Monday 27 January 2020

Trees need a purpose (4 of 4)

Tree planting has caught the mood of our time.  We all want to do our bit to contribute both to the restoration of nature and to the climate emergency.  Yet if you refer to my previous blogs, tree planting can cause problems.  Furthermore, there is another element that often gets forgotten.  Trees and woods need a purpose in society.  If they do not have one, then today’s planted woods will not be valued so will be cleared away to make space for other uses. 

Look at a map of England.  Where do you see the woods?  Are they in the most rural, agricultural areas?  No, not usually.  They are quite rare in areas of high agricultural productivity (think of East Anglia).  Even areas that have historically had a low human population can be poor in woodland.  If you look at the actual distribution of woodland, particularly ancient woods, you find they are not just in forgotten corners, they have survived in areas where they were most valued. 

Therefore, counter to what you might expect, the places where trees were valued for timber and fuel is where the woods remain.  They were not simply exploited and destroyed; they were conserved and valued.  The Weald of Sussex, Forest of Dean, Furness Fells in the Lake District and Coalbrookdale (near Iron Bridge in Shropshire) all have high concentrations of woodland, constantly needed for example in the iron industry.  Iron Bridge was one of the birth places of industry, fired by charcoal from local wood.  Where you do find woods in rural areas, they were there because they provided a vital agricultural product.  For example, you get hazel coppice woods in Hampshire, highly valued in the past to provide hazel hurdles to make sheep pens.  Being truly ancient, it is unlikely that any of these woods were planted.

Hence you get a quandary – woodland is conserved, not where it was most often planted, but where it was most often cut down!  A long history of cutting in woodland reflects a long history of use of woodland products, not a history of destruction.  The Forestry Commission have long recognised that woods are most likely to survive when they are managed to provide the woodland products that are wanted.  If not managed and their products not wanted, the woods get cleared.

Understandably, people are keen to expand tree cover by planting, or regenerating woodland.  However, perhaps the best way to conserve woods is to demand products made of wood.  When these products are used to make long-lasting, high quality products (like finely crafted furniture and in modern architecture) then the carbon that has been captured by the tree is locked-up in that product for decades (perhaps centuries), contributing to combating climate change.  Thus, the best way to conserve woodland is to encourage the chopping down of trees!

The old maxim “save a tree, buy PVC” could not be further from the truth!  Society needs a “wood culture”, a culture where the first choice in any product is wood – preferably in long-lasting, high quality items.  This is not just for antiquated trinkets (three legged stools and sheep pens!) but in high class, long lasting contemporary use of wood such as in modern buildings.

The current push for tree planting needs to be matched by a demand for products made from wood.

The story, however, cannot end there.  Woodland management can conserve woods and enhance their ecology; it can also be extremely destructive.  Checks and balances are needed to ensure management is sensitive and sustainable.  England does have a long history of sustainable woodland management, and modern regulations should maintain this.  But I’m not sure we have the political will, or that the authorities (like Forestry Commission) have the resources to ensure that management remains sustainable.

Finally, the way we value woods now, and in the future, may be different to how they were valued in the past.  Modern approaches show that other outputs can be far more valuable than traditional forestry products.  For instance, the best woods for locking up carbon are often the “old growth” woods, which are largely unmanaged.  These are rare and precious, so we need to protect, expand and appreciate them.  Forest re-creation to reduce flood risk is also a modern high-value purpose for trees.  And “green lungs” in and around urban centres consisting of new trees can provide huge recreation, health, wellbeing and community values. 

In short – trees need a purpose, maybe to lock up carbon, to reduce flood risk and as a green lung for urban areas.  But often for trees to achieve their purpose they might need to be cut down! 

You are more likely to conserve British woodland by buying a finely crafted oak table than you are by planting a tree!

Monday 20 January 2020

Trees – to plant or not to plant, that is the question. (3 of 4)

In my last two blogs I pointed out the dangers of tree planting.  The twentieth century saw massive damage done by reforestation – one of our greatest causes of habitat loss – we should be careful not to repeat the mistakes of the past.  We all want to do the best thing when it comes to addressing the twin problems of climate and ecological emergency.  All habitats contribute to combating climate change - we do not need to think “trees” all the time.  Legitimate questions now are:  when is it right to plant trees?  And how do we do it right?

In my mind you can probably break this down into a 10-stage process:

1.      Survey.  Find out what is present on the land where you are considering tree planting - with a new survey and by collating existing information.  Organisations like the Wildlife Trust will have some information to alert you to special places that would be damaged by planting.  But much is not known.  You don’t need a full species list, but you do need to have enough information to get to the next stage.

2.      Map and understand.  Map your plot, indicating the different habitats present and showing any special interest.  Then interpret what is there.  For instance, is the land degraded and species poor, so would be enhanced by planting or is it rich in species (such as grassland, heathland or wetland) that require open conditions so would be damaged by planting.  Also identify problems such as invasive species, overgrazing from deer or domestic stock etc?

3.      Make a plan.  What is the site like now and what would you like it to be in the future?  Then prescribe what management might be appropriate in different compartments in order to deliver your plan.  This should include planning to look after existing, sensitive, maybe unwooded habitats as well as plans for changing things perhaps with planting.  Get this wrong and you could cause more damage than leaving a site as it was!  So, it will be worth getting good advice.

4.      The role of trees.  You will then have a plan that includes places where more trees will be beneficial and places where they would be damaging. So, what tree species should you chose?  Look at other wooded sites in the area to see what mixtures work for the area.  Native tree habitats have been classified so, knowing the conditions on your site, it should be possible to copy a native wooded habitat.  Again, it may be worth seeking advice.

5.      Tree regeneration.  Natural regeneration is generally preferable to planting, giving a more diverse, locally appropriate mix.  So, will natural regeneration happen on a scale or of a type that fits your plan?  If not, then you have a rationale for planting.

6.      Tree planting.  Some trees are less good at being planted than others!  (eg oak is difficult, willow is usually easy).  Get good advice and ensure it is done well.  Where will stock come from?  Use reputable (eg WoodlandTrust) sources, preferably locally sourced, or even from seeds collected and grown on by local people.

7.      It’s not just trees. There may be value in adding other species, particularly shrubs and smaller sub-canopy trees.  The aim should be to create “vertical structure” – multiple layers of vegetation in clumps across a site rather than one even layer.

8.      Tree aftercare.  Planted trees will need more care than naturally regenerated ones.  They will need watering and removal of weeds in the first year or so.  They may need protecting with tree guards – more single-use plastic in the countryside, not really something we should be encouraging.  Or you could plant far more than you need and just allow for large losses – an approach that could deliver more diversity.

9.      Management.  How will the site be managed in the long term?  Non-intervention is only one option.  Maintaining diversity, especially in small woods, will require management.  This should also include management of open habitat.  However, try to avoid preconceptions about how a site may end up.  Nature may take a site in a different direction to your plan.  You’ll need to work out whether to fight it (eg more planting and more cutting) or adapt your plan.

10.   Long term plan.  For centuries of human history, woods only survived when they had a purpose, traditionally by providing products for people.  So how will you give the site a long-term purpose?  Will it provide products, timber, be a leisure facility, a community asset or what?  Planting and hoping is not good enough.  A future unvalued wood will just be swept away, and any temporary gains will be lost.

Replanting is not the same as rewilding.  Replanting is reforestation.   It may be true that replanting can help with rewilding, but the attitude is one of kick-starting nature, rather than designing and building a forest.

And bear in mind that the best ecological option in an area might be to cut trees down – not to plant them!  All habitats contribute to combating climate change, and healthy ecosystems deliver far more than just climate change mitigation (important though that is).  Nutrient cycling, flood prevention, erosion prevention, pollution amelioration, pollination and so on and so on.  We need to go into ecological restoration with an open mind rather than immediately reaching for the packet of tree seeds.  In nature, succession (tree growth) is in balance with natural disturbance.  Too much of the first and you get a dense, artificially dark forest of very low ecological value, which may also not reach an area’s best potential in terms of climate and the other benefits of nature.  Clearings and open habitats are just as much a part of the forest as the trees.

It would be perfectly legitimate to go through the 10 stages above and then come to a very different conclusion than tree planting.

Friday 10 January 2020

Trees and the climate emergency (2 of 4)

In my last blog I raised the huge potential damage that could be caused to the environment if forest creation was done poorly.  This generated some excellent discussion and I am glad that it stimulated interest. 

I do not plan to respond to all points raised but there was one set of comments where some expansion is worthwhile.  This is the point that we are in a climate emergency, the priority must be to get the trees in the ground as an emergency action.

This is very reasonable.  In nature conservation we often must press forward with the best approximation of the truth so, if the overriding need is carbon sequestration then we better get on with it.  It might be said that the problems are small in comparison to the needs of the emergency.  However, the follow points should nuance this:

First, the UK is only 13% wooded.  It should be possible to double this without causing any ecological problems.  To stress this further, concern about ecological damage should not be an excuse for reducing forest creation – we must just get it right.  For example, high nature value chalk grassland occupies only 4% of the South Downs here in Sussex.  If a tree planting plan can’t restrict itself to the other 96% then it is not trying very hard!

The second point is that, done badly, tree planting can cause a net release of carbon.  Soil disturbance in ground preparation, particularly on peaty soils will release more carbon from soil than the trees will make up, at least in the short term.  This should be avoided by good planting design and good attention to local conditions.  But an attitude that any habitat without a tree on it is a wasted habitat, will be very damaging.

Third, it is not only trees that lock up carbon.  Peatland holds more carbon than all our forests. Kelp forests in the sea lock it up far quicker than trees, and wetlands are particularly good at soaking up carbon on land.  Salt marsh is so good at building up soil on the coast that it is likely to keep pace with sea level rise from climate change – if left to itself.  Even grassland, which do not appear to have the obvious standing crop of carbon that you associate with trees, are very good at pumping carbon into the soil.  As roots in grasslands die off their carbon is left in the soil.  Rewilding is turning out to be one of the best ways of getting carbon into soils.  The mixture of trees, shrubs, ground cover plants, animals, dung and dung fauna working together to build up soils almost twice as quickly as organic farming.  And most of that new soil is carbon.

A fourth point is that planting a tree, or regenerating a forest, is only the start.  This is a long-term investment.  Throughout history, woods only survived because they had a purpose in the local community.  Traditionally, this meant woods being kept and managed to provide products for local use.  Hence, managed woods were more likely to remain than unmanaged ones.  This is still true today.  One of the best ways to create and maintain forests is to demand products made of wood, not just to plant a tree.  However, a purpose for forests might be broader today.  Wild unmanaged forests may be as valuable, but in a different way, to forests providing sustainable products for human use.

Part of the same fourth point is that we should not deify trees so much that management becomes a sin!  Part of appreciating trees is to appreciate the products they provide us and therefore drive their sensitive management.  Cutting trees down as part of sustainable management is not an ecological compromise, it is part of a much-needed woodland culture.  Furthermore, cutting down trees in the right way creates diversity in woods, mimicking the natural disturbance that wild forests might once have had.  One felled tree in a well-managed wood will be replaced by hundreds of saplings – without any planting.  (This is not carte blanche for any old management though!)

As I said before, simple answers to complex problems are always wrong.  I would add now that this is not an excuse for inaction, it is more a drive to understand and celebrate complexity.  Nature is complex – and that’s just great!