B&B vs. bare root & other planting stock

[Melanie McDermott]

The only parameter for planting stock is DBH. Have you found that differences in growth & associated benefits (CO2 sequestration , etc) do not vary significantly by the type of planting stocks -- balled and burlap, bare root, container grown etc? If the stock is advertised as, say, 7-gallon container grown, on what basis should we estimate the DBH? Is there a reasonable default to use?

To explain the context for my questions -- we are designing a treeplanting grant program and need to be able to rank project proposals relative to each other with respect to the C-sequestration and other benefits they are projected to provide. Thus, we are not concerned with absolute value -- at the proposal stage. Applicants are not required to have a detailed planting plan prepared -- if selected they will get the money to hire a professional to do that. The application form calls for an estimated number of trees and species --not specific locations. (Hence, my earlier question about ignoring building-specific parameters).

Many thanks for any guidance you can provide?

[Jason.Henning]

The i-Tree models do not include research around planting stock so planting stock type is not directly accounted for in i-Tree Planting. In my experience outside of i-Tree, the biggest difference between the different types of planting stocks is in the mortality rates. It may be helpful if you can consult the arboriculture literature to find different default mortality rates for projects using different types of stocks. This tree mortality literature review may lead you to some relevant references, https://www.fs.usda.gov/nrs/pubs/jrnl/2 ... rt_001.pdf.
As far as a tree size for trees that have not reached 4.5 feet in height yet I think it makes sense to use the smallest dbh available of 0.1 inches. The i-Tree tools are not well parametrized for such small trees because there is little available data on their ecosystem services because they are very minimal at such small sizes.
It may be helpful to run a few test scenarios to see how the tool performs under these different scenarios and see if the results will meet your needs.

[Melanie McDermott]

Many thanks for all your super-prompt and helpful answers!