Mooses Don’t Like Spruces

We traveled a few kilometers from campus to a private landowners forest for our silviculture class. The purpose of this trip was for our class to see a good example of a typical Finnish forest. I will share in brief the six main points of this trip and why this forest was a good example of a typical Finnish forest.

1. Finland’s four main commercial species of trees grew there: Norwegian Spruce, Scotch Pine, Silver Birch and Common Birch.

2. The forest was seeded and currently needs to be thinned for better forest health. Several of the trees had stopped growing. This was shown by the tree top having a rounded look compared to a growing phases triangular shape. In Finland this stage in the forest begins 80 years after seeding.

This created the opportunity for us to complete a few basic measurements to help decide what we should be cut.  We used a basic Finnish relascope to measure basal area (the amount of tree volume in a given area or “plot”). More on these measurements in an upcoming post.

3.The forest had some sections that had been thinned. We were able to compare and contrast what the forest looked like before and after it was thinned.

A forest is thinned for several reasons. The larger harvest ready trees are taken, leaving younger trees more space to grow in the future. Trees that are damaged or pose a risk for disease may be harvested to maintain the health of the forest. Typically in Finland they “thin up the living crown.” Trees that are small, poor quality and havea poor crown are thinned during the first thinning. Depending on the quality of the growing site the forest may be thinned once or twice more before the final cut. A forest would then be re-seeded.

4. The forest showed the two main types of forest in Finland. The type of berries growing on the forest floor tells you a lot about what type of tree grows best there. A blueberry forest type is mainly a spruce forest and a lingonberry forest has mainly Scotch pine.

The blueberry type is more moist and nutrient rich than the lingonberry type. This makes it an ideal location for spruce to grow. While this type is dominated by spruce the pine, and two birch types also grow here.

The lingonberry is a drier and nutrient deprived soil that the Scotch pine grows well in. While this type is dominated by Scotch pine, the birch and two birch types also grow here.

Two things that reduce tree growth in this forest are poor drainage and rocky soil.

5. The forest was an example of a “lower boral site” that typically supports 2,500-3,000 trees per hectare. Many of the forests in Finland are of lower quality which often means rocky and bog like. This is because forestland was left as during Finland’s early development because the land was unsuitable for farming.

6. Our final lesson of the day was that Finland foresters have to answer themselves questions about similar issues that a  Unites States Forester might. Do we clear cut or select cut? When is the best time to safely harvest? How do we regenerate this stand?  Regeneration is a common concern because like the United States the Finn’s care about the future of their productive forests. A common problem and reason for mixed stand planting of spruce and pine is because they commonly loose many young pine and birch trees to moose browsing. It seems mooses don’t like spruces.

The five Cal Poly exchange students and our silviculture professor Juha.

See my future posts for more information on Finnish Forestry.

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