I intend to use sawdust as a soil conditioner and as a mulch.
I have a good supply of (naturally) untreated Macrocarpa from a nearby mill.
Is there a problem is using Macrocarpa sawdust?
I would imagine that Macrocarpa waste would take longer to compost but its stability would make it more effective as a weed control mulch.
We have no information about Macrocarpa specifically, but our research indicates sawdust in general is recommended for blueberries and should not harm them in any way. One recommendation is for up to six inches of mulch for organic growers, although too much mulching may make them more susceptible to disease.
sawdust does not much influence the soil pH
Blueberries may ripen later but the yield will be better
Be careful that fresh sawdust does not crust, preventing water penetration
Be aware that sawdust can float away in heavy rain
Sawdust has a high carbon to nitrogen ratio of about 500:1 - so if using as a soil conditioner or adding to compost make sure you add plenty of nitrogenous materials