Ann Althouse is only one of the people highlighting the new "tax" on Christmas trees. Unfortunately USDA has a tin ear for political impact. In the old days when the Directives Branch processed a Federal Register document for ASCS there'd sometimes be a press release included in the clearance package, particularly for CCC board decisions. These days they probably should do a blog post in anticipation of an FR document publication; just try to get their side of the story out.
I'm playing catchup today but this sounds like a new research and promotion program, voted on by the Christmas tree growers and with the fees to be used for promotion. For some background on the research and promotion programs, here's the national ag law center's summary.