World Bamboo Day was declared by the Thai Royal Forest Department on 18 September in Bangkok, during the 8th World Bamboo Congress in 2009. This declaration is an effort to increase the awareness of bamboo globally.
Actually I never of this before. Just saw in the news flash as there was a activities to cerebrate this day in Sri Lanka. I'm not sure whether its officially accepted by the UN which normally do for other "days". However this is for the conservation and awareness of Bamboo therefore its good to have a "day" celebrate!
Back in Sri Lanka we do have several varieties of bamboo and we do use them for various purposes. But unlike in east Asian countries like Taiwan, China, Japan etc we do not eat them. In Taiwan Bamboo shoots are well famous as a food.