# Trees: What does "highly tapering stem" mean?

Trees: What does "highly tapering stem" mean?

Taper is a function measuring steepness of change in crown diameter when height increases upwards.

But "highly tapering" (sometimes also "high-degree of taper")? Is it "a large change in taper" (large steepness) or a "fine change in taper over a long height" (low steepness, but high fineness of change)?

• Good question. Apparently this not that simple as it sounds and there are different taper equations and "high" may mean both. Do you have a specific model in mind ? Searching "tree tapering" brings up a lot of material.
– user18607
Jan 15, 2020 at 12:08
• If the equation is not given, can you inferr what "high" means from the context ? Is it used to classify a the trees of one species, or to distinguish between different species ? Or to judge a growth history ?
– user18607
Jan 15, 2020 at 12:33
• @ebv In my case yes, but is this question then always "context-sensitive"? In that case I'd say that "highly tapering" is not particularly clear wording. Jan 15, 2020 at 12:58
• Yeah, without a broader context i'd say the same, sorry ...
– user18607
Jan 15, 2020 at 13:10
• Not "high"; highly : "to a high degree or level." Like, 'severely tapered' - which has nothing to do with height; the only thing it speaks to is the differential between the circumference at the base and that of further up the trunk. Palm trees have a comparatively higher taper than oak trees; the fact that they're usually taller than oaks doesn't matter. Jan 18, 2020 at 21:01

A "highly tapering stem" is simply that the trunk of the tree is less cylindrical and more conical in profile. It's a problem because while you may have a lot of timber volume you don't have as much timber that is usable because you'll end up with a higher proportion of sawmill waste.

I'm English and have a degree in forestry. Regardless of comments elsewhere, a "highly tapering stem" is perfectly good terminology, although I agree that it could be clearer. I would tend to say "a high degree of tapering" or a "more tapered stem" for clarity's sake.

A full description of this can be found in Forest Mensuration: a handbook for practitioners by Matthews and Mackie on page 114. (They refer to a tapering log, because they are discussing felled timber).

• Yes, but based on my reference searches it's used in different, sometimes opposite meanings. Sometimes it refers to trees that are thin and long, sometimes it refers to trees that are wide and short. Based on application, these can mean very different. Jan 17, 2020 at 10:15
• We should trust an expert and consider the possibility that we misinterpreted. Could it be, just for example, that highly tapered of one species are still statistically taller than more stout ones of another ? Do you have a text example ?
– user18607
Jan 17, 2020 at 10:25
• it describes the difference between stem diameter at the bottom of the tree, when compared to the top of the tree. Lots of taper mans that there's a big difference, less taper means a smaller difference. The length of the log may make the effect more pronounced, and this sort of thing is nearly always used when comparing with timber from similar species. does this make sense?
– Will
Jan 17, 2020 at 12:11

It means that the tree is thick at the base, but rapidly becomes thinner as it ascends. The use of "stem" is anomalous. An Englishman would speak of 'a highly tapering trunk'. Stem is used when referring to much smaller plants.

• Use of "highly tapering stem", "high degree of taper" or similar expression in context of geography, geographic imaging, forestry. Jan 15, 2020 at 13:04
• "A high degree of taper" is correct English and means the same as "highly tapering trunk" or "rapidly tapering trunk". Jan 15, 2020 at 13:09
• In my particular reference "highly tapering stem" meant low steepness, i.e. that the change from larger diameter to smaller happens finely/slowly. Which is opposite to your meaning. Thus the meaning can be ambigious. Jan 15, 2020 at 13:14