360 - Planting trees | Scoins.net | DJS

360 - Planting trees


Planting trees to combat climate change is far from enough. So says a CityLab article from Fergus O'Sullivan (who I rate). Yes, by all means (let us) plant trees; make sure they grow, show the records  show what happens to these trees, show how successful—or, particularly, not—the planting is, show what happens to the trees that are removed. Let us publish the percentage success, not just of planting at all, but of success in the tree growing (such as still there at five years, ten years, etc; what I'd call retention, in other circumstances). Data required. 

Discussion with my most local councillor showed how very expensive it is to plant trees in an urban environment. The roots require much the same volume as the canopy, so a pavement hole (a 'soil cell') for a new tree needs to be the size of the full-grown tree above ground. Emphasis here, on urban position; we had a few (six?) planted in town on a single street, one side, which entailed a trench some 3m deep and at least that wide, then lined with blockwork to contain the trees, along with associated movement of the services already in the pavement. This trench is then filled with soil, the tree planted and the pavement reinstated. Cost per tree about £10 000., perhaps twice that, but the cost of moving the services is significant for an individual tree and only worth consideration for a run of trees, where the services are moved for a whole street.  

Rural cost per tree—not at all the same thing—is about a dollar, but my own experience says more like £2 ($3). UK cost here at £12.90, but again that is rural and takes no account of failures. An urban planting is not a sapling but something already big enough to have leaves overhead, probably called semi-mature. Here says £1000 for a single tree, rapidly dropping for volume, £350 per tree for ten trees. Again that is just the planting, not the upkeep. I found a cost/benefit analysis, CBA. Note that the tree planted in a root space will provide about twenty times the benefits of a tree planted 'standard',  in what is effectively a small pot. I found a cost of $10k that I believe, consistent with the £10k quoted by my councillor. Do read the CBA, and note how long it takes to have cost benefit — thirty years. One of the points made is that many street trees are replaced every ten years (except I'll bet they aren't, they simply go missing). When this model is followed through, no benefits occur as the tree never reaches a size big enough to signify benefits in terms of leaf cover or ecosystem (e.g., insects, birds, water retention / attenuation, added oxygen, pollution absorption, etc etc).

The hype (overblown rhetoric) around big ideas like 'let's plant N million trees' all too often starts—and ends—with putting a twig into the ground. It should not; the trees need maintenance. In the UK we have one of these Big Ideas mumbling about a 'northern forest' (insert 'great' for hype purposes). I'm for this if this is repurposed fell and mostly deciduous; that would be using land we hardly gain use from (high, wet, mostly sheep grazing when we're supposed to be cutting back enormously on meat); I'm for this if we include plans for maintenance and access (as in roaming through it). I think we also have need for significant numbers of urban trees (huge relative cost but direct local benefit) and that we need to rethink our approaches to the use of trees in gardens. With that goes a collection of rules about light, tree pruning (maintenance) and a load of education about what it is we are having trees for. Connected, too, is how we act with regard to the pruning, maintenance etc (what we do with what we cut off) and how we attach value to existing trees.  I see no evidence anywhere that we are doing such thinking, certainly not in ways that suggest a government will take a long-term approach — the very thing we need with regard to climate change.

I was asked recently in a survey how I might order risks, including such as climate change and covid. I see them as remarkably different; covid is a relatively short-term problem that we (in the UK) seem to have accepted will become endemic (existing in the population much as 'flu does); with that is an acceptance of deaths per year and an assumption, I suspect, that any long-term damage is ignorable. I disagree with that last, rating long covid as a much more serious event equivalent to the several Chronic Fatigue (CFS) illnesses. I also bear in mind the immediate success of the covid vaccines and the relatively poor success of our flu vaccines, which we modify every year — and still lose what I think of as large numbers in (early) deaths per year. Not only all that, but the need for action such as a vaccine for covid is obvious, immediate and can be in many senses confined to a group of people or a class of such groups. We may even recognise that we ought to have such as vaccine manufacturing facility within our own borders. Climate change, on the other hand, requires much longer-term thinking and far greater wholesale change in our behaviour. So it is immediate—in the sense that we're acting late, if we act at all—but also it is less immediate because we need to be quite clear what classes of change we need to embrace. With covid we scream "Vaccine" and leave it to others to fix, such that we perhaps throw money at the problem but it still to a large extent goes away, or fades from political prominence; with climate change the need to action is a much slower build-up of demand (years rather than days or weeks). The short-termism that politicians live by probably means that we'll have a load of fudging, short-term fixes rather than large-scale change. Though I can hope that we have the fudges followed by the larger wholesale change. A lot of the problem is that we are apparently very bad at embracing change, especially long-term change. That is poor resilience, poor adaptability.

Re-reading this in September, I'm struck by the cynical thought that those who die early from flu are probably being thought of as non-Tory voters. Becoming more cynical still, one doubts that the gov't in power cares about non-blues.

I wrote some years ago (more than ten, essay 49) about sea level change, about the changes that follow from the melting of ice in places such as Greenland. I referred only briefly to the assumption we make that the Gulf Stream, which is what makes the UK nicer to live than say Korea or Japan (both nearer the equator and with colder winters), continues to be. Yet I noticed today that there is growing concern (I mean I'm finding more reporting) that the Gulf Stream system is headed to falter. And, if it falters, will it ever return... Suppose it stops, because the excess cold fresh water falling off Greenland messes up the bit of the system where heavy salty water drops to the ocean floor to circulate back across the Atlantic (look up AMOC, such as here); the changes to our weather patterns, patterns we predicate so much behaviour upon, might well be disastrous, turning the ground on which we grow crops to something quite different and demanding very different crops; we could experience (even) more extreme weather and result in hotter summers and markedly colder winters. it might also trigger a local sea level rise much greater than the global average — it is a continuing surprise to me that a small total increase in level has such dramatic consequences to the modelling of sea behaviour; of course, what we refer to is the behaviour of the sea upon our land possessions. We might well, if I understand the hints aright, grow a west Atlantic equivalent to the hurricane; so far this century by the time they arrive on the European coast they've diminished to 'mere' storm.

Balancing this doomsday scenario we have the IPCC fifth assessment report (AR5 link, 2014) which states with high confidence that the AMOC will not undergo a rapid transition. That does not say it won't change any more than it says (which it doesn't) that climate change is not happening. It does very clearly state that '83-'13 was the warmest thirty years period since 600AD, that the ocean has measurably warmed up, that the polar ice sheets have shrunk, that the sea level has risen, that we have the highest ever levels of greenhouse gases since man began and that all the pointers say these measures are worsening (heading to an even worse state). That is, things are not good and we've done nothing showing any effect as yet.

Of course, we'll have millions of trees planted just in time for them to catch fire spontaneously. Just this week Greece has had forest fires (actually longer than that, more like two weeks and counted as 500 fires). July 2021 listed a region of Siberia as on fire (ah; a data point, 1.5m ha lost). Turkey, no area given July 2021. 

General loss of forest reported somewhat here; 12 million ha lost, of which a third was from the tropics. This CO₂ gain equates to half a billion cars, I read, but I don't see that as a completed statement – cars doing what, their whole existence?. But that isn't entirely fire, even though (Brazil, notably) fire is often used to clear forest (to 'manage land'). Australia's losses 2019 onwards are far from deliberate. The US losses are dramatic  below, losing typically 7.5 million acres a year (3 million ha) since 2000. This is double the average for the previous decade. Looking for total figures, I can report that the US Forest Service has 193 million acres and loses about 2.5 million acres every year to fire. In total the US has 819 million acres of forest, some 3.3 million km², 36% of its land area. So it is losing about 1% to fire every year, undoing all that carbon capture. Britain aside, typical forest cover is 35% (most of Europe, the US, you could research this yourself), while the UK is at about 13%, of which England has a paltry 10%.

I tried to discover the carbon loss for a single tree afire. This source says Over a lifetime of 100 years, one tree could absorb around a tonne of CO₂. Similarly, burning wood (in complete combustion, or allowing it to rot) should produce a neutral result, else we'd not consider wood a renewable resource. But a neutral result presumably means that what was captured by the tree is largely lost in combustion. Reducing the carbon in circulation requires us to use the wood for other purposes.

DJS 20210811

AMOC: wikipedia Guardian reports 1 2 3 4 5

Global warming could, via a shutdown of the thermohaline circulation, trigger cooling in the North Atlantic, Europe, and North America.[9][10] This would particularly affect areas such as the British IslesFrance and the Nordic countries, which are warmed by the North Atlantic drift.[11][12]Major consequences, apart from regional cooling, could also include an increase in major floods and storms, a collapse of plankton stocks, warming or rainfall changes in the tropics or Alaska and Antarctica, more frequent and intense El Niño events due to associated shutdowns of the KuroshioLeeuwin, and East Australian Currents that are connected to the same thermohaline circulation as the Gulf Stream, or an oceanic anoxic event — oxygen (O2) below surface levels of the stagnant oceans becomes completely depleted – a probable cause of past mass extinction events.[13]

A slogan coming soon: "Plant a tree in '23"; except we're going to need more than one each and we needed them most of a lifetime ago. Already.

UK targets: Feb 2021; 30,000 hectares of new trees per year. Trees of what sort, pray? Numbers? Friends of the Earth target of 26% of land area; the woodland Trust says we need 50m (more) trees in 5 years, while the National Trust says 20m in ten years (five times fewer per year). The Forestry Commission report (FC, June 2020) shows that new planting has risen; 2018/19 1420 ha, 2019/20 2330 ha. How many trees to a hectare (1000-1750 on the figures I found) surely depends on the choices, so perhaps it is the land area count that matters and we then assume that woodland accumulates to a certain acceptable total density of growth. Yet the FC (Forestry Commission) figures hide a further 13460 ha of (UK) planting, so maybe we should be recognising more like 16000ha in 2019/20. The announced target (same link) is 30000ha per year by 2025. These reports are not written to be read except by those already involved. The graph copied from the FC report itself indicates a count of 1320 kilo-hectares (kha) total coverage in England, about 10% of the total area. I have put the calculation lower down the page in a colour, but we're looking at a target of 20% of England under trees, about twice what we have at the moment. That, then is a significant change of lifestyle, who works at what (forestry, a lot more, but not as many as you might think) and how we view the countryside (apparently covered in trees). I do hope we have sensible variety and place the trees where they'll do some good.  The next report is due September 2020.

You might look at the report on forest pests, which show that the push for more woodland is balanced already by losses (Guardian 2), a mere 7% is considered to be in 'good' condition, with causes given as over-grazing and invasive species. For example, ash die-back (a tree disease) could kill 120m trees (100kha) which is 4 years of maximal planting lost from the previous paragraph. Thus we need to not only build new woodland we much work at maintaining and protecting the existing. Given the dire state of our existing woodland, that looks to be a severely underfunded exercise. Of course, our ever-so-wonderful politicians are big on the hype and initial spend but consistently poor on everything to do with maintenance; if it isn't new, they don't want to know. Apparently.

Himalayan Balsam is the bad kid on the block. Go bash it wherever you see it (Guardian 3) which will be beside a watercourse.

1999-2019, England woodland went from 9.59% to 10.05% of land area. That's a growth of 2.1kha per year (P11 of FC report). That is 0.023% of land area per year equating to 2.1kha per year. So 30kha per year implies (for England alone) 0.33% of land area under new trees every year. That's not maintenance replacement but new coverage where there was previously no trees. 30 years (2019-2049) at such a rate is a further 9.86% of land area under trees, twice what we had in 1999 and about 19.9% of total English land area under trees by 2050. Call that 20%, but recognise that we're already behind, at 2kha per year not the 30kha we have targeted by 2025.

Can you identify the seven notifiable noxious weeds? If you have any noxious weeds on your land, you are responsible for controlling them. You must prevent them from spreading onto adjoining land. (source). The harmful (injurious) weeds are:  common wild oat, winter wild oat, spear thistle, creeping thistle, broad leafed dock, curled leafed dock, common ragwort. Then there are the non-native invasive plants. You do not have to remove these plants or control them on your land. If you allow Japanese knotweed to grow on anyone else’s property you could be prosecuted or given a community protection notice for causing a nuisance. (source). Non-native plants include: Japanese knotweed, Giant hogweed, Himalayan balsam, Rhododendron ponticum, New Zealand pigmyweed (this is banned from sale). These invaders cannot be composted and you must use a registered waste carrier and dispose of it within the regulations. Good luck with that. Identification of injurious weeds. Refer to the Weeds Act 1959. A notifiable weed is one which will do damage on agricultural land, so that any adjacent landowner is responsible (and to be held responsible  hence notifiable) for preventing the spread of an injurious weed onto others' land. For the non-native invasive plants, see here for identification and refer to the Wildlife and Countryside Act 1981.

Scottish tree planting is discussed a little in Guardian 4. Scottish Forestry reportScotland’s forests cover 18.8% of the total land mass area and the ambition contained in the Scottish Government’s forestry strategy is to increase this to 21% by 2032. In total, 10,860 hectares of new woodland were planted, the second highest level since 2001. That means that nearly 22 million more trees were planted in Scotland last year. The Scottish Government, as part of their climate change commitments, has already upped the planting targets for the future, rising to 15,000 ha a year from 2024/25. The yearly target for native woodland creation was achieved with 4,529 hectares being created, around 42 per cent of all the new woodland in Scotland.



related pages

2010 49 - rising water levels 

2013 100 - Peak Oil, 114 114 - Water, water and not a drop to drink

2106 184 - Drown-proofing

2017   225 - A New Dark Age (2)

2019 282 - CO2 sources             273 - Populism

2020 310 - Reducing Population   and  the several covid pages, all linked together  323 Where do we go from here?

2021 the several snippets pages have some ranting content, or content that turns into rants elsewhere, no matter how I try not to do that.

2021 358 - Climate Crisis

Way back 1993-05 we owned a couple of hectares in Cornwall. While we lived there, we planted (paid some to plant) 600 trees. At the time we told ourselves we were doing good and felt ecovirtuous (and coined the term). After selling the property the new owners got rid of all the trees and replaced this with horse. How this is allowed, I do not know; my understanding was that the trees had to stay in place a long time and longer than the ten years they were there or the grant towards the planting was forfeit. Further, removing trees should be done with due care for carbon release and none of them were by then big enough to be used as wood, only to be sold as semi-mature. I could hope that this was the case, but I'm pretty sure they were burned, which entirely defeats the point of the planting.  So, in terms of carbon balance, this act by others undoes all that good work and undoes the carbon capture contribution from the members of the family at that time. 

This is the tree version of removal of troops from Afghanistan. 

why?  Email: David@Scoins.net      © David Scoins 2021