3 pics for you. The tree is a Euc grandis (flooded gum) that was topped.
You can see in the pics the resultant epicormic growth, I suppose the growth is around 45' to 50' long (15m to 17m) and the largest dia where it joins the stem maybe 8" (200mm).
So, look at the pics and have a guess, how long ago was the tree topped or how old are those epicormic shoots?