Simone Staudt Vollmond, a policy consultant at DM Bio—a professional community within the DM trade union—joined the excursion to learn more about close-to-nature forestry in practice and to experience what many of DM Bio’s members work with daily. We followed Simone through Harrested Forest at Sorø Academy Foundation and asked her afterwards what take-aways she gained from the visit.
The excursion to Harrested Forest made a strong impression because it highlighted the range between timber production and nature conservation. Simone also found it fascinating and refreshingly down-to-earth, that a multi-million-euro EU project uses simple tools like yellow, blue, and white plastic plates to measure biodiversity.
Generating new knowledge on biodiversity
One of LIFE 4Forest’s key objectives is to create new knowledge about biodiversity during the conversion to close-to-nature forest management. This is achieved through systematic monitoring.
“In terms of biodiversity, LIFE 4Forest is the project I’ve been involved in that has collected the most data on biodiversity,” says David Bille Byriel, Postdoc at the Section for Forest and Landscape Ecology at the Department of Geosciences and Natural Resource Management, one of LIFE 4Forest’s partners. Learn more:
David works with biodiversity and nature management and is one of the driving forces behind LIFE 4Forest’s measurements.
At the second stop of the excursion, he demonstrated the methods developed to measure biodiversity in close-to-nature coniferous forests versus traditionally managed coniferous forests. He swept insect nets around, and showed the colored plates used to attract and collect pollinating insects.
Photo: Simone Staudt Vollmond
David Bille Byriel demonstrates insect collection using a sweep net. Photo: Janne Bavnhøj
Sweep Nets and plastic cups
By swinging a sweep net for 10 minutes in an area like the one shown on the picture, one captures both insects living on plants and insects resting in the vegetation. Researchers have visited all plots twice, and samples are analyzed using DNA and morphology to identify species.
Another method for collecting ground-active invertebrates involves a simple cup and plate. The cup is buried in the soil and filled with liquid; insects crawling past fall into the liquid and are trapped.
>> read more about biodiversity measurements
DNA samples from soil
Another technique is DNA collection from soil samples. “We took nine samples in each plot using a soil sampler hammered in under sterile conditions. Then we scraped a small amount of soil with a knife to collect DNA from soil fungi and invertebrates,” explains David.
Bird and bat monitoring
At selected sites, equipment has been installed to record birds and bats—a small box that detects and records their calls. The device typically activates at sunrise and during evening, and at nighttime hours to capture bat activity. This method is less weather-dependent than sending ornithologists into the field. Known challenges include recording outside the sample area and imperfect bird call identification, but the method is easier to scale.
Biodiversity indicators
Beyond collecting biodiversity data, the project aims to develop biodiversity indicators for coniferous forests. In collaboration with the INNO4EST research project, researchers are creating indicator variables based on field measurements. These can predict potential biodiversity, and the ambition is that forest owners can easily implement these indicators.
6 Coniferous stands
The participants visited six different stands, one of which is part of the biodiversity data collection, while the others resemble those included. LIFE 4Forest collects biodiversity indicators (e.g., deadwood) in nearly 200 different stands, and in a subset, biodiversity is measured (e.g., number of moss species).
The conifer categories studied for biodiversity include:
- Native to southern Sweden (Norway spruce)
- European conifers (e.g., silver fir, Nordmann fir)
- Non European/ American species (e.g., Douglas fir)
From Christmas tree plantation to close-to-nature forest
The first stop was a Nordmann fir stand planted in 1970 without underplanting — what many would perceive as a dark, species-poor coniferous forest. Light levels on the forest floor were low, as shown in the photo. This stand is used as a reference stand.
As Simone is noticing in the video, the contrast was striking when participants entered a stand under conversion. This was also a former Christmas tree plantation (Nordmann fir from 1970), but here conversion to close-to-nature management is underway through underplanting. Ditlev Reventlow noted that the strong light conditions were likely due to storm damage combined with thinning. Normally thinning this drastically would not occur in conversion.
Simone observed that, unsurprisingly, there were clearly more plant species in the lighter stand, which is expected to support more species overall.
Young grand fir and old Norway spruce
The next two stops compared a young grand fir stand planted after the 1986 storm and an old Norway spruce stand from 1960.
In the young grand fir stand, deadwood was left on the forest floor—a key indicator for many species groups. However, biodiversity is generally expected to be lower in non-native species such as grand fir, an American species.
This will be part of the report that Ditlev and David are writing on biodiversity, which may contain surprises.
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Older Norway spruce with light gaps. Photo: Janne Bavnhøj
From the young spruce stand, participants moved on to an old Norway spruce stand dating back to 1960. Following windthrow, a light gap was created, and grand fir and Douglas fir have been underplanted in the opening. One of the challenges is that the increased light has given bracken ferns a head start, making it difficult to establish new tree species.