Ash dieback and Alvecote Wood

An ironic twist, that ash dieback should rear its head in the UK just as all trees are dying back for the winter, making it much harder to detect.  It was with a heavy heart that we realised that we, like all small woodland owners, were vulnerable to this new disease which has made its way across the channel to the UK.  Betty’s Wood is particularly vulnerable, because we have planted a significant number of ash trees (about 10% of the trees are ash), and because Chalara dieback affects young trees more severely, and because the nursery from which we got them has had an outbreak of Chalara this year (although, thankfully, none of the batches we bought from them were affected).
We were extraordinarily careful with the provenance of our trees:  not just UK provenance, but we were careful to ensure that they were UK grown too.  It is very easy to cast blame on people planting trees for not checking the provenance, but it is also very easy to be misled into thinking that trees come from the UK when they don’t.  More needs to be done to ensure that the provenance of each tree is clear, via a passporting system to ensure we know where the seed came from and where it has been grown at each stage of development.
It is also easy to blame politicians of all parties for failing to take action:  the fact is that blame will not solve the problem we have now, of dying ash trees, spreading disease, and the prospect that ash trees will all but disappear from the UK until trees that are resistant to the fungus emerge.  I am sure in hindsight, many people could and would have acted differently – politicians may have taken action to ban imports sooner, movement of ash trees around the country could have been stopped sooner, the wider countryside could have been surveyed sooner, people planting trees could have asked more questions about where they came from, and those supplying trees could have been more open about where they came from too.  Lots of people made mistakes.  What is not needed is a lot of mud-slinging and blame-casting.  Instead what we need is a real, considered, careful plan so that this issue does not arise again with another species of tree.
This has led many to ask whether tree-planting is needed at all.  Can’t we leave it all to natural regeneration?  In many cases, yes, and perhaps there will now be more support and grants for people who wish to allow woodland to generate naturally, rather than plant, and also for those who wish to collect and sow natural tree seed and allow it to grow in situ.  At present the grant system is skewed towards planting.  But there are clearly places where planting is needed.  Like it or not, trees are a crop, and planting will help to produce a crop that is in heavy demand for wood-fuel and wood products.  There is also a need to improve habitat connectivity, and this cannot always wait for natural regeneration, which may take decades.  Then there is the need for landscaping along our infrastructure and in urban areas and building developments – trees are good for health, and they won’t just happen in many of these areas unless they are planted.
But there are messages from the crisis.  First of all, it is very important not to plant huge stands of one species.  Yes, we planted a lot of ash (and also have a lot of ash regenerating naturally around the edge of Betty’s Wood), but we planted a whole range of species.  This means Betty’s Wood will be resilient, and should we lose the ash trees it will not be a disaster (except for ash-specific species).  Second, it is important not to go round destroying ALL ash trees in the vicinity of an infected one – a few of those trees will show an innate level of resistance.  In countries affected by Chalara for a number of years, some trees have survived.  We need to look at the diversity of the trees, young and old, and work out why they are surviving, and preserve those genetically resistant to the fungus.  We cannot do this if we kill all the ash trees.  Third, we need to stop cutting back the expertise we have in plant pathology, mycology, arboriculture and tree disease research – cuts will not solve this problem, nor will contracting out to the private sector.  This is an activity of national importance that needs public funding, and needs to remain in the public sector, with support from the taxpayer.  The expertise is already at a critically low level – it needs to be retained, nurtured and developed to address the issues of future plant diseases.  Or we run the risk of failing to learn from this crisis, and of the same thing happening again, but to a different species of tree.
If 90% of our 700 or so ash trees die, then we will still have 70 ash trees that do not die from which to repopulate our site.  That is a good number of trees which will show genetic diversity, and from which a resistant population can emerge.  We just hope that Chalara dieback can keep away until these little trees are old enough to produce seed, so we have a seed bank in the ground.
At present there is no sign of Chalara in any of our little trees, or in any of our few mature ash trees, but that may change.  Like it or not, Chalara will spread on the wind, on the feet of birds, on the feet of animals.  That cannot be changed.  Chalara is a crisis, but also an opportunity.  An opportunity to get the resources that are needed into plant research, changing nursery practices, dealing with biosecurity, looking at ways to raise a diverse and resilient tree population.
In the end, most of our ash trees are likely to be lost.  We hope not all of them.  In the meantime, we will do our best to keep them healthy, free from disease, growing and producing seed.  The seed is the future.

The right tree in the right place by the right method

planting trees

There seems to be a perpetual tension between trees and other habitats, and within the tree category between planting and natural regeneration, sometimes with very entrenched and strongly-held views, particularly now the Independent Forestry Panel has weighed in with its support for increasing tree cover in England.

So how do we decide what is the right tree and what is the right place?

First of all, we could let the trees decide. That is what natural regeneration is, right? Well, I’m not so sure that is always the case. Many trees are pioneer species that will rapidly colonise other habitats. Indeed, many of these habitats are only as they are because one way or another the growth of trees is controlled: by agriculture, grazing, burning, climate or some other activity. It is wonderful to watch a habitat being re-colonised. Across the canal from us is a former spoil heap that has recolonized within my lifetime with woodland, mainly birch, oak and willow. Within our own wood, there are areas recolonising naturally too.

But there are also areas, such as heathland, which are valuable and declining habitats in their own right. The growth of trees there would endanger the habitat, and in many places, even in areas such as the New Forest, these trees need to be controlled to preserve precious habitat.

So, if we don’t let the trees decide, should we plant instead? There is a lot going for planting. You get quick results. The woodland becomes economically viable in a short time. You can connect fragmented habitat quickly. There are lots of grants and incentives to plant. You can engage the community in planting very easily. Young trees grow rapidly and fix a lot of carbon.

The problem is that there are also arguments against planting. The trees are likely to be all the same age, and it will take a long time for a diverse woodland to emerge. You may introduce disease, alien species, or cultivars that don’t thrive locally. Planted trees need a lot of maintenance, at least in the first few years. Planted trees don’t often come with associated mycorrhiza that are needed for healthy growth. Planted woodland tends to be less ecologically rich than naturally regenerated woodland. Planting may suppress natural regrowth and skew the balance of species locally.

Even on ground where woodland is wanted, and appropriate, regeneration is slow, and doesn’t come with appropriate subsidies, and it can also be taken over by invasive non native trees such as sycamore, and threaten other local woodlands.

So how do we achieve the right tree in the right place and who decides? I am sure our own decisions have been flawed, but were made in good faith, and sometimes because of financial constraints and incentives.

We have done our best to stimulate natural regeneration that was lacking in our own woods by bramble clearance, protection of saplings, introduction of light and so on. It seems to be working in some places and not in others.

We have also planted some areas to provide more diverse understory. Why? If we don’t do this, the elder growing on site because it is too fertile due to years of animal grazing simply takes over and we have had to resort to planting with species already on site to suppress this and allow the woodland to regain the diversity it has lost. How do we know it has lost diversity? Mainly because of the ancient hedge around the edge, and the diversity still present in the areas where animals were excluded.

Was this right? I don’t know. Some of it used our own seedlings, some didn’t. All I can say was it was done with thought, knowledge of the microclimate and soil, and careful weighing up of pros and cons.

Then there is Betty’s Wood. Appropriate for trees? Well few would say no. It was on poorly productive wet farmland, and connects two pieces of ancient woodland fragmented for years but clearly connected in the past.

The ideal solution would be natural regeneration. Except that the ground has been seriously disturbed and over fertilised with chemicals to maximise yield. Natural regeneration would be anything but natural. But planting is unnatural too.

What we have done is some of each. We have planted the centre section, and left the edge, where there are already trees to provide seed, to regenerate. In practice this seems to be appropriate in that there aree hardly any natural saplings growing outside this regen area. The centre section we planted with wildflower meadow and then planted into it, mindful of the soil, microclimate and the species already growing in the area. We planted in natural curvy lines to allow access for maintenance in early years and left large meadows, thickets, clumps and other features. Planting density varied, so some was spread out and the rest closer, to provide maximum variety.

It is no ideal. Many would say right place, possibly right trees, but wrong method. But the long and short is we wouldn’t get the money for natural regeneration alone. Herein lies the problem. I think in our case, planting was the best method, although others will no doubt disagree. But in many places it isn’t. But if we are to persuade people to allow tree cover to expand on their land, if it is right to do so, then we need to offer finance for this, or all the new woodland will be planted. At least we were allowed to regenerate over 16 thousand square metres of land and still get the money provided we met the density target over the whole site.

I don’t know if we have achieved the right trees in the right place by the right method. But I do think there needs to be much more flexibility over how expanded tree cover is achieved and in particular the method by which it is achieved. There also needs to be a great deal of thought put into identifying appropriate land for trees, so that neither productive agricultural land, nor precious alternative habitats are harmed.

Much will depend on the system put in place to achieve this. However given the target-driven nature of governments, planting is likely to get the nod. That is likely to create a lot of woodland very quickly, it of what quality? Do we really want lots of even-aged plantations? Will these really be well managed to encourage emergence of diverse ages and habitats? Will they be put in the right place or just the cheapest place? I have no idea. I just hope that people do put a bit of thought into what they are doing, and why.