Tree - to plant or not to plant, that is the question

Tree - to plant or not to plant, that is the question
Mark Hamblin/2020VISION

By Dr Tony Whitbread

Sussex Wildlife Trust President

In my last two blogs I pointed out the dangers of tree planting & the climate emergency.  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 (e.g. Woodland Trust) 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 (e.g. 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.

Comments

  • Nick Bailey:

    16 Mar 2020 18:09:00

    Thanks for this helpful balanced overview, which seems to encourage an enriching future rather than just salve a guilty past.

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