Thirty-five years ago Gristwood & Toms, which is now one of the country's largest firms of arboricultural contactors, was formed by two young men who used an old London taxi to carry their tools. Now, this sort of small-scale operation would struggle. The industry - at least the reputable part of it - is highly professional, with firms offering a variety of services extending beyond tree maintenance and removal through to tree surveys and consultancy.
There are currently around 20,000 people employed in arboriculture, spread across two main sectors. Utility arboriculture has arisen to meet the need of rail and electricity distribution companies to keep trees away from power lines and other infrastructure. This has developed into an entire sub-industry with its own professional organisation and an annual conference.
The other major sector of the industry is in amenity - looking after trees in parks, streets, estates and domestic gardens. While much of this work aims to ensure that trees are safe and not causing problems, this side of the industry also has to ensure that the trees are attractive to look at.
In both sectors, safety of practitioners and the public is paramount. There is also a keen demand for staff. Gristwood & Toms aims to recruit at least 20 people this year. Connaught Environmental, another major contractor, has also launched a recruitment drive.
The work doesn't suit everyone, as Andy Toms, co-owner of Gristwood & Toms, explains: "It looks lovely when it's a nice spring day, but it's not so much fun when it's cold and you're having to wade through a ditch to trim branches."
The manual work is physically demanding and requires a degree of upper body strength. Although many women have worked very successfully in arboriculture, the workforce is still overwhelmingly male.
Most practitioners establish themselves in the industry by acquiring the basic skills and accreditation to operate chainsaws, chippers, stump grinders and trucks. The courses usually last a few days each, and cost a few hundred pounds. Accreditation is generally through NPTC City & Guilds. Being able to demonstrate proficiency in basic skills then opens the door to both casual and regular work.
At this craft level, there is an enormous range of people working in the industry. According to one senior manager: "Some of my staff can't read and write. Some can barely speak English, while some are incredibly eloquent. They all have to be conscientious, have a good deal of common sense and be capable of dealing with the public."
Besides the craft route, an increasing number of people are entering through college courses, often through foundation degrees or BTEC courses. Because so many colleges now offer arboriculture courses, fewer firms are taking on totally untrained staff.
Myerscough College in Lancashire offers an Honours Degree in Arboriculture, in addition to a one-year certificate and a Foundation Degree in the subject. Dr Mark Johnston, research fellow at the college who leads the degree course, points out that a lot of design consultancies and conservation groups want highly skilled academics with an MSc in arboriculture.
At the craft level, most tree work is done in small teams of two or three people. There is a great demand for skilled workers, who can manage a team. Gristwood and Toms, for example, will usually start newcomers at minimum wage. However, people who can work fast and manage teams can earn up to £40,000 a year. Toms explains: "We've got a lot of million-pound contracts, and are prepared to pay good money to people who can get the work done."
Teams usually have a lead climber, a second climber and often an extra person on the ground. After a couple of years, most entrants will be second climbers. After a further couple of years they can expect to be lead climbers, running the team and organising the work.
Besides the physical work, arboriculture offers opportunities for those with higher levels of qualification. This includes consultancy work, often done for insurance purposes. In addition, most local authorities will have at least one tree officer to offer expert advice on dealing with street trees.
Such work is becoming increasingly strategic, setting out how the authority will manage its trees over a number of years, rather than merely reacting to problems as they occur.
Many firms are prepared to pay for staff training. Gristwood & Toms is currently putting 16 people through various on-line courses, and it is paying for two people to do Degrees.