In forestry practice, tree shelters are widely used to protect young trees during their establishment phase. At the same time, however, a growing environmental concern is emerging: many plastic shelters remain in the soil after use and can break down into macro- and microplastics over time. Ambiguous definitions of “biodegradable” further add to the uncertainty in practice. Under what conditions does complete degradation occur—only in industrial composting facilities, or also under real conditions in forest soils? And when can removal of the shelters be safely omitted?

Binding criteria and a transparent framework

“The challenge is to develop materials that are sufficiently durable to reliably protect young trees while also being fully biodegradable,” explains Mihaela Szegedi, Project Manager at Hohenstein. “Our testing methods allow us to specifically identify such materials.” This is where DIN SPEC 35808 comes in: it establishes binding criteria and standardized testing procedures for tree shelters designed to fully biodegrade under realistic forest conditions. The aim is to create a transparent and reliable basis for sustainable product decisions. Hohenstein contributes its extensive research and testing expertise in the field of biodegradation. The testing procedures include analyses of bio-based content, harmful substances, biodegradability under forest conditions, and ecotoxicity. To ensure realistic conditions, real forest soils are used, defined in collaboration with forestry authorities.

Greater guidance for users and manufacturers

DIN SPEC 35808 is aimed at both forest owners and forestry operations, as well as manufacturers of tree shelters. For users, it provides a reliable basis for decision-making, as tested products can be demonstrably converted into natural components without leaving behind microplastics or harmful substances. At the same time, manufacturers benefit from clear testing and quality criteria for developing sustainable solutions and can position certified products more visibly in the market. With this new DIN SPEC, Hohenstein makes an important contribution to reducing macro- and microplastics in forest ecosystems. The goal is to establish materials that do not require removal after use because they biodegrade naturally—thereby strengthening the long-term protection of soils, plants, and the environment.