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Sweden stopped forecasting berries in 2018

6 minJ

Revised 10 August 2026

The last one came out in the summer of 2017. For twelve seasons before that, anyone in Sweden who wanted to know whether it was worth clearing a weekend in August could read a regional forecast of the blåbär crop, published in June — before the berries existed — by a public university, from field counts made on a national plot network. Then it stopped. Not because it was wrong. Because the money went.

This is the part that deserves more attention than it gets: berries are the one wild crop in the Nordic forest that is genuinely forecastable weeks ahead, Sweden built exactly that, and Sweden is now the only one of the three big berry countries not running it.

What the Swedish forecast actually was

It was run by SLU’s Enheten för skoglig fältforskning together with Riksskogstaxeringen, the National Forest Inventory, and it produced annual forecasts of the blåbär and lingon crop between 2006 and 2017. The method is described in detail by Miina, Bohlin and colleagues (2021) in Silva Fennica, in a joint Finnish–Swedish paper that is the best public account of how both countries do this.

Two data streams fed it. The first was the inventory itself. Since 2003 berry assessment has been part of Riksskogstaxeringen: on two small circular sub-plots at each NFI sample plot the field crews record whether living plants are present, the height of the bilberry (Vaccinium myrtillus) plants, and the developmental stage — before flowering, flowering, unripe, ripe, shed. Crucially, between 2006 and 2017 they counted the flowers and the unripe berries too, not only the ripe ones.

The second stream converted those counts into a crop. A network of permanent plots in SLU’s research parks was visited at flowering, at the unripe stage and again at ripeness, which gave the ripening relationships needed to turn a June flower count into an August berry weight. SLU published regional forecasts in June for blåbär and in August for lingon, lingonberry (V. vitis-idaea) flowering later.

Why berries forecast and mushrooms do not

A mushroom forecast is a forecast of something with no visible precursor. A berry forecast is a forecast of something you can already count. The flowers are on the ris weeks before the fruit, they are countable, and the ratio of flower to berry is where most of the year’s variation gets decided.

The risks in that window are measurable too. Tolvanen (1997) applied artificial spring and summer frost to bilberry and followed the plants for three growing seasons: vegetative recovery was rapid, but sexual recovery — flower production — was not, with summer frost slightly worse than spring frost. Frost during flowering is not a folk belief. It is a known, datable, weather-station-observable event with a known effect on the crop.

Boulanger-Lapointe and colleagues (2017), working on a 40-year record in northwest Lapland, set the climate influence out as four stages: conditions the previous year that determine the flower primordia, winter temperature and snow cover, spring conditions affecting bloom and pollinator activity, and summer conditions determining how many pollinated flowers make viable fruit. Every one of those is upstream of the picking season.

And the spatial part is tractable. Miina, Hotanen and Salo (2009) fitted bilberry yield in Finnish mineral-soil forests as a function of the plant’s percentage cover, with separate equations for pine- and spruce-dominated stands and stand basal area entering the spruce model — stand structure and light, in other words, in an explicit formula. Turtiainen, Miina, Salo and Hotanen (2016) extended that to coverage and annual variation. Nothing comparable exists for a chanterelle.

What stopped, and what it says

SLU’s own page — now removed from the live site, readable in the Internet Archive’s 2021 snapshot — puts it plainly: SLU can no longer give a forecast, because the appropriations for its continuous environmental monitoring (fortlöpande miljöanalys) were reduced and the berry forecasts in particular had to give way to other projects. Miina et al. (2021) give the mechanical version: since 2018, for want of resources to assess the experimental plots, yield has been estimated from ripe berries counted in the NFI alone, and no seasonal forecasts have been made.

Note what actually broke. The national inventory did not stop; it still counts ripe berries, and SLU still reports yields in Skogsdata. What stopped was the forward-looking half — the flower and unripe-berry counts, and the research-park plots that converted them. Miina et al. note the conversion sites were few even at the end: four, plus some that varied annually. A national forecast was resting on a very small number of visits.

Finland kept theirs

Luke, the Natural Resources Institute Finland, publishes three to four berry crop reports a season, the first around midsummer once bilberry has mostly finished flowering. National yield monitoring in Finland dates to the late 1990s — Luke’s own page states it began in 1997, the MASI plot network has been measured since 1999 according to Miina et al. (2021), and Luke describes its current observation network, run with the 4H organisation, as operating since 2001. The public reporting has continued through the 2015 institutional merger that created Luke.

The 2026 forecast shows what that buys. On 13 July, Luke reported that at the observation sites roughly three of every four bilberry flowers had set fruit, that pollination had succeeded better than average in southern and central Finland, and that warm May and June weather had brought ripening forward. The maps in Luke’s Luonnonvaratieto service show pollination success nationally, combining the observation network with meteorological data. That is a specific, checkable, falsifiable statement about a crop that has not happened yet.

Norway, and what Sweden is left with

Norway is the part of this story I would correct. I could not confirm a standing public national berry forecast there on the Finnish model. What Norway has is research: the WILDBERRIES project, led by NIBIO with Nofima, UiT, Luke and the University of Turku, ran from 2019 to mid-2023 on Research Council of Norway funding, and produced national abundance modelling and mapping for lingonberry (Miina, Hauglin, Granhus, Hykkerud & Martinussen, 2024). Norwegian researchers give seasonal assessments to the press. A published forecast service comparable to Luke’s is not something I can point at, and I would rather say so than assert it.

Sweden, meanwhile, has the largest crop in the comparison. Miina et al. (2021) estimate the annual national yields on productive forest land at 336 Mkg of bilberry and 382 Mkg of lingonberry, against 208 and 246 Mkg in Finland. In the Swedish survey they cite — Fredman et al. (2013) — 54% of Swedes had picked berries. The country picks more, from more, and knows less about what is coming.

The authors themselves record that interest in restarting is high, that public and media interest has always been great, and that to forecast the current season you have to count the flowers and unripe berries again. It was not disproved. It was defunded. Those are different things, and the second one is reversible.

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