What's happening?

What is happening to our world! This tree hasn't lost it's leaves because of the autumn. It is dead! It's infected by elm disease! In our town, Lund, there is (was) a lot of elms, but during the past years a lot of them have died! They can't take them down fast enough so they stand there looking sad. Some of them are still green, but marked with an orange cross and you can see it's infected and soon will die too.