In recent years, it was found that common tree-ferns （Cyathea lepifera （Hook.） Copel.） in Northern Taiwan and in the Yangmingshan National Park had been dying from what seemed to be disease. To prevent further death of plant populations, the park initiated research on Cyatheaceae plant ecology and possible pathogens in 2009. In order to establish the cause of Cyatheaceae deaths, of which the common tree-fern was hit hardest, the park plotted the number of diseased and/or dead plants geographically and gradually eliminated possible suspects. At the same time, the park proceeded with the disease-control and conservation processes in hopes of preserving the remaining common tree-fern throughout Taiwan.

According to the Forestry Research Institute's Pine Wood Nematode Prevention Pamphlet, since the infection and death of Pinus luchuensis Mayr trees in New Taipei City's Shimen district in 1985, the disease—which is caused by a parasitic worm （Bursaphelenchus xylophilus）—has spread throughout the island. In Yangmingshan, the infection is most serious in the Longfenggu area; minor breakouts have occurred along the Yangjin Highway and Bailaka Highway. The park takes preventive measures according to the pamphlet annually in order to decrease the risk of the disease spreading and to prevent dead trees falling down and endangering the safety of visitors.

A common tree-fern in early stages of the disease

The common tree-fern with leaves turning yellow

The common tree-fern， withering and dying

The Pinus luchuensis Mayr are parasitized by the pine wood nematode