I'm always reluctant to recomend removing a tree to a customer because it's pretty self serving but I didn't have any quams in this case. A 100+ year old english walnut. The city moved out around it and it becamse like a city tree except the city doesn't take care of it. It had a limb break a few weeks ago and it looks like whatever was effecting the limb goes right down the trunk to the ground. Up by the crotch of the limb going to the left I poked a stick up there and there was significant rot. If that limb went it would take out the electric lines and several other targets and fall into a fairly busy street.