In August of 2018, the tallest of the two was measured at 28.36 meters in height and 46.8 cm dbh. The next tallest (but actually the one with greater overall volume) was measured at 27.36 meters in height and 64.5 cm dbh.
See: https://www.skogur.is/is/um-skograektina/frettir-og-vidburdir/frettir-og-pistlar/30-metra-tre-2021
Copy and paste the text into Google Translate in order to read this article.
So, now you know where to go if any one of us ever make a trip to Iceland!

Click on image to see its original size