We deal with the procedures of plant protection in the forest and their legal framework and restrictions. This includes the option of applying plant protection products (PPPs) in accordance with the integrated plant protection/pest management anchored in the [German federal] Act on the Protection of Cultivated Plants [“Gesetz zum Schutz der Kulturpflanzen”]. The following principle should generally be observed: Only after examining and exhausting all other possibilities can a PPP be applied as a last resort. This upstream, elaborate form of forest protection risk management is science-based, objective and transparent. Generally, it is always about preserving large contiguous areas of forest and thus also the multifunctional services they provide, if possible without using, or, where necessary, with the least possible use of chemical or synthetic PPPs.
As soon as certain insect species reach a population size that will cause damage (gradation) and that seriously endangers the forest stand, the implementation of a regulatory measure can be considered. In this context, the application of PPPs for forest conservation is only considered in special circumstances, for example in the case of mass propagation of voracious butterfly caterpillars such as the gypsy moth or the oak processionary moth. Depending on the threat, a helicopter may have to be used for application of the PPP in the crowns across an extensive area. In bark beetle management, by contrast, the selective application of PPPs can be a suitable tool for forest protection, e.g. when a wood pile is sprayed before the flight of the beetles.