> When exporting a subtree, the top-level outline becomes the title of the > document, i.e., the document becomes morally equivalent to: > > #+title: test > <2021-03-18 Thu 15:00-16:00> > body of text > > There is indeed no event to export in this case. Only level 2 outline > will become events. You may want to export region instead.
Thank you very much Nicolas for explaining; this was my mistake. My solution for now is to use org-narrow-to-subtree and then export it. Stephen