1903 is said to have been an intense year for Sweden's then Prime Minister Erik Gustaf Boström. The suffrage question and troublesome Norwegians who wanted to dissolve the union must have taken much of his energy, but so did the problems with Swedish forests. They stood cut down and sparse – harvested to feed ironworks and glassworks whilst timber exports to a growing Europe demanded their share. Forestry itself was mostly about selective cutting of the largest trees, with no thought of creating conditions for young seedlings to grow. The solution came in 1903 with the introduction of what has been called the world's first modern Forestry Act. Broadly speaking, it meant that anyone who fells forest is also obliged to establish new growth.
The same applies today. The Forestry Act's two equal objectives – that the forest's 30,000 species should be able to live and develop, whilst access to fossil-free and renewable raw materials is secured – have laid the foundation for modern Swedish forestry. Since the beginning of the 20th century, Sweden's standing volume has doubled. Roughly the same proportion of Sweden's land area is, now as then, covered by forest but the trees are growing more. The reasons are several. Increased knowledge and improved management are some, but access to improved seedlings is also an important factor.
Tree breeding
For Daniel Hägglund, forest regeneration manager at Holmen Skog, the journey towards a viable forest starts long before it's time to put the spade or planting tube in the ground. He's responsible for the entire chain from seed to finished plantation and readily uses the word “breeding” when he talks about his job.
“You could simplify it and say that we make sure to cross a good mother with a good father,” he clarifies.
Within the breeding programme, run by the research institute Skogforsk, trees with good characteristics are selected. During the actual crossing, pollen is captured from a selected tree, and then they ensure the right pollen reaches another selected tree's flowers. By attaching a bag around the flower, it's protected from competing trees' pollen. It's from seeds from these cones that are then planted out and carefully monitored.
“When we find something that seems to work well, we select quite a few individual seedlings and graft their branches onto older plants. This way we can get more specimens of the same individual with good characteristics. To spread their genes as well as possible, they're then planted out in a seed orchard according to a carefully calculated pattern,” says Daniel Hägglund.
Then it's just a matter of waiting. In the forest most things move slowly. Spruce and pine set cones at slightly different ages, but spruce often needs to be around 20-25 years old. When the cones are harvested, it's done manually. Daniel Hägglund and his colleagues look somewhat enviously at neighbouring industries.
“In other countries they harvest olives, grapes, apples or citrus with various machines. But if we tried to do the same with our conifers we would damage them severely. The cones sit so firmly on the trees. So it requires special ladders and skylifts to reach them.”
When the cones are picked, the seeds are extracted from them via a seed extraction kiln, and cleaned. These seeds are used in nurseries or for direct seeding on clear-cut areas in the forest. The seeds that aren't needed immediately are frozen in large stores. It's not always a good “seed year”, so when there are good years it's important to ensure storage, to guarantee that Sweden is self-sufficient in seeds.
“Spruce is a bit troublesome and doesn't readily flower. It only happens about every seventh year. But when it does flower, it flowers abundantly. At the same time it has many pests, like fungi and insects, so it's really important to make use of the seeds. We freeze them down to 22 degrees below zero. Then they can lie there for all eternity without being damaged,“ says Daniel Hägglund.
Some seedlings are first grown in nurseries before they're ready for planting. For spruce it takes one year, but for pine it takes about two years from cone to finished seedling.
“We place great emphasis on the root system. A seedling with poor roots fares worse when it reaches the forest, even if it looks fine above ground.”
Good genetic diversity
Improved seedlings have been very significant for the development of Swedish forests, but sometimes raise questions. For Daniel Hägglund, the answer is simple.
“Through the plant breeding programme there's greater genetic diversity than there would be if only trees standing right next to each other were crossed. There's a great deal of inbreeding in natural regeneration. We avoid that now. We have high demands for genetic diversity. As the climate changes, this becomes ever more important.”
“The climate is changing faster than trees can naturally adapt. With breeding we can stay one step ahead and plan for future conditions.”
Even though pine and spruce today are the most common tree species in Swedish forests, there's considerable interest in hardwoods.
“We see how research, forest companies and private forest owners are showing ever greater interest in birch. Naturally regenerated birch is quite crooked and not very attractive to saw into timber. There I can see a development opportunity.”
Text: Malin Age Photo: Kerstin Jonsson
