The cradle of healthy forests

19 January 2018

Tree nurseries look after seeds and seedlings like their own babies. Thriving genomes form the foundation of healthy forests.

A sleepy tree nursery is sprawled across rural landscape in Eastern Finland in the autumn. We are in Joroinen, an exceptionally warm microclimate geographically, where the soil is suitable for cultivation. This soft, stone-free ground was once a lake bed. Today, it is covered by a 27-hectare tree nursery.

This is the only tree nursery in Finland owned by a forestry company that exports hundreds of kilograms of seeds and millions of spruce, pine and birch seedlings every year. UPM supplies the world with over 50 million seedlings annually, including the production of eucalyptus in Uruguay.

The seed is where it all begins. With top-quality seeds, it takes less than 30 years to grow a strong, healthy forest. The journey from seed to a fully grown tree is a long and challenging one. The nursery in Joroinen aims to give each seedling the best possible start.

Anne Immonen is a seedling grower through and through.
Anne Immonen is a seedling grower through and through.

Living plants and automation

Nursery manager Anne Immonen gently stirs her hand through a bowl filled with pine seeds – her stress relief method of choice. These seeds can no longer germinate, unlike the batches waiting in plastic canisters in the seed depot, all sourced exclusively from Finnish seed farmers and forests.

Immonen knows the origin of every seed batch. Seedlings grown from northern seeds are sent north, southern-born seedlings head south. At harvest time, Immonen can tell a seedling’s place of origin by its colour. The seedlings from Kainuu in the north have a deep green shade, as they begin preparing for winter earlier than their southern counterparts.

“See, those reddish seedlings are already showing winter colours,” she says in front of a year-old lot of spruce seedlings.

“We only use the best seeds, as they are the foundation of a healthy forest. As with wines, every year is different, and we know each vintage.”

Immonen has been in charge of the tree nursery since 2006. In that time, the business has grown more technical and heavy physical labour has been replaced by automation to ease the daily routine. The latest investment is a new robotic seedling packing line. Next, an automatic sowing line will be installed beside it. The new control room is almost ready as well, so the growers will soon be able to check seed germination, plant house ventilation, seedling fertiliser requirements and other factors from monitors. This will improve work ergonomics and free up hands for other tasks.

Precise irrigation and heavy packing

On the edge of a seedling lot, grower Mari Nykänen is monitoring the irrigation equipment moving above the spruce seedlings. After irrigation, Nykänen will apply the autumn fertiliser – the last task before winter arrives. A dose of nitrogen gives the seedlings an energy boost to help them survive the cold. Grower Tero Kallinen checks the colour of the seedlings. A true expert can tell from a single glance whether a plant should be relocated or have its fertiliser and nutrients adjusted.

“You can end up with weak fertiliser if rain keeps washing it away, or you can apply the wrong fertiliser at the wrong time. We live by the weather here. Quick reactions were needed yet again this year, as our original plans needed adjustment.”

Jutaphak Jarotram, Tuija Räisänen and Mikael Smolander are busily packing in the middle of the seedling lots. Jarotram inspects the seedlings one by one, removing any weeds and weak seedlings. A good seedling has a well-formed top. There are no forks in the trunk or signs of the bishop bug, and the root ball is strong.

After quality controls, Räisänen removes the seedlings from trays and places them in boxes. In a month, the staff lift and carry 30 tonnes of seedlings. Once the new automated packing line is ready, the heavy lifting stage will luckily be eliminated.

In the final stage, Smolander moves the seedling boxes into containers. The nursery’s logistics expert, Timo Ikäheimo, has pre-ordered transport to get the seedlings on their way.

Soft landing into a harsh world

We take a look inside the greenhouse where a million tiny spruce seedlings less than three months old spread out before us. Eija Hynninen, Anne Hassinen and Jari-Pekka Koskinen are lying on a weeding wagon they call the Ferrari, weeding the seedbed by hand. The seedlings need to be cleaned for winter to avoid mould and other problems.

Lying on the weeding car aka “Ferrari”, Eija Hynninen, Anne Hassinen and Jari-Pekka Koskinen weed the spruce seedling bed.
Lying on the weeding car aka “Ferrari”, Eija Hynninen, Anne Hassinen and Jari-Pekka Koskinen weed the spruce seedling bed.

“These are our babies. Their growth rate is similar to a human’s and so is the length of their life cycle,” says nursery manager Anne Immonen.

From the greenhouse, the seedlings are taken outside to toughen them up.

“It’s a little hard for us in autumn, as we have to throw open the greenhouse doors and have the cold air wash over our million children,” says grower Anne Hassinen.
The delicate seedlings have been growing in controlled conditions until now, and they need the initial shock of the cold to prepare them for later planting. Finnish trees must cope with extreme weather.

In the outdoor lots, the seedlings are coated in artificial snow to protect them against the harsh winter. After a year, the seedlings are strong enough to be sold in the spring. The work at the nursery follows an annual rhythm – seeds germinate in the spring, seedlings grow in the summer and the harvest follows in autumn.

Innovations and research collaboration

In addition to basic seedling growing, the tree nursery also creates new products; the pikkukoivu (mini-birch) and the pikkolomänty (piccolo pine) are among their most developed innovations. The nursery works closely with universities and research institutes.

Nursery manager Anne Immonen dreams of one day expanding the nursery. In the near future, the staff will be able to pack seedlings in shifts all year round, not just outdoors when the weather permits. The foundation for year-long availability of high-quality seeds is secured.

We end our tour in the seed depot. Logistics expert Timo Ikäheimo opens a few cabinets to reveal white seed canisters with identification labels. These seeds are healthy trees in embryonic form, and the seedlings raised in Joroinen are prime genetic stock forming the foundation of Finland’s thriving forests.

Saara Pakarinen