It is well established that losses sustained after termination of a tenancy may be recovered, and that "damages awarded . . . in an unlawful detainer action for withholding possession of the property are not `rent' but are in fact damages." ( Haig v. Hogan (1947) 82 Cal.App.2d 876, 878 [ 187 P.2d 426].) Thus, a landlord is entitled to recover as damages the reasonable value of the use of the premises during the time of the unlawful detainer either on a tort theory or a theory of implied-in-law contract. ( Lehr v. Crosby (1981) 123 Cal.App.3d Supp. 1, 9 [177 Cal.Rptr. 96].)

Second, "[i]t is well settled that damages allowed in unlawful detainer proceedings are only those which result from the unlawful detention and accrue during that time." ( Vasey v. California Dance Co., supra, 70 Cal.App.3d at p. 748; accord Mihans v. Municipal Court (1970) 7 Cal.App.3d 479, 489 [ 87 Cal.Rptr. 17]; Haig v. Hogan (1947) 82 Cal.App.2d 876, 878 [ 187 P.2d 426]; Chase v. Peters (1918) 37 Cal.App. 358, 362 [ 174 P. 116].) Since the damages only arise from the unlawful detention, it is irrelevant whether the unlawful detention resulted from a contractual breach or a trespass; in both instances the defendant remains on the property unlawfully.

(See Stockton Morris Plan Co. v. Carpenter, supra, 18 Cal.App.2d 205 at p. 210; Samuels v. Singer, supra, 1 Cal.App.2d 545 at p. 554; Lehr v. Crosby, supra, 123 Cal.App.3d Supp. 1 at p. 9; Glouberman v. Coffey (1955) 138 Cal.App.2d Supp. 906, 907-908 [292 P.2d 681]; cf. Civ. Code, § 3334) "Ordinarily, it might be said that the agreed rent is evidence of the rental value, but . . . such rental value may be greater or less than the rent provided for in the lease." ( Harris v. Bissell (1921) 54 Cal.App. 307, 312-313 [ 202 P. 453]; accord Lehr v. Crosby, supra; see Karp v. Margolis (1958) 159 Cal.App.2d 69, 75 [ 323 P.2d 557]; D'Amico v. Riedel (1949) 95 Cal.App.2d 6, 9 [ 212 P.2d 52]; Haig v. Hogan (1947) 82 Cal.App.2d 876, 878 [ 187 P.2d 426].) (19d), (26b) No evidence was introduced concerning the reasonable rental value of the property.

It would also be admissible, in any case, for the limited purpose of assisting the court in exercising its discretion to treble the damages found to be due, as is provided in section 1174 of the Code of Civil Procedure. [5b]Stockton Morris Plan Co. v. Carpenter, 18 Cal.App.2d 205 [ 63 P.2d 859], Haig v. Hogan, 82 Cal.App.2d 876 [ 187 P.2d 426], and many others cited by the plaintiffs to establish that "the reasonable rental value is the proper measure of damages" do not in any instance involve a factual situation like the one we have here. In each case the plaintiff would have been entitled to the rent of the premises, and not as in this case where the plaintiffs would have to pay rent for the place to the owner as part of the cost of doing business.

Respondents were also entitled to recover damages incidental to obtaining possession of the premises. (Haig v. Hogan (1947) 82 Cal.App.2d 876, 878 [187 P.2d 426]; Stockton Morris Plan Co. v. Carpenter (1936) 18 Cal.App.2d 205, 210 [63 P.2d 859].) Damages consisted of mortgage payments, property taxes and association dues.

) We believe that the correct statement of the rule is that the lessor is entitled to damages for the unlawful detainer predicated upon the fair rental value of the property. (Stockton Morris Plan Co. v. Carpenter (1936) 18 Cal.App.2d 205, 214; Haig v. Hogan (1947) 82 Cal.App.2d 876, 878; Johnsons&sMoskovitz, Cal. Real Estate Law and Practice (1981) Landlord and Tenant, § 210.75, pp. 210-68 to 210-69.)         Although at common law breach of a covenant to pay rent did not effect a forfeiture of a lease, that rule has been modified by California's unlawful detainer statutes which permit the lessor, upon compliance with statutory notice requirements, to declare a forfeiture and terminate the lease for nonpayment of rent. (Sexton v. Nelson (1964) 228 Cal.App.2d 248, 256, 39 Cal.Rptr. 407.)