It is important to understand that biodegradability is highly dependent on the environment. Company claims of biodegradability should always be linked to a specific environment.
For example, wood may biodegrade relatively fast in environments, like soil or compost, while these materials can persist for decades in water or landfills. There are cases of perfectly conserved newspapers or banana peels from the 1960s found in landfills today.
As another example, standard PLA requires a thermal trigger (> 50 °C) before the biodegradation process can be started. These high temperatures are achieved in industrial composting facilities. However, when thrown in the composting heap at home this material will not biodegrade in the required time frame.
As this can be very frustrating for customers it is important for producers to clearly indicate in which environment the product is biodegradable and generic claims on biodegradability should not be made.
And please keep in mind, biodegradability should never be used as a license to litter.