Trespass to Property:

[52]  With respect to the claim of trespass to land Lederman J. in Hudson’s Bay at para. 9 states as follows:

Clerk and Lindsell define trespass to land, at p. 837, as consisting of “any unjustified intrusion by one person upon land in the possession of another”.  Halsbury’s, Vol. 45, para. 1384 states that “every unlawful entry by one person on the land in possession of another is trespassed for which an action lies…

[53]  The elements for the claim of trespass to land are set out by Crane J in Grace v. Fort Erie (Town), 2003 CanLII 48456 (ON SC), [2003] O.J. No. 3475 (SCJ) at para. 86:

The elements of trespass have been described as follows:

• Any direct and physical intrusion onto land that is in the possession of the plaintiff, (indirect or consequential interference does not constitute trespass).
• The defendant’s act need not be intentional, but it must be voluntary.
• Trespass is actionable without proof of damage.
• While some form of physical entry onto or contact with the plaintiff’s land is essential to constitute a trespass, the act may involve placing or propelling an object, or discharging some substance onto the plaintiff’s land can constitute trespass.

[61]  It is also beyond controversy that a plaintiff bears the onus of proving his or her claimed loss and the quantum of associated damages on a reasonable preponderance of credible evidence.  Further, as the trial judge recognized in this case, a trial judge is obliged to do his or her best to assess the damages suffered by a plaintiff on the available evidence even where difficulties in the quantification of damages render a precise mathematical calculation of a plaintiff’s loss uncertain or impossible.  Mathematical exactitude in the calculation of damages is neither necessary nor realistic in many cases.  The controlling principles were clearly expressed by Finlayson J.A.  of this court in Martin v. Goldfarb, 1998 CanLII 4150 (ON CA), [1998] O.J.  No.  3403, 112 O.A.C.  138, at para.  75, leave to appeal to S.C.C.  refused, [1998] S.C.C.A.  No.  516:

I have concluded that it is a well established principle that where damages in a particular case are by their inherent nature difficult to assess, the court must do the best it can in the circumstances.  That is not to say, however, that a litigant is relieved of his or her duty to prove the facts upon which the damages are estimated.  The distinction drawn in the various authorities, as I see it, is that where the assessment is difficult because of the nature of the damage proved, the difficulty of assessment is no ground for refusing substantial damages even to the point of resorting to guess work.  However, where the absence of evidence makes it impossible to assess damages, the litigant is entitled to nominal damages at best.

See also Cadbury Schweppes Inc.  v. FBI Foods Ltd., 1999 CanLII 705 (SCC), [1999] 1 S.C.R.  142, at para.  99; 100 Main Street East Ltd.  v. W.B.  Construction Ltd.  (1978), 1978 CanLII 1630 (ON CA), 20 O.R.  (2d) 401 (C.A.), 88 D.L.R.  (3d) 1, at para.  80; Penvidic Contracting Co.  v. International Nickel Co.  of Canada, 1975 CanLII 6 (SCC), [1976] 1 S.C.R.  267, at pp.  278-79.