He owns a 1% share of some timber company company as noted on factcheck.org (per Brian Williams). In 2001 he earned $84 on that 1% share.
Thing is I think Bush is directly talking about propriotorships and propriotoryships and not corporations. Owning 1% of some lumber company doesn't qualify you as a small business owner.
That's a private placement, where investors pony up to infuse capital into a private business, 1% is a small player, he probably is on a list of investors who are solicited for this type of venture capital.
Unless he was on the Board or an executive, he probably had no say whatsoever in the operations of the corporation.
President Bush's assets are in a blind trust. He doesn't know what he owns.
That's why I had to laugh when he said, "Need some wood?"