Invasive trees have no place in the wild: why the Ministry of Environment should ban their planting

In the near future, the Ministry of Environmental Protection will develop an official list of invasive tree species that are prohibited from being planted in forests. This is a unique chance to finally eradicate the barbaric practices of destroying Ukraine’s wildlife.

But there is no certainty that the ministry will really include all invasive trees in the list, because there is a powerful lobby of foresters. Why is this even important? Let’s start with the theory.

Each species of animals and plants has its own natural range. That is, the place where this species lives. Sometimes it happens that a person deliberately or accidentally moves animals or plants to places where they have never been. Such species are called “introduced”. Some introduced species begin to spread uncontrollably and rapidly. Then they are called “invasive”.

Invasive species are one of the main environmental protection problems on the planet. Taking over new territories, they displace local species. Because the natural enemies of invasive species do not travel with them.

In Soviet times and even earlier, the problem of invasive species did not bother anyone. Therefore, foresters actively planted everything that grew well in Ukraine. In 1809, the first red oak trees – plants originally from North America – appeared in Ukraine. It was believed that red oak tolerates frost well. Currently, red oak forests occupy tens of thousands of hectares, especially in the west of Ukraine. Their area is only growing.

Another example is robinia pseudoacacia, or, as it is often called, white acacia. This species also comes from North America. Robinia is found throughout the territory of Ukraine, mostly in the steppe and forest-steppe zones. Foresters love it for its unpretentiousness, so it is often planted on slopes to prevent erosion or to create forest strips. And foresters love robinia, because it grows even faster than our local pine.

But both robinia and other foreign trees in Ukraine have one big problem – they kill our native nature.

In the face of climate change, invasive trees gain an advantage over native species such as pine or Scots oak. And they begin to spread uncontrollably, turning forests from local species into forests from foreigners.

The same robinia aggressively releases chemicals that suppress the growth of other types of trees. Therefore, foreign robinia can develop in forests from our local trees, but local trees often cannot grow together with robinia.

Moreover, invasive species are displacing not only our native trees. Hundreds and thousands of other species of plants and animals are associated with trees in any forest. There will be no trees – there will be no habitat for them. This is exactly what happens when alien trees spread across Ukraine.

Studies of red oak forests show that they have far fewer insects and other arthropods than native tree forests. And most species of our birds do not settle in robinia forests. The same applies to plants and lichens. Our local species are simply not adapted to life in forests formed by alien trees.

Both robinia and its similar gledichia bear abundant fruit, attracting rodents. Birds of prey – natural enemies of rodents – do not like robinia forests. As a result, excessive numbers of rodents cause damage to agriculture and carry pathogens.

Robinia is often propagated vegetatively, i.e. by sprouting. Planted in the forests, it escapes to other ecosystems: it begins to take over the steppes, which are rare in Ukraine, turning them into something similar to a savannah.

Invasive species also affect local mushroom species. The roots of our trees, for example, pines, form connections with mushrooms. Robinia physically cannot form connections with mushrooms common in Ukraine, such as boletus or buttercups. Therefore, when a forest of robinia appears instead of a pine forest, you will no longer see mushrooms there. In addition to wood-destroying fungi, with which foresters are trying to fight.

What to do with it? Eradicating invasive trees in Ukraine is not easy. But you can take at least the first step – prohibit planting them. Because despite the whole array of scientific research, Ukrainian foresters continue to plant robinia, gledichia and red oak. According to foresters, there is no alternative to invasive species. In fact, there are many local species of trees that grow well even in the conditions of the arid Ukrainian steppe. For example, various poplars, willows, pears, apple trees, hawthorn, etc.

Yes, these trees usually do not produce as much economically valuable wood as the same robinia. But they perfectly perform other tasks (for example, counteracting erosion), without threatening our nature.

It is long past time to abandon outdated Soviet ideas about planting trees and their value. The Ministry of Environmental Protection has an excellent chance of banning the creation of new forests from invasive trees such as robinia, hemlock or red oak.

Will officials take the chance? Or will Soviet approaches win again?

Roman Lysenko, Yehor Hrynyk, biologists of the NGO “Ukrainian Nature Conservation Group”, especially for the UP. Life

Cover photo: Ejensyd

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