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.
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!
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.
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.
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.
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.
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.
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.
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 squamosus – it 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.
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).
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.
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.
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.
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!
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!
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!
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!
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.
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).
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.
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.
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.
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.
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.
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!
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!
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…