Geoff,

For a bit of wisdom you could look at

Jacobs, M. R. (Maxwell Ralph) & Commonwealth Forestry Bureau (Australia) & Jacobs, M 1939, A study of the effect of sway on trees, Commonwealth Forestry Bureau, [Canberra?]

Not sure if it is in this book, but I understand Max studied the impact of wind and lateral movement on the taper of P radiate.

Grahma

Hi Geoff

I'm not sure if you're focused on the limits of tree height or more on the factors that control annual height extension. In the case of the former there have been a number of papers that have presented different (and often competing) theories on the factors limiting the maximum height of trees. Barb Bond (Yoder) argued that hydraulic factors limited tree height (Ryan, M.G. and B.J. Yoder. 1997. Hydraulic limits to tree height and tree growth. BioScience 47(4):235-242.), while others have focused on biomechanical limits (King et al - Functional Ecology 2009 http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2008.01514.x/pdf). A Google search using the phrase "biomechanical limits to tree height growth" returns a lot of relevant literature.

I can ask other colleagues about the limits of annual height extension. Paulina Fernandez in Chile might also be able to help as she has developed a functional-structural model for radiata pine.

Cheers,

John

A simple question, but the answers are complex. 

Tree-to-tree genetic variation within any population will be of the order of 3-fold.

Then there is family variation.

Then provenance variation.

On top of that, the trees will have environmental adaptations relating to their geographic origin, that will interact in different ways with the environment of the planting site: day-length being an important variable; also of course temperature. For example, seed from west coast of US from scruffy-looking shrubby trees of sitka spruce grow fast into the best tall, straight timber trees when grown in Scotland - see literature written by MGR Cannell, R. Lines, back in the 1980s.

Cheers, Roger

Thanks for the above input and pointers; I have a lot of literature to work through over coming  months.  I'll try to comeback with some more specific insights and consequent questions. I'll be particularly looking at predictive models that have been applied and validated against data not used in their development.  

Matthew I found the Koch paper interesting; got me into a different set of literature.

Nicolas I will chase down the CASSIA paper was I can get access to a library account [it's a bit harder as a private researcher than when I was at CSIRO :-)]

In the meantime specific equations / logic will be of interest.

Hi Geoff

This is only my theory with only observations and no real evidence to back it up.

I have noticed that radiata are generally shorter when growing on deep sand than on duplex sand over clay sites. I believe this is due to physics more than anything else. It takes less effort to pump water uphill than it does to suck water uphill (ie pump at the bottom rather than at the top). Trees suck water up rather than pump it up. On coarse sandy sites trees access water from greater depths (have data to show this) than on heavier textured soils (because they have less water 'holding' capacity the water drains through more freely). Therefore when the tree has to pull water up from 12m - 14m below ground as opposed to say 3m - 4m it physically can not pull it up as high. Tracheid diametres will probably play a part as well.

Nutrients dont play a part in height growth, provided they are not deficient. Well supplied trees growing on deep sands still wont grow as tall as trees on heavier textured soils.

I have done some literature searching on this but didn't find much to either prove or disprove. My capacity to search and obtain literature is more limited than I'm sure you have access to. happy hunting.

Cheers

Ian

Hey Geoff, been a while.  Good to see your still working on the cambium.  In northern ontario as a few have mentioned elsewhere we see site as influencing height but also stand density, the more open the shorter, so essentially competition restricting multiplicative growth in favour of additive growth. Aside from genetics and site conditions competition seems to be a major driver.  If you look at some of the work Tony Zhang from FPInnovations did years ago it clearly shows this trend.

So what do people think of direct biomechanical controls over tree height? Competition for light drives the tree up, while increased exposure to buckling increases wood stiffness or diameter growth.  Open grown trees have less light competition and so more CHO goes into diameter than height.  Close grown trees tend to increase MOE as per Mike Watt's findings in NZ.  

The question then becomes, can biomechanical factors / stresses regulate cambial cell development directly?  Epigenetic factors seem a possibility here in influencing which genes are expressed????  cf wind exposure (open grown) increases more flex to promote diameter growth.

BTW Good to her from you Matt; trust all is going well.

Hey GEoff

I would say yes to that as anything that stresses the crown and its growth will affect hormone production, in particular IAA in the crown which may in turn affect GA presence and abundance.  These will directly affect cambial activity and xylem production one would think.  Also wind stress would affect production of reaction wood which may alter how much height growth occurs in order to accommodate wind loads via reaction wood formation.  Pretty interesting study, the genes expressed would be very interesting to see what is happening there during stress periods and if that can be measured and compared.  Maybe a controlled study in a chamber like we had in Creswick where some trees are in a calm environment and the others in a windy environment to see how much reaction wood formation affects height growth and also what genes are turned on when reaction wood is being formed, the hormone aspect would also be an interesting angle.  Funny how a question that relates to the cambium leads to even more questions rather than answers eh, we still have a way to go wrt the cambium and fully understanding it.  All is well in Thunder Bay, we are coming out of a cold winter but getting days int he 20s so nice.  Hope al is well with you and the family in Tassie, the boys must be in uni now?

Hi Geoff, See my attached paper for data and discussion on tree height variation in eucs. It may be of some value.

Hydraulic limitation of tree height has become almost universally accepted in some circles. Gradients between soil moisture and atmospheric demand for water do seem very well correlated with tree height across a range of conditions and may affect several of the parameters already mentioned including C intake and hormone production. Here are a couple more papers related to the Ryan and Yoder (1997) and Koch (2004) papers that have already been mentioned. They look at hydraulic limitation a little more critically. The second paper listed, (Becker et al.), should be particularly valuable to you for its literature review and consideration of genetic factors, although it hasn't been cited as many times as the others mentioned.

Ryan et al. 2006. The hydraulic limitation hypothesis revisited. Plant, Cell and Environment 29: 367-381

Becker et al. 2000. Hydraulic limitation of tree height: a critique. Functional Ecology 14: 4-11

I'm currently preparing a paper on tree growth theory in which the driver of growth, including shoot growth, is primordium initiation at the shoot apical meristem. In crude terms one may say that the more complex and larger the bud, the longer a shoot results from its elongation. Factors that limit shoot elongation do so either by limiting bud size/complexity; or degree of elongation acheived by the bud, usually the former unless the shoot is damaged or deprived of water. See my article "Patterns of shoot development in Pinus and their relationship to growth potential" , pp.223-243 in M.G.R. Cannell and F.T. Last, eds., Tree Physiology and Yield Improvement, Academic Press  1976. The reason you are having trouble with Monterey pine is because of its flexibility in primordium initiation and elongation patterns. The bibliography of the paper cited above has articles pointing this out.

I think it would be worthwhile to look into something completely different as well: wind sway. Vic Lieffers and Mark Rudnicki have been involved in some interesting work on lodgepole pine and have shown that preventing wind sway cause mature pines to increase their height growth again and expand their crowns. 

Meng, S.X., Lieffers, V.J., Reid, D.E.B., Rudnicki, M., Silins, U., Jin, M., 2006. Reducing stem bending increases the height growth of tall pines. Journal of Experimental Botany 57, 3175–3182. doi:10.1093/jxb/erl079

Meng, S.X., Rudnicki, M., Lieffers, V.J., Reid, D.E.B., Silins, U., 2006. Preventing crown collisions increases the crown cover and leaf area of maturing lodgepole pine. Journal of Ecology 94, 681–686. doi:10.1111/j.1365-2745.2006.01121.x

For an elaboration of my comment made earlier see "Primordium initiation drives tree growth" in Ann. For. Sci. 74(1): 1-7, 2017. DOI 10.1007/s13595-016-0612-z