Every year they’ll tell you.
Those well-meaning salespeople who, after you’ve managed to finally locate a Christmas tree that everyone can agree on, say, “Don’t forget to make a fresh cut about 2 inches above the base as soon as you get your tree home. Then place it immediately in lukewarm water and stand it in a sheltered place until you’re ready to put it up.”
Yet if they didn’t inform you, the pine fragrance and soft needles of your cherished tree would be short-lived.
Trees are like people: When they get a bruise, their system focuses on the site and tries desperately to heal it. In our case we bleed, form a clot, then a scab and eventually new skin. For a tree, even though at this time of year it’s nearly dormant, it still tries to heal itself.
Remember, the food is transported from the leaves where it’s manufactured down to the roots through long, narrow vessels or tubes called phloem. Water moves up and down throughout a plant via the xylem vessels. So when we sever the tree at ground level, interrupting these processes, the tree immediately senses something drastic has taken place and it sends a fix – its “blood.”
A tree’s “blood” is that sugary, food substance it manufactured in its leaves, which we often hear referred to as sap.
It doesn’t take long for this sap to congregate at the cut, since it can’t continue its journey down to the roots. And once exposed to air, it does exactly what our blood does, it solidifies or clots in an effort to stop any more seepage.
The kicker is, the sap, in its effort to fix what’s broken, not only clots itself but flows over and clogs the severed xylem.
By recutting the bottom, we remove the clotted sap and reopen those very important water vessels. And, by placing the tree immediately in water, we eliminate the sap’s exposure to air and let vessels remain open for water uptake.
But what’s with the “lukewarm” water? Why not just use cold water? If you take maple syrup right from the fridge and pour it over your pancakes, it kind of trickles ever so slowly, then as it warms up it cascades easily over the sides down onto your plate. Sap reacts to temperature in a similar fashion. Lukewarm water will help keep the sap thinner at the cut so it won’t seal over.
As for locating the tree away from a heat source, a cut tree that remains indoors a few weeks eventually will cease the normal process of water absorption.
The further away from heat or direct sun and the lower the room temperature, the longer you can fool Mother Nature by keeping the xylem active and the needles in a dormant state.
It’s when the heat intensifies that the needles think spring has sprung and begin to release moisture through a process called transpiration. Bottom line: The needles end up releasing more moisture into the air than the xylem vessels can take up, the tree begins to dry out, and the needles drop off.
The direction to store the tree in a sheltered location until moving it indoors helps protect the tree from drying winds and other environmental conditions that, under normal circumstances, the tree could handle. However, without roots these conditions are heightened, and again the needles lose more moisture than the xylem can take up.
When the tree is outdoors and subject to freezing temperatures, the sap is moving slower through the phloem, just like the cold syrup over your pancakes. This makes the branches a bit stiffer, but as the tree warms, the sap thins down and the branches begin to relax, giving the tree a much more normal appearance.
Follow these basic tips and you’ll have a longer-lasting Christmas tree.
