I would avoid using any variety of cedar mulch around apple trees. Mulch is acidic and holds moisture.As it decomposes it adds to the soil lowering PH. Best PH for managing apples is 6.2 PH to 6.8. Mulch can rot or damage the bark near the base and have found it to encourage bore damage. Multching tends to absorb heat during January thaws icreasibg sap flow which is trapped and frozen in the cambium risking sunscald damage. It won't cause cedar applr rust as the virus resides in the gulls of red cedar and other kinds of junipers and can't be transmitted by multching..
Something to ponder. There's something else going on with mulches and straws.
https://www.researchgate.net/public...ndscape_plants_and_the_environment_-_A_review
Mulch Problems — Real and Perceived
Acidification. Organic mulches such as wood chips and
bark are thought by some to be soil acidifiers. No scientific
research supports this, and in fact studies refute this percep-
tion. One study found neither pine bark nor pine needles had
J. Environ. Hort. 25(4):239–249. December 2007
244 J. Environ. Hort. 25(4):239–249. December 2007
any affect on soil pH (51). A second report (60) found bare
soil to be more acidic than soil covered by inorganic mulch,
and that shredded bark and wood chips were least acidifying
of all treatments. Similarly, a year-long study found that the
soils under organic mulches were either more alkaline or not
affected by mulch treatment (100).
It’s likely that in artificial conditions, such as nursery pro-
duction, that woody materials do have an acidifying effect
when they are used as part of a potting medium. Release of
phenolic acids is one stage of the decomposition of woody
material, and if this material comprises the bulk of medium
then acidification is likely to occur. In a field situation, how-
ever, where the woody material is used as a mulch (and not
worked into the soil), any acidification will be localized within
the mulch layer and have little effect on the vast underlying
soil environment below. Thus, soil acidification due to mulch-
ing with woody plant material is unlikely to occur under real
world conditions.