It’s amazing how many people shoot from the hip and assume their state landlords tenant laws are the same for your particular state
A very quick web search clearly shows if you occupied the rental for a period longer than one year the landlord Must give 60 day notice to end a month to month
http://www.osbar.org/public/legalinfo/1253_ResidentialEvictionNotices.htm
This site below contains the whole statute for landlord tenant law, find the exact statute number that requires 60 day notice in your fact pattern, then send a nice, simple, professional letter certified to landlord stating by law you have 60 days, name the statute number and then state you will be vacating on the 60th day not in 30 days
http://www.leg.state.or.us/ors/090.html
Additional info LOOK AT 3(C)
90.427 Termination of periodic tenancies; landlord remedies for tenant holdover. (1) As used in this section, “first year of occupancy” includes all periods in which any of the tenants has resided in the dwelling unit for one year or less.
(2) If a tenancy is a week-to-week tenancy, the landlord or the tenant may terminate the tenancy by a written notice given to the other at least 10 days before the termination date specified in the notice.
(3) If a tenancy is a month-to-month tenancy:
(a) At any time during the tenancy, the tenant may terminate the tenancy by giving the landlord notice in writing not less than 30 days prior to the date designated in the notice for the termination of the tenancy.
(b) At any time during the first year of occupancy, the landlord may terminate the tenancy by giving the tenant notice in writing not less than 30 days prior to the date designated in the notice for the termination of the tenancy.
(c) At any time after the first year of occupancy, the landlord may terminate the tenancy by giving the tenant notice in writing not less than 60 days prior to the date designated in the notice for the termination of the tenancy.
(4) If the tenancy is for a fixed term of at least one year and by its terms becomes a month-to-month tenancy after the fixed term:
(a) At any time during the fixed term, notwithstanding subsection (3) of this section, the landlord or the tenant may terminate the tenancy without cause by giving the other notice in writing not less than 30 days prior to the specified ending date for the fixed term or not less than 30 days prior to the date designated in the notice for the termination of the tenancy, whichever is later.
(b) After the specified ending date for the fixed term, at any time during the month-to-month tenancy, the landlord may terminate the tenancy without cause only by giving the tenant notice in writing not less than 60 days prior to the date designated in the notice for the termination of the tenancy.