Lee: I think that we said almost the same thing but you have a much firmer grip on the technical terminology related to these process than I do....I kind of wish I saw your post before I sent mine! Russ In a message dated 8/6/2009 9:43:27 A.M. Eastern Daylight Time, [email protected] writes:
RCM: I have not seen any systematic differences between determinate (aka pre-formed or single flush) and indeterminate (aka sustained growth, or recurrent flushing) species with regard to ring width. On the whole the two groups of species cross date pretty much the same. Furthermore, determinate species can continue to widen their rings throughout the summer if the soil continues to be moist, in the absence of another growth flush on top of the tree, since the existing leaves can increase their rate of photosynthesis in response to an increase in rainfall. Thus determinate species could have a second flush of cambial growth after a mid summer pause during a drought, just like indeterminate species. There probably are some differences in xylem cell size associated with flushes in growth, since a new flush of foliage might take away some energy from cambial growth, however, differences in xylem production and cell size associated with height within a tree are larger. Species response to disturbances such as wind, fire and logging, invasive earthworms, and droughts are more important factors in determining competition and winners among species than determinate/indeterminate growth status. Early, middle and late successional species groups in the eastern U.S. are each composed of a mixture of determinate and indeterminate species. This is also true for fire adapted species--fore example quaking aspen and red pine. Although respiration, foliage, flower, vertical and horizontal growth may fall in that order of priority in general, these priorities (except for respiration and foliage), actually change among species, from year to year within species, and as individual trees age. Old trees, for example, don't put on height growth, and many species have dramatic changes in degree of flowering and seed production from year to year. Jack pine changes from recurrent flushes in the first few years of its life to a single flush later on. Red pine has the least sensitive height growth response to current summer's weather of any species I know of. Its height growth is set by the size of the bud formed the prior year, which depends on rainfall that year. However, even in red pine, ring width still mostly depends on the current year's rainfall, although as with all species, there is some influence of the previous year, since in a good year, some extra photosynthate can be stored and used the following year. Lee RCM wrote: > This phenomena of growth rates in relation to rain is related to many > site and species characteristics obviously, but I did note that tree > growth habits (which are species specific) were not discussed above; > these habits will also have a large influence on growth rates in > response to rain. Some species exhibit pre-formed growth (e.g. oaks, > true firs, hickories, spruces, ashes), although second flushes can > occur if conditions, most notably moisture, allow. This means that the > tree grows in accordance with what has been 'pre-formed' in the bud, > laid down in the previous year, so there is a connection to last years > climatic/site conditions; upon completion of growth, a new bud is set, > and, conditions permitting, this bud may break again in the same > season, a second flush. A different growth habit, sustained growth, > also grows in accordance with what has been 'pre-formed' in the bud > but then may continue to grow, without setting a new bud, as long as > environmental conditions are favorable; species that exhibit this type > of growth are yellow-poplars, hemlocks, sweet gums, and red maples. So > obviously species that exhibit sustained growth habits would have an > advantage over those that exhibit pre-formed habits, an important > consideration in stand dynamics. > > Another note that may be helpful when thiniking about tree growth is > that photosynthate allocation is prioritized by 1. maintenance > respiration; 2. foliage and fine roots; 3. flower and seed production; > 4. primary (vertical) growth; and 5. secondary (lateral) growth/ > compounds. So to say that you could make a direct correlation, e.g. 2x > the moisture yields 2x the width of growth rings, is probably not > accurate, but undoubtedly there's a relationship. > > I would be curious to know if an examination of growth rings, cell > size within the growth rings in particular, could determine which > years had experienced second flushes; I suspect it would be a very > difficult thing to say with good accuracy. Anyone have any insight? > > On Jul 31, 6:04 pm, DON BERTOLETTE <[email protected]> wrote: > >> Gary- >> I wouldn't think that would necessarily follow...could you further explain? >> -Don >> >> From: [email protected] >> To: [email protected] >> Subject: [ENTS] Re: rain and growth rates? >> Date: Fri, 31 Jul 2009 16:34:43 -0400 >> >> So, given that lateral growth is more carbon-based than vertical does that mean that we should expect greater height with all this rain? >> >> Gary >> Prof. Gary A. BeluzoSystems EcologistHolyoke Comm College303 Homestead AveHolyoke, MA. 01040 >> >> On Jul 31, 2009, at 2:41 PM, Joseph Zorzin <[email protected]> wrote: >> >> Now that this is year is one of >> the wettest on record, at least in the northeast, just how much can we expect >> tree growth rings to reflect this fact? That is- if it rains twice as much as >> typical, during the growing season, will that result in a ring twice as wide? >> Probably not, but I wonder what sort of relationship there is between these 2 >> variables. >> >> I started thinking about this as I >> notice the trees in my backyard showing what appear to be greater growth at the >> top than previous years- especially noticeable on white and pitch pine >> leaders. >> >> Joe >> >> _________________________________________________________________ >> Windows Live™ Hotmail®: Celebrate the moment with your favorite sports pics. Check it out.http://www.windowslive.com/Online/Hotmail/Campaign/QuickAdd?ocid=TXT_... >> > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
