I assume that trees are not that different from cut flowers - recommendation is to cut the stem on an angle, thus making the exposure of the vessels to water larger. The cleaner the cut the better, although with wood I guess a saw is about as good as it gets, and as Puzzlegal mentions, there’s the issue of congealed sap. Changing water regularly helps. Unlike flowers, cutting a new bottom when the pores of the stem start to clog is not an option. And house humidity makes a difference, although making a house too humid has other issues.
I suppose too, if the entire “pencile-sharpened” stem could be immersed that would help. But otherwise, the outer edge of the trunk wood is where a lot of the sap travels, rather than the core, so exposing that to air and shaving it down (removing those outer layers of wood) is probably a seriously negative idea. Howver, IANAHorticulturist, so these are just educated guesses.
OTOH, we have an artificial tree, and we plan to take it down one of these days, …honest! I guess having a natural tree makes the decision less procrastinateable…
When we used to get fresh trees, I would cut about an inch off the bottom before putting it in the stand, then fill the stand with water immediately. I felt that the original cut would start to dry and seal, so I wanted the freshest exposure to the cambium as possible. The ‘pencil cut’ would seem to require cutting off a lot more. Most of our trees came from a ‘choose and cut’ place that we harvested ourselves, so we knew they hadn’t been sitting in a lot, drying out for days. When my in-laws downsized, we inherited their fake tree, so we haven’t had a real tree for nearly 10 years. I don’t like it very much, but I hate to think of that much plastic going to the landfill.
A week after Christmas, I cut a few hand-size, well-needled snips off my parents’ tree to burn. I got a nice pit of coals glowing and tossed in the first one. It lit bright almost instantly and let off the most enormous plume of nasty stinking smoke. Granted, my fire was really hot but I didn’t expect the applied fire retardant to burst quite so fast and acrid. I could smell it on my clothes and hair for hours, like scorched printed circuit board.
I remember seeing that done at the lot when I was very young. It was my first time seeing and hearing a real chainsaw.
My thought is that shaving of the outside 1/4 diameter of the trunk would remove 7/16 of the total trunk area, all prime sapwood that is more instrumental in keeping the tree moist.