Contact your local office of the University of Connecticut USDA Cooperative Extension Service and have the horticulturist come out and look. While I've not heard the Emerald Ash Borer is in Connecticut that does not mean they aren't. These wee larva are devastating Ash trees in many areas of the country and are spreading out. Here is a link that might be useful: Emerald Ash Borer

Yeah, I think the problem though is that there's some visual deception going on; by the time the core complete vanishes, A LOT of the wood is probably actually microscopically compromised. If that makes sense. I think higher up - the wood my tree guy carted away - the size of the "aperture" was larger. And that was where it split after all. He cut down about 6 feet from the point where it split to leave this a few inches off the ground. Like I said we get high winds around here sometimes, but it isn't as though a tornado came through! Most of my cherries, ashes and tulip poplars shrug such conditions off. The silver maples are clearly very weak wooded and in a dubious category of their own.

Thank you Embothrium! This is not a forest region - just a single tree in the middle of my yard. I planted an elderberry on the other side of the stump at about the same distance this spring, and it seems to be doing fine (although I didn't come across any roots of this size when planting that one). The weeds seem to like the area as well. :) Is honey fungus a problem outside of thickly forested areas?

as the bed is now.. its only wide enough for the iris there ... or any smaller perennial ... but you already spied the problem.. the big blank wall ... you CAN NOT change that in that bed ... there is not much you could get the height you need to impact the wall .. based on the width of the bed ... [one option might be something like a clematis.. on a trellis ... though then you might have a hard time attaching a trellis to the siding.. im kinda against drilling holes in my house for garden reasons ... but there are other ways ] move out into the lawn ten feet or so ... and plant a couple nice smallish decorative trees ... [where these should have been planted] if you want to go with huge shade trees.. move them out 20 or 30 feet into the lawn ... since there isnt really much you can plant there ... i would just cut it flush to the ground.. and apply a stump killer and be done with them ... no real need to dig them out ... plants are planted.. to HIDE the foundation.. not ON THE foundation ... as they were here ... frankly ... a proper bed leaves two or 3 feet at the foundation.. for house maintenance .. e.g ... window cleaning.. gutters.. hanging xmas lights .. painting.. none of which applies to your sided wall with none of the listed problems.. lol ... btw ... you have about 50 iris there.. those could be separated at the appropriate time ... and spread all over the place ... and that is usually after flowering ... ken