You could always configure your email client to treat all email from a particular address as spam. Then when the emails arrive they get dumped into your spam folder and automatically deleted at a later date. Of course, that means that you'll also miss out on important emails from the same email address.
Another thing to try is to identify a uniquely used word in the emails that are flooding your email account, then set your spam filter to treat all emails containing that particular word as spam. That way, if an important email not using that unique word arrives from the same email account, it won't get treated as spam.
There are actually hundreds of ways to reduce unwanted email. Heck, you could even set up a free email account at any one of a number of sites, then use that email account on your WikiTree account. That way, you have only WikiTree emails going to that email account and your regular email account won't get bogged down by WikiTree emails.
