EMÜ Associate Professor: Forest Residues Could Boost Estonian Mushroom Cultivation

Estonian University of Life Sciences Associate Professor Kalev Adamson believes that local mushroom cultivation has significant growth potential by utilizing forestry and agricultural waste. His experiments at Järvselja Teaching and Research Forest have shown that edible mushrooms can be successfully grown on stumps left behind after thinning felling. Within his professorship, Adamson also researches medicinal mushrooms and the potential of fungal viruses.

Estonian University of Life Sciences (EMÜ) Associate Professor Kalev Adamson highlighted at his venia legendi ceremony held on 12 June 2026 that mushroom cultivation is an increasingly growing sector both in Estonia and around the world. In his view, significant untapped potential lies in local forestry and agricultural waste, which could serve as ideal growth substrate for industrial mushroom cultivation.

"If we take a mushroom box from a shop and look at the country of origin, Poland is often written on it. There is not much local produce," noted Adamson, pointing out that there is ample room for development in Estonian mushroom cultivation.

Experiments in Järvselja

The working group led by Adamson and EMÜ researcher Marili Vester has conducted experiments on mushroom cultivation at Järvselja Teaching and Research Forest over recent years. Specifically, they studied mushroom growth on stumps removed during thinning in mixed forest. In spring 2024, stumps were inoculated with mushroom spawn of several edible species: oyster mushroom, lung mushroom, and velvet tooth.

The experimental results have provided initial clear indications. It became clear that not every mushroom strain suits every tree species: aspen stumps gave the poorest results, while alder proved to be the best growing substrate. The experiment also showed that a mushroom strain well-suited to alder may not grow equally successfully on birch stumps.

In addition to competition between mushroom species, the summer period presented a serious problem: slugs that consumed a large portion of the harvest. In contrast, velvet tooth grown on wood during winter sub-zero temperatures did not suffer from slug problems, making it an interesting option for year-round cultivation.

Labour-intensive and time-consuming process

Adamson warns interested growers that inoculating stumps with mushroom spawn is a very labour-intensive process. "It is also very time-consuming: going through all the stumps, noting down how many fruiting bodies have appeared, on what dates they appeared, and so on," he explained.

Growers should not expect a large harvest immediately-it can take three to five years before the mushroom has completely colonized the substrate and starts fruiting most vigorously. "At least three to five years, depending on the species, is the time in which the mushroom takes over the stump and starts producing mushrooms most vigorously," explained the associate professor. At the same time, each tree species breaks down at its own different rate.

However, forestry and mushroom cultivation are not mutually exclusive activities according to Adamson: "By managing forest, you can try to cultivate mushrooms at the same time and hope to get a harvest."

Medicinal mushrooms and fungal viruses

Adamson's professorship focus is not limited to edible mushrooms alone. He is also interested in cultivating medicinal mushrooms, particularly black truffle, which has received considerable media attention in recent years. To date, successful inoculation of black truffle has remained modest, and Adamson's goal is to improve it.

As a second important research direction, he addresses fungal viruses. The first fungal viruses were discovered in 1960, and their use has been modifying mushroom properties for decades. Black truffle has not yet had any fungal virus identified, but Adamson's working group has "the first ones obtained in the lab in containers," and corresponding research will be published shortly.

In summary, the associate professor sees the future of mushroom cultivation as part of the circular economy: "I investigate how their cultivation could be more successful and how various forestry waste could be better utilized so that circular economy goals can be met."