Sepcificity of Formulas

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hdelaconcha
Posts: 50
Joined: Mon Jul 11, 2016 8:10 pm

Sepcificity of Formulas

Post by hdelaconcha » Sun Jan 14, 2018 1:14 pm

I will be doing a City Plot Sampling inventory of Guadalajara and I have the following situation: Since in Mexico there is a big biodiversity in Pines and QUercus, I have several species that are not listed in the i-tree Data base. For example I have Pinus devoniana and douglasiana that apparently do not have formulas so I am classifying them as the closest cousin which is montezumae (PIMO6) as my best option. I am doing the same for P. lumholtzii that I am classifying it as leiphillae (PILE) and the two that I could find a close enough relative P. maximartinezii and tenuifolia I am just using the PINUS SPP (PI2) code. My question is how specific are the forumulas for growth and how much precision will I be loosing for species not in the database or using the generic code for a species. I understand de PI2 code is an average but how far from a specific species growth data 5-10-20%?

I still have to do the same for QUercus.

Thanks
Horacio de la Concha
AGRINET SA de CV
Cuernavaca MEXICO
hdelaconcha@agrinet.com.mx
azelaya
i-Tree Team
Posts: 324
Joined: Fri Jun 27, 2008 10:50 am

Re: Sepcificity of Formulas

Post by azelaya » Thu Jan 18, 2018 8:40 am

although there are 7000 or so individual tree and shrub species available in the i-Tree list, there are only a small amount of species specific growth equations available. Probably less than 200 although new ones are being integrated in the model.

If no equation could be found for an individual species, the average of results from equations of the same genus is used. If no genus equations are available, the average of results from all broadleaf or conifer equations is used.

For the pinus, I believe that these species have equations at this time, and averaging of these would then apply for other pinus species.

Pinus banksiana
Pinus contorta
Pinus echinata
Pinus elliottii
Pinus palustris
Picea rubens
Pinus resinosa
Pinus strobus

This is a limitations of available research for species, or the time and resources to integrate in new equations in the model. The Forest Service does encourage providing new species equations especially as the Eco model is being used more internationally.

We will try to get the list of available species with growth equations posted soon for further reference.

-Al
A member of the i-Tree Team
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