China's new 5 percent tax on disposable wooden chopsticks, reflecting concerns about deforestation, has been praised by environmentalists. The move is hitting hard at the Japanese who consume 25 billion sets of wooden chopsticks annually. Almost all of the chopsticks used in Japan come from China. The price of wooden chopsticks in Japan has increased by almost 50 percent. The price increase influences which factor of the external environment of restaurant owners in Japan?