It was a six-year saga in Yorkshire's 'outdoor city' where peaceful protestors were arrested by police and the unlikely bedfellows of Michael Gove and Jarvis Cocker were united in opposition to Sheffield City Council.
Sheffield's political leaders are keen to draw a line under the controversial tree-felling programme, which resulted in thousands of trees removed as part of a £2.2bn outsourcing contract and brought a succession of negative headlines to the city.
But according to Matthew Flinders, Professor of Politics at the University of Sheffield, the saga and the protests which sprung up over the years had an unintended consequence in acting "as a nursery for civic knowledge and political activism".
In a new book, The Politics of Street Trees, Professor Flinders argues that the failure of the Labour-run city council to engage with local campaigners "was not specific to the issue of tree maintenance but was itself symptomatic of a highly defensive political culture and very centralised decision-making process within the city’s political system".
Describing a spillover effect from trees to a broader range of issues, he writes: "The political skills, knowledge, confidence and insights that active citizens had developed while campaigning for the trees were increasingly applied to a broad range of areas.
"From road building standards to judicial review procedures, from arboreal practices to legislative frameworks surrounding the policing of protest, through to freedom of information and public finance initiative projects – the tree campaign inadvertently acted as a nursery for civic knowledge and political activism."
On May 6, the results of this trend will take a tangible form as voters across the city have their say on the way the city council is run in a legally-binding referendum that could have far-reaching consequences for Sheffield and local democracy.
It takes place alongside council and police commissioner elections as a result of a petition signed by more than 26,000 people in the city, representing more than five per cent of Sheffield voters and meaning that under the Localism Act 2011 a governance referendum must be held.
Currently, all 84 Sheffield councillors elect a leader who then appoints a cabinet made up of nine other councillors, each with responsibility for different areas.
It means that in practice decision-making powers are held by just ten councillors. Full council meetings of all 84 councillors have tasks including approving the council's budget but are usually a forum for political debate and questioning decision-makers.
Under the alternative committee system proposed by the It's Our City community group which organised the petition, full council would take on decision-making powers rather than the executive.
Decisions about policy areas such as transport would be made by a committee of 12 to 14 councillors from all parties, with the chair of each one sitting on a policy and strategy committee which would set the overall direction of the council.
The key difference, according to Ruth Hubbard of It's Our City, is that under a 'modern committee system' elected local councillors would play a bigger role in decisions.
And the group's website says the current system is "undemocratic, leads to bad decisions, and causes a focus on divisive party politics instead of doing the best for the city".
It adds: "The 10 councillors who actually have power to make most decisions (whether Labour or the LibDems in recent years) are unrepresentative of the city and are indebted to the council leader for their positions and the extra money they get.
"Power in the council is based on the feudal patronage of the leader, rather than ability or merit and it relies on secrecy and the exercise of power by the few.
"Full council meetings in Sheffield are dominated by tribal, party-political slanging matches where the small group in power acts as 'if you aren’t with us, you are the enemy'. The breadth and depth of experience and knowledge available from all 84 councillors is being wasted."
Though the strong leader model is operated widely by Yorkshire's town halls, the way it works in Sheffield has prompted particular criticism. Leeds city council's ruling executive committee has a Liberal Democrat and Conservative councillor on it, in what campaigners describe as a "benign" form of the model.
And the ruling Labour group in Sheffield received only 32 per cent of the vote in the 2019 local elections, a smaller share than in any other 'core city' and meaning its councillors only represent 9.7 per cent of the electorate.
Even if the current system is retained after the referendum, Sheffield City Council has promised to make changes. A new cross-party policy development and performance committee will look at major proposals before they are decided by cabinet or individual cabinet member as part of overview and scrutiny arrangements.
And seven new local area committees will be set up, each with £200,000 in funding, in a move the authority says will "revolutionise how citizens can influence the decisions that matter to them and their communities".
The council says these committees will be the "principal means by which the council engages, empowers, enables, and seeks the active participation of all residents and community organisations on any topic of local interest."
Paul Blomfield, Labour MP for Sheffield Central, says these plans to "shift power to communities" are more significant than the referendum itself. He told The Yorkshire Post: “The referendum misses the real point. How decisions are made in the Town Hall isn’t a big priority for most people. We should be giving people a proper voice in the issues affecting them locally."
It's Our City says changes to the system are backed by local councillors themselves. When it approached more than 140 candidates standing for election this year, around 84 percent across the political spectrum said they did support a switch to a committee system.
But Henri Murison of the Northern Powerhouse Partnership organisation, and himself a former senior Labour councillor in Newcastle, wrote in a recent article that the idea "would cripple Sheffield politically and economically, weakening its ability to make strategic, long-term decisions and diluting its capacity to affect real change for local people".
He adds: "I worry that businesses will not choose to invest in a city where they’re unsure of the future direction of travel. Nothing undermines confidence more quickly than uncertainty and a rocky political system could trigger a mass exodus in private investment leaving the city.
"Jobs, investment, livelihoods are at all at risk should voters choose this moment – as we make the first steps towards a COVID recovery – to overhaul the council and throw Sheffield’s local government into confusion and chaos."
According to Richard Wright, a former director of Sheffield Chamber of Commerce, a committee system “stifles dynamism”. He wrote this week: “Its very nature is inherently biased towards inaction. If no-one can agree on something, then the default is to do nothing.”
But Olivia Blake, Labour MP for Sheffield Hallam and a former senior city councillor, said the committee system “offers an exciting opportunity to open up local democracy in Sheffield”.
Sheffield will be joined by the London borough of Newham holding a referendum on a change to a committee system, which already exists at councils including Belfast, Nottinghamshire and Brighton.
And while Sheffield City Council appears to have been dragged unwillingly into reform and is staying neutral in the referendum itself, Newham's elected mayor Rokhsana Fiaz is enthusiastic about the changes and describes changing the way the council works "so that we build a culture of trust and openness that involves our residents in our decision making”.
According to Ruth Hubbard, the current council administration "has been effective in maintaining the status quo for so long and has sought to ignore and deflect for so long whilst clinging onto the power of the few under its extreme strong leadership practices - and despite its own party members calling for change".
She adds: "Communities and citizens have been 'locked out' and the work we have done, resident to resident, has been something of a turning point. It's somewhat ludicrous that we have to battle for a basic democratic right to be represented in decision-making but that's where we are."