RUAN Yisan's name is often in the papers these days. Everytime another old building is saved from the sword in Shanghai, it's reasonably likely Ruan is behind it.

Since June he has petitioned, successfully, to save Nie's Garden, an 8,000-square-meter, 1920s private estate in Yangpu District, and the 100-year-old Shanghai Rowing Club on the Bund. In March, he also petitioned to save several buildings in Shanghai's former Jewish quarter in Hongkou District.

As the city's foremost preservation expert, Ruan's is one of few voices that are listened to.

Officially, he is director of the International Historic Cities Research Center, a Tongji university professor, and founder of the Ruan Yisan Foundation for architectural preservation.

But he is better known for his part in saving high profile historic areas nationwide - many of which are now UNESCO world heritage sites. These include Pingyao in Shanxi Province, Lijiang in Yunnan Province and six water towns in the Yangtze Delta.

"If I don't do it who will?" said the frail looking man, now 75.

Delicately built and softly spoken, Ruan's words nevertheless pull no punches.

Speaking of his research on the Grand Canal's current application for world heritage status, he said he took on the project because, "Nobody else was doing it right. They take a flight there, drive around, have a banquet and call that research."

His bad temper has become his trademark in the Chinese media and when it comes to heritage architecture Ruan has a lot to be upset about.

Since the economic reforms of the late 1970s, sweeping modernization has bulldozed much of China's historic architectures. In the 1990s Shanghai earned the dubious honor of having the highest concentration of construction cranes in the world, and the World Bank predicts that from now until 2015 half the world's new building construction will take place in China.

In Shanghai, 12 conservation districts have been designated but according to Ruan these areas have favored high quality villas ahead of the more historically important longtangs typical of everyday life.

"I have long argued that longtangs reflect Shanghai vernacular culture, but for so many years we had no longtang protection zone," he said. Petitions made headlines recently as a result of a three-month research project led by Ruan at the end of 2008. With a 173 strong research team, he fine-combed the non-listed areas in Shanghai for more architectural treasures.

The report recommended expanding four of the 12 listed protection zones and adding another five areas. According to Ruan this would add another 2.62 square kilometers to the 27 square kilometers currently under protection. The report has been submitted and is awaiting official reply. Such efforts are symptomatic of Ruan's lifetime of campaigning.

In 2006, the now extremely valuable art district M50 on the banks of Suzhou Creek was slated for demolition. Ruan moved his offices into one of the warehouses and invited city authorities to listen to his petition in the houses they were planning to destroy.

Over two years from 2006 Ruan also travelled 1,794 kilometers of the Grand Canal by foot and slow boat to carry out thorough research.

In the Shandong stretch of the journey, Ruan was bitten by a dog in a local village and had to endure months of rabies injections. Recently while visiting Yanshan, he collapsed from exhaustion and was hospitalized for two months.

Ruan describes himself as a particularly persevering, almost stubborn man. If he sets out to save a building he has to follow it through to the end.

"I love my culture. As a Chinese person who has been abroad, I know that Chinese culture is so unique and irreplaceable. I hate to see it being violated or treated roughly," he said.

Ruan cites traditional woodwork techniques as particularly ingenious. Developed over hundreds of years and adapted to local conditions, wood joints using not a single nail result in buildings able to withstand earthquakes.

In 2007, Ruan renovated an historic area called Zhaohua in Guanyuan City, Sichuan Province. Consisting of mostly wooden structures, the old city survived intact while nearby modern buildings fell to the massive May 2008 earthquake.

"But there aren't any courses left to teach traditional wood building techniques," Ruan lamented.

He has spent most of his career at Tongji University. Graduating in architecture in 1958, he had the unique opportunity of working with a German professor from the Bauhaus Universitat Weimar while all other classes had Soviet advisors. Under his tutelage, Ruan's views of preservation became heavily influenced by Western European cities and how they dealt with post World War II reconstruction. "Europe went through a burst of post-war modernization, just as we are doing," he said. "But quickly they realized that they didn't have to destroy all their historic architecture to build a new city. That's the model we should follow."

Ruan was inspired during his studies by the professor's attempts to save an old wall in Suzhou, and fieldtrips in which he travelled with the students all over China for observation. Pre-1980s development, most buildings remaining from ancient China were intact.

The areas of Shanxi and Shaanxi provinces made a particularly deep impression on Ruan. He remembered its ancient walls, turrets, temples and residences dating back to the Ming Dynasty (1368-1644) were "incomparably complete" in the 1960s.

But on a return visit in the 1980s Ruan found ancient walls were being dismantled for roads. By then Tongji University had already gained national prestige for urban planning and Ruan leveraged it to lobby local officials.

He petitioned to take over the planning for Pingyao - a city in Shanxi Province and China's financial center during the Qing Dynasty (1644-1911). His urban plans preserved 300 sites of historic ruins, 4,000 residences and streets and storefronts that retain their historical appearance.

But saving a building from demolition doesn't guarantee its integrity.

Ruan's other famous "saves" - Zhouzhuang water town, and the world heritage site Lijiang - were to suffer for their beauty.

Ruan had recommended that instead of being bulldozed for skyscrapers they be retained for tourism.

His suggestions were implemented - but garishly so. Both sites have become overly exploited.

"I recommended around 3,000 tourists a day for Zhouzhuang," said Ruan. "Now there's 10,000 passing through it everyday."

As a consequence residents have moved out, renting their space to shops and restaurants.

The historic area itself has turned into a shopping arcade. Developers have moved in to surrounding areas to build apartments and hotels.

The protected site then becomes a piece of isolated countryside within a developed area. But doesn't true preservation cost too much money? "Preserving old buildings isn't expensive - land is expensive." Ruan emphasizes.

"It's about making 20 times more profit from building high-rises on the same plot of land."

When it comes to destroying historic architecture, Ruan believes money and greed are the roots of evil. There are consequences to this profit obsessed age he said: "If you eat three bowls of rice instead of one, you will get fat."

But the problem of money perpetually haunts this campaigner. The first round of funding for his foundation has come from appeals to businesses and connections in his personal, formidable contacts list.

But Ruan admits he is running out of ideas for a second round of funds, particularly as laws prohibit him from advertising publicly for donations. He is thinking of going abroad for funding.

His own children, now adults, also work at Tongji but not in preservation. He says, however, there are many students to carry on the work. The future of preservation will be a battle between profit and awareness, mind over matter.

"The ones who come after me will have an easier job, there is more awareness. But there will also be more economic pressure. There is opportunity and danger."