Pesticides: Toxic insecticides are used in the forest - Horgen 2

Pesticides: Toxic insecticides are used in the forest – Horgen

A walk in the woods is beneficial for the body and mind. Adults like to breathe the fresh air of the forest and enjoy the flora and fauna. Kids love playing hide and seek or climbing on a tree trunk. But this could be unhealthy, as some of the forest logging sites are treated with insecticides.

Although forest protection is enshrined in federal law, environmentally harmful interventions, such as the use of pesticides, are generally prohibited. But in some cases, the law allows exceptions. For example, when it comes to the fight against the beetle or the beetle, which is eating away at the wood. In order to avoid an infestation by these beetles and thus a degradation of logs, softwood logs felled in the forest are partially sprayed with insecticides. Are concerned berindete tree trunks, of high quality, that can not be manufactured at the time of beetle flight in mid-April of the forest and are therefore stacked on round wood warehouses. The cypermethrin insecticide is the most commonly used.

According to the Baudirektion of the Canton of Zurich, responsible for these derogations, 3.8 deciliters of cypermethrin neurotoxin were used in the district of Meilen in 2018. This corresponds to an amount of about 3.8 liters of the plant protection product commercial. In the district of Horgen, it was about half. The explanation of the difference: in the district of Horgen, fewer logs had to be stored during the same period.

Economic interests

Alexander Singeisen is the District Forester responsible for the municipalities of Meilen, Uetikon, Männedorf, Oetwil and Stäfa. "In fact, I do not want to use poison in the forest," he says. Therefore, if possible, it leaves the strains unfolded until February. "They can dry up before the beetles fly in the spring, and they are no longer fertile ground for breeding." However, for reasons of capacity, debarking is often not possible, explains the forester. Then the insecticide is also used on its territory. It must also take into account economic interests. "After all, we use a domestic raw material."

In 2018, about 800 cubic meters of tree trunks were treated with cypermethrin in the forests of the five communities, which equates to 40 log trucks. In the same year, 5000 cubic meters of wood were harvested. So far this year, there are about 100 cubic meters of tree trunks, so five loaded trucks have been sprayed. The order is given according to Singeisen always to the buyer of the logs. "He tells me what wood stores should be treated."

One of Pfannenstiel's timber buyers is the Rolf Unholz AG sawmill in Greifensee. "We buy about 400 cubic meters of tree trunks each year," said General Manager Rolf Unholz. He confirms that he refuses the use of the insecticide to the respective foresters. Strains containing Coleoptera are worth up to 50% less, he says. "Therefore, I have treated all coniferous wood stores, whose trunks can not be barked or removed in time."

"In fact, I do not want to use poison in the forest."Alexander Singeisen, Forest District Meilen, Uetikon, Männedorf, Oetwil and Stäfa

It may be a bit, because the contractor says that the wood will be offered partly from March. "So, however, debarking does not bring anything else." Breaking out of the forest all the trunks of the beetle flight in mid-April and so "getting safe" is not possible, says Unholz. He does not have much space on his farm. "Storing the logs elsewhere until they are used would cost too much." It only picks up the trunks close to a water plane, thus making the use of cypermethrin impossible.

Toxic for fish

Each use of the insecticide requires permission from the Baudirektion of the Canton of Zurich. Baudirektion spokesperson Wolfgang Bollack says the pesticide is only used when all alternative options are not practical. The Forestry Department attaches great importance to compliance with water protection regulations. Since the insecticide is toxic to fish and fishing animals, a distance of 20 to 50 meters from the waters must be respected. Spraying would only be carried out by persons with a corresponding permit. The site management records the coordinates, the type and quantity of the agent and the amount of wood that has been treated with the insecticide. According to Baudirektion, the sprayed bark is then used as energy wood. "These ovens are equipped with appropriate filtration systems."

But sometimes, the theory and practice differ, because apparently not all pulverized bark is found in a furnace with filtration system. Before the Unholz sawmill removes treated trunks from the forest, they are mechanically debarked at the site. "We do it in the forest because we do not have a bark machine on the farm," said Rolf Unholz. This leaves the bark treated on the forest floor. This is not a problem: "These places are always outside the water protection areas and over time, the spray loses its effect." The site director confirmed that the effect of cypermethrin decreased with time. Nevertheless, she points out that the approach to the sawmill is the exception. "Large processors, who handle most of the wood that is processed, usually have debarking machines in operation," spokesman Wolfgang Bollack said. There, the trunks were much easier to undo.

Dangerous substance

Martin Forter is the director of the Association of Doctors for the Protection of the Environment (Aefu), which intervenes in particular against the use of pesticides. "It's fierce," he says, hearing that cypermethrin-treated bark remains in the forest in some cases. "The bark belongs to the incinerators and not to the forest," says the geographer, a specialist in chemicals and waste. Cypermethrin is one of the most dangerous substances in the water. This would damage aquatic life at extremely low concentrations. "We are talking about picograms, that is, billions of grams." Special equipment would be needed to perform measurements in this area.

According to Aefu, insecticides such as cypermethrin usually have nothing in the environment and certainly not to look for in the forest. "Any insecticide or pesticide is a problem because the forest is a fragile ecosystem," says Martin Forter. The insecticide not only harms beetles, but also has a toxic effect on bees. How dangerous the poison is when children or dogs climb on treated logs, the geographer can not judge. "This is certainly not good." (Zurich newspaper)

Created: 02.07.2019 at 16:58