Young tree saplings are usually protected with plastic sleeves. They protect vulnerable trees from being basically chewed off by rabbits and deer. After some time these plastic sleeves are taken off and can be reused, but scientists say that they still pollute forests with microplastics while they are there. But researchers from UCL say that a more environmentally friendly alternative to those plastic sleeves is possible.
Scientists carried out a Life Cycle Assessment comparing the environmental impact of planting trees with and without shelters. Researchers found that even if that plastic sleeve is picked up after 5 years or so and recycled, the carbon footprint of planting the tree with a sleeve is at least double that of plastic-free planting. Even though some young saplings are killed by animals when they are not protected by plastic, scientists say that it is still the best option. Simply put, planting trees without any shelter leads to the best environmental results, because in this way planting leaves the smallest carbon footprint.
Interestingly, scientists say that polypropylene shelters are preferable to most bio-based alternatives. This is because polypropylene sleeves can be recycled or, even better, reused. Meanwhile the polylactic acid-starch blends, bio-polypropylene and other bio-plastics come with additional environmental impacts associated with agricultural processes for producing biomass. In other words, bioplastics biodegrade better, but their manufacturing processes are more carbon-intensive.
Charnett Chau, lead author of the study, said: “Our study shows that if we only consider Climate Change (or carbon footprint), tree shelters do not have much environmental impact. This is because the amount of carbon sequestered by a tree over its lifetime (25 years) is significantly higher than the amount of carbon emitted due to the manufacturing of shelters and planting activities. However, if we consider a full range of environmental impacts, then planting trees without shelters is environmentally preferred”.
But what if animals will most definitely destroy young trees? Planting them would be a waste of time and resources, which means that some sheltering is unavoidable. That is why The Woodland Trust in the UK is trialling plastic-free options, including cardboard and British wool. These options are viable and quite cheap.
We need more forests and we will have to plant them. But we need to do that in the most environmentally friendly way possible. Avoiding plastics is preferred, but we cannot let young trees die in the mouths of rabbits either.
Source: UCL