flora has changed. Over the last few days a vole has been seen entering a hole protected by the lifting bark.

In a year or two nothing will be left other than the central core of heartwood, but Oliver Rackham in his book ‘Woodlands’ writes that a dead oak stump takes more than a century to disappear, so, what next?