tree microclimate effects

[Drought Research]

   Has any one got equations relating tree cover/density to understory
   microclimate effects.

   ie. take a stephenson screen in an open grassland and try 
   to estimate the the effects of various levels of tree foliage
   cover on variables such as radiation,maximum temperature, 
   minimum temperature, pan evaporation, and humidity/VPD.


   As the most common measurements of tree density are tree basal area
  and tree foliage projected cover it would be useful to express all
  equations in terms of these measured variables. Measurements such as
  leaf area index take much more work to acquire in the field while
  density in terms of stems per hectare does not account for tree size.

   Equations in the following form are needed

   Temperature = open area screen temperature * function (tree basal area)


   I suspect that this is a nasty non-linear function. There may be quite
   a bit of single point type data around probably unpublished ie. people
   doing experiments at one or 2 points in a forest so I would be intrested
   in seeing any of this type data and construction the relationships
   my self as a last resort.








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John Carter                            e-mail: johnc at cocaine.ind.dpi.qld.gov.au
Drought Research Unit, QDPI, AUSTRALIA     or: dres at dpi.qld.gov.au
Phone 61-7-8779588   Fax 61-7-8779606
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