How Not To Plant “Woodland”

There’s a great and commendable enthusiasm about tree planting in the UK. We know the reasons why. Every year, especially when the floods come, people talk about the need for more trees. Tree planting might even be part of a new post Brexit agricultural settlement. We need to be careful about it, though.

There has been a great boom in tree planting in Ireland. Apparently forests covered less than 1% of the country a hundred years ago. That figure is now over 10% – still low. The government plans it to reach 18% by 2046. Hurrah! There’s a problem, though. This isn’t really woodland. The new planting consists of Sitka spruce plantations. Currently, only 2% of forest cover is mixed broadleaf woodland.

Is this an issue?

You bet.

plantation monocultureSitka spruce hails from the Pacific northwest. It’s not a great fit with local Irish ecology. It grows vigorously, and – as in the UK – advice is to plant at a tree per 2 square metres. Nothing grows beneath its dense stygian canopy. Unlike native broadleaf woodland, this monoculture needs fertilisers and pesticides. Plantations are springing up in bogs and across meadows. They might sequester carbon, they might have commercial value, but in biodiversity terms they’re… unhelpful.

Planting regimental ranks of broadleaf trees isn’t ideal either. Dense woodland, with no sense of the effects of what ecologists call succession, is sub-optimal. We need lower density mixed species planting, with gaps. This could be achieved by using a wider range of native species and by more extensive selective felling in any planting scheme’s formative stages.

woodland pastureContrary to earlier thinking, the chances are that dense forests didn’t cover Europe before iron age man started clearance work. More likely is that grazing livestock, like auroch and boar, chomped and rootled clear areas. These enabled much greater diversity of tree species, along with other flora and fauna. You can imagine Oaks establishing themselves among stands of Blackthorn, then spreading out. Wildflowers growing in sunnier meadows. Mottled sunlight through the canopy playing on a rich understory. More managed landscapes used to mirror this approach, which is becoming talked about again through the rewilding movement.

We’re surrounded by vestigial “wood pasture” in this pocket of Somerset. I’d love to see it restored. We should put a commercial value on that, payable from the public purse if necessary, as (I hope) we will – finally – do for planting for flood prevention.

I’m probably just cavilling about tree planting styles. Planting rates in England continue to be disappointing. Management of many schemes is poor and deer wreck others. England only has similar tree cover to Ireland. The government’s (unfunded) targets look like pie in the sky.

We need more trees, in a hurry. We should, nonetheless, get maximum value from them. They have to be the right trees, planted and managed in the right way.

When Tree Planting Sucks

On the radio today I was gratified to hear Oliver Rackham talk about the dangers of the globalization of the tree business, as I blogged about here nearly a month ago. It was also interesting to hear him talk about some other less than positive aspects of the recent fashion in the UK for tree planting, which has meant we now have as many trees as there were in the Middle Ages. Isn’t this a good thing? Well – er – not necessarily, as I’ve increasingly thought too.

1. There is always a tremendous hurry and lack of adequate cash about grant aided planting which means trees are often imported, increasing the danger of spreading pathogens and parasites and reducing the genetic variation of the plant population.

2. Inappropriate tree species are routinely introduced. There’s a “one size fits all” mentality about native tree selection, which seems very odd. In the world of wildflower plants, which shares many of the same problems, we always try to supply seed mixes appropriate to the sites where they will be sown, for example.

3. The groups of trees which are planted do not constitute woods. In particular, no-one bothers to establish an understory, which means they have less value for biodiversity than they should do. Demand for woodland bulbs is amazingly small and their purchase is never covered by woodland planting grants, for example.

4. This issue is compounded by planting densities being too high, which blocks out any light reaching the plants on the ground.

5. We sometimes establish these plantations, with limited ecological value, where more interesting habitat previously existed.

I’m not an expert, but it seems to me that the Ash tree crisis throws up an opportunity to discuss some of these issues. I’m sure tree planting IS a good thing, but we need to review how we’re doing it.