Existing and New Knowledge
The entire LIFE4Forest project focuses on gathering existing and new knowledge about close-to-nature forestry management with conifers at its core. This is done, among other things, through a baseline study and now also a collection of models for afforestation, are established with the aim of future close-to-nature management of coniferous forest. This involves establishing a forest from bare ground, with the long-term goal of creating a coniferous forest with multiple layers, species, and ages in a mixed setting.
>> Read the article: From Bare Ground to Close-to-Nature Forest.
The report presents four models for afforestation for close-to-nature forest management, based on four different main tree species:
- Douglas fir
- Grand fir
- Noble fir
- Scots pine
>> Download the report: Eksempelsamlingen for skovrejsning til naturnært skovbrug
The Climate Effect of the Forest
The forest is intended to have a significant climate effect, meaning that the reforestation models aim to establish a forest with high productivity and corresponding high carbon uptake.
Afforestation With Conifers Trees
The report thus exclusively focuses on models dominated by establishment of conifers forests but stabilized by different tree species mixtures and growth patterns.
Forest with More Variation
The focus in afforestation is not solely on timber production. In addition to high timber production, the forest should provide other relevant services. The goal of close-to-nature forestry is to create a more divers forest with many different functions.
The Multifunctionality of the Forest
It is a multifunctional forest that produces sustainable building materials but can also contribute to biodiversity, biomass, carbon sequestration, clean drinking water, recreation, landscape value, etc.
Biodiversity and Landscape Value
It could involve forest edges with the incorporation of flowering and berry-bearing bushes for the benefit of insects and birds, as well as the landscape experience. It could also involve creating open water surfaces, which can significantly contributes to biodiversity.
Recreation and Drinking Water
Recreational trails or other facilities for the public can be an option, just as forests located above areas for drinking water extraction help reduce unwanted leaching of nutrients or pesticides into groundwater.
Climate Effect: Flood Prevention
The forest can also contribute with a new form of climate service that has emerged in recent years: drainage systems in cities that migrate flooding during heavy rainfall.
Selection of Tree Species
When the long-term goal is to establish close-to-nature forests on agricultural land, the choice of tree species is crucial for achieving success.
Different tree species play various roles in the forestry system depending on their different characteristics:
- Shade tolerance/light requirements
- Stability of the tree species in youth
- Youth growth of the tree species
- Ability to self-renew
- Long-term production (both in terms of volume and value) and stability.
No tree species possess all the desired characteristics, and auxiliary tree species are necessary. Therefore, the choice of tree species, blending percentages, and blending patterns must be carefully considered.
Main Tree Species
Overall, it is important to select several tree species, but not too many, to ensure sufficient robustness against threats such as insect attacks and climate influences for future vegetation.
The location sets the framework for the tree species to be chosen. The different tree species' youth growth and stability are significant for the blending pattern and blending percentages.
Douglas Fir, Grand Fir, Noble Fir and Scots Pine
The four tree species Douglas fir, grand fir, Norway spruce, and Scots pine are considered the four most relevant future main tree species in close-to-nature Danish conifer production. They are all assessed to be resilient to climate change.
Auxiliary Tree Species
Norway spurce, Sitka spruce, and larch are deselected as main tree species but are included as significant auxiliary and blending tree species.
Furthermore, other blending species will be used, primarily deciduous trees, but also, for example, thuja.
Deciduous trees are generally considered stable in future Danish climate, although some studies suggest that drier summers could pose a problem for beech trees. Thuja is considered stable on par with Douglas fir, although there are not many studies in Northern Europe.
The Four Afforestation Models
The report sets up four models for afforestation for close-to-nature forestry, based on the four different main tree species:
Douglas Fir
The future main tree species is Douglas fir with a minor blending of beech and a significant blending of, for example, Norway spruce, Grand fir, Sitka spruce, Noble fir, or other.
Larch can be included as an auxiliary tree species, which is removed within the first 30 years of the stand's life. In the next generation, there is a self-renewing stand where the tree species composition can be adjusted according to the desired time frame.
Grand Fir
The future main tree species is grand fir with Douglas fir. Douglas fir should be part of the culture model for the model's long-term suitability in a close-to-nature cultivation system.
In the model, beech and other conifer species such as European larch, Norway spruce, Noble fir, thuja, or other should also be blended. In the next generation, there is a self-renewing stand where the tree species composition can be adjusted according to the desired time frame.
Noble Fir
The future main tree species is Noble fir with a minor blending of beech and a significant blending of Norway spruce.
Larch can, on frost-prone areas, be included as an auxiliary tree species, which is removed within the stand's first 30 years of life. Scots pine can also be included as a screen with a smaller proportion for variation and thus resistance sake. In the next generation, there is a self-renewing stand where the tree species composition can be adjusted according to the desired time frame.
Scots Pine
The future main tree species is Scots pine with a blending of, for example, Norway spruce, larch, oak, and birch. In the next generation, there is a self-renewing stand where the tree species composition can be adjusted according to the desired time frame.
Blending Patterns
In the report, you can read about the different blending patterns in afforestation and their advantages and disadvantages.
- Single-tree blending
- Row blending
- Group blending
- Islet blending
For example, an advantage of single-tree blending is the opportunity for high species and risk distribution on the area. However, there is a risk that one of the species becomes dominant. Islet blending allows for the utilization of the individual tree species' self-training effect but also carries a risk of gaps in the stand if one tree species dies out.
Single-tree and group blending are recommended
Overall, single-tree and/or group blending are recommended. Often, a combination of these will be a relevant choice.
>> Download the report: Eksempelsamlingen for skovrejsning til naturnært skovbrug
Written by Janne Bavnhøj