A wintry visit to Greenwich Park, London

Yesterday, as part of our monthly aim of visiting sites across the south east of England, a half-dozen strong group of arboriculturalists made the journey to London’s Greenwich Park – myself included. Indeed, as much of the park consists of deciduous specimens (principally, avenues of Castanea sativa and Aesculus hippocastanum), the park was rather bare in the foliage sense, though such barren canopies did allow us to appreciate the true magnitude of – most notably – some of the veteran sweet chestnuts. The frost-clad ground and crystalline sky provided a similar beauty, and thus we shall begin with one of the most iconic vistas from Greenwich Park – the city skyline.

As we stood adjacent to the observatory, we could admire – amongst the furor of tourists and scout groups – the sightly perverse beauty of a city. I say perverse, as such artificial and polluted landscapes don’t tend to suit those who don’t consider themselves urbanites, which includes myself.

Of course, we didn’t go there for the view, so let’s get into the main bulk of this account – trees and fungi. There’s no real order to how the below series of images rank, so don’t consider this post a chronological reflection of our trip!

Perhaps the best place in which to start the core section of this post are the huge sweet chestnuts, though we must begin on a rather sombre note. With a species of Phytophthora suspected on site and some of the older individuals exhibiting stunted and chlorotic leaf growth, there is a valid concern for the future of these veterans which is – without doubt – highly concerning. During the winter months, fully appreciating this contemporary issue is difficult, though we did spot some foliage on the floor that was certainly smaller in size than would be typically expected. Alas, this situation should not impact adversely on our admiration of these trees, and should in fact raise attention and draw intrigue to those within the industry and beyond, with an eye to ensuring we continue to care for the current and future populations of veterans. Therefore, promoting the Ancient Tree Forum and their most recent publication on ancient and veteran tree management is critical. And now, for some fine shots of various veterans!

This veteran sweet chestnut was the first one to greet us as we entered the park from the southern end. Not a bad induction!
As the city blocks paint the skyline to the right, we get a brilliant juxtaposition between the historic and the contemporary. In such a dynamic and ever-changing landscape such as London, this veteran sweet chestnut acts as a vestige of the old.
From another angle, the same sweet chestnut as above’s form can be more greatly appreciated. The helical patterns of the wood fibres and bark are as if they have been wound like rope.
This veteran has seen better days, though still stands proudly by the cafeteria. The ground beneath is woefully compacted, which must be having an impact upn the tree’s ability to function as a living being. Unlike the two shown above, it also doesn’t have a layer of mulch applied around its rooting environment.

Some of the veteran sweet chestnut we came across were also home to two annual common wood-decay fungi – Fistulina hepatica and Laetiporus sulphureus. Without doubt, the state of the fruiting bodies was not good, though when ravaged by time, wind, rain, frost and sun, to still even have a form is respectable! Certainly, a summer visit would have yielded a much greater haul of these two fungi on the sweet chestnuts, so a summer visit is probably on the cards.

One of Greenwich Park’s many veteran sweet chestnuts with an added extra – a small and rather weathered…
…you can see it…
…Fistulina hepatica! Picked off by parasitism before it reached a respectable stature, it still nonetheless produced a hymenium and thus likely produced spore.
A second sweet chestnut, this time slightly smaller, but again with Fistulina hepatica.
The state of it is, however, diabolical!
A smaller and thus younger sweet chestnut, in this instance.
It sports a fungal fruiting body, nonetheless!
A chicken of the woods, which is beaten and bruised.
Another smaller sweet chestnut, and another Laetiporus sulphureus.
Note how it emerges from behind a bark-covered area.
Again this sporophore is long beyond its best, though retains a little more dignity in the face of its impending crumble.

Away from the sweet chestnut, there was a variety of other large trees. Below, I share the ones that were home to fungi, through the identification of fruiting bodies. Absolutely, all trees on site are host to many species of fungi, though fruiting is not necessary in many instances, and it certainly costs the fungus energy to create and sustain. To begin, we’ll take a look at the ever-accomodating mature Robinia pseudoacacia in the park, which didn’t disappoint. In all, the population supported three species of wood-decay polypore, as we will see in the below images.

A very mature false acacia, with a very mature Laetiporus sulphureus fan on the main stem.
Well, sort of a fan – the remains of!
I imagine someone yanked this off, as it looks like a rather clean break.
Very close by, a second false acacia cradles another Laetiporus sulphureus.
Here, we can see how it’s at the base of the main stem, in place of higher up the structure.
This second one is far worse for wear!
A double-stemmed Robinia pseudoacacia, which was once at least triple-stemmed.
At the base, a senescent Perenniporia fraxinea and a cluster of broken active sporophores can be seen.
For good measure,here’s a better look at the entire bunch.
It’s a little disappointing that the fruiting bodies have been damaged, though that doesn’t stop them being Perenniporia fraxinea!
And a second example of Perenniporia fraxinea on this false acacia, too.
Right at the base, to the left.
This one appears slightly different to how it’d usually look (it’s not photogenic!).
Regardless, a showing of the trama reveals it as Perenniporia fraxinea.
It looks like the park managers are aware of the decay on this Robinia, as it has already been pruned!
If you look between the buttresses and into the basal cavity, you can spot a single Ganoderma australe. More were on the other side of the tree, though were old and worn.
With the sun behind the camera, this southern bracket looks rather pretty.

Steering attention away from false acacias, I now turn towards a focus on the brown-rotting polypore Rigidoporus ulmarius. With both horse chestnut (Aesculus hippocastanum) and beech (Fagus sylvatica) on the site, the chances are that there would have been a few examples of this fungus. Indeed, there were, as we will observe.

This first example, on horse chestnut, is an interesting one.
It’s the return of the cavity-dwelling Rigidoporus!
Away from the wrath of the elements, this sporophore doesn’t have the algal green stain atop and bathes in its own substrate.
A cutting identifies this specimen as Rigidoporus ulmarius, with the cinnamon tube layer and brilliantly white flesh.
The second horse chestnut sits in line for the toilets, patiently waiting for soneone to give it the 20p needed to get beyond the toll gate.
If you want, you can even sit down to inspect this tree!
This might well be this sporophore’s first season. I wonder how many more years it will see before it gets knocked-off or is aborted.
Half way up this steep hill, a beech stands seemingly without significant issue.
Oh, wait – here’s the issue!
Is that a shade of green?
From this shot, it looks most probably like Rigidoporus ulmarius. If so, we have two examples in one site of its cavity-dwelling abilities!

Greenwich Park also has a good number of large plane trees (Platanus x hispanica). The most abundant fungus on these trees was massaria (Splanchnonema platani), and there probably wasn’t a plane in the park that didn’t show at least some signs of its presence. However, it was the large plane with Inonotus hispidus that gained much of my eager attention, given I am not often around mature planes with extensive fungal decay.

A rather lofty plane tree.
As the crown breaks, we can spot a single Inonotus hispidus sporophore.
Whether there is an old wound at or around this site is hard to say, though for this fungus to be able to colonise one would expect so.
Perhaps an old branch stub above the fruiting body?

To round this post off, which has admittedly taken a long time to write, I’ll share some lovely images of a not-so-lovely bird – the parakeet (Psittacula krameri). Plaguing many of London’s parks and beyond, these things produce an utter cacophony and are certainly invasive, though one must admit that they are incredibly photogenic. Below, I share a few examples of where the parakeets were using cavities for shelter.

A horse chestnut monolith, seemingly vacant.
Wrong! Enter the parakeet(s).
This one stands proudly atop a pruning cut.
Along a plane tree branch, this parakeet appears to be guarding its abode.
“Oi m8, w0t u lookin’ @???”
A wintry visit to Greenwich Park, London

Urban fungi – streets and parks

It’s somewhat overcast at the moment and it’s rather cold outside, though that doesn’t mean the world grinds to a halt. Indeed, fingers might move a little more slowly and words might be slurred as the wind howls and the frost lingers, but one can retain enough sensibility to grab a camera and get out to look at trees and fungi. Perhaps this is when the urban heat island effect is appreciated a little, in fact – urban parks aren’t as cold as the open countryside! There’s probably a joke in there somewhere…

Poor jokes aside, my morning sojourn around an urban park and the adjacent streets was rather fruitful, in terms of fungi that could be found. Admittedly, as winter builds its temporary bulwark everything runs for shelter – fungi are often no different in this regard, with mycelium remaining cosily within its sheltered substrate. Sometimes, and notably for polypores, the weathered remains of old fruiting bodies signals the presence of colonisation, and thus many of the below finds detail this. Of course, one must still be able to identify the remains of fruiting bodies where they exist with some dignity, and therefore a mid-winter exploration can in fact yield very constructive results. For me, the diversity of finds in this state was quite pleasing, considering I spent perhaps two and a half hours essentially walking in circles. Granted, some fungi are true hivernophiles, so look out for fresh fruiting bodies, too!

My morning walk first took me to an oak I actually drove past two days prior, though unfortunately at the time I couldn’t stop. Thus, I detoured via this park first of all, and snapped a few (heh, a dozen…or two) photos of a senescent Laetiporus sulphureus with a great view of passing traffic.

In this dire light, this huge oak is almost a silhouette in the landscape.
Notice two historic pruning wounds where old poles (this is almost certainly an old pollard) were removed to allow for safe passage of vehicles.
The pruning wound on the right sees a single fan of Laetiporus sulphureus sit boldly over the road. Didn’t it ever get told not to play with traffic?

Detour over, I made my way to the main site for my morning’s walk. The first tree (or monolith) I came across, which was a horse chestnut (Aesculus hippocastanum), shown earlier in the year in this blog post, I inspected once again. With much of the dryad saddle (Cerioporus squamosus syn. Polyporus squamosusit had its name changed recently) now senescent and dressing the floor beneath, my focus was turned to the now much larger southern brackets (Ganoderma australe) and the myriad of silverleaf (Chondrostereum purpureum) sporophores that adorned the trunk. The latter were of interest to other park users, who were taken aback by the wonderful colourations of this species. In one of the below images, you’ll even be able to see its cerebral-like morphology.

Fungi everywhere. Literally.
You can see three species in this photo: Cerioporus squamosus (on the floor), Ganoderma australe (middle) and Chondrostereum purpureum (right).
Here’s the nicest sporophore of Ganoderma australe. It’s such a variable bracket in terms of its shape and colour, and this study alludes as to reasons why.
Some Chondrostereum purpureum that has both fresher and more mature (yellowed) sporophores.
It really does look like a brain, no?!

From here, I turned my attention to a few nearby trees. One hacked-at purple plum (Prunus cerasifera ‘Pissardii’) was littered with Ganoderma australe and cushion bracket (Phellinus pomaceus) sporophores, though I admit I was more interested in the high-up Laetiporus sulphureus on a lofty black locust (Robinia pseudoacacia). This is an association that is rather frequent, and given the higher parenchyma cell content of black locust, is perhaps less immediately serious when compared to the fungus’ colonisation of willow (Salix alba, notably).

The red arrow marks the spot!
Granted, this isn’t anything morphologically fantastic, though the longitudinal wound above to the right (complete with a woodpekcer hole just out of shot) probably is associated with the presence of Laetiporus sulphureus.
Zooming in 60x, this is the slightly blurred result. We can see the sporophores tucked neatly within the ever-common fluting present on mature black locusts.

Not too distant from this false acacia stood this ash monolith (this park is full of them, which is great), complete with four sporophores of Perenniporia fraxinea at and slightly distant from the butt. As you’ll recall from my recent post on the hosts of Perenniporia fraxinea, it actually has quite a broad host range (add hornbeam to this mix, too), though ash is arguably its most frequent host. The examples here aren’t too brilliant, though the one on a main anchorage root provides us with a curious example of why we should not just look at the stem base of the tree for this species.

Fraxinus ex-excelsior…!
Spot the three Perenniporia fraxinea at the butt and one just behind on a principal root (look to the top right).
This angle is probably slightly better for spotting the one out on the root, though in front of that is this rather flashy example of Perenniporia fraxinea in its less beautiful state.
If you still felt you had to re-position the Hubble Telescope to see the one out on the root, worry not – here it is!

Not wanting to now litter this blog post with countless examples of Inonotus hispidus on ash, I’ll instead take you to a close relative of this species: Inonotus cuticularis. Most often found on beech (Fagus sylvatica), though sometimes also oak, it operates in a similar fashion to its relative on ash and is therefore found most routinely on or around branch and stem wounds. Here the beech was directly roadside (and just outside the park), and the wound the sporophores were seen on probably arose from a branch removed during road construction / management.

A busy arterial road might separate us, but that doesn’t mean you can’t be spotted…
…for repositioning the Hubble granted us this image of Inonotus cuticularis!
And this one too, actually. Certainly far more interesting than the nebulous notion of there being countless star systems littered across an endless spatiotemporal vacuum…?!

Funnily enough, this beech stood almost opposite a silver maple (Acer saccharinum) – again roadside – that sported a few sporophores of Ganoderma australe. The future of this silver maple is potentially questionable, at least in its current un-pruned state, given the aggressive pathogenicity of this fungus.

Not the largest silver maple, though its position certainly would prompt a discussion of its future management needs.
It appears that there could be the beginning of what is considered ‘bottle butt’, which would be facilitated by the selective delignification of Ganoderma australe.
It looks as if something caused the upper tier to break in the recent past (last few years), as new growth has been initiated beneath and thus a new bracket is forming.

Getting back into the park, there are a few fingal finds that are interesting enough to be shared. The first we have already seen on this virtual fungal tour, though this time it was colonising a poplar (Populus sp.) and was still attached to the tree. Yes, I’m harping on about Cerioporus squamosus! Up high on an old pruning wound sat a small duo of sporophores, senescent and probably sun-, frost- and wind-scorched!

I’m being kind once again – the arrows guides the way!
There’s some serious dieback around these old pruning cuts, in fact. Plenty of barkless area can be seen, and thus at least decay within these (hopefully effectively compartmentalised) regions of wood.
The 60x zoom coming in handy again for this shot of Cerioporus squamosus!

To round off, there was also another monolith (!!), and once more provided courtesy of a horse chestnut, acting as a host to two species of fungus: Ganoderma australe and the giant polypore (Meripilus giganteus). The southern brackets, by virtue of their perennial nature, endure winter quite effectively. The giant polypore, on the other hand, does not. Nor, probably, does it appreciate dogs tearing it apart and urinating upon it! Regardless, the sight of a wrangled and devastated Meripilus giganteus is a rather common one at this time of year, and for all you fungal sadists out there this is for you!

If you hadn’t already noticed (the eagle-eyed lot that you are), there is a tuft of grass growing out from the top of this monolith.
A water-soaked, blackened, deflated, slightly rotten Meripilus giganteus.
This one is, too!
At least this little Meripilus giganteus retained some form of dignity, staying somewhat upright and dry.
Urban fungi – streets and parks

A visit to Wrest Park, UK

Last weekend I explored Wrest Park with a small group of other individuals, and we certainly saw plenty of interesting sights! For those curious, it is just north of Luton adjacent to a lovely old village called Silsoe, and for those arriving early you can even hear the bells of the nearby church ringing for Sunday morning service and explore the village to look at all the listed buildings.

However, as this blog is about trees, we shall keep it on all things tree-reated, and without further ado I’ll get into some of the features of this park that we passed by…

First of all, we came across this absolutely wonderful Wisteria sp. on the wall of the gardens. Without a shadow of a doubt, it is one of the largest examples I have seen, outside of the one at Kew Gardens. When trained well or given space to thrive, wisterias really do add a degree of formality and regality to a place, and one could hardly argue that the wall would have anywhere near as much character if this wisteria was absent!

Here we can see how the wisteria envelops at least a segment of the much larger wall.
And a great look at the stem morphology. The fluted appearance also gives this wisteria an old feel, which is probably because of its likely good age!

Just around the corner from this fine wisteria was a very sizeable cedar (Cedrus sp.). I recall it as probably being a cedar of Lebanon (Cedrus libani), though we’ll run with a species of cedar when noting my inability to remember specifics! I might add that this was a sizeable cedar, actually – it is now less so, but is certainly still a very impressive specimen. What is interesting about this cedar was the cavity three quarters of the way up what was left of the main stem, which sported some now rather senescent sporophores of the dyer’s mazegill (Phaeolus schweinitzii). The common name for this fungus comes from the fact that the fruiting bodies were used to make purple dye (a phenomenon not restricted to this fungus, as a very many fungi are used for dyes). Always be sure to check stem cavities for this fungus on conifers, and notably old cedars and pines, as they can yield some great fungal treasures!

Wider than it is tall. I know they say that cedars flatten-out atop in maturity, though this one takes it a little too far!
Of course, this cedar was a lot larger, though unfortunately lost its top – probably during high winds.
But that isn’t a problem – the cedar still lives. And other things live within it, too – such as this dyer’s mazegill.
A closer inspection with the camera reveals a small tier of fruiting bodies, and given the deep fissure they are emanating from it is certainly an historic wound and not a recent one.

Further around the gardens, we came across a huge copper beech (Fagus sylvatia ‘Atropurpurea’). As well as a discernible graft line that has begun to bulge, we can spot some highly distinct stretch marks on the bark. Evidently, the more recent annual increments have been quite marked in cross-sectional area, and the bark has therefore split to reveal a fresher bark layer beeneath. As we know, beech usually has a gloriously smooth bark, though in some instances that smooth bark is lost to a much rougher one. Is this a problem? Almost certainly not. It might however be associated with the graft point, if there are additional mechanical stressors acting on the area.

Here’s the copper beech, in all of its bare glory.
The trunk not only adopts a very stretched appearance but also has a pronounced bulge around the graft union.
A closer look just to appreciate the degree of bark stretching. Perhaps a visit to Boots would help this beech tree reduce the prevalence of the stretching!

As luck would have it, we then saw a lot of fungi. First came this horse chestnut (Aesculus hippocastanum) stump, which had on it not only Bjerkandera adusta, Chondrostereum purpureum and Flamullina velutipes, but many Mycena sp. on roots surrounding the stump. All, in this case, are saprotrophic fungi, meaning that they feast upon the abundance of dead wood, though in the case of Chondrostereum purpureum the mycelium will parasitise upon the mycelium of other fungi (a bit like how Trametes gibbosa will attack Bjerkandera adusta).

A quite massive horse chestnut stump. In death, it still provides life for many species of fungi, as we can see…
Some very fresh and guttating Chondrostereum purpureum. This species is very common on cut ends of fallen logs and stumps during autumn, and is able to parasitise upon other fungi. Thus, it is a fungus that is a secondary resource capturer, as it follows other fungi that came in before.
More Chondrostereum purpureum alongside some rather old Flamullina velutipes.
And a select few of the bonnets (Mycena sp.) surrounding the stump, which are very likely saprotrophs of dead roots.

Our walk then took us through the woodland garden, where Inonotus hispidus reigned supreme on some of the ash (Fraxinus excelsior). This woodland garden was rather peculiar, in the sense it was utterly laden with laurel (Prunus laurocerasus and Prunus lusitanica), huge yew (Taxus baccata), oaks (Quercus robur) with wonderfully straight boles, limes (Tilia x europaea) completely ravaged by mistletoe (Viscum album), and other tree species (such as ash, as was noted above). The growing amount of deadwood is certainly valuable for any invertebrates, fungi and bacteria, though the laurel does certainly require some management as it currently dominates the understorey.

Obviously, as it is now late autumn, the leaves are off of the ash and the shaggy brackets are blackened (by-and-large). Here, we can spot one just before the stem break.
Conveniently positioned beneath an old branch abscission point. Note the spindle-shape surrounding the old branch stub, which is the optimal way of ensuring there are no huge stress pockets in the area.
This second ash is a little more sheltered but still doesn’t escape the ravenous hunger of Inonotus hispidus.
Again, we can see it is associated with a wound. In this instance, the wound is a little larger in longitudinal extent. The area also sags slightly just beneath, indicating the white rot present (and thus delignification of wood) that is being caused by the mycelium of this fungus.

Also within this woodland, we came across a large oak that had lost its top during last winter. The debris now dressed the ground beneath, and it was not very surprising to see Bulgaria inquinans present on the fallen wood. This fungus is present as a latent organism within the vascular system of the oak, and upon death of a branch it quickly colonises (often quite brilliantly and over vast swathes of wood) to make use of the carbon readily available. In this example, the colonisation wasn’t so glorious, because the wood had been cut into smaller segments, though if left in tact the fungus would have produced black jelly discs across the entire upper stem.

A victim of the wind, though still alive. This loss of the upper stem might in fact allow the oak to live for a longer period of time, as it significantly reduces the risk of entire failure by the wind.
Some discs of Bulgaria inquinans, all of which are maturing or already mature.
Other equally mature examples on another piece of fallen wood. Absolutely abundant, as is to be expected.

After exiting this woodland garden, we were allowed access to a part of the site closed off to the public. Not only is this good because the area is often not trampled down, but what you can find in there away from the haunts of man is often a great treat, and we were not let down on this front, as you will see by the below images! However, before entering the gate, we stopped a beech (Fagus sylvatica) that had a great example of Perenniporia fraxinea at its base.

I suppose you could say it’s the guardian of the gate. It didn’t do a very good job though, as we had a key and the beech can’t actually move.
Here’s the sporophore, tucked away between two buttresses and covered by bramble a little.
Pay attention to the white spore beneath, which differentiates it from the slightly similar Ganoderma australe.
The brown context is another identifying feature of this fungus.

We then saw this fungus again, immediately upon entering the gated area. However, this time, it was on a host I had never seen it on before – hornbeam (Carpinus betulus)! And a great example it was, too.

A rather contorted but very large hornbeam, with bark that one could almost describe as black locust-like.
Around the butt were many sporophores of Perenniporia fraxinea, but this was by far the best one.
Now here’s a postcard picture! Who wants to see a picture of a beach with palm trees when you can see this…!?
And again a shot of the context.

Walking down alongside the lake we then came across a fallen weeping willow (probably Salix x sepulcralis ‘Chrysocoma’) that, upon its stem, was dressed with sporophores of the blushing bracket Daedaleopsis confragosa. This is rather common dead parts of willows (including Salix caprea), though generally the brackets are a little smaller and less sublime. However, in this instance, they provide us with a great example of how it looks.

Willows doing what they do best – break!
…and then providing great habitat for wood-decay fungi.
This dead section of the stem is covered by over a dozen Daedaleopsis confragosa fruiting bodies.
And when we look closer we can spot the brilliantly-textured upper surface. The pores below are between gills and pores, being quite elongated in nature.

So not to bore you all with fungi, I shall share one last example of Laetiporus sulphureus ssp. on yew (Taxus baccata). If you look around old yews you will often see chicken of the woods, though make sure never to eat it as it won’t do you any good and could end up with a visit to the hospital!

If yew look closely…
…you can almost see the tree weep at such a vile pun.
This Laetiporus sulphureus ssp. even had a cherry on top. But don’t eat it…
…because it’s blue and mouldy. And poisonous to some!

And now that I’m blue in the face from blaring out so many horrific puns, here’s a few images that will lighten up your day – lightning damage on oak!

Here we can see an old lightning wound that spans the entire length of the stem. Note the old ribbing to both sides and the central shallow fissure where the bolt probably tracked.
Another oak close by shows a similar style of wound, though less extensive in circumferential damage. Both oaks have survived, and long-term this damage might create some interesting habitat!

Well that is everything. I do suggest this site to those who are nearby, or want to make a trip at a weekend to explore a formal park. It is worth it, though please try to look beyond the huge yews that were topped to try and recreate a hedge! It isn’t easy, but I suppose the dead stumps make for some curious landscape features…

A visit to Wrest Park, UK