This is the Refuge champion mesquite tree near the HQ complex. I had just interviewed a long-time resident of the area who brought us pictures of this same tree taken 50 years earlier...and the tree looked as big back then as now. The dbh is on the order of 40" (see image of the trunk with my 6" binocs). It is likely to be on the order of 150 to 200 yrs old.