Mushroom maps: six species, all of Finland

The mushroom map colours in, across the whole of Finland, the forest stands where a species thrives. It does not tell you whether mushrooms are up today: it tells you where a walk is worth taking. Each species is its own layer, and in the app the layers can be turned on one at a time or stacked.

The species

Other map layers

Alongside the mushroom layers the map has one layer with a different job: it tells you what in the forest is about to change.

Metsähakkuut, the fellings layer

The layer draws the metsänkäyttöilmoitukset (forest use declarations) currently in force: the stands where a felling has been declared. How the layer works and what the colours mean.

What the prediction is computed from

The base is the map data of the multi-source national forest inventory by the Natural Resources Institute Finland (MVMI 2023). It describes every forest in Finland in 16 metre squares: the volumes of spruce, pine, birch and other broadleaf, the fertility of the kasvupaikka (site type), the mire type, stand age, total volume and canopy cover.

Each species has five or six coefficients, one per variable, and they are multiplied together. The multiplication is deliberate: one clearly wrong factor is enough to zero out a square, just as it is in the terrain. On kuiva kangas (heath forest at its driest) the mustatorvisieni prediction drops to zero even when the trees are otherwise right.

Toward the north the prediction is damped species by species according to observation data from GBIF and Laji.fi. The damping is scaled against the number of all fungus observations at the same latitude, so that sparser recording in the north does not look like the species being absent. Without this the model painted the birch woods of Lapland as kanttarelli terrain.

When it is worth going

A species layer says where the species does well. It does not change with the seasons, because the forest does not either. The map has two options that add what has happened recently on top of it: Painota sään ja kauden mukaan fades a layer where the species is out of season or the ground is dry, and Missä on nyt parasta colours the map from red to green so you see the direction at a glance. Season weighting explains where the numbers come from and what they do not promise.

What it is not

No yield prediction. A species layer describes habitat, not how many mushrooms come up this year. The weighting brings the weather in, and even that promises no harvest: a dry summer can empty the best stand.
No observation data. Colour does not mean that someone has found mushrooms there. Your own markings are observation data, and only you and the groups you choose can see them.
No up-to-date picture of the forest. The data is from 2023, and a felling changes a stand in one stroke. That is why upcoming fellings are their own layer.

How to use it

In the app the layers sit in the map layer menu under the group Sienet (Mushrooms). The colour is the same as the species' markings on the map, so your own find and the prediction speak the same language. The light base map is the best background for the layers: over the aerial photo the colour drowns into the terrain. The guide covers the rest.

Learn the species in the field

The map tells you where a walk is worth taking; recognising a species is learned in the forest. The Martha Organisation (Martat) runs mushroom courses and guided forays around the country, and their mushroom pages (in Finnish) are a good source for identification and the kitchen.

Mushroom maps © Natural Resources Institute Finland 2023 (MVMI, CC BY 4.0) · Observation data GBIF and Laji.fi · Maps © Maanmittauslaitos

Six species, six forest types.