Keep the use on the surface
Maryland Extension’s guidance is limited to surface use around trees and shrubs; it does not recommend these chips around annuals or vegetables. Working chips or sawdust into soil can deplete soil nitrogen, so surface use is not a reason to mix them into soil. No fertilizer treatment or dose follows from that warning. Maryland Extension: Mulching Trees and Shrubs
The page gives a shallow one-to-three-inch layer and about three inches clear of the trunk base; mulch should not touch bark. These are general horticultural guidelines, not a site diagnosis or a prescription to bury a root flare or raise the soil grade. If the guidance is hard to apply, ask a qualified arborist or local extension professional rather than digging or piling material against the trunk.
Set the keep-or-remove terms before the crew leaves
Ask the contractor to confirm in writing what the material is, which portion you are keeping, where it may be dropped, what access and space are available, and who is responsible for any remainder. Clarify quantity and cleanup expectations without assuming a particular load size, price, delivery, or free material. Do not treat logs, soil, sawdust, stump residue, or a pile simply called “debris” as interchangeable with identified fresh arborist chips. If the source or intended use is unclear, do not assume the pile is suitable; ask for separate retention and removal options. Unknown site conditions and material quality remain unknown.
Do not enter an active work area, handle unstable wood, or operate a chipper to inspect or move material. If you cannot identify a suitable surface-mulch destination or agree on what stays and leaves, resolve that with the contractor before work ends rather than accepting a surprise pile.