raking the floors of the forest

In Sweden, the forestry industry is an important part of our exports and is one of the base industries. The trend is that the demand for wood-based raw materials is increasing, wood as a building material, in addition to the production of paper for writing (newspapers, books, office printouts) is decreasing, the demand for liquid cardboard and paper packaging and paper bags is increasing, especially now that plastic products are being phased out.

In Sweden, the majority of second-generation biofuels (made from non-food biomass) are produced from the forest, based on thinning residues, forest waste and energy forest. These biofuels are mainly used in the industry for the production of electricity and heat for district heating networks. The largest consumer of the biofuel is the paper and pulp industry, which uses by-products from its process for incineration. From the 1920s, the timber stock in Sweden has increased sharply, from 1720 million m³sk (m³sk = forest cubic meters – the timber volume including bark, excluding branches and roots) to todays amount 3549 million m³sk, an increase of >100% (Forest data 2020). When forestry was industrialized in the 19th century, the forests were cleared without any thought of regrowth, short-term profit interests reigned, and Sweden’s forest stock decreased sharply. Today, we are on a deforestation that is in balance with regrowth, despite the fact that fellable productive forest land has decreased when large forest areas are biodiversity protected.

Climate change with higher temperatures and more CO2 means that forest growth has increased, at the same time the higher temperature – especially the milder winters – means that certain pests can attack our forest, the current problem is spruce bark beetle infestation and forest fires during hot and dry summer months.

Sweden has large areas of mires that can be drained to expand usable arable land, but with the digging of mires, problems are created with large emissions of greenhouse gases, but with research there may be a solution to this if the need for larger forest areas arises.

Biomass from three steps of the wood supply chain, IRENA (2019):

• primary biomass, from harvesting and thinning residues and discarded and low-value wood.

• secondary biomass fuels from sawmills, pulpmills and the wood-working industry, like bark, sawdust, chips, black liquor and tall oil.

• tertiary post-consumer biomass, like paper in municipal household waste, recovered wood and sewage sludge.

Biomass and energy flows from Swedish forest. Source:Svebio analysis of data from Statistics Sweden (SCB), Swedish Energy Agency (SEA), Swedish Forest Industries (Skogsindustrierna), Swedish Forest Inventory, SLU, Swedish Pellets Council (Pelletsförbundet) and others (2018)

As shown in the picture above, stumps, roots and slash are left in the forest after harvest (energy content of
138 TWh). They will eventually decompose and release CO2 into the atmosphere. A larger share of
the fellings could be collected, improving carbon balances so “raking the floor” is not so stupid.

It feels like we are only at the beginning of using all the possibilities of the wood raw material. If there is the political will, Sweden can replace the mixing of fuels with ethanol or perhaps even better with methanol that can be extracted from the forest raw material and is an excellent fuel mixer instead of importing ethanol based on food crops.


References
Forest statistics 2020, Official Statistics of Sweden, Swedish University of Agricultural Sciences Umeå 2020, ISSN 0280-0543 https://www.slu.se/globalassets/ew/org/centrb/rt/dokument/skogsdata/skogsdata_2020_webb.pdf
 
IRENA (2019), Bioenergy from boreal forests: Swedish approach to sustainable wood use, International Renewable Energy Agency, Abu Dhabi. https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Mar/IRENA_Swedish_forest_bioenergy_2019.pdf

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