Parkslide, hur blir man av med den?

Sammanfattning: Japanese knotweed is a big problem in Sweden and there is no known control that can eliminate stands of the plant. Therefore the aim with this thesis is to investigate the effect on Japanese knotweed of two control methods: mowing and hot water. The control methods chosen are the ones used by the Ängelholm municipality since this thesis is done in collaboration with them. The methods were investigated through comparing 18 stands in total, all the stands were located in Ängelholm municipality. There were three groups of stands, controlled by hot water, controlled by mowing and not controlled at all. Data for the comparison was collected through field work in october 2021. In the stands, an area of 1x1 m was randomly laid out. Inside the area three factors were measured, height on highest point, diameter of five stalks and number of stalks. This was repeated three times. A mean was calculated and statistically analyzed for the three factors to compare the three groups of stands. The results were that mowing appeared to change the growing behaviour of Japanese knotweed but it did not seem to eliminate the stands. However, since other studies have shown that mowing can stop the growth of the stand the method can be used for that purpose. Hot water had effects that could suggest that, with enough time given, the method can eliminate stands of Japanese knotweed. Elimination with hot water might nevertheless prove very expensive since the method probably needs to be applied with a high frequency for successful elimination. Therefore the hot water should only be used where the benefits justify the costs. More studies need to be done to find a control method that is not just effective but also has a cost that is in proportion to the effectiveness.