Real-time flexural fracture behaviors and toughening mechanisms of bamboo slivers with different fiber content and moisture content

•Real-time fracture generation and propagation were measured in bamboo slivers during bending.•Fractures formed and progressed faster in bamboo slivers with low fiber/moisture content.•Tensile strengths of pure fiber cells and parenchyma cells were 624 MPa and 24 MPa, respectively.•Fiber and moisture content contributed to toughening by deflecting fractures.