Irrigation of forestry crops

The irrigation of young forestry crops is increasingly being discussed as a way of increasing the likelihood of tree survival in the start-up phase. This is becoming increasingly important, particularly in connection with the reforestation of damaged areas and increasing drought due to climate change. In recent years, large calamity areas have been created, particularly in northern Bavaria. In some cases, considerable losses were observed during reforestation due to drought.

Initial practical experience shows that the survival rates of young forest plants can be significantly increased through targeted irrigation in the particularly critical start-up phase. To support reforestation, such irrigation measures have also been financially supported as part of forestry funding. However, there are still many unanswered questions regarding practical implementation. Existing experience from Agriculture, Horticulture and the tree nursery sector cannot be directly transferred to the forest. Complex, stationary irrigation systems are not very suitable for forest crops, where irrigation should be as short and extensive as possible to ensure the survival of the plants in the critical young growth phase. As the root system becomes more developed, resilience to drought events also increases. For the forest, it is therefore important to develop mobile and easy-to-use solutions.

In addition to the pure addition of water, other aspects must also be taken into account in the forest, e.g.

• Early detection of the need for irrigation,
Effects of water addition on plant development or
• supplementary measures such as the introduction of additives.

In view of the increasing frequency of drought phases due to the climate changes that have already occurred and are predicted, the importance of these issues will continue to increase in the future.

Practical scientific field studies are supplemented by work under controlled conditions (desiccation and greenhouse studies). The spatial focus of the investigation is in Franconian areas with a high risk due to the edaphic and climatic site conditions. Areas are selected in close coordination with forestry practice. Furthermore, close cooperation with (forest) tree nurseries and companies with experience in irrigation is planned.

Existing experience in the Agriculture/Horticulture/Tree nursery sector as well as in the international environment with regard to irrigation systems will be analyzed with regard to their suitability for the Central European forestry sector. Suitable elements will be integrated into forestry processes or developed further.

Since the irrigation of forest crops has hardly been an issue in Central Europe to date and has only been practiced by private forest owners in isolated cases, there is only rudimentary practical experience in Central Europe. In-depth scientific studies have not yet been carried out.

Increasing forest damage, also due to climate change, requires increased efforts to reforest calamitous areas on the one hand and a further acceleration of forest conversion on the other. This also requires extensive planting, particularly in coniferous forests that are far from natural. At the same time, there are increasing drought-related problems with reforestation in the dry areas of Bavaria.

The project therefore aims to develop new, innovative methods in cooperation with tree nurseries and irrigation companies in order to ensure the plantations' chances of success even under the changed conditions. It can be assumed that the need for innovative irrigation methods will increase in view of the predicted climate changes in Central Leupea. There are also numerous areas around the world where afforestation requires supportive measures with regard to drought risk. The technologies being developed as part of this project therefore also offer great potential for innovation in the international arena.

The call for potential forest trial areas for the 'Irrigation of forest crops' project in the district of Kronach and neighboring areas ended as planned on July 31, 2022.

"We, the project managers at Weihenstephan-Triesdorf University of Applied Sciences and the district of Kronach would like to take this opportunity to thank the numerous forest owners who wish to make their land available to us for the implementation of irrigation trials. Due to the high level of participation, we will not be able to consider all areas, for which we ask for your understanding. We will sift through all the information received and make a pre-selection. Please be patient if we have to wait a little longer for a concrete response."