If the tree's leaves have been brown and dried since spring, it has died or was too damaged and weakened to recover, especially if it has not produced new growth by summer. We can't tell from the photo what the exact cause of its demise was (girdling roots, the winter cold snaps coupled with last year's drought, opportunistic insect borer or fungal infection, etc.), but a certified arborist might be able to narrow-down a diagnosis, though it may be harder to do so after the tree has been in this state for that long. Earlier this growing season, we received many questions about mature and well-established, hardy plants that suffered some damage or major dieback from this past winter's cold snaps, and last year's significant drought likely predisposed many species to additional environmental damage due to the underlying stress.

Miri

We aren't able to offer a site visit consultation, but the photos show a typical response to canopy dieback (or weakened canopy branches that may die later), which is rampant suckering and water sprouts. This is a normal reaction when plants are trying to regrow from significant stress or damage, and sometimes it enables them to recover over the long term (it will take years to re-form a canopy from new growth), and sometimes it fails if the root system or other areas are too compromised or develop another problem in the interim. The branch attachment points of suckers are normally not desirable, so they are pruned off, but in this case, you probably don't want to remove too many of them since they are probably the only viable growth points left on the tree -- trimming them won't necessarily allow the tree to put that energy into other growths, and their removal will also set the tree back a bit by diminishing its ability to photosynthesize.

Consult a certified arborist if you want to prune or help the tree recover. (Dead wood, at the very least, should be pruned off.) For the future, do not fertilize unless a laboratory soil test has measured a particular nutrient deficiency; artificial intelligence tools don't often get plant care recommendations or diagnostic information correct. Adding fertilizer to soil that is not deficient in nutrients could stress roots or be a waste of nutrients that might then pollute water runoff. Plus, added nutrients won't necessarily "push" a plant to generate more growth, and too much lush growth may backfire as the plant will not be able to defend it as well against disease, or keep it hydrated if roots need to catch up to canopy growth.

Miri