Timber customer magazine 2023

#1 Nordic wood

“Rauma sawmill is the world’s most modern sawmill, and its development will benefit the whole sawmill industry.”

A timber lorry pulls into the yard of Metsä Fibre’s Renko sawmill and halts, brakes wheezing, as it waits for its logs to be unloaded for grading. Renko sawmill in southern Finland is one of Metsä Fibre’s two spruce sawmills. It produces sawn timber for various sectors of industry, such as internal and external cladding, furniture making, construction and carpentry products. Finnish sawn timber from Nordic tree species – pine and spruce – is known worldwide for excellent quality. Its unique features are derived from a combination of wood’s natural properties and Finnish forest management competence. Examined close up, there are rings on the sawn surface of a log. Each millimetre-thin ring represents the tree’s growth in one year. Slow growth and a close grain are repeated from one log to the next. They mean good density and strength properties that are valued by converters. “The strength of Nordic spruce lies in its consistency. If you convert spruce into one hundred packages of sawn timber, all the packages will be of the same high quality,” says Jussi Lehtosalo , Mill Manager of Renko sawmill. In the case of pine, slow growth results in the formation of heartwood at the core of the tree. The substances that accumulate in heartwood act as natural wood preservatives. For example, pine heartwood used in doors and window frames is exposed to ever-changing weather conditions but still lasts for hundreds of years. It takes an average 80 years for Nordic trees to grow into logs. Correctly timed forest management work and thinning of young stands will ensure that their growth is channelled into trees of the highest quality.

Johanna Harjula

In 2021, side streams from sawing and other forest industry operations generated 112 terawatt-hours of power in Finland. This is more than all the energy produced from fossil oil and coal.* However, power production is just one way to use side streams. Bark can be used for landscaping and to make compost soil, for example. Ash resulting from energy production is suitable as forest fertiliser. It contains the right proportion of tree nutrients which it releases over a long period of time. Following the path of resource efficiency even further, side streams of Nordic wood are found in surprising places. For example, crude turpentine, generated in wood pulping, is used as one of the ingredients of perfumes.

#3 Technology

At the sawline in Metsä Fibre’s Rauma sawmill, you need to keep a close eye on the process. Blink at the wrong moment, and the log has already whizzed by. “A pine log becomes sawn timber in just over a second,” says Johanna Harjula , who has worked in Metsä Group since 2010 and will start as Mill Manager of Rauma sawmill in June 2023. Rauma sawmill was constructed to meet customer demand and began continuous production in September 2022. Its output is mainly targeted at demanding end uses, including window and door production, component manufacture and woodworking. Machine vision, robots and automation are used throughout, and the overall process is run from a central control room using special cameras. “Central control room work allows the operators to spend time on quality control and user maintenance, which are important components of the sawmill’s operating model,” says Harjula. Rauma sawmill is a frontrunner and trailblazer where development work benefits the entire sawmill industry.

#2 Resource efficiency

The sawline at Metsä Fibre’s Vilppula sawmill is about 100 metres long. Each log on it is first optimised before being debarked. A chipper canter removes the outer surface and it is then sawn into rectangular logs, slabs, and finally into heartwood boards. The modern single-line spruce sawmill is one of Europe’s largest and produces about 530,000 cubic metres of sawn timber annually. On average, around half the volume of a single log can be used for sawn timber. The rest is woodchips, sawdust, and bark. Log wood is valuable raw material so it is used to the last splinter. “The woodchips produced by sawing are converted into pulp, mainly at Metsä Fibre’s Äänekoski bioproduct mill, while the sawdust is sold to Neova, a partly state-owned company, which converts it into wood pellets for power plants and to heat buildings and homes. We convert the bark into bioenergy and use it in our own kiln drying department,” says Tomi Saine , Mill Manager of Vilppula sawmill.

* Source: Ministry of Agriculture and Forestry of Finland

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