A Chinese university has created a special filter to mimic the effects of falling cherry blossoms to stop tourists damaging the trees for the sake of a selfie. Wuhan University in central China is famed for its thousand cherry trees, which attract large crowds of visitors when they bloom in the spring. But some of these hundreds of thousands of visitors have caused problems in the past by climbing onto the trees or shaking them to make the petals fall around them. The new filter, designed in partnership with the video and live-streaming platform Douyin, allows visitors to add this “cherry blossom special effect” to their own shots without damaging the tree. Douyin users are already posting pictures taken using the special effect on the site. For example, one young woman, who said she was a student at the university, posted a short video of her blowing the virtual petals in the air and smiling and waving as they rain down on her. The university is also taking further measures to control the crowds that descend on it to see the blossoms. A notice on its website says that tourists can visit between 7am and 7pm but only if they register at least three days in advance and leave their name and ID number. Crowd sizes will also be capped to 15,000 visitors on weekdays and twice that at weekends. Visitors will then have to provide ID and undergo facial recognition scanning before they are allowed onto the campus. The website also said the university hoped that visitors would “maintain order, protect public facilities, flowers and trees, behave well and have a good viewing experience”. But despite these precautions there have already been some examples of unruly behaviour. On Wednesday the university posted a picture on its official Weibo account showing tourists climbing the trees. The post read: “The cherry trees are hurting, please leave them alone! Please don’t climb the cherry trees, don’t break off the branches, don’t spit everywhere and don’t litter.” Other scenic spots have had similar problems from unruly tourists, who in some cases have destroyed the delicate natural phenomena that attracted them in the first place. Last year a field full of pink grass flowers in a riverside park in the eastern city Hangzhou was destroyed by hordes of selfie seekers who trampled all over the grass.