I don't think I'll ever tire of Taiwan's sign culture. I photograph signs around Taiwan all the time. Some of them are amusing. Others are eye-catching and brilliant examples of advertising. A lot of the time, Taiwan's signs can be downright baffling. I ask locals and they don't know what they mean either.
I asked a local about the one below and she thinks it's related to mountain-top deforestation, which is carried out for the purposes of construction and betel nut farming. As anyone living here can tell you, the scraping away of trees from Taiwan's slopes has been met with disaster time and time again. Tree roots hold soil and rock in place. Once they're gone, there's not much left to prevent landslides, which seem to happen every time we have a typhoon or heavy rain. It's true that betel nuts grow on trees. The roots of betel nut trees, however, are shallow, making them a poor replacement for the cypress, yew, etc. that belong at medium to high altitudes.
I have some serious doubts about this sign, taken at up in Baoshan (Bao Mountain), nonetheless:
1. Taiwanese people don't normally own Cat excavators. They have cars, scooters and bicycles instead
2. If the operator goes ahead and actually digs into that slope, he or she is taking a plunge
3. I think you'd have to have some kind of official permission, even if you were doing it on your own property, to proceed; hence, there's no need for a sign
Of course, we can play the devil's advocate and say: "There must be a precedent, or there wouldn't be a sign." Whenever I see something goofy like this, I ask myself: "How is the company that makes these signs connected to the government? Is he or she related to an official?" Simply put, I look for the corruption angle.