A series of carbon nanostructures were prepared via a biotemplate method by catalytic decomposition of bamboo impregnated with ferric nitrate. The natural nanoporous bamboo was used as both the green carbon source and the template for the in situ growth of carbon nanostructures. Scanning electron microscope, field emission transmission electron microscope and energy dispersive X-ray spectroscope were used to characterize the product. Four distinct structural types of carbon nanostructures have been identified, namely nanofibers, hollow carbon nanospheres, herringbone and bamboo-shaped nanotubes. The effect of reaction temperature (from 600 to 900 T) on the growth behavior of carbon nanostructures was investigated and the corresponding growth mechanism was proposed. At low temperature the production of nanofibers was favored, while higher temperature led to bamboo-shaped nanostructures. (C) 2014 Elsevier Ltd. All rights reserved.