How do we assess the conversion of conifer plantations?

The question of how we experience a forest has just as many answers as there are visitors looking at the forest. A recent study has examined how we rank pictures of different types of conifer plantations under conversion to close-to-nature forest management.

The Danes’ outdoor recreation under scrutiny 

The Department of Geosciences and Natural Resource Management, Ditlev Reventlow, in collaboration with Professor Emeritus Frank Søndergaard Jensen, have added a question to a national outdoor recreation survey that has mapped forest recreation in Denmark since the 1970s. 

The first results are now available, based on approximately 2,500 responses. They show that Danes rate a young spruce plantation highly when the stand is in the process of being converted to a close-to-nature forest management system. The survey also indicates that this positive perception does not apply in the same way to older spruce stands undergoing conversion.

From previous outdoor recreation studies, we know that forests are an important recreational space, and that public opinion plays a role in how forests are managed.

Which of the forest photographs do we like the most?

Conversion to close-to-nature forest management changes how the forest looks like in several ways such as several storeys, mixed species and natural regeneration. We now know more about how we perceive the conversion.

The participants were asked to rank 8 photographs according to which they prefer – more precisely:

Which forest environment do you prefer as a forest visitor? Below are 8 photographs of different forest environments. Please rank them in order – from the one you prefer the most to the one you prefer the least.

The 8 photographs from the survey were shown in random order for the participants

We like large trees the most

The study confirms previous studies that forest visitors prefer old stands and large trees.

LIFE4Forest focuses on the management of coniferous plantations based on close-to-nature principles. Therefore, all 8 photographs show scenes from conifer forestry. The researchers have taken photos of coniferous forests at different ages and at various stages, ranging from plantation forestry to the completed close-to-nature forest system.

Young forest – with or without traces of conversion

Two of the photographs are from a 44-year-old stand, where one was 27 years old when the conversion began, while the other continued under traditional plantation management. The Trees are now 20 meters tall. 

Photo 1 young spruce plantation

Photo 2 young spruce plantation during conversion with beech planted in groups

The most distinct result in the survey concerns photo 1 and 2. The participants rate the young stand undergoing conversion (photo 2) higher than the young stand which is not being converted (photo 1). Photo 2 is also the photo that most frequently appear in the top 3 out of 8.

When does conversion pay off?

From a forest owner’s perspective, it is generally more expensive to open up younger stands to allow for the underplanting of beech, because these stands are not yet mature for harvesting. However, from the visitor’s point of view, converting young stands adds value. Therefore, it may make sense to prioritize the conversion of young stands, for example in peri-urban forests or other areas with high visitor activity. This is especially relevant for stands that are already weakened, for instance due to bark stripping by deer, gaps caused by bark beetle attacks, or similar damage.

Older forest - in five stages

Five of the photographs show an older spruce forest, 107 years old.  The conversion began when the stand was 89 years old, and the trees are now 25 meters tall.

Here, the results are quite different: Danes do not consistently rate stands under conversion higher than traditional plantation forest, as they did with the younger stand.

Evidence suggests that a coniferous understorey generally does not contribute positively to the recreational experience, whether it consists of abundant natural regeneration or thinned natural regeneration.

On the other hand, it is clear that the older stand is rated more positively than the younger one.

Natural regeneration rates lower than plantations

Photo 3 Older spruce plantation without conversion

The classical plantation image without conversion (photo 3) is rated higher than stands where the forest floor is covered by naturally regenerated conifers (photo4)

When comparing stands with natural regeneration – photos 4 and 5 – the public prefers the stand where the naturally regenerated spruce has been thinned (photo 5) over the stand where the understorey has not been thinned (photo 4). These photographs show naturally regenerated Norway spruce that has been thinned.

In a close-to-nature system, new stable conifer species such as Douglas fir or grand fir are typically planted, and it is reasonable to assume that the evaluation would be similar to that of the thinned Norway spruce understorey. If the goal is to win public favour, it appears that conversion must be managed carefully

When the understorey consists of beech

Photo 6 Older spruce stand with shelterwood and under plantings of beech.

Photo 7 Older spruce stand with under plantings of beech in groups.

When comparing photos 6 and 7, where the difference is underplanting beech in groups versus beech scattered under shelterwood, photo 6 – with planting under shelterwood – receives a slightly better rating than the grouped planting.

An interesting result is that underplanting with beech in older stands does not lead to a better rating (photo 3 of the older spruce plantation without conversion is actually rated slightly higher than photo 6 with regeneration), whereas introducing broadleaved trees in young conifer stands (photo 2) results in a significantly better rating. This supports the idea that we prefer many large trees.

The completed close-to-nature forest system

Photo 8 Completed close-to-nature forest system.

An image of the forest of the future

The two photographs that receive the highest ratings are photo 8, which illustrates the completed close-to-nature system (second-best rating), and photo 2 of the young stand under conversion (best rating).

The Norway spruces in the photograph of the completed close-to-nature system are 147 years old, while the remaining beeches are 182 years old. The system is therefore significantly older than photos 3–7 of the old plantation/conversion stages.

The photograph has been edited to include slightly more natural conifer regeneration than was present in the actual forest landscape. It is important to emphasize that this photo should be seen as an example of what our future close-to-nature systems could look like.

Indicator of views on close-to-nature forestry

This study cannot provide definitive conclusions about Danes’ preferences for the final close-to-nature systems, but the results indicate that people rank the completed close-to-nature management system quite highly when a number of large trees are left in the overstorey for a long time.

The survey has provided a good indicator of how forest visitors are likely to respond to the appearance of spruce stands undergoing conversion.

About the survey

In Denmark, we know quite a lot about how and how much we use forests for outdoor recreational activities – and what preferences we have for forest design. Researchers have been asking Danes about their forest visit habits since 1976, and national outdoor recreation surveys have been conducted in the 1970s, the 1990s, the 2000s, and now again in the 2020s.

These surveys show, among other things, that forests are Danes’ most preferred setting for nature visits, which makes it relevant to investigate what we think about what we see.

This survey was sent to a representative sample of the Danish population aged 15 and above. Responses have been weighted so that the statements are representative in terms of gender, age, region, and education.

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This is the first result from the survey. A scientific article based on this study is on its way, along with further analyses of the data, which we will also share on this channel.

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If you want to receive the results of the entire new national outdoor recreation survey, follow publications from the Department of Geosciences and Natural Resource Management – University of Copenhagen. https://ign.ku.dk/english/publications/