Radar will be used to find the best sites for planting urban trees in a pioneering research programme. The $1.45 million, two-year programme will, for the first time, apply state-of-the-art equipment normally used for geological surveys to sort through the tangle of wires, cables and pipes beneath pavements earmarked for trees. Hong Kong University Department of Geography Professor Jim Chi-yung said the ground-penetrating radar allowed tree planters to see beneath the surface. Negotiating the obstacles under Hong Kong pavements and a lack of quality soil make tree planting costly and inconvenient. Many sites lack sufficient water, nutrients or soil stability. Professor Jim said the radar could avoid the need to dig up potential sites to determine their suitability. 'We have to test the applicability of this equipment to the urban soil situation, to potential site locations and to try to see whether it is suitable for the Hong Kong environment,' he said.