Dormant Tree Trimming in Indianapolis
My phone blew up with the warmer days we had in Indianapolis recently (I saw a blessed 67 degrees on my weather app at one point). People flocked outside and inevitably began thinking about their trees. On informational calls multiple people asked: “when should I trim my trees”? I’ll answer that question here, but it’s worth noting that there are equally important questions to address. (P.S- If you’re the kind of person who values credentials, I am an ISA certified arborist who is also certified in tree risk assessment and prescription pruning.)
When Should I Trim My Trees?
Don’t shoot the messenger, but my intentional answer to this is “when the risk from a condition of concern outweighs the benefit the tree is providing”. If you have a newly cracked limb that is squarely over your house, it doesn’t really matter if it’s the prime season for the transmission of oak wilt, dutch elm disease or any other threatening tree fungus- the cracked branch needs dealt with. Now there are non-invasive responses which can be utilized like dynamic tree cabling, but the point is that in every situation the risks are weighed against the benefits.
That said, I’m going to assume that most people asking this question don’t have an imminent concern or else they would’ve googled “tree trimming service near me”. For those of you who are genuinely trying to learn and don’t have an imminent risk, the answer to “when should I prune my tree” is almost always dormancy. In Indianapolis we are in zone 6a (check the full map here), and dormancy will vary slightly by year and by species. That said, you can pretty regularly count on December through early March, with a little bit of give on either side.
Reasons For Trimming Trees in Winter
The primary reason for tree trimming in winter is to avoid the transmission of fungus. Here in Indianapolis we have numerous susceptible species, and the wrong fungus can take a tree out in a matter of weeks. While there are other modes of fungus transmission, far and away the most common is from insects carrying the fungus (see this article from University of Minnesota or this article from University of Illinois). While this conclusion is intuitive, I would appreciate anyone who has conducted more research on the topic emailing me since I am less than satisfied with the volume of research I’ve seen on this topic. It is worth noting that while connected roots of the same species in a connected geographic area can convey fungus to another tree, the fungus would have to reach the trees in that area first through some vector like an insect. Susceptible species include red oak, elm, birch and Ash (you knew that last one already though). Feel free to try and look up the last confirmed case in your area though before coming to your own conclusions!
The second big reason we arborists like to prune in Winter is that we can see the entire branch structure of the tree. Since structural pruning and risk mitigation pruning focus so much on aspect ratios (helpfully explained by Ed Gilman out of University of Florida in this article) this visibility is pivotal. Simply put, you cannot fully see how aspect ratios are affecting the growth and structure when trees are in leaf. I used to think referencing the visibility was a sales tactic of arborists to provide work for the winter, but after years of experience I can tell you hands down that I can do a better pruning job in the Winter. Similarly, your arborist will both catch what they DON’T need to prune in addition to everything they DO need to prune in winter. It’s not impossible to accomplish an effective structural prune when trees have leafed out, but the branch structure is objectively more obscured.
A Plug For Structural Tree Pruning in Indianapolis
In that paragraph above I mentioned Ed Gilman, who is the most prominent voice in pruning in the United States. His research has literally gone so far as to take structurally similar trees, prune one of the two, put both in front of a jet engine propeller and observe the impacts - pretty impressive stuff.
Ed’s research has definitively shown that the immense opportunity to positively affect the structural integrity of a tree through focused pruning in the first few years of its life. Unfortunately, most people only take care of tree work when there is an imminent concern, like a dead branch over the playset or branches brushing up against the house. If you can take my word for it, have a certified arborist in Indianapolis (it doesn’t have to be me- but it can be!) look at trees that are less than 30ft tall in your yard. For dollar figures like $450-$700 (which is peanuts when it comes to removing trees later on) you can probably help your tree avoid huge costs later on, improve the structural stability and set it up to look beautiful for the long haul. Please take my word for it, and trim your trees while they are young.
You know what? I wasn’t even planning on that being my concluding thesis, but I think it will be. When should you pursue tree trimming in Indianapolis IN? When they are YOUNG (and in the wintertime)!
P.S- There are thousands of pages on appropriate pruning out there; this article is not meant to be exhaustive, but barely introductory!
