This chapter shall not be construed to impose any liability upon the city, its officers or employees for the performance of any act or the failure to perform any act under this chapter, and shall not relieve the owner from the duty to keep any tree upon owner's property in such condition as to prevent it from causing damage or constituting a nuisance. By enactment of this chapter the city is not assuming responsibility for the maintenance or major maintenance of street trees. (Ord. No. 1230, § 4 (part); Ord. No. 1300 § 4 (part).)