Marcus B-T

The EU contracam project ended some years ago but the website is still active Also Nigel Straw and myself wrote a paper in the arb journal most of the content is still relevant Roßkastanienminiermotte - Cameraria ohridella

The calculator works like this. If you think the tree you are looking at has changed i.e. is decayed and/or has had sheltering buildings and/or trees removed. Then the calculator uses the ratio of height to DBH (in the way that t/R, tree pulling etc) to determine whether you should be concerned about the tree or not. What version of XL do you have?

Two updates the NMN website is finally up though there is no content just yet go to National Meripilus Network i am coding up the model on this thread in excel so you can make use of the graphics. There is also some more free info on Itsey Limited

In the measuring software I developed, you can add in quatities per length and associated costs, would this be useful for this kind of application? strangely it is very popular for making curtains.

We have our basic model in place and it is time dependent, so the next step is to put in some contols. I will be using developmental switches based on light intensity and temperature, so that for each developmental change you can have temperature, light or both as the switches. This means we can introduce things like bud break, flowering and leaf fall based on temperature and/or light. More on this later. I will code this all up over the comming weeks so that we can all play about with it and compare outcomes. I will leave the partitioning of roots and shoots out just for the moment to keep it simple.

Hi, thanks for the ref, I Will get it out at the British Library next time I am down there. Larcher is the name of the Swiss guy by the way, look up his book Physiological Plant Ecology, it is a fantastic read. Also the work of the great Neil Turner from Australia is worth looking up, particularly his work on drought adaptations.

Version 5 of the Height to DBH calculator (the one for towns and cities) is now available free to download at the following url https://sites.google.com/site/howbiggbbo00/about-us/trees-and-woodland If you have any qustions on how to make the most out of it, I will try to ansew them. Enjoy Marcus

The term dormant can be misleading. Firstly what do you mean by this? Even when there are no leaves on trees they can still have periods of growth in the roots and cambium (work by Shigo, and also a Swiss guy whose name escapes me for the moment), also the the transport of resourses to storage pools and also their maitainance over the winter takes up energy. Then which species are we talking about? Some coniferous species show very little dormancy in the UK. Also even with deciduous trees can have only brief periods of revalive inactivity. Although leaf abscision may be temeprature /and/or light triggered any true dormancy is probably controlled by temperature and may be a temperature/pressure thing as has been show in Sugar Maple. This whole dormancy thing is perhaps the first area where information is a little thin but I might be wrong. Some of the research is probably quite old so if anyone out there knows of any good references on this let me know please.

A number of things. All this info has been in my head for some time but is more use written down in some form. But it may not be correct so putting it up here makes it both accessible and subject to review. By having the model we can compare the collated knowledge to experiences and management outcomes. This helps remove some of the guess work. It will also point out the knowledge gaps and where knowledge is thin. So keep posing questions and i will keep building.

OK, we have a very basic model here that describes the inter-relationships between each of the pools and even with a basic model like this it starts to raise some very interesting questions. First is partitioning of carbon between each of the pools. What are the controlling relationships. Initailly all the net carbon (P') production will go into the transient transport pool which I have defined as part of storage S. Then we could look at the partitioning as a kind of pecking order, there will be initially a large demand from B (biological pool) and/or R (reproduction) depending on the timing of flowering. However, trees are a bit chicken and egg. Their perennial biology means that there will be overwinter storage pools which will contribute to B and R so infact the early growth, i.e. leaf emergence and/or flowering will be fueled by stored carbon. Then later after S has kick started the process there will be contributions direct from P' with S used for a brief period. Then stem extension and later leaf growth will be heavily influenced by P'. Timing of stem extension, leaf area duration, flowering and seed production are big issues here. We haven't even started on roots yet!

OK the storage pool. The most interesting work on this has been carried out on a relatively narrow number of species and also mostly with younger trees, (look up the work of Abod and Webster from the 1990's) or the WRC work on willow and poplar published in the Arb Journal or some of the French work on London Plane. So there has to be note of caution here. The first thing is that storage pools are transient, i.e. carbon will go in an out of pools depending on seasons and stress. Also they are all over the tree so there are very small pools in leaves and larger ones in roots and shoots. With the simple model we have so far you can see that if you reduce leaf area then you put extra dependency on storage pools to make up the difference. If the tree is under strain (either seasonally demand on stored resources, or impossed due to environmental, biological or physical stresses) then resources will be low and there will be a greater effect on the biology of the tree. Therefore leaf area reduction should be in tune with the activity of storage pools and the environment.

I didn't get involved on that link because I don't have that particular book though I have many of his others. Funny you should mention the network. A long story but to cut it short, I had the web address taken from me and this caused all sorts of problems with sponsors and other things, but I have recently got round these so it will rise phoenix like from the ashes this week. Regarding the Merip postings, this posting will address the issue so keep watching. So back to the thread. We now have a situation where if you reduce the photsynthetic area A you potentially reduce the size of the biological pool and therefore, eventually the amount of structural wood. Now then, we hit a first critical point. Supposing you have a tree that is deemed to be structurally unsound and the recommendation is some kind of reduction. Then if the redcution is too severe then A will be reduced to an extent that the contribution to the biological pool B is significantly reduced and so then the contirbution to the mechancal pool M is significantly reduced. Not only that but the further contributions back to A may be reduced. If this last one happens then the tree is effectively in a downward spiral, because it is nolonger self supporting.

Keep following all wil become clear. Also you are a fine one to talk having posted the stuff on FS' book. Read the last two bits! and think about what it tells us. "So dA/dt = a dB/dt and if dB/dt is reduced then A is reduced. And if dB/dt is reduced then M is reduced. " Also if A is reduced then dB/dt is reduced!! dB/dt is biological growth rate dA/dt (approximates to leaf area growth rate) A (approximates to leaf area) M is mechanically structural wood

A few requests if you want to post on this thread. By all means give opinion, this is how we get the ideas that are 'outside the box' but if you can back things up with a reference all the better. OK model version one. Based on a large number of plant models but the books of Kozlowski, Pallardy and Kramer are as good as any. Incident light energy (I) is inetercepted by the Photosynthetic Area (A) This gives rise to net amout of photosynthate (P) some of this is used up in respiration © and so what is left over (P') can be thought of as the dry mass (well nearly all, there is the nutients to add in as well) of the tree and is divided between biological structure (B) and includes the leaf area and vascular system so A is actually related to B. P' is also divide into storage molecules (S) which intially we can put transport sugars like glucose and sucrose into as a temporary transient storage pool. Finally P' also can be used for reproductive organs ®. So initially P' = B+S+R Over time part of B will loose its function and become a structural pool (M) so that overall Net photsynthate P' =B+S+R+M This is not a static system, the storage pool can be used in either B or R, and also there is a movement from P' to B to M. These are described as fluxes so that they can in theory go in either direction, e.g. the mass can flow from S (storage) to B (biological) but also back to S. Before we go any further, we can already see some intereting relationships. First you can only have mechanical structure if you have biological structure i.e. M relies heavily on B, but also it all relies on A for the interception of I (radiation). Also the balance between the four pools of P' is also important. Back to the fluxes if we use b to describe the fluxes of B; s for S, m for M etc. we can call the flux of P' to B bP', and the flux of storage molecules to B bS etc this allows us to do two things. Firstly the fluxes are over time so we can introduce development of the plant over time so that at any point. dB/dt which is the rate of change in B with time is equal to bP' + bS - bM -bO dR/dt (the rate of change in Reproductive material) is rP' + rS - rO The term O is introduced as the loss of material during shedding, abscision or sencence. O for organic. We can add include decay as part of the O pool later. As we can see the relationship becomes complex but at the center is P'. The less P' we have the less of everything. Also trees can divert P' to B without necessarily compromising the production of M. The last thing to point out is the relationship between A and B which can be described as A = aB where a is an area density ratio of the part of B that goes into the production of A . The relationship between I, A and P' is not described yet. So to conclude so far reducing A will reduce P' and therefore B,S,R and M these can feedback to further reduce A since A also changes with time and the elements of A (the leaves) have a finite lifespan. So dA/dt = a dB/dt and if dB/dt is reduced then A is reduced. And if dB/dt is reduced then M is reduced.

OK; we all know that trees are basically a balance between biological productivity (the building blocks); Structural stability (the frame work) and reproductive development (continuing the species). But at some point in the trees life it all breaks down and this is what we ulitmatey want to know. Also, if we manage a tree we want to know how to balance these aspects, i.e. we don't want to promote one to the detriment of others. Now the problem is that this is a complex relationship and this is where the opinion and argument comes in. So it strikes me that a model of the system in some way will help the process. Now I could just write one publish it and let everyone prop up the bed with it. Or we could start a thread, i.e. this one and I can produce the model in real time and you can all review it as we go along. So here is the starting point. The canopy area intercepts light and uses the enegy to convert water and CO2 into photosynthates (building blocks). These are then distributed to various parts of the tree based on a thing called sink strength (relative demand for photsynthates). This determines what grows at what rate. Ok who's next where does it go from here?