On Mon, 14 Nov 1994, David Yates wrote: > I read your reccent message and would be interested in any refernce you > can give me to work on Nelder wheel experiments in NZ. > We have a Nelder wheel set-up with hoop pine and Queensland maple. It is > part of our work on rehabilitation of degraded land - or land that was > lceared for what is now considered 'unproductive'. A couple of students > are working on the site at present. The only reference describing analyses of Nelders I'm aware of in NZ is my thesis: Mason, E.G., Decision-support systems for establishing radiata pine plantations in the Central North Island of New Zealand, (1992), University of Canterbury, 301 pp Bob Tennent at FRI may have some more information. His email address is tennentr@tawa.fri.cri.nz. There is an internal FRI report on the subject. > Something that worries me - and we will be looking at - is that while the > design allows for a variety of spacings (and replicates) - the physical > environment for trees on say a northern side of the centre is different > from that of trees at a similar spacing on the south side. This could be a problem perhaps, although I've not heard of it before. I didn't test for it. The analysis is usually done ignoring the outer 2-3 and the inner 2 circles to avoid edge effects. > This is especially a problem in our case where we have a mixed planting > because there are fewer replicates. How did you mix them with respect to the Nelder? > I really write to ask for refs to the height vs density differences > before competition is apparent. Apart from my thesis the reference given by Ryde is the one I had at my fingertips. I haven't seen any elsewhere, except for a "BBC Science" program describing some similar effects studied in non-tree crops in South America (I wish now I'd recorded the details), reputed to be due to infrared reflectance from neighbouring plants. Please let me know if you find any other references, and I'd also be interested to hear how you get on with your Nelder analyses. Regards, Euan ================================================================== Dr Euan G. Mason Silviculture, Modelling and Lecturer in Silviculture Decision-support systems School of Forestry University of Canterbury New Zealand's professional Christchurch, New Zealand Forestry School ==================================================================
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