The weather has helped, but bark beetle is still a problem

2. 11. 2020
The weather has really helped Czech foresters this year. They have a chance to recuperate from the bark beetle calamity that affected predominantly spruce forests. Thanks to a rainy end to spring, a damp summer and lower temperatures than those of previous years, this year the highland regions have seen the emergence of only two generations of this dangerous beetle, and insufficient time for a third before the frost of winter. There were three generations last year, even four in lower areas. The weather this year has given forest owners valuable time to limit further serious damage. The rain has also assisted in the renewal of forest clearings, notes Radek Pokorný of the Department of Silviculture, FFWT MENDELU.

“The weather has helped to slow the course of outbreak, but it won’t manage to stop the bark beetle completely. But now the foresters know what to focus on,” says Pokorný. Forestry workers are even using drones and planes to keep an eye on the situation in the forests. Infested trees, with active stages of the beetle, are still being cut down. In springtime, specialists will determine, from these felled bug traps, how many of the beetles have survived in the soil as well. According to Pokorný, the removal of these trees from the forest should eliminate the rest of the bark beetles that have survived winter.

The calamity has developed gradually in various areas of the country. It currently affects mainly the Czech-Moravian Highlands. Forestry workers have to focus felling capacity wherever the bark beetle can be eliminated, and the infested trees removed. The dry trees could be left standing, but in three to five years they would still begin to decay, and would need to be cleared.

Reforestation work has been complicated by the coronavirus pandemic, and a shortage of workers. “Although the beginning of spring was quite dry, the rainy weather that followed benefited the new trees. That was fortunate. Hope springs eternal, and the replanting must be successful. Nature has helped this year; it will actually be a seed year. The worst thing is to leave open spaces,” said Pokorný, who explains that a big problem in renewal is the forest animals, which nibble the young trees. Foresters therefore have to regulate population growth.

“Personally, I just can’t understand why the forestry company Lesy ČR got rid of the care of animals and gamekeeping activity, not only by leasing the hunting rights, but also the game reserves themselves. As a businessman, there’s no way I would let property out of my hands. When the big clearings rejuvenate, and they’re covered with young trees in a couple of years, no-one will be able to see the animals, and it’ll be really difficult to keep their numbers down,” said Pokorný.

At the moment, the problem is replanting the clearings. Especially in those big forest clearing it isn’t possible to plant the target shade trees. According to Pokorný, the clearings could be planted with spruce, which has a pioneering growth strategy, but even if they survive, they will still need other plants beneath them, just like other preliminary trees. “I expect that, at least because of the spruce disappearing, the forests will be richer in species. Spruce covered up to 50% of forest acreage, now we’ll manage to keep it to about 35%,” said Pokorný.

In the future the forests will be richer in species, if only because of the changing climate. “Growth and production conditions in Central Europe will be suitable for white elm, various oaks, for example common oak, sessile oak, downy oak, cerris, frainetto, northern red, for wild cherry, sweet chestnut, black locust, and for black pine, among other evergreens. Other native drought-resistant trees include wild service and sorb, or field and Norway maple. Because of its water consumption, the European beech isn’t as appropriate among these as foresters might think. Suitable growing conditions for beech can be found at more moderate elevation,” added Pokorný, who feels it is important that, even at lower elevation, trees are growing at all, even if they are non-native.

Contact for further details: doc. Ing. Radek Pokorný, Ph.D., tel.: 605 236 551, Department of Silviculture (FFWT),

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