Transplantation of seedlings from plant growth chamber trays to traditional growing trays. The transplantation is robotized: a grapple grips the seedling and moves it to another tray filled with peat. The transplanted plants can then be further cultivated directly or at a later stage.
Text and photo: Ellinor Edvardsson
Planting new forest is a fundamental part of the forestry cycle. Approximately 375 million seedlings are put in Swedish soils every year. These seedlings are produced in nurseries spread across the country. By combining hi-tech with solid science and nursery management expertise, it is possible to produce seedlings of high quality in a cost-effective way. This saves both nursery space and the environment and at the same time reduces the effects of seasonal variation. This is what Holmen Skog did in their nursery in Friggesund.
Holmen Skog has two forest nurseries and produces about 35 million plants every year. In one of these nurseries, Friggesund in mid-Sweden, seedlings are not just produced in a traditional way but since 2012 also in a large climate-controlled plant growth chamber. A plant growth chamber has many advantages over a traditional greenhouse. The 100 % control of the environment allows for exact regulation of temperature, humidity, light intensity and day length. This in turn allows for good conditions for the production of high quality and even sized seedlings. The light consists of LED light with optimal wavelengths combined with some UV light.
The large plant growth chamber also allows more seedlings per production cycle. This is because the seedlings are grown very densely in trays and the chamber has 8 floors for the production, compared to just one floor in a traditional greenhouse. The trays move automatically to a special water / fertilizer zone when this is needed. When seedlings are about 4-6 weeks, they are moved (transplanted) to larger containers for further growth immediately or after a period of rest, depending on the time of the year. A bonus effect of this plant growth chamber is that it releases no greenhouse gas from the heating system as no fossil fuel is used.
One of the challenges in the management of this hi-tech forest plant production is that staff must have not only expert skills in classical nursery management but they also need hi-tech know-how. It is extremely important that the seedlings are exposed exactly to the correct light regime, but also proper water and nutrition supply are important of course. As a manager you need to be innovative. You need to adapt and fine-tune the system in order to fit the high-tech and the traditional production stages together. The final goal, as always, is to produce healthy and well-growing plants at the right time for delivery.