A head for heights is a fundamental requirement for would-be scaffolders. Even so, the early years can test the resolve of the most daring apprentice. 'When I first started out I was pretty scared,' says 57-year-old Chiu, who entered the trade when he was 15. 'But there wasn't much that could be done about it. You just had to be brave and climb up the scaffold.'

Like other novices, Chiu's duties in the first six months were restricted to fetching and carrying. 'All we did was carry tools, bamboo poles or whatever was needed up to the sifu,' he says. 'Naturally, they didn't let me handle any of the actual construction of scaffolds.'

It was years before Chiu got to work on 40- or 50-storey scaffolds. At those heights work gets more complicated. 'There's a lot more wind, so we would be swaying while hanging onto the scaffolds,' Chiu says. 'Sometimes the wind gets so strong we can't work at all.'

Many factors contribute to the popularity of bamboo scaffolding in Hong Kong, but the main ones are that it's cheaper and faster than alternatives. It can be put up three times faster than metal frames, Chiu says. 'One worker can put up 750sqft of bamboo scaffolding a day. But for metal scaffolding, three to four workers would be needed because it's much heavier.'

Over the years, the building industry has experimented with other materials. One company developed a synthetic rod designed to be just as light and strong as bamboo. But each pole cost $20, so no one used it, says Tang Sung-yuen, a scaffolding instructor at the Construction Industry Training Authority (Cita).

Bamboo also has the advantage of being suited to odd-shaped structures. 'Metal scaffolding just doesn't have the flexibility to accommodate odd shapes,' Tang says. 'Take the Hopewell Centre or the Bank of China building, for example. I can't imagine how anyone could use metal scaffolding for those surfaces.'

On the mainland, low labour costs make metal scaffolding a feasible alternative to bamboo. 'You could hire someone across the border for $70 a day,' Chiu says. 'But in Hong Kong, getting the work done quickly and with few workers makes a big difference because the union rate for scaffolders is $850 a day.'

As well, the mainland was forced to use metal during the heyday of the construction industry in Hong Kong because its supply of good bamboo was exported here, he says.

Mainland builders use a mixture of bamboo and metal because the sites are much bigger, with room for larger foundations. But Hong Kong's high building density means scaffolds rest on smaller foundations, restricting builders to poles that weigh less than 5kg each, Tang says.

To the casual observer, there haven't been many changes to the craft apart from the bamboo strips for tying the poles together being replaced by plastic cords. This simple switch has helped speed construction, says Tang. 'Because plastic is stronger, we can use fewer poles, which means structures take less time to build.'

Scaffolding used to be solitary work. 'In my day, we were pretty isolated even though there would be several scaffolders on the same site,' Chiu says. 'Everyone just went about their business and there weren't many opportunities to chat.'

Loneliness was never an issue, he says. If you were working, you were earning money. 'Now, it's different because machines lift the bamboo up, so it's more of a group exercise and people gather together more. Previously, workers had to have a lot more stamina and independence.'

Safety has improved considerably. Workers are required by law to wear harnesses, and years of public education has raised awareness of safety issues. Accidents still occur - two workers were killed last July after the scaffolding they were working on at a San Po Kong industrial building collapsed - but Chiu says there are fewer tragedies.

However, cost-cutting has resulted in an assembly-line approach that Chiu says is eroding skills. '[Less experienced] workers put the poles into place and all the sifu does is tie the knots,' he says.

Chiu says his objections don't spring from nostalgic yearning. Because younger scaffolders aren't given a range of tasks, many no longer know how to construct more complex structures, he says. Relying on cranes or other machines to haul poles to different levels also has an impact. 'It might seem like just manual labour, but lifting bamboo also trains endurance and agility,' he says. 'Bamboo scaffolding isn't just a construction tool, it's a traditional Chinese art form, as well.'

According to legend, the earliest Chinese tribes were granted knowledge of bamboo construction by Youchao-shi, one of three kings who ruled the world when it first began. This is why scaffolders revere Youchao-shi as a patron deity and celebrate his birthday on the 19th day of each lunar year, Chiu says.

Bamboo scaffolding is ingrained in Hong Kong culture. Chinese opera stages are constructed out of bamboo for major events such as the Tai Ping Sun Chiu festival at Sheung Shui Wai village earlier this year, which occurs once every 60 years.

At the 1986 World Expo in Vancouver, the Hong Kong pavilion was made entirely of bamboo, with craftsman changing the facade throughout the event.

Whatever form it may take, bamboo scaffolding is here to stay. With the construction slump after the handover, there was about 40 per cent less work for scaffolders, compared with the golden years of the early 90s, says Tang. But the trade is now enjoying an upswing. 'Our current crop of students don't graduate until August, but we've already been getting calls from employers.'

Scaffolders are also in demand outside construction sites. Scaffolds are needed to help fix leaking pipes, install neon signs or air-conditioners, repaint facades and other maintenance work.

'There are a lot daily maintenance jobs out there that need doing,' Tang says. 'If the government passes the bill requiring buildings more than 20 years old to be inspected every seven years, then there will be even more work.'

Apprentices these days have the advantage of Cita's programmes, which are funded by a 4 per cent tax on all construction work exceeding $1 million, Tang says.

When he followed his father into the trade 33 years ago, training was 'entirely haphazard'. Novices had to pick up skills on the job. Since the establishment of the statutory body in 1975, youngsters can receive training in nine different trades, including scaffolding.

'I'd say that one year here is worth three years outside because everything is taught in a much more systematic manner,' Tang says. 'Obviously, we can't teach everything in one year, but we give them a foundation, and afterwards we help them find a job where they can practise what they learnt.'

And because a lot of trainees are teenagers, he says, the instructors don't just teach techniques but also how to be a responsible person. Learning to work with others, to have right attitude and be responsible is all as important in the workplace as technique, he says. 'If I teach even one person well, then it will be a service to the trade.'

Ng Tsz-kin, 17, is among this year's batch of Cita trainees. 'The hardest part of the course was learning to tie secure knots, but it was satisfying to see the first scaffold I built.'

Ng can expect to earn about $350 a day after completing the course. And if he passes the advanced trade test after three years on the job, he'll be recognised as a master scaffolder, entitling him to a daily wage of between $800 and $1,000. That may seem a long way off, but Ng sees scaffolding as a lifelong career. 'I will definitely stick with being a scaffolder.'

Chiu, who just retired from a 16-year tenure with Cita, can empathise. 'Once a scaffolding man, always a scaffolding man,' he says.