Cluster Woodland and forestry

Germany’s forest or woodland areas amount to approximately 11.4 million hectares which equates to roughly a third of the entire land surface. Owing to their multiple ecological, economic and social functions, woodland and forest ecosystems are of particular importance. The Federal Forest Act therefore requires that the forest (including woodlands) is to be conserved, and all its functions are to be maintained and, where necessary, enhanced and its proper management is to be safeguarded.

The heat and drought years of 2018 to 2020 as well as 2022 have demonstrated with unprecedented clarity to what extent climate change is a threat to the forest’s existence. Quite suddenly, the issue is no longer ‘just’ to safeguard the forest’s condition, growing capacity and good structure but its conservation in general. It has become a challenge to safeguard the actual forest area, while the reforestation of calamity areas has turned into a Herculean task making substantial demands on financial and staffing capacities. The objective must remain to maintain the forest functions for protecting water, soil, biodiversity, regional climate and as a source of recreation for human being; functions that are even more important in the face of climate change. Not least, forest conservation is indispensable also in terms of climate protection, as woodlands and forests are important carbon sinks. Whenever a vast expanse of forest dies or burns down, it becomes an additional source of greenhouse gas emissions – completely contrary to this goal.

Climate change and the associated extreme weather patterns – such as heat and drought and possibly also storms – combine to confront forestry with one of its greatest challenges. The impacts on the nation’s forests have to be taken very seriously as climate-related changes are progressing at unprecedented speeds, thus overwhelming the natural adaptability of long-lived forest ecosystems.

The impacts of climate change can be seen both in natural, unmanaged woodlands and in forests which are more or less subject to intensive silvicultural utilisation. It has now been 30 years during which the condition of the forest has been recorded in order to obtain an integral picture of the vitality of trees and forests (cf. Indicator FW-I-3). Up until the end of the 1990s, data reflected the positive effects of a decrease in pollutant inputs. However, after the summer of 2003, it became evident for the first time that drought and heat were having serious detrimental effects on forest and woodland ecosystems, especially in areas with site-inappropriate growing stock. The drought years of 2018 to 2020 later demonstrated the momentous scope of the problem. There was increasing evidence of the canopy breaking up. From 2019 onwards, it became obvious that all tree species (including a proportion of dead trees still standing) were increasingly affected by dieback. As far as spruce and pine are concerned, the dieback rate peaked in 2020, while values for the deciduous beech and oak were continuing to rise in 2021 (cf. Indicator FW-I-4). In those years, numerous trees died completely, thus having to be removed from forest stands. The proportion of unscheduled utilisation (in technical parlance: arbitrary use) of damaged timber, compared to the logging total, reached record values in 2019, amounting to 67 % and in 2020 reaching almost 75 % (cf. Indicator FW-I-5). In 2021 this proportion – with just under 61 % – still amounted to almost the same percentage as in 1991 after hurricane Lothar. Up until 2018 the peak values of unscheduled or arbitrary use of damaged timber had been due to severe storm events. As of 2019, the ‘insect timber’ amounted to just under 70 % whereas by 2021 it distinctly accounted for the bulk of the proportion of damaged timber, with more than 81 %. The bark beetle, in particular, benefitted from recently deceased or weakened trees as a result of warm weather patterns and an abundant supply of breeding sites. This enabled a distinctly greater number of reproduction cycles and broods (regionally up to six cycles) annually (cf. Indicator FW-I-6). This mass reproduction of beetles affected spruce trees in particular: The volumes of damaged timber owing to infestation with spruce bark beetle in some Länder in the years 2019 to 2021 was a hundred- to two hundred-fold higher than on average in the years of 1998 to 2017 (cf. Indicator FW-I-7).

Heat and drought also made their mark on the forest fire statistics. During the period between 1991 and 2017 the expanse and number of forest fires was still decreasing despite – in meteorological terms – an increase in forest fire hazards. Forest fire prevention and rapid intervention as soon as a fire was breaking out, made it possible to prevent major damage. However, in 2018 and 2019 the extreme weather patterns were also clearly reflected in the forest fire scenario. There were considerably more and – in the north-eastern Länder – more large-scale forest fires. The most extensive forest fire occurred in Mecklenburg-Western Pomerania where an area of 944 ha was destroyed (cf. Indicator FW-I-8).

As already mentioned in the 2021 Climate Impact and Risk Analysis (KWRA) major risks were identified for the middle of the century regarding heat and drought stress, stress from pests and diseases as well as detrimental effects on timber yields. A high risk of forest fires is expected to arise by the end of this century. Nevertheless – as for the other climate impacts – there is limited certainty regarding this projection. The experience of recent years has demonstrated – especially in the field of forestry – that it is necessary for any calculations to allow for surprising developments. As far as wind-throw damage is concerned, the risk for the present up to the end of this century was assessed as consistently medium (within an assessment grid of low – medium – high), because so far there are no development trends regarding storms discernible. Likewise, there is limited certainty regarding this assessment. The risk of limitations to the recreational function of woodlands is assessed as medium – albeit with low certainty – as of the middle of this century. Largescale forest damage can impose major restrictions on the recreational quality and attractiveness of woodlands and forests. If, at the same time, the recreational function were to gain in importance, the utilisation pressure on healthy woodlands and forests might increase.

Any changes in the composition of tree species and in terms of growth are recorded within the framework of the National Forest Inventory (BWI); however, this survey is conducted every 10 years only. This is also the reason why it is not possible to include a statement in this Monitoring Report on the prevailing tree species mix or the proportion of mixed forest stands. Already in 2019, it was not possible to provide new data for this important indicator (then entitled FW-R-1 Mixed forests) compared to the 2015 Monitoring Report. For an update, data are required from the 2022 BWI which will only be available in 2024 after the submission of this report. The indicator on mixed forests is therefore based temporarily on the 2023 Monitoring Report. Interim inventories identify the condition of the German forest estate on the basis of a restricted range of characteristics for a quarter of the BWI inventory focal points; the data provided refer primarily to the greenhouse gas reporting submitted at Federal level. The interim inventory data from 2017 in respect of carbon reserves made it possible to update and re-issue the indicator for humus reserves in the forest (cf. Indicator FW-R-3). Furthermore, it was possible to make use of the inventory data in respect of the timber increment (cf. Indicator FW-I-2).

Research projects are underway exploring issues such as the utilisation of satellite image data in order to obtain information on any changes in the composition of tree species in a higher temporal resolution than the BWI. For example, the TI for Woodland Ecosystems – in the joint project ‘WaldSpektrum’ financed from the Waldklimafonds (woodland climate fund) – identifies remotely-sensed data on the prevailing spruce stocks in order to provide forestry employees and forest / woodland owners with an improved planning tool. With a view to the rapid progression of changing forest scenarios as a result of drought years and the intensive efforts in respect of forest transformation, the BWI conducted every ten years will no longer suffice to illustrate actual changes in a timely manner.

There are also still gaps in terms of data and information regarding the identification of calamity areas and the volume of damaged timber. The diagnosis of wind-throw areas or large areas with tree death symptoms as a result of pest organisms is possible – both operationally and in terms of real-time observation – by means of remotely-sensed satellite data; the methods for identifying the volume of damaged timber have not yet been properly established. This gap is to be closed at least partly, as of 2023 by the woodland climate fund project entitled ‘Fernerkundungsbasiertes Nationales Erfassungssystem für Waldschäden’ (FNEWs / Remote-Sensing based national detection system for forest damage) operated by the TI. This system is to provide information regarding areas affected by tree death, the volume of damaged timber and other adverse effects on the economy.

Data from the intensive Environment Monitoring in Forestry (LEVEL II) have so far not been used in terms of indicators for the DAS woodland and forestry action field. For the ‘soil’ action field, an indicator was developed in respect of soil water in forest soils (cf. Indicator BO-I-2) on the basis of a case study for Bavaria. As before, explorations at LEVEL II regarding nationwide assessments continue to be restricted despite harmonisation efforts. As far as soil water is concerned, the TI is currently involved in work aimed at generating homogeneous and gap-free time series with the aid of water-balance models.

While it is already possible to illustrate a wide range of themes in respect of impact indicators for the woodland and forestry action field as part of DAS-Monitoring, there are still gaps at the level of responses in relevant fields of activities. For example, as yet it has not been possible to develop a suitable indicator regarding the theme of woodland conservation measures (controlling deer damage, deer management monitoring, monitoring and curbing forest pests). Neither has it been possible yet to illustrate forest fire prevention and control by means of data.

Given that forests are very long-lived ecosystems, forestry managers need to plan far ahead to take account of changing growth conditions. The aftermath of the drought years has shown that forestry managers are required to be highly responsive. Scheduled management tasks will always have to yield to priority challenges in order to ensure that there is sufficient capacity available to cope with extreme events.

There is policital and operational support available at many levels for the conversion of forests towards more climate-stable stands. Apart from the funding provided for research within the framework of the woodland climate fund, the financing of forest transformation in state-owned forests as well as the funding available for privatly-owned forests , especially within the framework of GAK have been expanded considerably (cf. Indicator FW-R-1). At the end of 2018 GAK introduced a new eligibility status ‘Funding for remedying impacts on woodlands caused by extreme weather events’ in order to expedite the clearing and reforesting of calamity areas. Furthermore, in 2022 the funding programme entitled ‘Climate-adapted forest management’ was established by BMEL for the benefit of private and municipal forest owners; this fund is endowed with funding from the Climate and Transformation Fund (KTF) for the purpose of accelerating the development of stable and climate-resilient forests. Among the eligibility criteria for funding are, for instance, the requirement that measures are implemented for water retention as well as the conservation and maintenance of humus (cf. Indicator FW-R-3). The BMBF also provides funding for innovative climate-protection solutions for forest and timber management by means of the ‘REGULUS’ funding measure.

In order to ensure a site-appropriate and future-resilient selection of tree species in the process of rejuvenation and reforestation, the federal states’ forestry departments and institutions revised and re-issued their planning advice, for example by including recommendations on the selection of tree species. In addition, advice to private forest owners has been given more impetus (cf. Indicator FW-R-6), in view of the great need for action also in this field.

The Forest Protection Institute (Institut für Waldschutz) launched in 2021 at the JKI is tasked with conducting research into issues of biology, avoidance and integrated control of pests and diseases in forests, and of strengthening any natural control and defense mechanisms prevailing in forests. It is intended that this should lead to the formation of concepts that are suitable for practical forest protection, with due consideration of climate change.

In the process of forest conversion and the associated changes in tree species composition, it is also important to advance the timber market. The challenge is to open up new opportunities for the increased use of timber from deciduous forests for the production of material objects (cf. Indicator FW-R-4), to support and expand the range of practical applications in timber-based construction, and not least to gain experience in practical applications (cf. Indicator FW-R-5).