The death and life of city trees: What's gone wrong?

In real life, landscape architect Elaine Cresswell, founder of reShaped in Liverpool, works on sites in the north of England to make spaces for people to play and connect with nature. They are known for recycling materials and enhancing biodiversity.

But on LinkedIn, Cresswell is something of a landscape vigilante. Her posts often share images of shoddy tree-planting on developments in the UK or fresh research on biodiversity – from turf laid over construction waste to raising awareness that urban honeybee hives are bad for wild pollinators.

One recurring topic is urban tree death: 30% of newly planted trees die within the first year, according to the Forestry Commission, while the Arboricultural Association says it’s not uncommon for 70% of newly planted trees to die.

“And that’s just the average,” Cresswell says in an interview for The Developer Podcast. “In Gloucester, they planted 13,000 trees and 95% died due to lack of watering in the first year.” In King’s Lynn, just 10 per cent of 6,500 trees planted were estimated to have survived after being planted too early, The Telegraph reported last year. 

Dead trees are not just an inconvenience, they’re a failed promise and a lie. “It’s greenwashing,” says Cresswell. A dead tree releases all the carbon it’s said to have absorbed over its past and future lifetime – and this absorption will have been figured into net zero and offset calculations. Meanwhile the carbon it is supposed to offset has already been released into the atmosphere, emitted during the sourcing of materials and construction on site.

Why do so many trees die? “People are more expensive than trees,” summarises Cresswell. Replacing a dead tree in the ground is considered more cost effective than paying for maintenance and watering. When 89,000 newly planted trees died along the HS2 route in 2018, a spokesperson said it was a “more ethical use of resources” to let the trees die when compared to the cost of watering them, estimated at £2m.

Drill down into the specifics on every dead tree, however, and there is a longer list of possible reasons, from soil contamination to bad planting – in summary, wrong tree, wrong place.  

“The majority of the issues start long before planting, when the tree is still growing in the nursery,” says Cresswell. “There’s quite a lot of structural problems, in terms of how things are funded, changes in specification, the way the tree is put in the ground, how the soil is prepared, and maintenance.” Cresswell also names a chronic skills shortage in construction as a factor – too few quantity surveyors and landscape contractors have the time, fee or know-how to get it right.

“I’ll get my spade out and dig around in the ground, and generally there’s no soil at all. The turf is laid right over the construction material”

Although trees can take over a decade to die, most problems are there from day one – and many trees can’t be saved. “If they survive for that first year, the lack of maintenance causes problems later on.”

In one case, when brought in to remediate someone else’s work, Cresswell found out of 29 trees, just 16 had survived and most had not grown. The soil was so poor, she had to dig it out and start again.

Another issue is that landscape budgets are spent at the end of a project and are often cut or delivered by the lowest bidder. In addition, landscape contractors are often faced with shocking site conditions: “The soil is so compacted, so full of concrete or type 1 gravel used for scaffolding, that the landscape contractor can’t put the tree in the ground without a pickaxe. Often they’ve under-priced the job and limited their time, so they’re told to just get on with it. Either they walk off the job or put the tree into whatever is there.”

When Cresswell is brought in to identify the problem, it’s usually not hard to spot: “I’ll get my spade out and dig around in the ground, and generally there’s no soil at all. The turf is laid right over the construction material.