Arborist Expert WitnessesDefendants appealed the trial court’s decision for Plaintiffs awarding them damages after Defendant destroyed 31 trees on Plaintiff’s property.

Defendant argued that the maintenance of a lime pile uphill from Plaintiff’s property line and trees wasn’t the direct cause of the destruction of the trees and that the trial court abused its discretion by admitting expert testimony in the form of an opinion pursuant to Indiana Rule of Evidence 703.

The parties were neighbors, both owning adjacent farming properties in Clark County, Indiana. Plaintiff’s property included 31 mature ash trees, clustered near each other close to the Defendant land, which created an “arboreal setting” in the back of Plaintiff’s property. Plaintiff saw that the trees began to rot, wither, and die—at the same time, Defendant had piled lime dust uphill from the Plaintiff’s property line and the tree cluster. After noticing the trees’ deterioration, Plaintiff took soil samples from around the tree trunks for testing. Eventually, the trees rotted from the ground up and the entire cluster died and had to be removed.

On appeal, Judge Patricia A. Riley stated that at common law, a plaintiff bringing a trespass action must establish two elements: (1) the plaintiff must show he possessed the land when the alleged trespass occurred, and (2) the plaintiff must demonstrate the alleged trespasser entered the land without legal right. Further, a trespass could occur if there was a direct causal relation between the actor’s conduct and the intrusion of the foreign matter upon the possessor’s land that caused the harm.

Not disputing the admissibility of Plaintiff’s expert testimony on the issue of valuation, Defendant claimed that the trial court incorrectly admitted the expert’s testimony on the issue of causation. Defendant maintained that because the expert’s opinions about the soil’s pH composition were based on a report generated by an independent company and the expert had not personally taken or tested the soil samples, it was inappropriate to rely on his testimony.

Judge Riley noted that although inadmissible evidence typically can’t be introduced at trial, inadmissible evidence may nevertheless be relied upon for the purposes of expert-rendered opinion testimony. Indiana Rule of Evidence 703 provides that “An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed. Experts may testify to opinions based on inadmissible evidence provided that it is of the type reasonably relied upon by experts in the field.”

However, there are limits to the extent that a party proffers opinion testimony that is merely a “conduit” for placing inadmissible evidence before the court without meaningful opportunities for cross-examination. Judge Riley quoted the Indiana Supreme Court, which recognized:

Some experts customarily gather information from a variety of other experts and authoritative sources and rely upon it in reaching their opinions. When an expert witness’ own independent opinion is arrived at in this manner and it is introduced into evidence and the expert witness is subject to cross-examination, that part of the substrata of information which aided in the formation of the opinion, though hearsay in nature and though not falling within any hearsay exception, may nevertheless be admissible for use by the trier of fact in judging the weight of the opinion.

However, the judge said that such hearsay is inadmissible where it is merely a restatement of another’s conclusion “as a conclusory answer to an ultimate fact in issue,” such that the veracity of the statement is not “subject to the test of cross-examination.”

Judge Riley said that upon first noticing the trees’ deterioration, Plaintiff took soil samples from around the trunks which she had tested by an independent company. At trial, Plaintiff introduced a certified arborist—whose credentials were not challenged by Defendant—as her expert. The expert explained that the “compounds of the soil” are included in the “field of arbor culture.” He elaborated that even though he occasionally performs soil tests for customers, Plaintiff only hired him to calculate the value of the damaged trees.

During trial, the arborist testified that Plaintiff sent him the report of the soil sample analysis, and based on his review of the test results, he reached his own independent conclusions. The expert explained that the test results of the soil indicated a high pH, in “the category called alkaline.” Offering his own study of the test results performed by the testing company, he explained the results’ meaning and reached his conclusion as to what happened to the trees based on his evaluation of the test results, opining that the pH content of the soil killed the trees.

Judge Riley explains that, rather than being a mere conduit to introduce the report and to regurgitate the report’s information, the expert interpreted and explained the test results. Subjecting these results to his independent analysis, he reached his own conclusions, which were subject to Defendant’s cross-examination. Therefore, the Indiana Court of Appeals held the trial court did not abuse its discretion by admitting the expert’s testimony with respect to the cause of the trees’ deterioration.

The judgment was affirmed.

Zollman v. Costello,2018 Ind. App. Unpub. LEXIS 1542 (Ind. Ct. App. December 21, 2018)


Review our arborist expert witnesses and some of the related disciplines: ArboricultureLandscapingTree AppraisalTreesTree SafetyHorticultureTree FailureUrban Tree ManagementPlant PathologyTree Root DamageForestry, and Forest Management.