Turns out, a lot could go wrong. But, if it does, the neighbor whose tree limbs inspired you to climb the ladder, chainsaw in hand, probably won't be responsible, at least according to the holding in Corbisiero v. Schlatter.
In Corbisiero, plaintiff was a tenant in mixed-use property that was adjacent to defendant's property. In Spring 2013, some twigs and branches fell from tress located on defendant's property onto the property where plaintiff lived. Plaintiff asked defendant to cut down some of the branches that extended onto the property, which defendant did. A few months later, plaintiff asked defendant to cut down some more branches. Defendant told plaintiff that she would do it when she had time.
Apparently unwilling to wait for defendant to get to it, plaintiff spoke to her landlord about cutting the branches herself. Her landlord told her that "if [the tree limbs] grew over his property . . . we [can] cut them down." The landlord also told plaintiff that he would reimburse her for the cost of a chainsaw to be used to cut down the limbs. It is unclear if the landlord was suggesting that plaintiff both buy the chainsaw and cut the limbs down (as opposed to buying the chainsaw and having someone else do it), but plaintiff nonetheless chose to take matters into her own hands and do both.
On the day of the accident, plaintiff approached defendant and said: "I want to cut some trees." Defendant recommended that plaintiff wait for defendant's son to come home and do it, as he had done a few months before. Plaintiff ignored this advice. Instead, she "stood on a metal stepladder she owned and proceeded to use the chainsaw to cut one of the presumably overhanging branches." Unfortunately, "the branch broke and fell in front of her, striking the chainsaw causing her to fall over the top of the ladder." Plaintiff claimed that she feel to the ground and landed on her face.
Plaintiff sued, alleging that defendant "carelessly and negligently maintained, inspected, created and/or permitted a hazardous, dangerous, and defective condition to exist on [the] premises which extended onto the adjacent premises . . . [of which] the defendant knew or should have known . . . as a result of [which] the plaintiff . . . was caused to fall." (As an aside, only lawyers would think that "caused to fall" is a better choice than "fell.") Defendant moved to dismiss the complaint and the trial court agreed, holding that defendant owed no duty of care to plaintiff because: defendant did not "personally request, participate in, or otherwise aid [plaintiff's] cutting of the tree branches;" defendant was unaware of "plaintiff's intent to get on a ladder and use an electric saw which she purchased with her landlord's approval;" and defendant actually recommended that plaintiff wait for defendant's son to come home and cut down the branches as he had done in the past. Plaintiff appealed.
The Appellate Division affirmed the trial court. It held that defendant did not create the "inherently dangerous condition that caused [plaintiff] to fall and injure herself." Rather, plaintiff created the condition when she decided to carry out the "ill-advised task" of climbing the ladder to cut the tree limbs with a chainsaw. The Appellate Division noted that landowners can be liable, under a private nuisance theory, if a tree falls from a landowner's property onto adjacent land and causes damage. Even in such cases, however, liability is only imposed if the landowner was, at the very least, "negligent in not making reasonable use of his property," which requires a court to consider "the nature of the incident, the danger presented by the presence of the tree, whether [the landowner], by making inspections, could or should have known of its condition, what steps he could have taken to prevent it from falling onto [plaintiff's] property, etc."
In Corbisiero, the Appellate Division held that, taking these factors into account, there was no evidence of any negligence by defendant. More importantly, plaintiff was not alleging damages caused by a tree that fell on her property. Rather, she was alleging damages caused by her ill-advised decision to prune the tree limbs. Her "unilateral" decision to do so caused her injury, therefore defendant could not be liable.