In Sweden, public awareness of change in the environment has increased in recent decades (Gillberg 1999). An important tool which contributed to an understanding of how the flora is affected by changes in the environment was created by Ellenberg (1974). Six ecological factors, namely light, temperature, continentality, moisture, reaction and nitrogen, were each divided into 9 (in the case of moisture 12) so-called indicator values. A species given a low value occurs mainly where the factor is less pronounced, and vice versa, species in light class 1 prefer full shadow, 5 half shadow, and 9 full light.