Close-to-nature forest management has long been considered a potentially beneficial practice for enhancing biodiversity and improving ecosystem services, such as CO2 storage. With almost half of Denmark’s forest area covered by coniferous forest, converting these to close-to-nature forest management represents a significant potential for increasing national biodiversity. Similarly, there is potential in afforestation according to close-to-nature principles.
Despite decades of attention to close-to-nature forest management, our knowledge of its specific contributions to biodiversity is still limited. This Is where two projects, LIFE 4Forest and INNO4EST, come into play.
Fact: Protocol
A measurement protocol is the measurement procedure that researchers use to measure biodiversity in a selected area. This may include which groups of species are measured, how the measurements are conducted, how long traps should be set, what time of year measurements are taken, etc.
Fact: Indicator Variables
Indicator variables are data that can provide information about the potential biodiversity in an area. These are variables that are easy to measure and readily accessible. They can thus be used to predict potential biodiverisy.
A typical example is the amount of large dead trees – dead wood – in the forest. Other examples include the occurrence of specific insects and plants.
Sometimes the term “proxy variables” is also uses for indicator variables.
First Step Towards Protocol Development
One of the nine actions in LIFE 4Forest focuses on specifically on measuring the effects of close-to-nature forest management on CO2 storage and biodiversity.
>> Read more about the action for biodiversity and corabon stock
Standardized Biodiversity Method
LIFE 4Forest is taking the first steps towards developing protocols for measuring biodiversity in forests. In collaboration with the research project INNO4EST, researchers in this action are developing indicator variables based on field measurements. These variables can predict potential biodiversity, and the ambition is for the indicator variables to be simple and effectively implemented by forest owners.
The purpose of developing indicator variables is to create a standardized and comparable method that forest owners can use to assess biodiversity in the forest and monitor its development over time.
Knowledge About the Effects of Afforestation
The purpose of the INNO4EST project is to identify the main effects afforestation has on four selected ecosystem services as well as trade-offs and synergies between the services. The four ecosystem services the projects investigates are.
- Carbon sequestration
- Biodiversity
- Nutrient retention
- Recreation
To develop the final indicator variables, researchers will begin collecting data on a number of selected case areas and utilize available remote sensing data. Based on this data, researchers select operational parameters that are included in the final indicator variables for biodiversity. These are subsequently validated in the actual afforestation projects.
Valuable Collaboration Between LIFE 4Forest and INNO4EST
The two projects overlap thematically as both examine biodiversity in close-to-nature forests; INNO4EST investigates, among other things, afforestation with conifers, while LIFE 4Forest examines the conversion of coniferous forests to close-to-nature management, but also close-to-nature afforestation dominated by conifers.
Furtherore, several of the afforestation areas in LIFE 4Forest serve as case areas in INNO4EST. This collaboration between LIFE 4Forest and INNO4EST represents a valuable effort to understand and improve biodiversity in Danish coniferous forests through close-to-nature forest management.
LIFE 4Forest Well Underwat With Data Collection for Conversion
In LIFE 4Forest, an extensive data collection program is underway with approx. 200 strands representing different conifer species. Ditlev Reventlow is responsible for the program, which focuses on converting existing strands to close-to-nature management.
Biodiversity in Conversion to Close-to-Nature Management
In approx. 200 stands, data is collected broadly relating to biodiversity, including dead wood, structural variation and soil conditions, large trees, etc. Thus, a number of important indicator variables have been identified in the projects, which are expected to have a significant impact on biodiversity and are collected in all measurement strands.
The plan is also to try to use remote sensing, which means examining an area’s physical characteristics from a distance – for example, using satellites.
In 26 strands, a much more detailed approach is taken. These are primarily strands laid out for long-term experiments, measures over the next 50-100 years.
When there was a need for other categories of strands not represented in the long-term experiments, conversions have been udes, which are only measures over shorter periods. These strands are divided into the categories of Norway spruce, other European conifers, and overseas conifers (primarily Sitka spruce).
The 26 strands, both short-term and long-term, consists of two strands in pairs: one strand being converted and one strand not being converted – thus, approx. 13 of each.
A protocol for biodiversity collection is almost fully developed. So far, soil samples from the 26 strands have been collected in 2023 or eDNA analysis. In the summer of 2024 will be followed up with extensive biodiversity data collection covering
- Insects
- Birds
- Bats
- Fungi
- Plants
- Mosses
- Soil organisms
- Microorganisms
Students Investigate Biodiversity
In addition, the Department of Geosciences and Natural Ressource Managment IGN flere studerende, som måler biodiversitet på "baseline bevoksninger". has several students measuring biodiversity in “baseline strands”. These are strands that were converted long before LIFE 4Forest started often in connection with the storms in 2005 or 2013. Baseline strands are also compared with the strands that have not been converted.
>> Read also: Baseline Study for Close-to-Nature Forest
A biology thesis from 2023 showed that ground beetle diversity Is reduced due to forest environment disturbances in the areas where beech has been planted. Researchers have yet to elucidate the spatial and temporal effects of this measurement.
Furthermore, a BSc-student investigated what happens to the soil in a conversion and its indirect impact on biodiversity. The study showed that so far, no effect on the carbon-to-nitrogen ratio (CN ratio) have been observed, suggesting that soil changes take longer to occur when beech is planted in coniferous plantations.
Furthermore, several other students will be working on biodiversity in these baseline strands during the spring/summer of 2024, both regarding the extent to which remote sensing and the initial approach to practical indicator variables can be used to predicts biodiversity.
INNO4EST – Identification of Biodiversity Indicator Variables
Field-Tested Methods
Partners in INNO4EST met in September to take the first step towards developing the protocol. Biodiversity experts from the University of Copenhagen and Aarhus University gathers for a field workshop to coordinate measurement methods and discuss the selection of parameters for measuring biodiversity. This included exploring and testing field methods for capturing insects and preforming eDNA analyses of insect and fungi based on soil samples.
Big Data to Qualify the Methods
Currently, researchers at the University of Copenhagen and project partners at DHI GRAS A/S are analyzing strands using remote sensing methods. This provides a basis for more specific field measurements. Researchers have access to both map and satellite data on the strands, which allows them to analyze, for example, where wetlands are and what variation exists in a growth, etc.
With this data, they have a good basis for going out into the fields to measure more specifically. INNO4EST is this also working on indicator variables regarding the prediction of biodiversity. The methods for field measurements include, among other things, coring, height measurement, dead wood, and include data collection on insects, soil, and plants. This means measuring:
- How many large trees there are per hectare
- How many growth layers there are
- How much dead wood there is above a certain diameter
One might think that large trees are not immediately relevant to an afforestation project, but INNO4EST does not only examine young afforestation projects. The project also examines afforestation projects up to 70 years old, where there may be large trees in the area.
Actual Biodiversity Measurements
Data is collected for various organism groups such as arthropods (insects) and vascular plants, such as ferns and horsetail.
This is supplemented by soil samples for eDNA analyses and registrations of the forest’s structure and measurements of various biodiversity proxies (e.g., dead wood, heterogeneity, hydrology, damage, age range, species composition, strand density, etc.). Measurements thus resemble those biodiversity measurements conducted in LIFE 4Forest, a lot.
When Will We See the Final Biodiversity Protocol for Afforestation?
Asked when we will see the final indicator variables for biodiversity in afforestation, Mathilde Østergaard replies: “We cannot specify a specific time yet.” Biodiversity data is collected during the spring/summer season of 2024, and data analysis will likely be completed in early 2025. Then, the foundation for the selection of the final indicator variables will be ready, and development can begin.
Written by Jane Bavnhøj