Made of bamboo.

ETYM Malay bambu, mambu.
1. The hard woody stems of bamboo plants; used in construction and crafts and fishing poles.
2. Woody tropical grass having hollow woody stems; mature canes used for construction and furniture.
Any of numerous plants of the subgroup Bambuseae within the grass family Gramineae, mainly found in tropical and subtropical regions. Some species grow as tall as 36 m/120 ft.
The stems are hollow and jointed and can be used in furniture, house, and boat construction. The young shoots are edible; paper is made from the stem.
Bamboo flowers and seeds only once before the plant dies, sometimes after growing for as long as 120 years.