Spruce pellets

Spruce as a raw material

Norway spruce is a coniferous tree that for decades was the main commercial species in many Central European countries. Large volumes of its wood go to sawmills, and spruce sawdust and shavings are a natural raw material for pellet producers in the region. Spruce pellets are therefore usually made from wood-processing residues — group 1.2.1 in the ISO 17225-1 classification — or from stemwood (1.1.3). Both groups are allowed in the highest ENplus class, A1^[1].

It is worth saying straight away what “spruce pellets” does not mean. It is not a quality class or a certificate. The wood species is not one of the mandatory markings on an ENplus bag^[2], so the term “spruce” is commercial information from the producer or the seller.

What the data say

Among the sources this site relies on, the best-documented data on spruce wood come from a Finnish VTT study. Below we set them against the ENplus A1 requirements.

The conclusion is simple: clean spruce wood is a good raw material. VTT states that debarked stemwood usually has 0.3–0.7% ash, and that the higher calorific value of coniferous species results from their lignin and resin content^[44]. Spruce bark, however, contains several times more ash than the wood — so the result for a specific pellet depends above all on how much bark went into the raw material. According to FAO, the typical range for softwood bark is 2–6%^[45].

In the VTT data, the calorific value of spruce is slightly lower than that of pine (19.31 MJ/kg) and slightly higher than that of birch (approx. 18.6–18.7 MJ/kg)^[44]. Differences of 1–4% are smaller than the effect of a few percentage points of moisture. We show this in the article on combustion differences and on the calorific value page.

Where spruce wood comes from

Spruce accounts for a large share of the region’s forests, but in many countries that share is clearly falling:

• Czech Republic — spruce covers 40.3% of forests (previously 42.9%)^[51].
• Austria — approx. 49% of commercial forests, compared with over 56% in 1986–1990^[58].
• Germany — 21% of the forest area; since the 2012 inventory, the area of spruce stands has fallen by 17% as a result of storms, the 2018–2021 droughts and bark beetle^[57].
• Slovakia — 20.9% of forests; the share of conifers is falling, mainly because of damage to spruce stands^[50].
• Latvia and Estonia — spruce is the dominant species on 19% and 18.2% of the stand area respectively^[54],[55].

More on individual countries on the pages for the Czech Republic, Germany and Austria, Slovakia and the Baltic states.

Bark beetle wood — is it a problem?

In recent years, the spruce forests of Central Europe have suffered from drought and bark beetle outbreaks (Insects (mainly the European spruce bark beetle) that colonise weakened spruce trees under the bark. Mass outbreaks force large-scale sanitary felling.)Insects (mainly the European spruce bark beetle) that colonise weakened spruce trees under the bark. Mass outbreaks force large-scale sanitary felling.. In the Czech Republic, total timber harvesting rose from 16.16 million m³ in 2015 to 35.75 million m³ in 2020, of which 34.49 million m³ was softwood. In 2024 the harvest was 17.80 million m³, of which approx. 45% was salvage felling; biotic damage — almost exclusively bark beetle on spruce — accounted for 2.4 million m³^[51]. In Slovakia, insects damaged 3.54 million m³ of wood in 2024^[50].

Does this mean poorer pellets? Not necessarily. Spruce attacked by bark beetle and harvested in time is still stemwood. ENplus does not exclude wood from sanitary felling — it does, however, exclude raw material that is rotten, contaminated or contains a large amount of bark^[1]. The risk therefore arises when the wood has stood in the forest for a long time and started to decay, when it is processed without debarking, or when it picks up sand and soil during harvesting and storage.

How to check spruce pellets

1. Ash. The best indicator of the bark and contamination content. For A1, the limit is 0.70% on a dry basis^[1] — more on the ash page.
2. Ash deformation temperature. Shows the risk of clinker; A1 requires at least 1200 °C^[1]. See ash melting temperature.
3. Mechanical durability and fines. These depend on the process, not the species — see mechanical durability.
4. Certificate. Check it in the ENplus register, not on a copy of the document — how to do it.