Fungal succession and wood decay in living trees – a seminar report (Part II)

See Part I here.

The second part of this cluster of blog posts is one the first of the duo of talks presented by Lynne Boddy. Lynne is a well-known mycologist and researcher and thus, as regards wood-decay fungi, is a good authority from which we can all learn a substantial amount. For a fungi enthusiast such as myself, learning about fungi from one of the best is, in and of itself, very exciting. However, the information presented was equally as exciting, which I shall run through below.

As a slight aside, please watch out for her new book, which is currently being written and should be finished later this year, currently entitled Fungi in Trees. This book will be aimed at the arboriculturist. Lynne is also planning to re-write Fungal Decomposition of Wood, which was a magnum opus co-authored with Alan Rayner.

Fungi invading trees

Primarily, we must accept one core tenet of wood decay: the anatomy of wood has a massive impact upon mycelial networks that sojourn through the wood substrate and selectively metabolise woody cells and their deposits as they go. Indeed, in an ideal world, fungi would gun right for the ray parenchyma, which are incredibly nutritious living cells. However, these cells are very challenging to get to, by virtue of their ‘aliveness’ – living cells in good condition are not easily devoured. Further to this, the sapwood also offers a great for invading fungi, though again – because of the high moisture condition meaning the environment is largely anaerobic (fungi are aerobes and require oxygen to metabolise) – this part of the wood structure is not easily accessed. Of course, the vascular wilts have a better time invading sapwood that is functional, though many fungi will have to bide their time or arrive opportunistically onto and into dysfunctional sapwood if they are to have any means of success in acquiring the treasures within. Thus, is recognising that such living (i.e. conductive and functional) areas of wood are likely just beyond the reach of many fungi, wood-decayers will typically resort to the back-up food source: non-functional xylem vessels within the heartwood or ripewood.

The heart rotters

Now, in accepting this, we come on to perhaps the broadest cohort of wood-decay fungi in living and standing trees (fallen trees have their dysfunctional sapwood metabolised like ravens engulfing a fresh meal) we know of: the heart rotters. These fungi will enter the central wood (i.e. ‘the heart’) through exposed areas of this central column by either sufficiently deep root, stem or branch injury – ultimately, there generally needs to be a continuity of viable ‘heart’ substrate, if any significant degree of colonisation is to take place. Where continuity doesn’t exist, or the fungus finds itself limited to only a certain area, the only manner in which is will typically be able to continue existing is by (1) exiting and finding another host or (2) biding its time and waiting for currently functional sapwood to become incorporated into the heartwood or ripewood, in which it can then spread into – assuming the tree doesn’t lay down defensive barriers that cannot be breached, in order to protect its sapwood, which is in itself a pursuit undertaken to safeguard and hence sustain the high-moisture content of its sapwood (contrary to Shigo’s model, which infers compartmentalisation is largely there with the end in mind of prohibiting fungal succession into the wood). When we look at the ripewood of beech (Fagus sylvatica), we can observe this phenomenon very well – a rosy-coloured ripewood (red heart) with lots of separation lines between instances of decay successions. Ganoderma australe, Ganoderma pfeifferi and Ganoderma resinaceum will afford the most acutely observable examples of this, given their ability to breach such zones by metabolising the phenolic deposits laid down by the tree (this touches upon the idea of a fifth wall in the CODIT model, which will be discussed more later on).

laetiporus-taxus-baccata-yew-3
An old Laetiporus sp. on yew (Taxus baccata).

By virtue of the heartwood or ripewood being the least inhospitable (heartwood, in particular, is still often disgustingly harsh, as regards its environment), we can observe immediately some species-specific associations. For instance, the dyer’s mazegill (Phaeolus schweinitzii) will frequent gymnospermous hosts, such as the cedars (Cedrus spp.) and pines (Pinus spp.), whilst chicken of the woods (Laetiporus spp. – often L. sulphureus, though by all means not always, as we will see) will be found often on oak (Quercus spp.), sweet chestnut (Castanea sativa) and yew (Taxus baccata) – it can, indeed, be found on other hosts, as well. On the face value of things, these three tree species have seemingly little in common, though all three have extractive-rich heartwood that this genus can metabolise effectively. In terms of why the genus is referred to and not the exact species, Lynne is of the stance that what we term ‘chicken of the woods’ and default to as L. sulphureus is actually a variety of different species each with their own specialisations – perhaps even down to a specific host tree species (notably for yew, where the chicken species is most pertinently viewed as being a different one).

From a tree management perspective, Lynne then addressed the importance of the heart rotters – what is their impact? Put simply, they change the way in which we view the tree from a safety perspective; as in, when fruiting bodies of heart rotters are identified, if the tree is standing and there exists a target, management considerations are routinely entertained and sometimes the tree is felled. Additionally to this, however, we have other things to appreciate:

  • heart rotters do a great job at recycling nutrients, which can then be re-assimilated by the tree when they are uptaken back through its roots (including adventitious aerial roots) or the mycorrhizal fungi the roots associate with
  • the wood qualities produced by heart rotters are ideal as habitat for saproxylic insects and nesting birds
phlebia-tremellosa-fagus-sylvatica-pollard-2
The heart of this beech has been hollowed-out by decay fungi. In the process, before its failure, what conditions did this decay provide for insects and, crucially, what habitat does it provide now?

Latent colonisers

Considered the specialised opportunists, such fungi are present within the sapwood or bark, as propagules (thick-walled resting spores known as chlamydospores). Biding their time until conditions are right, wherein the sapwood becomes dysfunctional through means such as wounding or drought (causing embolism), they are perhaps most acutely observed in the years after drought years where they can trigger the formation of strip cankers and resultant reaction growth by the tree (see the below photo). Thus, this year, in the UK, is one to watch out for, as regards such fungi (it might also explain why Kretzschmaria deusta was so abundant this year, given Ascomycetes love dry conditions, which prevailed last summer).

B nummularia Eutypa spinosa beech canker strip
A strip canker in beech caused by the latent fungus Biscogniauxia nummularia that has induced reaction growth, which can be seen cross-sectionally in the bottom right image).

At this point, a delegate enquired as to whether Massaria disease of plane (Splanchnonema platani), as an Ascomycete, could be prevailing in urban conditions recently, because of dry conditions (such as London, where it was been very severe these past few years but prior to that un-noticed). Discussions continued and Frank Rinn interjected to add his thoughts:

  • massaria progresses quickly in dry conditions
  • recent dry summers have allowed for massaria to thus progress very rapidly (killing branches in as little as three months)
  • the lowering of water tables in cities for the construction of basement levels of buildings has meant that plane trees can no longer tap into groundwater supplies
  • mature plane trees afford the best conditions for massaria; notably lower lateral branches, which are shaded from the rest of the crown and thus may be most prone to stress
  • there have been reports since 1903 from Croatia where large plane trees have shed branches and the massaria fungus was termed the “branch-cleaning fungus”
  • conditions are collectively ideal for massaria to become prevalent, as they stand

Reverting back to latent fungi, Lynne then mentioned that she considers fungi to be latent across a broad variety of trees. For example, the coal fungus (Daldinia concentrica), whilst found most often on ash (Fraxinus excelsior) can be isolated from the sapwood of a great range of different broadleaved tree species in the UK. It is, indeed, only when specific conditions arise that are preferable for this fungus that it begins to create mycelial networks – such conditions might not arise in particular trees, or may arise only after conditions suitable for other fungi have arisen and thus D. concentrica then has no capacity to colonise the substrate. Hence, ash remains the core host of this species, in the current climate. However, for the jelly ear fungus (Auricularia auricula-judae), which is also a latent fungus within the vascular system, having been found largely solely on elder (Sambucus nigra) in the 1950s, it is now found on over 20 host species – this marks a huge increase in host range, prompted perhaps by changing climatic conditions.

Wall V

The CODIT model, offered to us by Shigo, details four walls – as can be seen here. As mentioned by Frank Rinn, Shigo himself was considering the possibility of a fifth wall, though this never ‘made it into’ the model. However, Lynne argues that there is the potential for a fifth one, which hearkens back to what was discussed above, as regards rot within the heart of beech wood).

Specifically, whilst the barrier zone (fourth wall) is a zone laid down at the time of wounding by the vascular cambium, the dynamic responses by the tree that occur in real-time as fungal decay advances constitutes a distinction from this initial barrier. Indeed, as decay advances, living cells within the heartwood or ripewood (they do exist; though through mechanisms not fully appreciated, but thought to be associated with the rays running radially through the wood), in addition to the functional sapwood, will, in order to protect the sapwood and keeps its high-moisture quality intact, will plug woody cells beyond the current zone of decay with extractives and phenolic compounds – this will occur within the sapwood most often, though may also be able to occur in the heartwood around the regions where pockets of living cells exist. This response resultantly produces incredibly dense zones of wood that afford the tree’s sapwood a means of protection, which it would otherwise lack, assuming the barrier zone (Wall IV) failed to contain fungal decay. Of course, if this fifth wall fails, another will form, and so on and so forth.

Ganoderma pfeifferi beeswax beech failure 3
See the myriad of demarcations across this cross-section of a beech that failed from decay by Ganoderma pfeifferi, which suggest a dynamic fifth wall being effective.

Perhaps we will see this idea discussed more in Lynne’s re-write of Fungal Decomposition of Wood.

Fungal succession

When a tree decays, the fungi that initiated the decay process will not end it. This is because, much like all other ecosystems, as an environment changes those organisms that are best-placed to utilise it change as well. In this sense, fungi are no different – they succeed into a dynamic and ever-altering substrate (wood). Such a phenomenon can be so readily observed when walking into any woodland, when comparing the fungi on standing trees and those in early stages of decay and those much more heavily decomposed. In instances where an entire tree falls and stays largely intact, succession can be most acutely observed, as Lynne detailed with a little help from Ted Green and some research students.

The tree in question, a mature beech, failed and was left, in sections, for ease of its movement into an accessible place, to decay. Along the beech, it was found, through analysis of the wood in the laboratory and by presence of fruiting bodies, different fungi were observed colonising different parts at different stages of decay (as shown below). Such an observation does seem readily apparent, though to have it confirmed through scientific means affords us with an understanding that is more concrete than merely the anecdotal. Indeed, whilst Trametes gibbosa was not isolated from this beech, the presence of Bjerkandera adusta infers that, at some point in the future, T. gibbosa will be found – it parasitises upon the mycelium B. adusta, before then colonising the wood substrate itself. We are, in a sense, therefore, witnessing fungal warfare.

beech fungi succession analysis
The different fungi found at different parts of the beech at different stages of the decay process (open in a new tab to see this in a slightly larger size).

Delving further into the notion of fungal warfare, what is essentially meant is chemical warfare. Fungi synthesise and secrete enzymes, which they use principally to degrade wood, though that can also be used to defend territory or attack other fungi. The result of any fungal battle can be one of four things:

  • deadlock, whereby neither fungi gains any ground against the competing fungus
  • replacement, whereby one fungus loses its territory entirely by the other
  • partial replacement, whereby one fungus loses of some its territory to the other
  • mutual replacement, whereby the fungi essentially ‘trade’ places with one another and neither gains any net ground

So how does one determine the outcome of any such skirmish, you ask? Unfortunately, there are so many variables in play that even pitting two fungi against one another in a laboratory is only going to give a slight allusion to what really occurs, though there does nonetheless exist a limited hierarchy of combativeness from which we can assume who the victor will be, under most circumstances (see here at 25:09 timestamp).

Of course, even in assessing this we still have so many caveats to throw in. For example, where moisture conditions are drier because the wood is more exposed, Ascomycetes (i.e. Hypoxylon spp.) will have a better time in securing more wood substrate, as they operate effectively under dry conditions. Indeed, the wood qualities of the substrate itself will even play a role – did the tree uptake pollutants during its life or is it exposed to such pollutants currently, for example. More crucially, if a dead piece of wood (or entire tree) is standing and has thus been subject to relatively dry and exposed conditions suddenly falls to the woodland floor, those fungi reigning when the tree was standing will likely succumb to wood-decay fungi adapted to higher moisture levels and cooler more stable conditions.

The next part of this series will be a brief one on bacteria in wood, as discussed again by Lynne Boddy. I hope to have that written up in the coming few days.

Fungal succession and wood decay in living trees – a seminar report (Part II)

Fungal succession and wood decay in living trees – a seminar report (Part I)

See part II here.

First and foremost, it is absolutely critical for me to extend my deepest thanks to Jon Hartill of Hartill Trädexpert for organising such a superb single-day event (here is an overview of the itinerary) in Sweden. Indeed, bringing together three such critical speakers (Ted Green, Lynne Boddy and Frank Rinn) who, as was expected, but more acutely so in hindsight, worked well as a unit and offered much in the way of vital information and data, was not likely a simple task. Of course, it worked, and my 12 pages of hand-written scrawlings is testament to this. Thus, the purpose of this blog post (or posts, should I say) is to share the information gathered, so that it can be disseminated more widely and stimulate thoughts amongst the internet audience.

sweden delegates seminar fungi decay trees
Some of the delegates from this seminar. As you’ll see from the below picture, the setting was also rather fitting for a discussion on trees…
sweden delegates seminar fungi decay trees 2
Say hello to the town of Kungalv!

Ancient trees – what secrets remain?

The day was opened by Ted Green, the founder of the Ancient Tree Forum. Here, however, his role was not so much to discuss what is known of our ancient trees, but of what we still need to know – what don’t we know? Granted, there’s probably an utterly frightening amount we are yet to understand, though Ted’s talk was not to wallow in such an angst but instead to prompt directed focus towards aspects of ancient trees we really do need to understand next.

Principally, it was important to set the tone of the presentation: hollowing is an entirely natural process, which very few ancient trees escape. In fact, do they even want to escape such a ‘fate’? Arguably, the answer is no. Anyway, at this early stage, Ted made the distinction between the decay of central wood, separating the decay of heartwood (i.e. Quercus) and the decay of ripewood (i.e. Fagus). ‘True’ heartwood forms when phenols and other extractives and toxic substances to fungi are deposited within the non-living (largely) woody tissues, as sapwood becomes redundant. Ripewood, conversely, forms via different mechanics associated with wounding and other events. However, this was a point posited just to illustrate context, more than anyway.

The real ‘meat’ began when Ted began assessing where the notion of hollowing being bad came from: forestry. As an economic practice, it is obvious that hollowing would be seen as destructive, as basal decay hampers return upon the investment of a stand. Despite this, when moving away from forestry, we can observe that hollow trees don’t drop like flies under wind-loading events – as was the case when the 1987 storm (hurricane) hit the UK and hollow trees stood whilst solid neighbours fell. Certainly, hollow trees did fail and when they did it was oft at the point where the internal hollow met sound wood, though the general jist is that hollowing does not necessarily infer a risk of failure beyond that of what a solid tree would be considered to possess. Ted speculated that this hollowing meant that, under wind loads, the main stem could flex and ‘safely’ deform (a bit like a hosepipe when squeased slightly) under tension and torsion, thereby protecting the stem from forces that could overload a solid stem, which cannot deal with such a load in a similar manner (because it is not hollow, to any degree). In oak, for instance, Pseudoinonotus dryadeus (the Eiffel Tower fungus) can actually be seen as a fungus that aids with tree stability, by prompting pronounced buttressing and the creation of wood that over-compensates for the more centralised decay (as was discussed by Frank Rinn later on), whilst also allowing for the oak to deal with wind loading more effectively, given the presence of the hollowing internal to the trunk.

Pseudoinonotus dryadeus colonisation senescent old 7
Strong buttressing as caused by Pseudoinonotus dryadeus decay on oak. Does the internal hollowing even impact upon the tree’s structural stability, assuming the buttress roots laid down afford the necessary support? Thus, dooes pruning even have a beneficial impact upon reducing risk, when accepting that pruning damages the tree’s ability to photosynthesise and thus manufacture the sugars demanded for wood formation in these buttress zones?

Indeed, reaction growth comes in forms beyond buttressing – stems also flute; sometimes, quite majorly, in mature and veteran trees. This fluting can, in times of wind loading, afford the tree additional stability, through the over-compensated high wood quality, which allows the tree to deal with loading forces by acting akin to a coiled rope. Certainly, torsional loading against the direction of fluting is going to be a marked issue, though otherwise such fluting can be beneficial for stability – even when there are appreciable central hollows. In fact, this led on to another important point: the extent of hollowing and the resultant residual wall thickness (think Mattheck’s t/R or part of the Wessolly’s Statics Integrated Approach model) means very little, as it assesses a tree in blatant disregard for its wider context (exposure, lean, leaf area, wind drag coefficient, management history, the off-set nature of the hollow, etc). Without appreciating these factors, of which there are numerous, how can one state that hollowing is bad and will increase the risk of tree failure?

The talk by Ted then actually moved away from hollowing somewhat and onto other aspects of ancient trees. Specifically, the practice of pruning arose, wherein Ted commented that pruning back to the branch collar in older trees is potentially more destructive than leaving stubs – stubs that will afford epicormic growth and the formation of a new crown / part of the wider crown area. Interestingly, he used the example of beavers felling trees not at their base but a little up from the base, from which these trees oft repsrouted and formed natural coppice. The same, he suspected, could be the case for aerial pruning – leave a stub.

This consideration took Ted onto further points, of which the main one was that of where trees fail most routinely. Indeed, aroung 70% of all failures within a tree at at the branch level – of these, many fail not at the collar but out along the branch itself, thereby leaving a stub. Using examples of trees from Windsor and elsewhere that failed in such a way, he demonstrated that new but lower crowns were formed in the years after; even in cases where every single major limb failed on the tree, thereby creating a tree form like what can be seen in shredded trees.

veteran tree natural shred wind hurricane
An oak tree that lost almost all of its crown in the years after the 1987 storm. Only one limb actually remains (red square). The other limbs all failed (green arrows) and have since resprouted and formed a new crown. Should we be managing our older trees like this and, to extend this question, should we be managing all of our trees like this, if we are to mimic natural forms of failure?

Further to this, Ted got talking root failure in strong winds. In his experience, following the 1987 storm, some older trees began to decline either partially (in select area of the crown) or wholly in the years following, for no outward apparent reason. Ted’s suspicion is that, in place of aerial failure, structural roots failed and the connectivity to specific connected parts of the crown from these roots thus was severed, triggering localised dieback and retrenchment. Therefore, the question of whether localised root plate damage caused localised aerial dieback in older trees was asked and, assuming the answer was that this does occur, it could actually be beneficial for the longevity of the tree – it can retrench, form a lower crown and thus increase its safety factor. In fact, it would also suggest that the occurrence of fungi such as Meripilus giganteus on older trees, in certain instances, would be as a consequence of saprotrophism, in place or parasitism – the fungus follows the root damage and metabolises the severed roots. I then asked Ted whether he thought that the same phenomenon could occur in grazing ecosystems, in which cows, pigs, sheep or otherwise are grazed amongst wood pasture. His answer was one of grazing also being a cause of retrenchment, wherein grazing pressure damages certain structural roots and this leads to subsequent localised aerial retrenchment.

root damage crown retrenchment tree wind
Can select root damage under wind-loading conditions bring about select crown retrenchment, through the connection of certain roots to certain portions of the crown? If so, can this damage, assuming not all roots are severed, improve the longevity of the tree and increase its stem’s safety factor, in spite of hollowing and major yet probably transient dieback?

Other questions raised within Ted’s talk were as follows: (1) are animal pharmaceuticals, often in the form of de-wormers, harmful to the mycorrhizal networks and the tree’s rhizosphere (i.e. soil biota), when they are excreted by the animal in the vicinity of the tree?, (2) is acid rain the most damaging impact upon our old trees, because of its impact upon the soil?, (3) are earthworms the most crucial soil organism for older trees, given their ability to aerate soil and to recycle nutrients by consuming absiced leaves (including those where over-winter pathogens reside, such as oak mildew), and (4) does stress throughout the tree’s life give it the best chance of reaching the veteran or ancient stage, when noting that slower growth and a more responsible management of energy is more sustainable? To these questions, we do need more research.

Take-away points from this talk are, therefore:

  • major hollowing of trees isn’t perhaps an inherently bad thing – notably in older trees,
  • we need to understand the species-specific and age-specific impacts of fungal decay upon trees before confidently exclaiming an increased and unallowable risk of failure,
  • a tree’s situation and history has a direct and marked impact upon the risk brought about by a hollow
  • damage to tree roots on older trees and the possible associated crown effects demands more investigations,
  • we need to determine how we should be pruning older trees, if we are concerned with their longevity, and
  • the rhizosphere’s importance for the health of older trees is a very viable area of research

I’ll write part II up in the coming times, which will focus on Lynne Boddy’s presentations. The third part will be Frank Rinn’s incredible afternoon talk.

Fungal succession and wood decay in living trees – a seminar report (Part I)

Fistulina hepatica’s anamorphic version: Confistulina

Having been informed earlier by a friend that they have an article coming out soon in the journal Field Mycology and having then read the article, I considered it important to build on the information and photos shared in the manner I am most familiar: ramblings. I do not want to spoil the article so please do source the article yourself, though as a form of executive summary, this fungus, Confistulina hepatica, is the anamorphic (asexual) stage of the fungus Fistulina hepatica (beefsteak), which is common on oak and sweet chestnut. I have found it once on beech, though it generally sticks to the first two hosts. This anamorphic stage produces asexual spore, which adorn the fruiting body’s outer portion in abundance. The reason for its emergence is not known, though it might be weather-related. More information is absolutely required from across its host range – not just England!

Disclaimer: The older finds, because I didn’t know what I was looking at, are quite poor photographs. A huge shame, but alas!

Disclaimer 2: I suspect many of these are the anamorphic stage Confistulina hepatica, though none were confirmed so please do not assume they all are. This blog post is simply to begin building a knowledge base that builds of the limited resource pool of present.

The first oak that I’ll share is perhaps one of the more interesting of the bunch because, two years in a row (2015 and 2016), the outwardly anamorphic fruiting body appeared in the same location; albeit, in 2015, the fruiting body was larger. Nonetheless, it infers that, in a crude manner, the same mycelial colony has done the same thing two years in succession. Unfortunately, during 2015, I didn’t get a shot of the whole tree so the location of the arrow points to the 2016 occurrence. However, from the positioning of the ivy, we can see the location is the same.

Confistulina hepatica Fistulina anamorphic oak Quercus 1
The arrow points to the location, which is on the southern side of the tree right at the base.
Confistulina hepatica Fistulina anamorphic oak Quercus 2
The 2015 version in its rotten glory!
Confistulina hepatica Fistulina anamorphic oak Quercus 3
The fruiting body sports what looks like burns, in addition to exuding a tar-coloured liquid alongside the more routinely observed reddish exudations common to young fruiting bodies.
Confistulina hepatica Fistulina anamorphic oak Quercus 4
A closer look at the darker liquid from the 2015 version.
Confistulina hepatica Fistulina anamorphic oak Quercus 5
And a puncture wound (so it appears) in the fruiting body.
Confistulina hepatica Fistulina anamorphic oak Quercus 6
And the smaller 2016 emergence!
Confistulina hepatica Fistulina anamorphic oak Quercus 7
Again, we can see the darker liquid exudations. The morphology is also somewhat similar.
Confistulina hepatica Fistulina anamorphic oak Quercus 8
Closer still on the 2016 find.

The next series of shots were taken on my mobile phone back in 2015 and again from oak. Once more, the adornment of the fruiting body with exudations, of which some are darker, can be observed. 2016 saw the fungus return, with a vengeance, and in a different position, again, an anamorphic fruiting body.

Confistulina hepatica Fistulina anamorphic oak Quercus 9
Yes, this oak has been hammered. Poor tree! (2015)
Confistulina hepatica Fistulina anamorphic oak Quercus 10
At the base we can see the fruiting body.
Confistulina hepatica Fistulina anamorphic oak Quercus 11
Oozing everywhere!
Confistulina hepatica Fistulina anamorphic oak Quercus 12
Looks like something out of Alien, quite honestly!
Confistulina hepatica Fistulina anamorphic oak Quercus 34
2016 checking in. What a load of rubbish!
Confistulina hepatica Fistulina anamorphic oak Quercus 35
Further round the tree (note that the 2015 location was to the right) sits an anamorphic fruiting body.
Confistulina hepatica Fistulina anamorphic oak Quercus 36
A close(ish) look.
Confistulina hepatica Fistulina anamorphic oak Quercus 37
Closer still.
Confistulina hepatica Fistulina anamorphic oak Quercus 38
And closer yet further.

From here, we go to another 2015 find. This time, the fruiting body was a little elevated on the oak and evidently emanating from an area of burring / accumulation of dormant buds beneath the bark surface. This one quickly became senescent after perhaps a week so whether it’s Confistulina or not is tough to say – I include photos of both times I visited it. It did not reappear in 2016.

Confistulina hepatica Fistulina anamorphic oak Quercus 13
The first visit to this fungus, which was very small – maybe 5cm across.
Confistulina hepatica Fistulina anamorphic oak Quercus 14
A closer look.
Confistulina hepatica Fistulina anamorphic oak Quercus 15
A week later it had senesced.

The remainder of the photos take us into 2016 and most (but not all!) are taken with a better camera, which is good! First, we venture down to the New Forest and look at a well-decayed oak log, upon which a cluster of fruiting bodies sit atop the log.

Confistulina hepatica Fistulina anamorphic oak Quercus 16
Yes, yes, this photo was taken with a potato.
Confistulina hepatica Fistulina anamorphic oak Quercus 17
A very odd form but once again we can see the tarry liquid.
Confistulina hepatica Fistulina anamorphic oak Quercus 18
A side profile. Looks like a toe!
Confistulina hepatica Fistulina anamorphic oak Quercus 19
Yep, definitely a toe – a wrangled one, at that.

The next series are taken a month apart (late August and late September). What’s curious with this one is that we can see two anamorphic fruiting bodies and, come September, Laetiporus sulphureus fruiting directly alongside. The host, as can be seen, is oak, which is in a hedgerow of oak and ash.

Confistulina hepatica Fistulina anamorphic oak Quercus 20
Fading light caused the blur!
Confistulina hepatica Fistulina anamorphic oak Quercus 21
At the base we can see a dueo of fruiting bodies.
Confistulina hepatica Fistulina anamorphic oak Quercus 22
The first…
Confistulina hepatica Fistulina anamorphic oak Quercus 23
…and the gruesome second.
Confistulina hepatica Fistulina anamorphic oak Quercus 25
A month later a wild chicken appeared!
Confistulina hepatica Fistulina anamorphic oak Quercus 26
Two, in fact. Here we see the beefsteak and chicken side-by-side.
Confistulina hepatica Fistulina anamorphic oak Quercus 27
And here it’s in the distant murk.

Now, we move to a curious case of two fruiting bodies next to one another, again on oak, where one became a teleomorph and the other an anamorph. Why? Who knows. Very interesting, however, as I am sure you can appreciate.

Confistulina hepatica Fistulina anamorphic oak Quercus 28
An oak pollard by a swing. Look at the old pollard head.
Confistulina hepatica Fistulina anamorphic oak Quercus 29
A duo forming.
Confistulina hepatica Fistulina anamorphic oak Quercus 30
Looking pretty similar. Now watch…
Confistulina hepatica Fistulina anamorphic oak Quercus 31
…they change! No longer are they twins.
Confistulina hepatica Fistulina anamorphic oak Quercus 32
Exactly why this happened is a mystery though I’d really like to know – anamorph left) and teleomorph (right).
Confistulina hepatica Fistulina anamorphic oak Quercus 33
A side profile for comparison with the earlier one taken from the same position.

In October of 2016, I came across this majestic oak in a field. On a buttress root was what appeared to be an anamorphic fruiting body of Fistulina hepatica, which we can observe below.

Confistulina hepatica Fistulina anamorphic oak Quercus 39
Yup – majestic.
Confistulina hepatica Fistulina anamorphic oak Quercus 40
Also majestic??? (not sure!!)
Confistulina hepatica Fistulina anamorphic oak Quercus 41
Eh, nope. A bit more ugly, to be fair. Has the outward character of an anamorph though please don’t assume it is (wasn’t confirmed via microscopy).

Lastly, here’s one I suspect on sweet chestnut. I didn’t return to check how it did, though this year I’ll certainly keep more of an eye out and be more thorough in my inspections of the samples! Please share any examples you might have found of this, too – it’s important we build up a knowledge base.

Confistulina hepatica Fistulina anamorphic sweet chestnut Castanea 1
A lovely old coppice stool.
Confistulina hepatica Fistulina anamorphic sweet chestnut Castanea 2
Here sits the sample.
Confistulina hepatica Fistulina anamorphic sweet chestnut Castanea 3
Whether this is or is not is tough to say, though it does resemble an anamorphic stage somewhat.
Fistulina hepatica’s anamorphic version: Confistulina

David Attenborough on Richmond Park, London

Nothing much need be added, in light of who is narrating. As a 20-minute long film, it’s something you can readily watch at any point where you have some time going spare. There’s a few good segments on trees, including on ancient trees, deer, deadwood and wood-decay fungi. Really a fascinating watch!

Support the Friends of Richmond Park here.

David Attenborough on Richmond Park, London

Book review: Manual of Tree Statics and Tree Inspection

First and foremost, for those interested in purchasing the English version of the book, you can do so via the publisher Patzer Verlag, Summerfield Books or the Arboricultural Association. It’s not a cheap book and thus, for many, demands strong consideration before purchase, which is one of the core tenets behind why I wanted to read and review this book promptly following on from its publication. Therefore, my intention with this review is to give more information about the book over and above simply the listing of the chapters and sub-chapters, which are provided by the book sellers. Hence, interspersed amongst my review are photographs of the book, which will hopefully help guide you in your decision-making process. In fact, here’s an image for you, off the bat!

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Quite a nicely presented hardback. The select illustrations you see on the front here occur throughout the book – hardly a page goes by where there isn’t at least one such image.

As regards the content, therefore, the book begins with a very succinct introduction followed by an extensive assessment of the countless aspects pertaining to tree biology. This biology section is adorned with illustrations that, as is the case across the entire book, help greatly with the simple conveyance of the core messages put forth by the authors – indeed, as is so prevalent and well-received across Mattheck’s works (in spite of the disagreements the autors have with the t/r ratio and h/d ratio, which they detail within). Somehow, I doubt this inclusion of illustrations is coincidental and instead a homage or emulation of what works well when describing detailed concepts in only a few words. Critically, with a book detailed as one that covers tree statics, the incorporation of tree biology into the statics model is included, which keeps the book on track from the beginnings and saves it from veering off course into just one that echoes prior understanding.

At this point, an interjection is necessary. Specifically, for the purpose of highlighting some of the very curious qualities of this chapter – in the good sense. Principally, an addition to the developing understanding of summer branch drop is provided, whereby the authors detail that, on top of the impact drought has on the failure of large branches, temperature plays a possibly significant role. Why, you ask? Because, as the authors detail, the pretensioning of a tree’s wood fibres (i.e. the manner in which it loads itself under its own weight and optimises itself for this) is lessened by heat, which relaxes the wood fibres – including atop branch junctions. When compiled with the fact that trees are much stronger under tension than compression, the developing compression zones underneath the branch junction (and just behind the branch collar) as the wood fibres relax atop build up and, alongside other factors (including drought and probably many other unknown variables), the branch can subsequently suddenly fail. The authors delve into this phenomenon more in the third chapter and beyond. Other intriguing and enlightening aspects of this second chapter include the remarks on how construction works impact upon tree stability, in addition to the efficacy of ivy to be both a bane and a blessing for the tree, as regards oscillation and damping during wind loads.

It is however the third chapter that arguably provides the most appreciable benefit to the reader, as it takes us into the realm of tree statics in the direct sense. The intricacies of the chapter will, of course, largely evade this review, as the intention of this post is not to ‘spoil’ the contents of the book to any marked degree and make its purchase redundant. Instead, what can be said is that it delves effectively into critical facets of statics and, in my personal opinion, the segment on wind loading and the impact of crown architecture and elevation on loading forces is most brilliant – even down to the illustrations and mathematical examples, which really do simplify an evidently complex engineering approach to tree risk assessment.

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A segment from this third chapter, demonstrating how the authors blend text with diagrammatic models and more general illustrations.

Moreover, the discussion on the importance of hollowness for trees and why it should not always be considered a concern to the tree inspector is welcomed (unless it’s an open cavity and then, please, do be more worried straight off of the bat). In fact, and I quote: “the dimensions of a cavity in a tree have absolutely no informative value, as long as the occurring loads are not known.” Therefore, the t/r ratio Mattheck provided, the authors allege, is meaningless and incorrect.

Amazingly (from a factoid perspective), the authors then detail that a tree with a dbh of 1m and a central cavity leaving only 10cm of sound radial wood around the circumference has the same load-bearing capacity as a tree that is completely sound and has a dbh of 84cm! Of course, from an angle of understanding where the maximum loads occur, the fact that wood fibres stretch and compress far more at the outer sections of the stem than they do internally (with the neutral axis generally being the centre) gives credence and context to this assertion. The understanding of hollowness on older (veteran) trees is also discussed in a very articulate manner and, as it so seems, the greater risk for such trees is not failure of the trunk or root plate but of large lateral limbs attached to a hollowing trunk that can no longer sufficiently support such a mechanical load.

On this note, the outlining of root plate architecture is also deserving of mention. In this third chapter, the authors do a superb job of explaining why and how root plates fail and why, for all intents and purposes, extensive buttressing and adventitious rooting is not necessarily to be looked upon as defective. Using the example of a mature beech (see a below photo that I took recently), they allude to the often very pronounced root plate acting as a counter-balance to the lever arm that is the trunk (think of a very wide-based wine glass and compare it to a narrow-based one – which tilts more readily?). Indeed, where fungal decay is evident, as in the below photo, the effectiveness of the wide root plate comes into question, however.

Fagus sylvatica mature buttressing Ganoderma Meripilus 8
The admirable root plate of a mature beech. In this case, Ganoderma australe is compromising the butt and principal rooting structure, though where decay is not evident or is limited then a wider root plate is very effective at supporting the tree during times of wind loading – certainly more so than where such a wide root plate is not evident, on mature beech.

At this point, the notion of slenderness also enters the equation and, very curiously, the book asserts that slender multi-stemmed trees are more likely to oscillate excessively in wind loading conditions and fail, when compared to single-stemmed trees of equal slenderness. However, more crucially, why slenderness equals higher oscillatory frequency and thus denotes a greater risk of failure is detailed, which drives home the importance of not thinning out groups of trees and expecting the remaining ones to be able to stand wind-firm (the so-called ‘domino effect’ is also defined, whereby trees at a woodland edge successively fail, as those around become exposed after an initial tree fails and then those around it also fail).

And my favourite quote(s) of the third chapter? In reference to reaction growth laid down by the tree due to decay or other structural matters: “the development of symptoms is an expression of the vitality of the tree, not of its weakness” and that “focussing on so called symptoms can be absolutely counterproductive” – assuming, of course, you don’t quantify the weakness by ascertaining its load-bearing capacity (which is where statics comes in). Assumptions, therefore, are not good (though we all do assume, every day, when we assess trees, when working with outward symptoms solely).

P1270710
A segment of the fourth chapter. This double page spread is certainly one of the rarer examples of where illustrations do not dress the paper in abundance.

Moving into the fourth chapter, we’re first greeted with a rather novel take on tree assessment: do not negate the emotional aspect of the act. To be precise, from this, I understand it as the authors inferring that the intuitive assessment of a tree, from afar, takes into account both our logical deduction of its form (based on the scientific understanding of what denotes good structural architecture in trees) and surrounds (targets, exposure, etc) and also its innate emotional ‘appeal’ (i.e. is the tree ‘harmonious’ and flowing well, or is it a rough and jagged structure that is abrasive to the eye and clearly there is something awry that demands more investigation). Here, the authors then throw in the concept of a female breast being harmonious (and not at all like a brick…!) to a child, who can appreciate the allure of that particular aspect of female anatomy for its biological purposes. I presume this wasn’t a translation error (of which there are a few, across the entire book, but it largely flows very well)! Thus, trees are like female breasts: harmonious (I could end the review here, quite frankly, for the comedic value).

Anyway, this fourth chapter then goes on to outline, to a very detailed degree, with the support of various diagrams in the sixth chapter (the ‘Annexes’), more about SIA (static integrated assessment). For something that I admittedly had considered quite complex, which it still certainly is, the authors do a stellar job in simplifying the concept and utilise diagrams and drawings to help ensure the reader can understand the message being conveyed. The explanation of the rationale behind why this methodology, provided in preceding chapters and also in this one, helps to contextualise the methodology and, quite truthfully, it’s a form of tree assessment that I am now keen to put into some form of practice. The statement the authors make about microdrills essentially being redundant now that sonic tomography has arisen from the mulch is also a curious one, which is deserving of some consideration, when appreciating that the former causes damage to trees and the latter, almost wholly, does not; in addition to the ability for a tomograph (i.e. PiCUS or ARBOTOM) to plot an entire cross-section and not just track the path of a single drill bitand provide information from that sole path.

A further useful segment within the fourth chapter is that of the pests and pathogens of the leaves and shoots of many common European tree species and genera. Indeed, the assertion that horse chestnut leaf miner is not solely an aesthetic issue is a welcome one, as for whatever concerning reason that understanding of it being only an aesthetic pest is still accepted by some in the industry. The section also has a really nice little bit of information on Massaria disease of plane, with a distinct Teutonic angle (as one would expect, from German authors).

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A double page spread of the section of pests and diseases of the shoots and leaves of trees common to Europe.

The (‘technically’) last chapter, the fifth, draws upon the information provided within all prior chapters and provides the reader with guidance on how to, following the identification of a need to manage the tree (be it a newly-planted tree or veteran in a park or construction site), effectively enact a management regime that will be of benefit to the longevity of the tree in the landscape (this is why we manage many trees in ways that doesn’t see them get felled). Indeed, this chapter presents a lovely succinct look at the need to strongly consider management options, as in deciding upon a route there is then, in theory, no going back upon that decision (once scheduled work has been completed).

The encouragement by the authors to refrain from using a rigid support system, be that system a stake for a young tree or steel braces for old trees with slender co-dominant limbs, and instead utilise a flexible and dynamic system, is therefore well-received, as they present their argument in a sound and logical manner. Importantly, for bracing, the authors even go so far as to detail what angle a brace should be applied at and the load that it should be able to bear relative to the size of the parts being connected, which elevates this book to a level beyond that of others that, from memory, do not provide as much detail. Their comments on propping with A-frames and not upside-down V-frames are also welcomed and articulated so well with so few words. Again, illsurations really help instruct the reader and break the text apart, thereby making the reading more ‘bite-sized’.

limb propping tree lateral load a-frame
This duo of props fails to suppprt the limb against lateral forces, given their design. In lacking an A-framed design, these props are thus not optimally positioned to keep the limb of this sycamore from failing under a torsional load.

Finally, the appendices presented in chapter 6, which support many of the assertions made in the earlier chapters, arrive. There exist some fabulous tables showcasing the wood properties of different tree genera (cellular make up, strength, etc), the speed at which tree genera move water up the trunk in metres per hour, the compartmentalisation ability of different species and genera, and a comparison of various forms of tree assessment and their strengths / weaknesses. Also within these annexes is information on how hollow trees fail and a description of principal wood-decay fungi and their significance. The fungal section is limited in detail and species diversity (because it’s only an annex and thus cannot possibly be as detailed as a dedicated book on fungi) though, concerningly, the brittle cinder (Kretzschmaria deusta) is described as a white rot in a comparitive table (whilst being correctly marked as a soft rot in its descriptive text). Proofing of the text should have picked this up, as it is perhaps the most significant mistake in the book (all other issues identified are largely translation errors or typos, from what I could spot). The comments on Perenniporia fraxinea preferring robinia (Robinia pseudoacacia) over any other host tree in urban areas where soil is compacted are, nonetheless, very interesting. Anecdotally, I can understand and agree with this assertion.

So, my thoughts to summarise? This is a very useful book that serves not only as a primer for the statics integrated assessment model but also for tree visual assessments on the whole. The eagerness of the authors to promote analytical thinking of the reader was pervasive throughout and, in some respects, this book could essentially serve as a 101 for tree inspections and management to any tree inspector. Of course, the title alludes to this by referring to tree inspection, though I admit I was taken aback (in a positive sense) on how much breadth this book covered in so few words and so many images. For me, the mix works well and therefore the looming threat of a wall-of-text was evaded. Perhaps it is just me, though I can pick up influences from Shigo and Mattheck, in the use of few choice words to describe complex matters and to support such words with harmonious (see what I did there?) images.

If you have around £115 to spend and want a book that you can refer to routinely, this will be worth purchasing. Don’t think you’ll be getting an impossibly wordy book that delves into tree statics down to the minute level, however. That is reserved for other literature and, in my perspective, rightly so.

Book review: Manual of Tree Statics and Tree Inspection

Book scores; including on tree statics (!)

The library amasses further numbers with the below six books, which arrived during this month. All, quite obviously, pertain to trees and the landscape, and of notable interest will be the new tree statics book that was recently translated into English from German and published. Expect a detailed review of this book in the coming few days (currently around half way through reading it).

As always, links to where you can buy the books are given at the end of this post. Note that those ordered from Oxbow were acquired for a good third of their suggested retail value, as they were doing a clearance sale. Quite honestly, for anyone who likes anything to do with landscape history and ecology, bookmarking this particular publisher and distributor will yield some awesome results. For tree lovers, the imprint Windgather Press is probably one to keep a tabs on, as many of the books published involve trees.

new book purchases tree statics

To the left, we have a very interesting book on the mapping of Norfolk by William Faden and how the landscape has changed from then through to now. Tom Williamson, one of the authors, is a prominent authority on landscape history and thus the book does delve into the rural landscape of Norfolk and, to a degree, arboreal heritage. I picked it up for £10 (down from £30), and as of the time of this blog post it is still on sale and can be purchased here.

Along the top row working from the left, we first have the new book on tree statics and visual assessment, which, as I mentioned, will feature as a detailed review in a coming blog post. It’s certainly an expensive book so it is one to research before purchasing. By all means, await my review before deciding. This book I acquired for £115 from Summerfield Books at this link.

Adjacent is what looks to be a truly captivating book on the Cedar of Lebanon and its prominence in human history. From my readings on this tree in the culture and religion of many historic peoples, this will be next on my list of reading material and will undoubtedly be rich in information that helps build my view of the tree further. As a very recently publication, it can be purchased via Archaeopress for £36 here. Please, consider trawling their book store as there are some other very great books they sell that involve trees and the natural landscape.

The lower duo are books on the historic gardens of Derbysire (left) and hedgerows across Britain (right). Following on from the information provided in Mark Johnston’s Trees in Towns and Cities: A History of British Urban Arboriculture, I have been keen to learn more about pleasure gardens and earlier arboretums / plant collections, so this book specific to Derbyshire will hopefully supplement my learning on this front and can be bought here from Oxbow Books. As for the latter, the detailed exploration of hedgerow characteristics and distribution throughout Britain is somthing that, would you have guessed, I also find intriguing. Indeed, hedgerows have historically – and still are – being gutted, for a variety of reasons, which means understanding what makes them unique (even down to a specific region) and crucial ecological and cultural features very necessary. This book is currently reduced from £25 to £10 on Oxbow Books and can be purchased here. The book is clad with images and can easily be read entirely in a day.

The last book, which is all the way to the right, further expands upon my desire to learn more about botanic gardens. Instead of Derbyshire however, this book takes the reader to Manchester – specifically, the Manchester Botanic Garden. At £5, though reduced from £25, its acquisition was a no-brainer and, from scanning the book, it appears an utter steal. Again, this was purchased via Oxbow Books via this link.

Keep an eye out for my review of the tree statics book. Hopefully, if all goes to plan, it’ll be online before the close of the bank holiday.

Book scores; including on tree statics (!)

Interesting cases of wood-decay fungi

I have been absurdly busy so haven’t been blessed with the time to get some blogging in, though I have been graced with thirty minutes of time this evening so without any further utterings we’ll delve right into the good stuff – trees and fungi (in my usual frenetic and incoherent manner). Plus, listening to some early Hawkwind has really got me in the mood to do something useful!

The cases are all from an absolutely splendid park down in Maidstone – Mote Park. Honestly, if you live anywhere near there, do pay it a visit and explore as much as you can (it’s massive!). The sheer abundance of mature and veteran trees provides for a magnificent display of fungi and, so I am told, there is a need to record the saproxylic insects on site on the many monoliths and moribund trees.

To kick this post off, I take you to a very interesting case of Pseudoinonotus dryadeus on oak – three of them, all of which are within 8-10m of one another and share a crown. All fruitings of the fungus are historic though its presence on all three trees makes for some tempting considerations – namely, the synchronicity of fruiting (are they similar genotypes?) and the means of colonisation (spore or something else?). Indeed, I can only infer some sort of fungal mysticism or sorcery in positing both aspects for consideration (there is no proof of either, per se), though it did make me think. Perhaps it will make you readers think as well! (!?)

Pseudoinonotus dryadeus colonisation senescent old 1
The recipients of the Manchurian Candidate!
Pseudoinonotus dryadeus colonisation senescent old 2
Exhibit one!
Pseudoinonotus dryadeus colonisation senescent old 3
At the base (to the left).
Pseudoinonotus dryadeus colonisation senescent old 4
Quite an old bracket but a bracket nonetheless. Lovely buttressing, too.
Pseudoinonotus dryadeus colonisation senescent old 5
Exhibit two. More brackets and more buttressing.
Pseudoinonotus dryadeus colonisation senescent old 6
Shame these got yanked off, too.
Pseudoinonotus dryadeus colonisation senescent old 7
Exhibit three! SOme glorious buttressing here, yet again. Thus the fungus gets its common name: the Eiffel Tower fungus.
Pseudoinonotus dryadeus colonisation senescent old 8
Old, dead (not really but who cares for semantecs?) but not forgotten.

And then…and then…more Pseudoinonotus dryadeus – literally 100 yards down the same path. Oh how Mote Park delivers! This example also really does demonstrate the magnificent buttressing induced by its decay on oak, as you’ll see.

Pseudoinonotus dryadeus mature oak butt decay 1Pseudoinonotus dryadeus mature oak butt decay 2Pseudoinonotus dryadeus mature oak butt decay 3Pseudoinonotus dryadeus mature oak butt decay 4Pseudoinonotus dryadeus mature oak butt decay 5

Would you then believe it? Essentially opposite (no joke) were two colossal beech trees fenced-off (as if that ever stopped me??!) that, as anyone who has seen mature or veteran beech buttressing all over the place like egg whites pour out of a broken egg when broken too aggressively (nice analogy? – likely not), drew me in. Was I disappointed? Not at all! Ganoderma australe and Meripilus giganteus all over the option.

Fagus sylvatica mature buttressing Ganoderma Meripilus 1
Good cop (right) bad cop (left) – something something pun something something copper beech and tell better jokes
Fagus sylvatica mature buttressing Ganoderma Meripilus 2
The copper beech to the right with roots all over the option.
Fagus sylvatica mature buttressing Ganoderma Meripilus 3
Ganoderma australe and Meripilus giganteus – dual decay. Decay squared? That raises a good thought – is decay by more than one fungus simply a cumulative issue or instead a geometric or even negatory issue (i.e. is decay of two types ‘less serious’ than from one only)? Question galore and no answer. Someone ask an expert!
Fagus sylvatica mature buttressing Ganoderma Meripilus 4
Merip (foreground) and Gano (background). Also plenty of blades of grass for the monocot enthusiasts who stumbled across this blog because I wrote the word monocot.
Fagus sylvatica mature buttressing Ganoderma Meripilus 5
Ganodeerma australe being illuminated by a sunburst.
Fagus sylvatica mature buttressing Ganoderma Meripilus 6
The diddy little brackets further up the stem weren’t blessed with sun.
Fagus sylvatica mature buttressing Ganoderma Meripilus 7
And between some more buttresses there were some more Ganodermas.
Fagus sylvatica mature buttressing Ganoderma Meripilus 8
Onto the plain old beech now. Exquisite buttressing here!
Fagus sylvatica mature buttressing Ganoderma Meripilus 9
Did someone say fungi?
Fagus sylvatica mature buttressing Ganoderma Meripilus 10
Nope – nothing to see here.
Fagus sylvatica mature buttressing Ganoderma Meripilus 11
Nor is there anything to see here. I’m just tired of writing captions!
Fagus sylvatica mature buttressing Ganoderma Meripilus 12
Oh look, finally. Something. Some nice husks. Probably some Ascomycetes on them (Xylaria carpophila).

To finish up, because I’m getting tired and I am up early tomorrow, here’s something to sit on whilst you ponder the plethora of ultimate questions spewed forth from my mind with little restraint – a dryad saddle. The host? Not sure – lots of ash about though one can never rule out sycamore (unless you’re in the middle of a Douglas fir plantation?). These had actually already over-matured, which means you can see dryad saddle (i.e Cerioporus squamosus – named, prior to that, Polyporus squamosus) out there if you look!

Dryad saddle Polyporus Cerioporus squamosus 1Dryad saddle Polyporus Cerioporus squamosus 2Dryad saddle Polyporus Cerioporus squamosus 3Dryad saddle Polyporus Cerioporus squamosus 4

Interesting cases of wood-decay fungi