How to use the automatic cull of some diameters?

You first need to set the needed parameters in the Storage module. You can do that by clicking on the gear icon at the top right corner and choosing Timber from there.

If you scroll down, you should see a Culls section among others. You can add your own parameters by clicking the green button with a plus sign on the right side of the screen.

Then in the app, after taking a photo and measuring, you can set your personalised parameters to cull any logs that you do not want. You can find the field to do so after you check the show advanced fields box in the measurement view.