This is a fully automated machine translation. The quality and accuracy of machine translation can vary from one text to another and between different language pairs. Forest Knowledge Gateway admins do not guarantee the accuracy of the translation and accept no liability for possible errors. Please refer to the original text in its original English version if there is any doubt. Some content (such as images, videos, files, HTML links and acronyms) may not be translated or may be inaccurate due to the technical limitations of the system.
Menu

Replacing spruce monocultures with diverse, climate-resilient stands

A way to restore Central European forests after bark beetle outbreaks

Good practices

Sep 05, 2025
Go back to results
photo

Restoring bark beetle clear-cuts through a combination of natural and artificial regeneration, supported by effective game protection.

Forest restoration efforts after bark beetle outbreaks focus on replacing degraded spruce monocultures with diverse, resilient stands better adapted to climate change. This involves increasing the share of natural regeneration - particularly of pioneer species like Betula, Populus, Alnus, Sorbus and Salix - and planting native broadleaved species such as Fagus sylvatica, Abies alba, Quercus sp., Acer sp., and Tilia sp. However, restoration is often limited by a shortage of suitable planting stock, especially for rare species and broadleaves. Seasonal availability often delays planting activities and reduces flexibility in planning. High game pressure further complicates regeneration, making it difficult to establish mixed stands without costly protection measures. The presented methodology offers practical solutions to overcome these silvicultural challenges and support effective, climate-resilient forest regeneration. 

Context:

The forests in the Czech Republic have undergone dramatic transformation due to the impacts of climate change and associated disturbances. Historically dominated by Norway spruce (Picea abies) monocultures, these forests have become increasingly vulnerable to droughts, windthrows, and bark beetle outbreaks - particularly the European spruce bark beetle (Ips typographus). These factors have triggered large-scale forest dieback, prompting the need for urgent and systemic restoration measures.

Restoration strategies in the region are shifting towards the establishment of resilient, mixed-species stands that are better adapted to future climate conditions. This includes increasing the proportion of natural regeneration using pioneer species such as Betula, Populus, Alnus, Sorbus and Salix, as well as planting a wider range of tree species like Fagus sylvatica, Abies alba, Quercus sp., Acer sp. and Tilia sp. These efforts aim not only to rebuild forest cover but also to enhance ecological stability, biodiversity, and a wider range of ecosystem services.

A key component of restoration is the improvement of forest water retention capacity, addressing one of the root causes of bark beetle outbreaks - prolonged drought stress. The transformation from even-aged, monospecific stands to structurally and compositionally diverse forests is designed to strengthen resilience to both biotic and abiotic threats.

At the same time, restoration efforts are designed to support multiple ecosystem services beyond timber production. These include carbon storage, soil protection, biodiversity conservation, recreation, water provision and education. The restoration model being tested in this region reflects broader shifts in European forest management towards adaptive, multifunctional and climate-smart forestry.

Problem Description:

Despite well-defined restoration goals, the practical implementation of forest recovery in the Czech Republic faces several persistent challenges. One of the most significant is the scale and severity of damage caused by bark beetle infestations, wind and drought. These overlapping disturbances have devastated large areas, often leaving behind degraded sites with limited natural regeneration potential. 

Another critical constraint is the limited availability of planting material, especially for rare native species, Abies alba, and many broadleaves. Seasonal shortages further exacerbate delays in planting schedules. This bottleneck makes implementing the desired species diversity in new stands difficult.

Moreover, high densities of game often undermine regeneration success. Browsing pressure often prevents natural regeneration or establishment of broadleaved species, requiring costly fencing or other protective measures. Without addressing this issue, the creation of stable, mixed-species stands is nearly impossible in many areas.

These challenges significantly reduce the speed and effectiveness of restoration efforts. Addressing them requires coordinated policy support, sufficient funding, streamlined procedures and wildlife management reforms to enable large-scale, climate-resilient forest recovery in the region.

Implementation Steps:

Step 1: Site assessment

Evaluate the size, morphology, slope, soil, hydrology, presence of seed sources and other relevant characteristics of the clear-cut using field survey and existing typologiocal and forestry maps. Also record natural and artificial terrain boundaries (watercourses, terrain breaks, skid trails, erosion gullies, etc.), trees or groups of trees left after harvesting, lying or standing deadwood and other biological legacies (natural regeneration, ingrowth, etc.). Existing terrain boundaries can advantageously be used to delineate different silvicultural techniques. Timing: as soon as possible after the calamity harvest. 

Step 2: Spatial zoning for restoration

Divide the clear-cut into functional zones based on site assessment. Designate areas for artificial planting, with high potential or existing natural regeneration, or a combined approach. Prepare a detailed site map with each zone's boundaries and surface areas and recommended restoration methods, including a five-year work plan to complete the restoration of the entire area within this period. Timing: immediately after site assessment and before planting operations.

Step 3: Tree species selection and planting design

In accordance with site typology and legislative requirements, select a diverse mix of native and site-adapted tree species. Combine species with complementary ecological traits to increase resilience against pests, drought and storms. Define planting patterns (generally clusters, groups, or lines are more favourable than individual species mixtures that tend to disappear) that reflect micro-site conditions and natural succession potential. Adjust density to balance competition control, biodiversity goals and operational feasibility. Prepare a planting scheme map showing species composition and layout. Timing: before seedling purchase and planting operations.

Step 4: Soil preparation and plantation

Prepare the soil only where necessary to ensure seedling survival and root penetration, while minimising disturbance. Remove dense grass cover or competing vegetation in planting spots. Retain woody debris in strips for moisture retention and biodiversity. Plant seedlings according to the planting design. Ensure correct planting depth and firm soil contact with roots. Immediately after planting, ensure protection against browsing damage. Timing: spring or autumn, depending on local conditions.

Step 5: Condition control, improvement and follow-up care

Regularly monitor the condition of planted and naturally regenerated seedlings, recording survival, growth and signs of stress or damage. If required, replace missing seedlings with suitable species. Release young trees from competing vegetation and apply protective measures against browsing, drought or pests. Conduct these activities annually during the first 5-10 years to secure successful establishment and balanced species composition. Timing: first 5-10 years after the initial restoration activities.

Knowledge Types:

Scientific knowledge
The general recommendations for forest restoration after bark beetle calamities are grounded in scientifically supported findings, which clearly demonstrate the need to foster biodiversity and natural processes across all levels of the forest ecosystem. At the same time, they reflect the production characteristics of individual tree species as well as the socio-economic aspects of forest management, with significant implications for rural areas.

Practical knowledge
Forest restoration after bark beetle calamities also relies on practical knowledge that comes from long-term forestry experience and ensures the feasibility of restoration measures. It includes tested silvicultural practices, such as the suitability of tree species on specific sites, soil preparation and planting techniques. Practical expertise also covers economic and organizational aspects, such as cost efficiency, labor availability and planning of interventions. 

Replicability:

YES, the practice has been tested and replicated in multiple contexts and scales and therefore, can be easily transferred and/or adapted to other initiatives with similar goals.

Between 2019 and 2024, similar approaches were applied in the restoration of areas affected by bark beetle calamity in forests managed by LČR (approx. 59,000 ha), VLS (9,500 ha), as well as by other smaller owners and forest managers. LČR currently estimates the area of endangered stands - primarily spruce and partly pine in lower elevations - at 95,000 ha, while VLS estimates 5,200 ha. In the event of large-scale dieback, similar forest restoration measures will also be implemented in these areas.

Key Success Factors:

Key success factors include the selection of appropriate restoration practices, particularly the choice of tree species and their mixtures adapted to site conditions, as well as sufficient technological and logistical capacity as a prerequisite for effective implementation in the field. The practice emphasises natural regeneration, especially through pioneer species (Betula, Populus, Alnus, Sorbus, Salix). Planting of native broadleaves (Fagus sylvatica, Abies alba, Quercus sp., Acer sp., Tilia sp. etc.) is key. 

The logistical demands of restoration increase proportionally with the size of the disturbed area. In the medium term, effective monitoring and subsequent silvicultural measures are essential to regulate stand composition and to achieve an optimal balance between the productive and non-productive functions of the forest. Establishing mixed forests may entail higher requirements and costs for forest owners and managers, while potentially resulting in lower expected revenues from timber production. Therefore, the introduction of targeted financial support mechanisms is essential to ensure the long-term economic sustainability of the forestry sector.

Common Constraints:

Restoration of calamity areas after large-scale forest dieback often faces technical problems related to the shortage of planting stock, wildlife protection materials and labor, combined with difficult terrain accessibility. These challenges are addressed by artificial regeneration with reduced initial planting densities, a combination of natural and artificial regeneration, spreading restoration over several years, diversifying suppliers and employing mechanization as well as volunteers. The main economic obstacle is the decline in timber prices and limited financial resources, which can be overcome depending on the current situation through subsidies or funds accumulated in silvicultural reserves. Social challenges lie primarily in the public's negative perception of large clearings; therefore, emphasis is placed on communication with municipalities, education and active involvement of local communities. For this reason, the use and promotion of pioneer tree species with the ability to regenerate quickly and restore the typical character of forest environments is also applied. Environmental risks include soil erosion, the spread of invasive species and loss of biodiversity, which can be mitigated by mosaic restoration with greater species and age diversity, as well as by leaving biological legacies.

Main challenges
- Shortage of planting stock (rare species & broadleaves) 
- Limited seasonal availability 
- High game pressure requiring costly protection

Positive Impacts:

  • Increased climate suitability of tree species
  • Increased soil health
  • Increased structural diversity
  • Increased tree species diversity

The use of tree species mixtures with different growth dynamics, combined with the diversification of regeneration in both spatial and temporal scales, creates favorable conditions for the development of higher structural diversity within a relatively short period after reforestation. By integrating species that grow at varying rates, forest stands quickly form multiple layers, enhancing ecological stability and resilience. Typically, e.g. the combination of fast-growing birch in the overstorey and silver fir in the understorey. Spatial diversification, such as mosaic planting, prevents uniformity, while temporal diversification, achieved through planting over several years, promotes continuity in stand development. Together, these approaches foster structurally complex forests that are better adapted to disturbances and climate changes.

The proposed approach applies a wide spectrum of broadleaved and coniferous tree species in an optimal combination to ensure the fulfillment of both production and non-production functions of forests. The basic principle is the creation of site-adapted stands composed not only of native tree species but also of non-native or introduced species with suitable ecological requirements and silvicultural characteristics. This diversification makes it possible to increase forest resilience to pests, diseases and climate changes, while at the same time maintaining or enhancing biodiversity and ecosystem services such as water retention, soil protection and carbon sequestration.

Combining species with different ecological niches, growth strategies and silvicultural requirements adapts the forest to a broader range of biotic and abiotic environmental stressors. Mixed stands balance species with varying rooting depths, leaf phenology and water-use efficiency, which improves resource utilisation and reduces competition stress. This diversity lowers the risk of large forest disturbance because when one species is negatively affected by pests, diseases or unfavourable weather, others can compensate and maintain essential ecosystem functions. In this way, species mixtures ensure greater forest stability, productivity and resilience.

The described approach puts a stronger focus on tree species that have a proven positive effect on soil's physical, chemical and biological properties, thereby enhancing fertility, stability and resilience. These are mainly litter-rich species such as birch, alder, poplar, maple and lime, contributing significantly to soil organic matter content and nutrient cycling. A serious challenge is soil compaction, which can reduce root penetration, water infiltration and microbial activity. Retaining areas with biological legacies helps limit the movement of heavy machinery during salvage logging and subsequent reforestation, thereby protecting soil structure and supporting long-term productivity and ecosystem functioning.

Negative Impacts:

  • Reduced timber quality or quantity

Creating mixed forests may place higher demands and costs on forest managers, while also being associated with lower expected revenues from timber sales. The fundamental shift in species composition and the increasing share of harvests in lower diameter at breast height (dbh) classes will require substantial adaptation in the wood processing industry and related technologies. Reduced harvest volumes and smaller dimensions will place additional economic pressure on forest owners, driving the need for more efficient and cost-effective forest management approaches and strategies. Consequently, introducing targeted financial support instruments is crucial to maintaining the long-term economic sustainability of the forestry sector.

Source/Author(s)
  • Lukáš Bílek
  • CZU Róbert Marušák
  • CZU
Topic
  • Active Restoration
  • Passive Forest Restoration
  • Planning & Upscaling
Stakeholders
  • Landowners & Practitioners
  • Planners & Implementers
Purpose
  • Afforestation, reforestation
  • Restoration after natural disturbances
  • Tree species/functional diversity
Biogeographic region
  • Continental
Countries
  • Czechia
Degradation Driver
  • Environmental
Scale Area
  • The restoration practice was applied on an area of 100 hectares within the implementation of the project SUPERB – Systemic solutions for upscaling of urgent ecosystem restoration for forest-related biodiversity and ecosystem services (Horizon 2020).