yes, it does not normally cover owners. But by using subs without the W/C policy you are all but asking to pay the W/C fees on subcontract dollars you pay out.
If you have no employees and pay no payroll, the W/C policy (here anyway) only costs around 550-600 bucks per year. When you start paying payroll is when you remit based on your rate.
Aside from that, when clients ask about WC coverage, you have a policy. Looks and sounds much better than using the "I dont have employees, so I dont need it" line of crap.
If you are in the tree business with or without employees, you are asking for trouble by not carring a policy.
But, what do I know?