Two mainlanders were being held for questioning last night accused of stealing Buddhist pines after being nabbed in a 10-minute high-speed chase off Sai Kung. Marine police found six of the prized fung shui trees in the boat after the chase on Monday night. It was the seventh such case this year. There were 13 cases in the whole of last year. A further eight trees were found in a broken-down speedboat adrift off nearby Conic Island. A third boat escaped after picking up the driver of that craft. The arrests were made after an anonymous tip on Monday that Buddhist pines were being stolen in Sai Kung Country Park. An air watch was mounted and at 9pm police in a Government Flying Services helicopter spotted three speedboats heading into Hong Kong waters towards the village of Sai Wan in Tai Long Wan. Three pursuit craft were sent and as they approached, a speedboat was seen fleeing at high speed towards mainland waters. 'The speedboat with two men on board refused to stop and zigzagged in an attempt to avoid interception,' Superintendent Jackie Ling Wai-po said. It was intercepted after a 10-minute chase and two men aged 28 and 30 were arrested. As another police boat was searching the coastal area, the two other speedboats took off, one breaking down off Conic Island. Police said no trees could be seen on the third boat as it fled with the driver of the disabled boat. 'We believe there has been a rise in such thefts because of an improving economy and greater demand for the pines on the mainland,' Superintendent Ling said. A police source said mainlanders previously were paid $60 a day to come to the city to steal Buddhist pines, but were now paid $100 because of greater demand. Buddhist pines, believed to bring good fortune, can fetch between 6,000 and 8,000 yuan.