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.