Abstract Background Trees near construction sites and roads are exposed to an increased risk of stem injuries, and urban trees are also vulnerable to vandalism. Such injuries can result in large wounds, leading to reduced water and nutrient transport, taking several years to occlude, and the apparent risk of decay. Covering the wounds with plastic wrapping has been discussed over the years, but the evidence for its efficacy is not complete. During winter 2020/2021 a total of 248 trees were systematically vandalised in Malmö, Sweden. The two organisations responsible for these trees handled the injuries differently; one wrapped the stem wounds with plastic, and the other did not. This provided a rare opportunity to compare the treatment outcomes in urban field conditions. Methods We studied the effects of plastic wrapping on tree wounds by comparing data from measurements that were performed in 2021 with measurements in 2023. The study focused on 3 genera: maple ( Acer ), birch ( Betula ), and linden ( Tilia ). Results Tree wounds in both linden and maple wrapped in plastic occluded faster than unwrapped trees, but no benefit of wrapping could be seen in birch. There was an overall difference of occlusion rate between the genera, where the linden trees wrapped in plastic occluded faster than the wrapped trees of maple and birch. Conclusions Plastic-wrapping can benefit urban trees with stem wounds. However, the effect is at least genera, if not species, specific. This highlights the need for further studies of differences across different genera and species.
Lund et al. (Mon,) studied this question.