In short rotation tree crops for industrial use in agroforestry need to develop a growth models for comparison of growth in sole plantation and in under agroforestry plantations. What are the essential parameters to be monitored or variables to taken for development of growth models of such tree species.
Diameter at breast height, tree height, canopy development, and mortality. Maybe even local competition.
I hope this helps!
Andrew :-)
The project agrofornet focused on short rotation plantations on soils that were formerly used as agricultural land. They did not include competition by another canopy layer. But, using the variables:
temperature
precipitation
soil quality,
they achieved very good results. However, the variable for soil quality is a highly aggregated one and without a big amount of data (like exposure, inclination, water capacity...), you won't be able to replicate it. But these three variables were sufficient to estimate the per area biomass growth.
The results were published here: http://eu.wiley.com/WileyCDA/WileyTitle/productCd-3527337644.html
If you want to add a canopy to this model, you might want a simple indicator like canopy cover. In german forestry we use something called "Kronenschlussgrad" which can be loosely translated to crown coverage percentage. It can vary between 0.1 and 1.3 and is an indicator for competition in even-aged stands. So you might need a multiplicator to adjust for the asymmetric competition with higher trees.
Other concepts for competition modelling you might want to look into are the Zone of influence (ZOI) and the more complex Field of Neighbourhood (FON). These can be adjusted to circumstances, where competition for PAR is not dominant but other resources (like water) are scarce.
You can find some definitions in my B.Sc.Thesis on symmetrical and asymmetrical competition:
https://www.researchgate.net/publication/230815907_The_Influence_of_Symmetric_and_Asymmetric_Competition_on_the_Size_Distribution_of_Forest_Ecosystems_-a_Simulation_Study
Good luck.
Thesis The Influence of Symmetric and Asymmetric Competition on the...
Thanks Klemens. I will see the project details and text send by you.
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