Misconception: Trees are planted "too close together"

Reality: Overstocking helps a woodland establish even when there are losses.

This post is written by Phil Sturgeon, co-founder and Chair of Protect Earth. It’s a series of posts discussing the grey areas in tree planting and forestry.

Swirling within and around the community through the media are misconceptions about the reforesting industry.

I feel it useful to look at these misconceptions to clear the air. In this piece, I'll discuss what overstocking land with trees means - whether it is truly a bad practice or what benefits may come.

Misconceptions about tree planting density

I have heard a lot of concerns about the density of saplings being planted, where the concern is that saplings planted closer together will not have room to grow to their full potential.

Trees will be in too high competition for them all to reach maturity, and the ground will be too stressed to play its part in bringing trees to maturity.

The misconception here is this dystopian idea of a mass tree graveyard.

The reality and benefits that come from trees that do die

The truth is, not every sapling is going to reach maturity.

Several things could go wrong: it could be eaten, suffer from drought, suffer from a warm spring followed by harsh cold snaps, could be trampled by a deer, and even slugs and insects might eat the leaves.

We take this into account when we consult and plan a new project. If the project is sheltered and few losses are expected, you might plant 1,200 trees/ha. If it's incredibly exposed to wind and cold, like the Orkney Islands (something we're in the early stages of planning), then you might ratchet sapling density up to something extreme, like 3,000 trees/ha, knowing that a lot of them will not make it. The stocking density depends on the conditions of the site.

The average stocking density is around 1,600 trees/ha. Of that, 80% are expected to survive. When 20% of those saplings fail, they can be replaced in the first few years, and eventually, the trees will be big enough to look after themselves.

Pesticides could be sprayed everywhere with expensive fencing all over the countryside. Still, the less invasive approach is to recreate what nature does: trees produce far more seeds than are expected to survive. From thousands of acorns, only a few will find the right conditions to germinate, and they may well be in competition with each other, and other saplings nearby.

Now, let's address the misconception that trees planted too densely together is a bad thing.

There is no real downside when an area is "overstocked" with saplings. If some saplings and trees fail, that's more deadwood which becomes good habitat. If "too many" of the saplings planted survive for them all to have the right amount of space, then the trees can be "thinned out" in phases every 5 or 10 years until a healthy tree canopy exists where the most healthy trees remain and the least healthy were removed. The alternative would be planting exactly the number of trees hoped for, and if anything goes wrong, the result is a field with only a few trees in it.

To sum up

There is a general guide on the density of trees to plant per area and species.

That withstanding, this is nature. And, time and time again, we've been amazed by nature's ability to thrive.

There are two factors to look at when it comes to this misconception.

The first is the short-term financial cost of over-planting. Yes, trees cost money, and if the trees planted die before maturity (i.e. before they can hoover up the full potential of carbon they can), this does represent a loss.

But, on the other hand, there's the long-term view of providing natural benefits. On the longer term horizon, planting "too many" trees begins the cycle of regenerative growth. Trees will fail, and trees will die. In this, there are opportunities to establish a healthy ecosystem inviting insects, small animals, and on to join the fray until a thriving system of life pulsates.