Being able to define biodegradability for a product that lasts 5 -7 years is highly complex. Whilst there are a number of tests available, they are generally for short life-span products such as weed mulch, which only needs to last three months.
The key for innovative ‘bio’ materials is to understand the result of the PBT (persistent, bioaccumulative and toxic) assessment, which defines whether the material is persistent in the environment. More on this to come.
However, if you’re a professional forester looking to make a judgement on which of the current ‘bio’ offerings is going to degrade in a timely fashion in the natural environment (as promised), then nothing beats the evidence before your own eyes.
This picture was taken of the base of a NexGen tree shelter at Avoncliff Wood near Bradford-on-Avon. After nearly three years in the soil, it’s clear to see that the base of the shelter is beginning to break up, and we can also see a white fungus or mould growing on the surface of the tree shelter, which looks very similar to that found on decaying wood. We’ve already reported the mosses, lichens and algae growing further up the NexGen tube, all of which goes to show that when it’s passed its useful life, NexGen’s unique material will be colonised, then absorbed into the natural surroundings and subsumed by soil organisms, exactly as planned.