When looking to the events.log file I find a lot of changes of values of items in there.
Some of them are traced quiet often and they are of no value to me.
Is there a chance to avoid the tracing of a dedicated item (or a thing) to the events.log file?
Reading the docs is a good starting point.
I don’t think that you can filter out specific items from the events log.
You could (by reading the docs as @namraccr linked above)
a) increase the log level for certain loggers to make the log file more “quiet” or
b) send the logger to a separate file
Example to modify the log level for (some) event type loggers (from the openHAB console):
log:set INFO smarthome.event.ItemCommandEvent
log:set WARN smarthome.event.ItemStateChangedEvent
log:set WARN smarthome.event.ItemStateEvent
log:set WARN smarthome.event.ThingStatusInfoChangedEvent
log:set WARN smarthome.event.ThingUpdatedEvent