Sunburn on trees

Sunburn can occur in certain types of trees. We protect these sensitive species using materials that maintain a natural appearance. This protection is applied both at the nursery and during planting projects.

In common parlance, sunburn usually refers to sunscreen, a product used to protect your skin from intense sun. Some skin types are more susceptible than others. The situation is no different for trees. Certain trees must be protected from intense sun, otherwise, their bark can burn, causing sunburn. This leads to irreparable loss of quality, which we, of course, want to prevent at all times.

Which trees are sensitive to sunburn

In reality, all trees with a thin, smooth bark are susceptible to sunburn. Well-known examples from practice are lindens and beeches, but maples can also suffer from it. In recent years, the conditions for sunburn have been favourable: prolonged drought combined with extreme heat. Sunburn can especially occur at the end of the afternoon and towards the evening when the sun shines almost directly on the trunk. The angle of incidence is then the largest, which means that the heat on the trunk is the strongest. In the morning, the sun is usually not that strong. Around noon, when the sun is at its highest and reaches its maximum strength, the trunks of trees are protected by their own crown and foliage.

At the nursery, the outer rows are most susceptible to sunburn because the angle of incidence of the sun is greatest there. Therefore, we protect the trunks with coconut fibre mats around them. Generally, one mat (40 by 200 cm) provides sufficient protection for a trunk, starting from the ground. If this is not adequate, we wrap two mats around the trunk.

When protecting, it is important that the material is airy around the trees. There must be sufficient airflow so that the trees can cool down in the heat and can lose their moisture to the ambient air. The climate around the trees then remains as natural as possible. That's why we never wrap the trunks tightly with jute. We always advise against this.

How to effectively protect trees from sunburn

At the nursery, we use the coconut fibre mats from the planting of thicker trees, from trunk size 25-30 cm. The mats also provide protection against frost damage in the winter. We protect the trunks of smaller trunk sizes against sunburn with wild tubes (80 cm height). The trunks remain protected until the crowns have enough volume to provide shade; then sunburn usually can no longer occur.

In some countries, it is common to paint or lime tree trunks white to protect them against sunburn. However, for a more natural appearance, we recommend the use of coconut fibre mats. We can supply these mats together with the trees. As an alternative, reed or bamboo mats can be used in projects to prevent sunburn. Bamboo is generally stronger than reed. No matter what material a tree is protected with, there must still be sufficient air circulation around the trunk.

When selecting trees for a project, one must take into account the environmental factors and the sensitivity of the tree to sunburn. An example of this is a white paved square, surrounded by reflecting buildings, which causes increased reflection of sunlight.

Trees for this application