Recommended fungicide for oak?

[Sinjun]

Last year I very reluctantly had to have a large old oak cut down because of Ganoderma rot. There is another even older oak close by which is healthy, but has recently been damaged by a careless lorry driver scraping against a root buttress and stripping some bark off. I'm worried now that fungal spores from the stump of the original oak could transfer and would like some advice on how to prevent this - I was thinking of applying a fungicide but don't know whether this would be appropriate, or what sort. Any ideas gratefully received.

[sloth]

Best option - leave it. If there is any scope to improve the rooting area that would benefit the Tree anyway. How did the lorry get near it, prevent it happening again. Signs, bollards? Can the road/driveway be moved or diverted? If compaction is an issue sort that out, any room for much? Etc...