Reader Q&A

Here's another good (and common) question and answer about how to care for a fresh Christmas Tree.

From: O.A.
Sent: Wednesday, December 05, 2007
Subject: Tree care - additives to water or not?

I'd like to know if additives (i.e. preservatives) to the water for Christmas Trees are helpful and/or necessary? A well-respected garden store in my town even told me to make a scrape in the trunk of the tree (that would be in the water) with a steak knife, saying that would help with the water intake. In your tree care info, you don't even remark about this so does that mean NCTA doesn't advocate additives/preservatives?

Answer: Well, you've got two issues to address here.

First, scraping the trunk does NOT help with water uptake. I wish they hadn't told you that. In fact, if you cut off pieces of the bark and into the cambium layer, it can inhibit the tree's ability to absorb water. Think of the tree as just a bigger version of fresh flowers in a vase. Before placing flowers in a vase, you snip off the bottom with a pair of scissors. With the tree, you cut about a 1/4-inch piece off the trunk ... and for the same reason, it opens up the plant tissue that absorbs water molecules. The whole system works much like a siphon. As water molecules evaporate out of the foliage, water molecules and other compounds are moved up through the cambium layer. That is the softer plant tissue just below the bark. Not much water is moved up and down in the center of the center stem/trunk where the denser woody mass is located. What stops a siphon system is air. After a period of time, typically 4-6 hours, air molecules enter the cambium layer when the cut surface is exposed to air. When you make a fresh cut, you are removing the air and "re-priming" the plant's system to siphon water again.

Does that make sense?

Second, believe it or not, there have been many controlled studies conducted by plant pathologists over the years measuring various water additives' affect on water uptake and needle retention. Nothing has ever been shown to imrpove water uptake consistently across all species better than plain tap water.

I'll share a quick anecdote. After my first season of working for NCTA, I was talking with a grizzled old tree farm about all the concoctions people put in their tree's water. He got a thoughtful look on his face and said," You know, I don't get it. That tree spends eight years out in my field drinking nothing but rain water, and people get it in their hom and think it suddenly needs a 7-Up. I never it a 7-Up once."

Reader Response: Hi Rick - I knew I'd get a good answer from you! If you don't mind, I plan on forwarding your e-mail to my local well-respected garden store. It didn't make sense to me to scrape the bar, but what do I know? And, it never made sense to me either, why a person had to add preservatives to a tree that had grown on water alone. Thanks again for the information. I want to make the most of my seasonal investment: my tree.