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Pine Tree Growth Habits

Posted by scotjute z8a Tx (My Page) on
Wed, Jun 6, 07 at 13:22

After the initial "candle" has formed or elongated, and then filled out, does another candle then form or elongate and then fill out in a cycle continuing on thru the summer?
In another words, do pines continue growing all summer long? Think I've seen candles on them well into summer, but don't remember for sure. Will pay attention this summer, but thought I'd ask now. Am interested in southern pines particularly, but all pines in general.

Follow-Up Postings:

RE: Pine Tree Growth Habits

Should have looked harder before posting. Answer per USDA for Loblollies is : height is determined by series of 2-5 growth flushes. Temperature is most important variable, followed by day length, soil moisture, nutrient level of soil, competition, and genetics.

RE: Pine Tree Growth Habits

Your source is unhelpful. "Flush" terminology should not be applied to loblolly or similar pines because it is used imprecisely. A flush is a period of growth activity; it is not a physical part of a shoot, as foresters in the south consistently forget.
The behavior of the shoot works like this in loblolly: an overwintering bud elongates in spring to form a spring shoot; usually this consists of a length of "candle" with one or possibly two whorls of branches along its length. All of that was present, miniaturized, in the winter bud.
At that point, the apex of the candle may spontaneously put out a new candle, and maybe another after that. These are "summer shoots" and they were never part of a dormant bud. Their growth is phased in with the original spring shoot growth so it appears as one process, unless carefully measured and graphed. Now a new winter bud will form, containing all the elements of next year's spring shoot; and the cycle continues.
The result, in a young vigorous tree, is an annual shoot consisting of a lower part and its branches, formed in the winter bud; and an upper part consisting of one or more lengths of "added on" stuff. Length of the spring shoot depends on growth conditions while the bud was being formed. Length and number of the summer shoots depends on conditions during and after elongation of the spring shoot.
Yes, it's complex, and has been badly misunderstood as a result.

RE: Pine Tree Growth Habits

Are you saying that after the current winter "candles" have filled out, that the tree will then generate other "summer" candles or summer shoots? (assuming conditions are favorable) Will these tend to form "whorls" of branches also or just the dominant candle? Been around these trees most of my life, but never paid attention to exactly how they grow.

RE: Pine Tree Growth Habits

Scotjute -- yes to both questions. And there will normally be lateral branches at the base of each summer shoot, but not always. Those lateral branches will be pretty small and wiry compared to the main laterals that are attached at the base of the spring shoot; and which were present in the winter bud.
Shortleaf pine behaves like loblolly, so does pitch pine. But slash and longleaf do not. Their spring shoots consist of a single unbranched length of shoot. They add summer shoots to that, and I have seen up to four of these formed on small trees outside my Florida dentist's office, which made me wonder if all his patients got home safely.
BTW, the way to identify a shoot as being a spring shoot (that is, from a winter bud) is by looking at its base. If there is a ring of bud scale scars bunched up at the base, it came from a bud.
If the only scales there are wide-spaced, it grew opportunistically, not from a winter bud. Summer shoots like that stop forming in older trees, which just put out simple candles like in red pine or ponderosa pine.

RE: Pine Tree Growth Habits

How would one correctly describe this process in P. bungeana? The intial spring shoot elongates and once complete, the tip appears to act like a shoot apical meristem, producing new needle buds as it grows taller. I haven't been able to observe if this secondary growth is predetermined in the spring shoot or if it's governed by summer growth conditions?

Can anyone shed some light on this?

RE: Pine Tree Growth Habits

yes this does happen all the time i've seen almost every souther pine with secondary summer growth

RE: Pine Tree Growth Habits

P. bungeana can put up summer shoots, i.e. they are not predetermined in the bud. The same is true of several of the pinyon pines.
I did dissection studies on these species about 1970 or so, which appeared in the Canadian J. of Botany if you have access to that and want more details.The paper was called "Origin of the Summer Shoot in Pinyon Pines".
Bungeana shoots are really beautiful if I remember them right.

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