Except as required by section 47-11-02 or a statute other than chapters 59-09, 59-10, 59-11, 59-12, 59-13, 59-14, 59-15, 59-16, 59-17, 59-18, and 59-19, a trust need not be evidenced by a trust instrument, but the creation of an oral trust and its terms, or an amendment or revocation of an oral trust, may be established only by clear and convincing evidence.