UNIVERSITY OF BASEL
No year since weather records began was as hot and dry as 2018. A first comprehensive analysis of the consequences of this drought and heat event shows that central European forests sustained long-term damage. Even tree species considered drought-resistant, such as beech, pine and silver fir, suffered. The international study was directed by the University of Basel, which is conducting a forest experiment unique in Europe.
Until now, 2003 has been the driest and hottest year since regular weather records began. That record has now been broken. A comparison of climate data from Germany, Austria and Switzerland shows that 2018 was significantly warmer. The average temperature during the vegetation period was 1.2°C above the 2003 value and as high as 3.3°C above the average of the years from 1961 to 1990.
Part of the analysis, which has now been published, includes measurements taken at the Swiss Canopy Crane II research site in Basel, where extensive physiological investigations were carried out in tree canopies. The goal of these investigations is to better understand how and when trees are affected by a lack of water in order to counter the consequences of climate change through targeted management measures.When trees die of thirst
Trees lose a lot of water through their surfaces. If the soil also dries out, the tree cannot replace this water, which is shown by the negative suction tension in the wood’s vascular tissue. It’s true that trees can reduce their water consumption, but if the soil water reservoir is used up, it’s ultimately only a matter of time until cell dehydration causes the death of a tree.
Physiological measurements at the Basel research site have shown the researchers that the negative suction tension and water shortage in trees occurred earlier than usual. In particular, this shortage was more severe throughout all of Germany, Austria and Switzerland than ever measured before. Over the course of the summer, severe drought-related stress symptoms therefore appeared in many tree species important to forestry. Leaves wilted, aged and were shed prematurely.Spruce, pine and beech most heavily affected
The true extent of the summer heatwave became evident in 2019: many trees no longer formed new shoots – they were partially or wholly dead. Others had survived the stress of the drought and heat of the previous year, but were increasingly vulnerable to bark beetle infestation or fungus. Trees with partially dead canopies, which reduced the ability to recover from the damage, were particularly affected.
“Spruce was most heavily affected. But it was a surprise for us that beech, silver fir and pine were also damaged to this extent,” says lead researcher Professor Ansgar Kahmen. Beech in particular had until then been classified as the “tree of the future”, although its supposed drought resistance has been subject to contentious discussion since the 2003 heatwave.Future scenarios to combat heat and drought
According to the latest projections, precipitation in Europe will decline by up to a fifth by 2085, and drought and heat events will become more frequent. Redesigning forests is therefore essential. “Mixed woodland is often propagated,” explains plant ecologist Kahmen, “and it certainly has many ecological and economic advantages. But whether mixed woodland is also more drought-resistant has not yet been clearly proven. We still need to study which tree species are good in which combinations, including from a forestry perspective. That will take a long time.”
Another finding of the study is that it is only possible to record the impacts of extreme climate events on European forests to a limited extent using conventional methods, and thus new analytical approaches are needed. “The damage is obvious. More difficult is precisely quantifying it and drawing the right conclusions for the future,” says Kahmen. Earth observation data from satellites could help track tree mortality on a smaller scale. Spatial patterns that contain important ecological and forestry-related information can be derived from such data: which tree species were heavily impacted, when and at which locations, and which survived without damage? “A system like this already exists in some regions in the US, but central Europe still lacks one.”
###
At this time of year the loony stories are pushed into the public domain.
I don’t think anyone really buys it any more…but they keep trying.
This is not a “loony story”.
I live in Germany. We go hiking to the Eifel nearly every weekend.
It is a real disaster.
Huge parts of the forest are dead.
Mainly spruces are affected.
In some areas all of them are now dry, grey and dead.
I never have seen anything like that.
It is devastating!
Not even during the Acid Rain scare?
Is that Spruce a native species or is that introduced farmed wood stock ? I thought Spruce was a northern species, from Scandinavia and Scotland. Most genus Picea grow in the very north of USA or mainly in Canada.
Best chop them down and burn them a “bio mass” then. That’s what ecologists like doing to “save the planet”.
Of it’s pieces abused then it should be good for making violins, cellos etc. Shame to burn it.
Bloody predictive text.
If it’s picea abies etc.
In the north, you have JUST Spruces.
Here, we were used to mixed forests, where birches, beeches, oaks and other deciduous trees were mixed with spruces.
Apparently, the climate change passed a tipping point.
Spruces do not survive here anymore.
The change is very vivid.
/
something other than you climate has changed
Greg,
Point of interest.
There are no native spruce in Scotland, only Scots Pine (aka Scots Fir), Juniper and Yew.
This species impoverishment is a consequence of island isolation and glacial wipe-out.
There were spruce growing in the east of England during prior interglacials (Cromerian and Hoxnian).
Agreed, in Wales apart from plantations ,there are numerous small pockets of Scots pine 2-10 trees, I have a forest which had a natural copse of around 6 Scots pine they were big and all died I’m assuming they died of old age? At the same time. The rest of the forest is sitka spruce as you know a native originally of north east coast USA and a few other areas, 70% of UK commercial forests are sitka spruce , Norway pine in the UK is grown as Christmas tree stock, there maybe commercial plantations but the tree is a slow grower, along with Scots pine both species are good joinery grade pine as opposed to sitka spruce which is building grade at best.
As far as I know the Eifel was “spruce-free” since the last ice age ended… until people brought them in for commercial reasons. Now that it’s a national park and sick trees are not removed and the bark Beatle has been given free rein.
This is really not all that bad, since the space left by the spruces will be taken up by a more diverse leaf forest that is more suited to that climate.
But…has it happened before? When? All this is a bit odd, since in France summer temperatures are around 1.05 degree hotter than, say 1940. Warmer OK, but not critically I believe. As I well remember, 2004 was scorching, before a cool period and I heard nothing about ‘forest stress’ then.
http://www.meteofrance.fr/climat-passe-et-futur/climathd
Obviously, your lifetime is no guide to historic world temperature, which today is colder than almost any other period in the last 100 million years. The natural state of the earth is ice free according to the geological record, and Antartica’s survival is unusual.
(Gribben, J, ‘Science a History’, pp480 – 482)
Anything can happen of course; the future may well be hot. However, the earth is fruitful when it is warm, as the NASA study showing the greening of an area worldwide twice the size of the continental US since 1980 shows clearly.
Spruces were killed by insect(bark beetle) last year – same in Czech republic.
Mods,
Please rescue my reply to Alex.
Thanks
This one please
https://wattsupwiththat.com/2020/07/16/heat-stress-the-climate-is-putting-european-forests-under-sustained-pressure/#comment-3036546
“It is devastating!”
You are expressing a deep and genuine emotional response to what you are observing. Let me try and give you an ecological perspective on the changes you are seeing in your beloved forest.
In what follows I am going to have to make a large number of assumptions, some of which will inevitably be wrong and will attract criticism of the “oh but” variety, but while fools like me rush in at least they make an attempt to do something.
The first and most obvious comment is that all trees die, it is part of the natural cycle. If you have an even-aged population in your forest then inevitably the cohort will tend to die en-masse, particularly when exposed to a pervasive environmental stress.
The second comment, and this too is very important, is this. How, when and where did these trees germinate? At first sight it seems odd to ask where did they germinate, because trees naturally grow where the seed first sprouts, don’t they? Well not if these trees are plantation stands and the seedlings were first grown in a nursery and then moved out into the forest.
When young I spent a lot of time growing seedling trees of various species, and then planting them out on a nature reserve in the Lake District. I soon learnt from my many failures how difficult this process actually is. Leaving aside the issue of grazing damage, the biggest factor in my failure was the bracken that each summer overtopped my saplings and killed them by competition stress. E.g. Stress by water and light, suppression (physical collapse of the bracken in the autumn, followed by snowfall loading of the fallen fronds), root competition etc.
I therefore became very interested in the processes that allowed for natural regeneration to occur, for example what local site factors were important, and how these factors were species specific. In the case of the bracken I noticed the role of the bramble (blackberry) in providing a framework to stop bracken collapse. I also observed that the bramble thorns were an excellent defence against grazing pressure.
With my interest activated I undertook an ecological study of the role of natural regeneration in the species composition changes in native woodlands. At that time in 1979, following the drought summer of 1976, it was obvious that many environmental stress factors were causing species changes in the composition of our native British woodlands. In my study of the beech dominated woodlands of Epping Forest I identified the following factors: –
1. Mature high canopy beech stands have little or no herbaceous plants growing beneath them. The shade these beech trees generate is too deep and the surface root competition is too intense for anything other than moss to grow beneath them. In the absence of soil disturbance from foraging hogs (wild or farmed) there was no beech seedling regeneration beneath them. What there was however was dense local patches of birch.
2. Birch species are pioneers, they have a very light wind disbursed seed and the damp moss covering of the ground beneath the beech makes an ideal seedbed where light levels are sufficiently good.
3. Trees optimally form hexagonal close packed arrays; this is the maximum possible surface areal density of a set of even sized discs set out on a planar surface; (seen from above trees appear as green circles as the little girl who lived in a high rise flat once drew when asked by her teacher to draw a tree).
4. So, even with a closed high canopy, there will always be edge gaps somewhere were shafts of light can reach the ground, ideal for birch seed germination.
I now applied my experience of planting saplings in the bracken dominated hillside of the Lake District to the next stage of the process of woodland regeneration in Epping Forest. If birch naturally replace beech what happens next when the beech trees are dead and fallen and the birch canopy is established?
Within Epping Forest there are many areas dominated by mature birch and the decaying wrecks of long dead beech. Birch are a physically small species with a low-density leaf canopy, consequently in these areas the herbaceous ground flora (including bracken and bramble) is very dense. It is here, with the thick litter layer that the small seeded birch with their low energy seed package cannot germinate. Instead a species with a large seed capable of growing a vigorous ground penetrating tap root takes over in the species succession. Oak and Sweet Chestnut therefore replace the birch. The beech can come in here too but there is a twist to this tale.2
I wonder if I can continue to post here now?
Alex, don;t worry too much–I drive from the lower 48 to Alaska every year and a few years back there were large swatches of forests just brown and dying. It was truly frighting in some spots with acres and acres brown and dead. We were told it was climate change at that time too. It was the bark beetle which gained a foothold with drought stressed pines. I was horrified as I could see the changes over several years and could not image what we would do without our northern forests–but the brown slowly and surely gave way back to green again–I don’t know if it was a new species or what. Now I drive up and those acres and acres of brown no longer exist–mother nature did her thing and my spirit is at peace. These are regular cycles and we need to respect and trust the natural variations. AND you don’t hear about it anymore because its fine–but you’ll not hear from MSM that it is now OK…
Thanks Shelly,
I have been trying to give Alex a similar message but the current WUWT difficulties are making this task impossible to complete at present.
I can see the same thing in Sweden.
But it has little or nothing to do with climate. The reason is called Ips typographus the European Spruce Bark Beetle.
Best cut the infected trees down fast before it spreads. And stop planting single-species spruce stands in areas where they don’t grow naturally.
Here in Sweden we have a particular problem. Since the authorities refuse to cut down infected trees in protected areas, private forest owners often don’t bother any longer, since it won’t do any good if not everybody does it.
Is this the new site hosting url? Just checking. Didn’t need to clear cache or anything.
All droughts are someday followed by lots of rain. Hopefully won’t take 7 years:
https://www.nbcnews.com/storyline/california-drought/california-drought-officially-over-after-more-seven-years-n983461
Anything coming from German-speaking countries should be taken suspiciously.
Anything coming from the rest of Europe should be just laughed at.
Northern Europe is getting warmer and Europeans are afraid of that…
Do Europeans even know that the British Isles, Scandinavia and the coastal areas of the North and the Baltic Seas should have been a lot colder, if not for very specific changes that occured a few thousands years ago?
Germans just want Europe to buy their wind turbine technology and buy Russian, Azerbaijani and Eastern Mediterranean natural gas.
They have also partnered with the Chinese so that wind and solar energy are promoted all around the West.
That would be fine, if other sources of energy were roughly equally efficient as solar and wind energy.
The problem is that solar and wind energy are NOT equally efficient. They are subpar.
Germans just take advantage of naive liberal Americans’ care for the environment.
But I love what you, Americans, did to Germans with Round-Up.
You heck’d them up big time.
Bravo!
That forest photo tells it all – total devastation, not a living tree in sight.
“According to the latest projections, precipitation in Europe will decline by up to a fifth by 2085, and drought and heat events will become more frequent. Redesigning forests is therefore essential.” Er, what planet are they studying? Where in Europe has there been a declining rainfall trend over the last, say, 100 years? Since the issues with acid rain decades ago, where have forests been suffering in Europe (aside from being chopped down)?
What drivel.
If future global warming is projected to cause more droughts, why do climate models use a positive feedback assumption that global warming will cause more water vapour in the atmosphere, hence more greenhouse effect and hence more rain and hence less droughts. Seems that you can’t have it both ways.
Palaver,
And don’t forget that more moisture in the atmosphere means more snow in winter which means more surface reflection of sunlight as the albedo increases, This then leads to less absorbed sunlight in summer to warm the Earth which leads to more cooling, and also more snow falling onto the land means a build up of ice which leads to a lowering of sea levels…
That cannot be right, I just made logical mistake somewhere /sarc
In my experience pines don’t have a healthy crop of cones when under stress. Those trees are loaded.
No, they tend to produce a lot of seed when stressed
Survival mechanism
I am now suffering from Negative Suction Tension. What do I do about it?
Suck it up !
LOL, the two previous comments gave me the laugh I needed today. I now can go forth.
The spruce trees in shot are full of seeds,pine cones, when spruce is stressed it drops its cones ,clearly not the case in the shot, the next stress test is dead needles which we cant see, the first stress test is a weeping lead runner which again according to the shot is not the case. The spruce trees in shot are not stressed in any shape or form.
Predictions, sorry projections, are now targetted at 2085. Modellers are obviously learning to only project on a timescale long enough to ensure that none of us present deniers will likely be around to say “told you!”
“The damage is obvious. More difficult is precisely quantifying it and drawing the right conclusions for the future.”
Hint: more money needed to draw “the right conclusions.”
The only place in Switzerland where forests are suffering, is where the authorities chop them down in order to introduce so-called new trees which are better adapted to warmer climates. For this, they get CO2 certificates. What about the planted trees? They don’t look after them and they practically all die out due to lack of water and shade. The next year they replant the same trees and get the CO2 certificates again. Advantage: this time they don’t have to clear the land… the following year… Perpetuum mobile = Green Blob economy…
it’s called renewable funding
Sustainable solutions for a sustainable revenue source.
So what is the track record of these “projections” of precipitation?
I’m only interested in hearing “projections” from people with a proven track record in successful, accurate projection.
German source
The spruces origins are mountain forrests, but during the reforestations mentioned above, they were planted everywhere and have now problems wizh weather conditions they are nor adapted to.
Thanks, as I pointed out above Spruce is a northern genus. I was not aware this went back as far a Prussian empire.
So the presence of these Spruce is human interference and nature is trying to correct the imbalance. This is being spun as human induced climate change.
It would have been the best choice for a Europe still in the cold Little Ice Age fase. The spruces must have come down the mountain in a natural way when conditions were in its favour. Of course higher up the mountain it disappeared.
That is what i am witnessing here in Germany. We have many spruces in our forests and they are mostly imported. There are some “wild” spruces in the Harz mountains maybe 800 meters MSL, but most original german forests consist of beeches and they are doing fine.
“…..the average temperature during the vegetation period was 1.2C above the 2003 value…..” What is a vegetation period. Normally trees do not die from unusual ambient temperatures except in Aussie bush fires or extreme prolonged cold causing freezing. What will kill trees is extreme and prolonged drought. Some species are more susceptible than others. Drought is usually accompanied by warmer than usual temperatures which exacerbates the situation because the vegetation requires more ground water for transpiration to keep cool.
“…..the average temperature during the vegetation period was 1.2C above the 2003 value…..”and…. “ as high as 3.3°C above the average of the years from 1961 to 1990.”
Must be a very special forested place since Northern Hemisphere average is only up 0.6 degrees C since 1970. The trees look healthy, maybe scientifically determine that they are good tree-mometers, start by assuming fixed climate average and test the hypothesis that the Urban Heat Island Effect on weather station recordings has been 1.2 C since 2003. Seems like a more realistic endeavour.
From Wikipedia:
It’s when some scientists take time off, stop thinking and publish climate drivel. For some scientists, this “vegetation period” extends for many months, often years.
See also, “vegetation period: journalists”, “vegetation period: politicians”, “vegetation period: sheeple”
(ok, probably not from Wiki)
Love it. You cracked me Redge.
Vegetation period is used when being unable to sound technical because of the flimsy knowledge of your subject material. Everybody understands growing season, to use another term is to hope that the listener perceives you as having superior knowledge. The paucity of knowledge in the rest of the dialogue perhaps indicates the opposite
Seriously, hotter and dryer than the 30s?
I know it is only weather, but it was cool and wet here in the northeast US last year. My trees, grass, and garden plants are going crazy. The only one feeling any stress is me, trying to keep up With the lawn mowing.
The talk about Europe, Gemany, Switzerland and Austria. Your weather in NE USA doesn’t care.
Black Forrest (Schwarzwald) Matters
I didn’t.question it, as it isn’t in NE USA. or am I talking Chinese ??
Photo caption:
IMAGE: IN A FOREST NEAR BASEL RESEARCHERS STUDY THE EFFECTS OF CLIMATE CHANGE ON THE MOST IMPORTANT AND SENSITIVE PART OF THE TREES – THE CANOPY. A TOTAL OF 450 TREES…
The rest of the caption:
…between 50 and 120 years old grow on the 1.6 hectare research area.
Small area, cleared area in the background. What else surrounds the research area?
Full article at the University of Basel:
https://www.unibas.ch/en/News-Events/News/Uni-Research/Heat-stress–the-climate-is-putting-European-forests-under-sustained-pressure-.html
From the article:
Original Source: https://www.sciencedirect.com/science/article/pii/S1439179120300414?via%3Dihub
The trees may die, but not the frrest.
The dead trees are food for new trees, as they realised in some national parks in Germany, where they do nothing more than to protect the streets.
German source
“Even tree species considered drought-resistant, such as beech,”
Say what? For anyone old enough to remember, the drought summer of 1976 in the south of England was so severe that the shallow rooted beech trees of Epping Forest suffered catastrophically. Only the deep-rooted species, such as English Oak and Sweet Chestnut were able to maintain contact with the water table in the forest and so were able to survive the drought relatively unscathed. So I find the idea that beech are a “drought resistant species” to be a complete ecological nonsense.
Beech is a late succession, shallow rooted, highly shade tolerant species that specialises in “mining’ the mull soils created by the leaf fall of the prior oak canopy woodland. The species successional cycle of 1. Pioneer Birch to 2. Deep rooted soil improver Oak to 3. Shallow rooted soil exploiter Beech and then, following successional collapse, back to Birch is one I studied for my Conservation degree.
Mulholland, P. 1980. A study of the cycle of regeneration in the beech dominated woodlands of Epping Forest, Essex using a Markovian matrix analysis. Thesis (M.Sc.)–University of London,
Interesting! Thanks, Philip!
Thanks JMac
I would like to continue to contribute to this thread, but it appears that I will have to wait.
Hopefully this discussion will be allowed to continue after the transition back to WordPress
Maybe we will get the editing function back.
It is sad how the Alarmists push these lies on unknowing people. That is why I never assume anything they say is true.
Amazing that they can perform such an analysis.
Michael Mann once claimed, “While paleoclimatologists are attempting to update many important proxy records to the present, this is a costly, and labor-intensive activity, often requiring expensive field campaigns that involve traveling with heavy equipment to difficult-to-reach locations (such as high-elevation or remote polar sites). For historical reasons, many of the important records were obtained in the 1970s and 1980s and have yet to be updated.”
Don’t trees stretch their roots deeper during droughts? Oh, nevermind– shame on me for thinking such things. I’ll be off now.
Are the tests carried out at the same time of each year or are they going out of their way to find an anomaly.
I believe the above story is phony.
What about the forest that was ripped out for wind turbines. Speaking of which.
Wind turbines do not produce the legally required 50/60Hz energy essential to our homes and industry.
They do produce useless harmonics which through smart meters are fraudulently added to consumers power bills.
A wind turbine cannot boil a jug.
If we really cared about the forest we would leave it alone.
The German forest is dying in the newspapers at least since the 80s. Funny as the forested area is steadily increasing since decades (if not cut down for wind power…).
The underlying problem is mismanagement of excess tree plantation of fast growing but not soil fitting trees and too much tree chopping in former intact forests. The mild winter and the droughts of 2018/19 are only bringing these problems to the surface they are not causing them.
Btw, Sweden and Norway are now loosing net forested area for the first time since centuries – all in the name of green power. Well done!
“No year since weather records began was as hot and dry as 2018.”
In Basel. They just forgot the qualifier.
Did a dry year stress trees? What an important scientific discovery.
“No year since weather records began was as hot and dry as 2018. A first comprehensive analysis of the consequences of this drought and heat event shows that central European forests sustained long-term damage”
“2018” is time constrained to a period less than 60 years of climate data and “central european forests” is geographically constrained to a small section of the globe selected post hoc and subject to confirmation bias. The internal variability of the climate is such that no impact of fossil fuel emissions or of agw can be inferred under these circumstances. Pls see
https://tambonthongchai.com/2020/07/16/the-internal-variability-issue/
I wonder how all the trees managed to survive the warm period around the year 1,000, when the Norse living in Greenland were raising oats, barley and rye on over 200 farms. (Reference: Time-Life series Planet Earth, book Atmosphere, published 1983, revised 1987, pages 156-157.)
Sounds like the problem is lack of rain, the trees are older, and continued nutrient drain of the soils.
Ozoneburst.
“and continued nutrient drain of the soils.”
Spot on correct.
I highly doubt that tower crane is solar powered or some other form of alternative energy. More info about species and other can be found at:
https://deims.org/5a57bb0e-69b0-42d0-8776-8d49e9d134ca
How fortunate that higher CO2 (which is causing the hotter, drier climate, of course) also allows plants to get by on less water. Or something like that. Please send money.
Meh, they’re going to have to cut them down for wind and solar farms anyway. Think of it as saving on petroleum-fueled forestry equipment.
I suggest that they import some Bluegum seedlings and put them in.
I have seen them grow in the highest towns in the World such as Pune in Peru at lake Titicaca and in Sri Lanka, Saudi Arabia, Brazil and anywhere else you care to name.
And they love the heat also.
Philip
“import some Bluegum seedlings”
Please say you’re joking. Eucalyptus are a fire climax species.
You want more forest fires? Plant Bluegum.
Trees under stress, let’s convert from the only known economic system that works to one that has killed 100,000,000 people in the name of the various leaders greed. Yes makes sense (sarc)
And yet there’s a place in Spain called La Pineda.
Guess what types of trees thrive in La Pineda?
Especially in Germany this summer is cold and rainy. I don’t know where people got this data from.
Heat stress. According to BBC news yesterday it’s affecting humans too. They interviewed nurses who have discovered that working in hospitals without AC, dressed head to toe in plastic PPE makes them sweat. And of course, it’s only going to get worse.
https://www.bbc.co.uk/news/science-environment-53415298
No year since weather records began was as hot and dry as 2018. A first comprehensive analysis of the consequences of this drought and heat event shows that central European forests sustained long-term damage
Utter nonsense. I live there. Yes, we have had several months without rain, usually July, August and september, but that’s just about normal. Recent summers, such as the current, have been significantly cooler than almost every summer upto about 2012 and especially 2003. We have also had flooding rains every spring for the past 7 years. This year my mobile reversible heat pump has remained in the cupboard, so far.
HOWEVER, some trees show signs of suffering although fruit trees have been stunning for years. It may just be that if you look hard enough for what you want to find you will find it.
“Even tree species considered drought-resistant, such as beech”
These are the same beech tree’s I suppose that have been expanding across Europe since the end of the last ice age.
From UNESCO, Ancient and Primeval Beech Forests of the Carpathians and Other Regions of Europe.
Quote:
“Since the end of the last Ice Age, European Beech spread from a few isolated refuge areas in the Alps, Carpathians, Dinarides, Mediterranean and Pyrenees over a short period of a few thousand years in a process that is still ongoing. The successful expansion across a whole continent is related to the tree’s adaptability and tolerance of different climatic, geographical and physical conditions.”
Except of course a couple of years where it got a bit hot in 2018/2019 that stopped them in their tracks, oh please, and the massive heatwaves of the early 1300’s, or the year 1540 when you could cross the Rhine on foot, or the 70 day heatwave of 1911, what happened then?
The world didn’t start when your weather records began, what the hell is happening to history?
Darwin noted this type of struggle in his great tome ‘Origin Of Species’ Chapter 3, ‘The Struggle For Existence’.
Here Darwin details instances where the competition for food or predators will tend to keep populations in check, but more powerful factors can be diseases, or changes in climate with extended times of cold or drought.
Even when the climate varies in such ways which might seem more favorable for survival of a particular species, one individual may have a variation which helps them prosper over the others and in turn crowd out the original for precious resources. And in a contrary way, climatic conditions that should tend to go against a particular variety or species may give rise to a particular (rogue?) variation(s) that survives much better, or even thrives. Such is the complex nature of survival.
Overall Darwin noted when climates are extreme species tend to struggle against the environment, when more hospitable the struggle is between species and their varieties.
A day late and a dollar short, but I was speaking with an old friend, talking about the weather and the start of our summer monsoon here in the Southwest. He was very interested in the study and wanted to contact the authors with a question: “Have you seen any entwives?” -Treebeard.
The dryest summer I recall in the UK was 1976, which followed a dry 1975 and dry winter.
The whole countryside was bleached a fawn colour, crops and grass. Corn harvest mostly finished a month early.
Except for the hedges and trees which remained dark green and alive, although some beech trees suffered where they were on shallow soil.
Much more damage was caused to trees in our neck of the woods by very high winds in 1987 and 1990 where trees and in some cases whole woods were blown down, some in as little as 3 minutes the gusts were so strong. Beech trees were particularly affected and where blown over looked like huge mushrooms on their side with the root ‘plate’ showing the shallow rooting depth of the beech trees.
Where trees had been pollarded regularly they were not affected as the bulk of their mass was in the wide trunk, although a whole avenue of beech trees at Longleat that had been pollarded in the past but not for some years provided more resistance to the winds and were toppled.
Whole hillsides of trees (most often shallow-rooted tuliptrees and white pines) were uprooted by a massive ice-storm in 1994 in mountainous southwest Virginia where I lived. Seems trees near the hilltops fell downhill and acted like dominoes caused uprooting all the way down to the bottom. Deeper-rooted oaks got branches broken, but usually resisted uprooting.
Spruces are shallow root trees.
In our garden, we have groundwater in about 7 m depth, and I measured this year an increased volome of groundwater in comparision to last year. Nevertheless, in our surounding in other gardens, the spruces are all dead.
2018 was just a warm spike during a warm AMO phase, the warm AMO phase dries the region, and the warm AMO phase is normal during each centennial solar minimum. I doubt that it was warmer or drier than 1540, 2003 saw more high temperature records, and moreover, all of these major heatwaves are discretely solar driven, and cause climate change, climate change cannot cause them.
https://www.linkedin.com/pulse/major-heat-cold-waves-driven-key-heliocentric-alignments-ulric-lyons/
No year since weather records began was as hot and dry as 2018. A first comprehensive analysis of the consequences of this drought and heat event shows that central European forests sustained long-term damage.
Local conditions. Few years were as wet in the US central Appalachians as 2018. Forest & crop growth was extraordinary — field corn was 12 ft high.
I hope this this gets posted:-
To establish the next stage of the cycle, how beech replace oak, I studied a mature oak woodland in the New Forest of Hampshire. Here, after a few hundred years of soil improving by the deep-rooted oaks, the beech trees were taking over. Beech species are very shade tolerant, and have a drooping leader in the spring growth season. The ecological advantage of a drooping leader is the beech is able to rapidly penetrate the branches of the overlying oak canopy, quickly straighten up and so avoid wind lash damage to its apex growth point. (Hemlocks – Tsuga species and false cypress have exactly the same growth strategy for the same reason).
Beech grow physically taller than English oak (Quercus robur) and so in Epping Forest the beech will eventually overtop and kill the oaks by shade competition. In the New Forest Durmast Oak (Quercus petraea) co-exists with the beech, (I only found 6 mature durmast specimens in my Epping Forest study area). Durmast oaks are physically taller than Q. robur and so are not overtopped. In Epping Forest the Q. robur naturally co-exist with the much smaller Hornbeam on the damp valley lows where the shade tolerant moisture loving hornbeam (Carpinus) replace the Beech in the species pattern, but do not overtop the English oaks.
To study this process of natural cyclical succession I used a Markovian Matrix with the key parameter of age at death of my three species, Birch, Oak and Beech. The data were obtained by coring dead specimens in the study area. Canopy size is also a feature, in general 3 mature birch equals one oak in a dense woodland setting where upward competition for light is severe and canopy diameter is constrained. The purpose of the Markovian analysis is to establish the stable population age profile of the three dominant species that results in a smooth transition for the woodland as a whole; so that somewhere in the species pattern there are always patches of new replacement regeneration in an endlessly repeating series of growth and decay.
I have not studied coniferous woodland succession but I have observed how in the mature Scots Pine pioneer woodland at Aviemore in Scotland, the woodland is being replaced by saplings of Douglas Fir (improver) and Hemlock (shallow rooted shade tolerant exploiter) growing in the shade of the pine under-story in this ancient mono-species forest.
So, what message do I want to give you? My Markovian Matrix analysis showed that managed forests in which a multi-aged mix of stands of pioneers (birch or pine), improvers (oak or silver fir) and exploiters (beech or spruce) is the most ecologically stable and diverse. This is because with a managed areal pattern and a large age profile there is always somewhere for the herbaceous species to move to, and somewhere were the soil seed bank is being replenished.
End of message.
Yes it makes perfect sense scientifically that temperatures above 20 C are an intolerable stress to plants, unsurpassed with the possible exception of an innocent mushroom being misgendered.
Like all progressive climate science it hangs together so well and consistently with our knowledge of past climate disasters. Climate itself is always a disaster. As we now know. Like Donald Trump and Brexit.
That’s why at the Holocene optimum 9000 years ago with temperatures 2.5C warmer than now, 25 % of all life went extinct. Including polar bears. And at the optimum of the previous Eemian interglacial 110 Kyrs ago that was 5 C warmer than now, 50 % of all life went extinct! Including all insects.
And during the Cretaceous 100 Myra ago with temperatures 10 C warmer than now, 100 % of life -all of it – went extinct!! Since then there had been no life.
Can’t see what problem skeptics have with any of this settled science.