The sweet chestnut that refuses to die....

Auckland park, in Bishop Auckland, has an interesting collection of old trees and these venerable sweet chestnuts are amongst the finest.

Some, like this one, are in the prime of life and produced a very heavy crop of chestnuts this year. 

There are four mature trees that were planted in a line beside a small stream. The ground under them is covered in a thick layer of their serrated leaves, spiny fruit husks and nuts that will keep the squirrels well fed for weeks to come.

The low-angle late autumn sunshine this morning showed off their fissured bark beautifully. 

One of the four has been dying for the thirty five years that I've known it. It has shed most of its branches, much of its bark, has been attacked by wood boring beetles and fungi .....

... and yet every year it sprouts new growth, refusing to die. There could be decades of life left in it yet, unless the roots finally rot and it's blown over by a gale and ......

...........that would be a pity, because I'd really miss this gnarled old trunk. It's one of the park's characters.

A magnificent veteran beech tree

There are some fine stands of native trees scattered throughout Hamsterley Forest's commercial conifer plantations here in country Durham. None is more impressive than this venerable beech tree, growing next to an old dry stone wall that must have been part of the field system before the forest was planted. 

This is one of the largest and most impressive beeches that I've encountered and it probably benefits from the shelter of the surrounding conifers, although the top of its crown is taller than they are. But it's real glory lies in its magnificent convoluted bole - folded, fissured and branching from low down in a way that suggests that it must have been pollarded or lost its leading shoot earlier in its life. 

Now all those folds and cavities make it an excellent wildlife habitat. Over the last decade or so it has acquired a fine fungal flora, in the form of ......

....... these massive brackets of Ganoderma australe, commonly known as the southern bracket. The fungus is undoubtedly killing the tree very slowly. The crown is still as leafy as I remember it when I first saw it, almost 40 years ago. I would not be in the least surprised it it survives for several more decades.

Ganoderma is a perennial bracket fungus, producing a new hymenial layer (the spore producing tissue) annually over a decade or more. Here you can see this year's fresh white hymenium on the underside of the brackets.

The tan-coloured stain on the trunk is a coating of spores, that are released in billions.

The 'shelf' formed by the upper surface of the old brackets has become carpeted with mosses ......

..... while the upper surfaces of those immediately below becomes covered with a thick layer of spores, like a coating of cocoa powder. The dark area under this bracket is one of several temporary pools formed when rainwater trickles down the trunk and collects in folds and rot-holes. Temporary pools like this are known as phytotelmata and are home to vast numbers of tiny protists and animals. When I took a sample from this one and looked at it under the microscope it was seething with oligochaete worms and tardigrades, feeding on the single-celled protists which in turn were feeding on the soup of fungal spores in the water.