All those ground up wood chips from the ground up stump will eventually decompose and settle, so you should allow for this by raising the grade when you replant.

Scot, good point. David, thanks. Sounds good. I was planning to get a Lacey oak which is native to my area and said to be oak wilt resistant, but I was told by two nurseries that none are available from their wholesalers this year. Also just read on line that it had been shown to be susceptible to oak wilt, so guess that variety is out. First I was considering a very different tree just because I liked it's looks and don't need a dense shade tree, Palo Verde 'Desert Museum'. It was widely available last year, but now same thing -- none of the wholesalers are carrying it. Anybody know why? I'm almost tempted to wait for it IF I thought I could get it later. Any ideas? Here is a link that might be useful: FYI Scroll down to The Bad News ...

There is some evidence that rose roots do give off a growth inhibitor. Title: Growth inhibitor accumulates in the nutrient solution of closed system rose cultivation. Author: Sato, N. Authors affiliation: Shizuoka Agricultural Experiment Station, 678-1 Tomioka, Shizuoka, Iwata, Japan. Published in: Acta Horticulturae (2005), 697(Proceedings of the International Symposium on Soilless Culture and Hydroponics, 2004), pages 511-516. Abstract: "The circulating soln. was collected and analyzed for its nutrient concn. Three types of solns. were prepd. for the bioassay. One was the circulating nutrients soln. Activated charcoal was added to second soln. The third soln. was prepd. to the analyzed formula of nutrients soln. using distd. water. The rooted cuttings of rose were planted in each soln. and incubated in the growth chamber. The rate of change of fresh wt. before and after the incubation was biggest for the prepd. soln., which does not include the circulating soln. The fresh wt. growth rate was smallest for the circulating soln., and the results for the activated charcoal treatment was between them. Since the activated charcoal does not have a sterilization effect, it is possible that the growth inhibitors accumulated in the soln. during the circulating cultivation of roses. " Here is a link that might be useful: link for above

I think you are worrying unnecessarily. Commercial orchardists routinely replace dead apple trees with a new one in the same spot. Very few diseases of any significance to apples will remain present in the soil and most of those can be circumvented by selecting a disease resistant cultivar (which Honeycrisp is) and by the appropriate rootstock. Your biggest worry is going to make sure you have the stump and roots of the old trees out of the way to make planting easy. btw, mummified fruit can just be as simple as fruit that never fell or eaten by any creatures and has started to deteriorate/decompose on the tree. And most old, untended apples will look 'diseased'......it is just a symptom of old age :-)