A GEOLOGY professor is spearheading a campaign to stop Hong Kong's country parks from being blighted by concrete slopes. For 20 years, Professor Gordon Maxwell has led groups of geology students to Sai Kung Country Park to spend a day scrutinising volcanic rock formations that date back at least 140 million years. But last week, when Professor Maxwell brought this year's batch of Open University students out to study the cliff face, they found it was lost behind a wall of concrete. 'We found our outdoor lab had been destroyed,' said Professor Maxwell. 'There's a terrible contradiction between promoting country parks for eco-tourism at the same time as the waterworks are coming out and covering them up with concrete.' To prevent landslides, the Government coats precarious slopes with a spray-on 'shotcrete'. But scientists and some conservation officials believe the concreting has gone too far in country parks and is ruining the natural landscape of Hong Kong. The official policy is to cover steep slopes in concrete only as a last resort. Alternatives include planting grass and stabilising vegetation on the slopes. But in reality often the road maintenance and waterworks departments apply concrete first - with safety in mind. Following several fatal landslides in the early 1990s, the Government increased its slope-stabilisation budget from $70 million a year to $900 million last year, said Dick Martin, chief geotechnical design engineer for the Hong Kong Geotechnic Office. In the past five years, the Government had quadrupled the number of slopes it covered in concrete, from 30 a year in 1995 to more than 150 last year. In the next decade, 200 would be covered, he said. Along with every slope, came a white slope-identification sign that community members had begun to complain ruined the park atmosphere. Mr Martin said slopes in country parks were often smaller than their urban counterparts and did not tend to present the same landslide risk. 'It's not possible to give hard-and-fast rules about which slope should be covered,' said Mr Martin. 'From a design point of view, we prefer the use of grass, but all things being equal shotcrete is safer.' But Professor Maxwell said using shotcrete in Sai Kung amounted to throwing the baby out with the bath water. In Sai Kung Country Park, knee-high slopes and rocky outcrops had been covered near High Island reservoir, although they did not present any danger of landslides, the professor said. Students needed to have access to the rocks to learn about the earth science and they needed to have hands-on access to the history of the formation of Hong Kong, Professor Maxwell said. The students were introduced to spectacular rock formations - weathered maroon, orange and black cliffs that might sink 400 metres into the ground in columns. Professor Maxwell is not alone in worrying about excessive concreting. Dr Wong Fook-yee, assistant director for the country and marine parks for the Department of Agriculture and Fisheries, said the Department was concerned about the impact on the environment. 'We are trying to take the initiative to reduce it, but if you want to make the slopes stable with seeding, it is likely it will take more effort and be more costly than shotcrete,' Dr Wong said. He has called for a meeting of all government departments that deal with slopes to try to come to a consensus about reducing the amount of shotcrete used. Professor Maxwell said the concrete would damage the slopes in the long run in country parks - slopes that were stable for hundreds of millions of years. 'When water gets behind the concrete, it can come off in a big slab. They'll have to keep covering it and eventually it will damage the slopes to remove it.'