Can Wastewater Save Trees?

Trees make a massive different to urban environments. Not only can they remove carbon from the air (thus contributing to the fight against global warming), but they can also absorb heat, dampen noise pollution and boost human morale. While the UK government has set itself ambitious targets to plant millions of new trees every year, it consistently falls well short of realising them.

What’s more, even the trees that are planted often die out within the first few years of their life. That’s because the councils charged with their upkeep do not have the proper funding to give them sufficient water for the crucial establishment phase of their life. This problem is exacerbated by the fact that it’s often cheaper to replace trees than to nurture them, meaning many die out without ever being given the chance to flourish.

However, there may be a better way. Arboreal experts say that if volunteers living in the streets where urban trees are planted were to pitch in with their own wastewater, the saplings would have a much better chance of putting down roots, so to speak. Tap water or grey water would be equally effective in tackling the problem and could help the UK meet its targets at long last.

Lending a helping hand

One of the main issues surrounding urban forestation is that too much emphasis is placed on the actual planting of the trees, with little thought to their upkeep thereafter. However, water is critical to the environment and that’s especially true when it comes to young saplings, which require at least 20 litres of water every single week in the summer, and even more on particularly hot days.

Unfortunately, councils often concentrate on the headlines that planting trees will generate and can’t stretch to nurturing them after the initial commitment. But it doesn’t have to be this way. “If you plant trees from good stock, at the right time, and provide enough water, you’d lose almost none prematurely,” explains Russell Miller, a tree specialist based in London. “But get that wrong, and more than half can die.”

Instead, these problems can be overcome if the general public becomes involved. Instead of forcing young trees to rely on rainfall to satisfy their nourishment needs in the earliest years of their life, local residents could water them with grey water from their house. This could include dirty dishwater, bathwater, washing machine grey water – in fact, any source that does not contain bleach.

Meeting targets

Last year, the UK government pledged to plant 5,000 hectares of new trees, but succeeded in only meeting 29% of that target with 1,420 hectares. When the number of trees which did not survive past infancy are factored into the equation, it’s clear that tree-planting efforts are not even close to meeting their aims.

Even more worrying is the fact that the Committee on Climate Change (CCC) – an advisory branch of the govern which offers expertise and insight into environmental affairs – has said that the UK must plant at least 30,000 hectares and perhaps even 50,000 hectares of new trees every year until 2050 in order to meet its global warming obligations.

While Scotland is picking up some of the slack in this respect (11,210 hectares of new trees were planted north of the border in 2018), the overall picture is not optimistic. As such, any supplementary help that the public can provide, whether it be in the form of planting new trees themselves or contributing wastewater to ensure they become established, is most welcome.