Major difference between managed and unmanaged forests

Clearing has been used to create more space for the desired tree species in the stand, which in this case is pine. A large proportion of the deciduous trees has been removed in those parts of the stand that are focused on timber production. Deciduous trees have been prioritized in other parts instead, such as wet hollows, stream buffer zones and the edges of the stand. The pine trees that are damaged or sick have been removed, while the healthy trees have been retained.

After clearing, the residual stems have space to spread their crowns. This allows them to capture more light and grow better. Clearing also allows more sunlight to reach down, which warms the soil. The warmth creates better conditions for the roots to grow, become stable and absorb more nutrients. Clearing therefore enhances the growth and vigor of residual trees.

By not clearing, the opportunity to choose a dominant tree species for the stand is lost. The result is that deciduous trees usually take over. The pine trees find it difficult to compete, which means they grow slower and are thinner.

There is also a major risk that the branches of the deciduous trees will whip and damage the pine stems when strong winds blow. This type of damage makes trees susceptible to fungal disease.

In an uncleared stand, the competition for light and nutrients is intense. The growth rate of the stand is high, but because it is distributed between a large number of stems, most of the stems are thin. Trees that are damaged continue to grow, alongside healthy and more vigorous trees.

Here we can see how a high-quality pine stand has been formed. A first thinning has taken place, where mainly slow-growing stems, or stems that were damaged in some way, were removed. The healthiest pine trees have been retained for the future. It was easy work for the forest machines, which is good economics.

Stands are always sensitive for a few years after thinning, but because this stand was effectively cleared, the stems have been able to grow relatively thick, and the roots have developed well. This makes the forest more resilient to snowbreaks and windfalls.

Because thinning was carried out at the right time, before the tree crowns became too ‘lifted,’ the risk of damage is also reduced. (The branches at the bottom of the stems die as it becomes denser and darker at ground level. When a large section of the stem is bared, this is referred to as ‘tree crown lifting’)

There are not enough nutrients or light for all trees. Since no selective clearing has taken place, nature has made the decisions. Deciduous trees, which initially grow faster than conifers, have begun to take over the stand and some pine trees have died in the competition. Most of the living pine trees are healthy with strong branches, but thin stems. Thinning at this stage would mainly involve the removal of broadleaf trees that are standing too close together and a few pine trees that could be used as pulpwood.

Any options for the future are limited. It is difficult to promote anything other than a sparse pine forest with a large proportion of deciduous trees. If the original intention was to create a pine forest, it would be a major financial disappointment. Thinning would also make the pine trees more susceptible to snowbreaks and wind, since the stand has never been cleared.

One alternative would be to reconsider and invest in the creation of a deciduous forest with high conservation value, or a deciduous stand to produce pulpwood or perhaps birch sawlogs. But that would also require active measures.

The stand has been thinned for the second time. The thinning enabled a selection of the trees that should be removed and those that should be retained. A large proportion of the stems had grown thick enough to be classified as sawn timber and therefore yielded high income. The harvester could work fast and efficiently, which led to lower costs for thinning. Very few trees have been outcompeted.

Once again, the highest-quality stems were selected and retained, in order to extract as many valuable sawlogs as possible in the forthcoming regeneration felling. The final goal is within reach! Thinning also presents good opportunities to fertilize the forest, which further improves growth and value.

Several pine trees have been outcompeted and died, and the proportion of birch in the stand is high. The living pine trees have a wide spread in terms of quality and diameter, but their stems are generally thin. Spruce has begun to grow under the pine trees and deciduous trees. The stand is scrubby and difficult to penetrate.

There are very few options remaining now. Thinning would lead to a major risk of snowbreaks and storm damage. The trees have never been able to grow thick and establish stable roots and are therefore far too sensitive. Thinning would probably require clearing first, so that the harvester could work efficiently. The sawn timber yield would be very low, resulting in poor profitability. It would probably be best to wait and make an early regeneration felling instead.

By making active selections when planting, clearing and thinning, the goal has been achieved – a vigorous and valuable pine forest is now standing here. Only the highest quality stems have been retained. The trees have had good conditions for growth right up to regeneration felling and the thick stems will generate a really high sawn timber yield – about 80%.

Active management has also led to a relatively low risk of damage throughout the rotation period of the stand. The trees have been able to grow large and strong. Since they haven’t stood so closely together, they have always been exposed to some wind and snow and therefore been able to adapt.

The entire stand is, however, varied in terms of appearance. Some areas have more deciduous trees in order to create variation and a living forest.

The pine trees have been exposed to intense competition throughout the entire rotation period and have not therefore had the right conditions for growth or the development of thick stems. A high percentage has already died.

The sawn timber yield is low, only about 20%. This results in lower timber income, and higher costs per cubic meter felled. The trees that have taken over and produced most sawn timber have not been actively selected, so their quality is highly varied. If the aim was to achieve a high-quality pine stand, this would be a major disappointment.

If the aim was to achieve a stand with high conservation value, the results would not be very satisfying either. Active management would have created much better conditions for biodiversity.