I recently cleared out several bayberry trees and plan to replace them with figs, but I noted some of the roots of the bay berries had golf ball size tumors caused by nematodes. Are figs resistant or do I have to treat the soil?

Figs are very susceptible to nematode infestation. It may be best to grow them in pots of your soil is infected.

Plant an indicator species like Okra or something and see if it gets infested. The galls should be pea sized so it does not even sound like RKN. 

See Anti-Nematode Crops and Rotations here,
https://www.uaex.edu/publications/pdf/FSA-7529.pdf

Thanks for the info. From the size of the knots I am hoping it is a disease ofm the bayberries. I have a few weeks before the area is cleared and I'll have the county agent take a look at them.

• Actinorhizal plants such as alder and bayberry can also form nitrogen-fixing nodules, thanks to a symbiotic association with Frankia bacteria. 

Don't I wish! These are on the roots of the bayberry and look like large knots. I'd include a photo but I guess there is a file size limit of 1MB.

UPDATE:
NC DA&CS Agronomic Division report
# of Nematodes per 500cc
Dagger       20
Lance         30
Ring           30
Sheath       10
Spiral         40
Stubby Root 10
Verdict: No expected harm to crop production>