Russ: Your account of the response of trees to the recent rainfall actually adds a lot to what I said. We are in a severe drought here, and so I can't make any such observations. The weather forecast indicates a change in the pattern that has been going on all summer--tropical moisture is forecast to make its way north in the next few days, which creates the chance of thunderstorms with heavy rain along with the 90 degree temperatures and 65-70 degree dewpoints that are forecast. Its been 11 months since we had a rain event of 1 inch or more here, a stretch that will hopefully be broken soon. The trees did put on some ring growth this spring, using snowmelt and the little rain that did fall during May. If it does rain (people here are skeptical of forecasts, since they have forecast rain about 20 times in the last few months), maybe this will be one of those years where trees put on a a double ring.
Lee [email protected] wrote: > 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. 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