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“Flawed” UCD research on BusConnects and trees should be retracted, says campaigner

— Research counted trees in 20 and 10 metre widths on all routes but took no account of proposes, including where there’s no road widening or tree removal planned.

LONG READ: A cycling campaign who has spent over 7 months researching the BusConnects corridors and written 10,000s of words on the project has called on University College Dublin to retract what he said is “completely flawed” research.

The BusConnects core bus route plan by the National Transport Authority (NTA) is a project to improve 230km of bus infrastructure and 200km of cycle routes. But the project has been hit by a large number of objections and public transport user group now fear its roll out will be delayed.

The research on trees by UCD Associate Professor Gerald Mills has featured in the Sunday Independent and the Herald newspapers, on UCD’s website and on, a website run by the UCD Urban Environment Research Group.

An article posted on UCD’s website this week was under the headline “Thousands of trees may face the chop to accommodate BusConnects routes“. The article states that: “Associate Professor Gerald Mills, of the UCD School of Geography, has found that there are more than 4,700 trees growing within a 20m wide corridor along the 16 bus routes earmarked for possible major road-widening.”

In the article, Associate Professor Mills is quoted: “I’m not saying [NTA] are going to cut all these trees… [but] I think they have a responsibility to show where they are going to take away the trees.” But cycling campaigner Kevin Baker said that it’s the “clear implication he created” that the trees are at risk.

In a Twitter thread, Baker has detailed analyses of the issues with the UCD research. Baker said: “The methodology [of the report] is completely flawed. They drew a 20m wide corridor along each route on satellite photos and attempted to count the number of affected trees. This completely ignores the actual published maps from BusConnects.”

An image by Baker showing an example where trees will not be affected:

Baker said that at first the research methodology seems reasonable, but it unrealistically takes a 20 metre example layout that the NTA published and applied it to all routes. Baker said “However, sometimes there is a median or grass verges” and also no road widening where there’s planned car restrictions in the form of bus gates.

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He used the Malahide Road as an example of where there’s a large median with trees on it which will not be changed, while he said that on the Blackrock route there’s also no road widening as the NTA mainly are planning to paint one of the existing lanes as a bus lane.

IMAGE: The NTA’s artist’s impression example of the “Optimum Road Layout”.
IMAGE: An example of a more detailed design where the central median is retained.

Baker also used the example of a residents’ group in Inchicore who want a one-way system for cars so that trees can be maintained.

He concluded: “We can reduce the number of trees that will be affected if we set out our priorities. Do we want to maintain space for private cars at the expense of trees? If not could we make more roads one-way to save trees? That will save trees. To sum up we should #KeepTreesLimitCars. That way we can build a more liveable city that is easy for everyone to move around using sustainable modes. It’s how we improve livability, quality or life and tackle climate change.”

“Why is it wrong to count trees…?”

When contacted by by email, Mills repeated: “At no point did I indicate that all of the trees identified within these buffer zones would be felled, in fact I specifically stated that. So, there is nothing to retract.”

In a further email he said: “Why is it wrong to count trees that will not be directly impacted by bus connects (by removal) if I am assessing carbon services? I did not claim that all trees in the 20 m zone were to be felled, if that were the case, why provide the 10 m results also. Are there trees in the median of very large roads that won’t be removed, probably. Are there trees between the 10m and 20m buffer that may be removed, probably. What is the flaw – is it how it was reported in the Sunday Independent?” replied to ask what was the reason for counting trees in relation to BusConnects when most of the trees counted are not planned to be affected by the project, but there has been no response as of the time of publication of this article.

This website also outlined that it is not just the Sunday Independent that has implied that the trees he has counted are at risk, but also what has been published on UCD’s website and shared widely using the university’s social media channels.

Since sending that email we also have found that the homepage of the UCD Urban Environment Research Group current states that “Our latest research activity is investigating the impacts on trees from the proposed bus corridor” — another clear indication that more than a few people dealing with Mill’s figures think it relates to trees at risk because of BusConnects.

UCD figure triple of unpublished NTA estimate 

Before the Sunday Independent article at the weekend, media reports to date mostly outlined an estimated 500 to 1,000 trees to be cut by the current bus connects plan — in the course of research for this article, has found that this is an underestimation.

The BusConnects public consultation documents for each corridor lists the number of trees possibly to be affected and the combined figure of between just over 1,500 to 1,600 trees. The difference in the figures relates to options on St Mobhi Road in Glasnevin — option A limits through traffic in the northbound direction, while option B removes trees in order

This makes the UCD figure triple the combined NTA estimate of trees at risk, as listed in BusConnects documents.

Saplings vs mature or semi-mature trees

In the article on UCD’s website, it also quotes Mills as saying: “Young trees do a fraction of the work of mature trees so replacing [them] with saplings will greatly diminish [this] existing resource,” but nowhere in the BusConnects documents mentions planting saplings, while mature or semi-mature trees are repeatedly mentioned.

A number of BusConnects documents includes the following line: “Where trees are removed from roadsides and footpaths we will put in place a comprehensive replanting programme. This programme will use mature or semi-mature ready-grown trees where appropriate and, where it is feasible, plant them as close as possible to the original locations.”

“It’s not buses against trees”

“It’s not buses against trees,” said Grainne Mackin , head of communications for BusConnects. She said “we’re trying to find a balance” while maintaining car access. Options being looked at includes more car restrictions by using more one-way systems for cars, and less car parking.

Mackin said: “As part of the detailed design phase we will be carrying out an Environmental Impact Assessment report.” She said it is at that stage where the NTA will know the exact details. is reader-funded journalism. That means it's funded by readers like you.

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Cian Ginty


  1. Uninformed lazy application of a 20m buffer along each of these routes does not constitute research. It’s baseless propaganda plain and simple, designed to mislead the media and public. He’s bringing his university into disrepute and damaging its reputation, though the university seem to be rather complicit in promoting this propaganda on twitter etc.

  2. This is why there is such a problem in delivering cycling infrastructure in this country. People in Universities, Government Departments, TII/NRA, etc drawing lines on maps and then carrying out desk top analysis with no regard to the effect this line will have on the ground. Cycling infrastructure needs to be delivered from the ground up.


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