NEP does not include emissions from DOC

[BlaneG]

I am a bit confused by the difference between the implementation of NBP and NEP. In stock_changes_view.py:

df["Net Ecosystem Productivity (NEP)"] = np.where(
    tfi.DistTypeID == 0,
    tfi.GrossGrowth_AG + tfi.GrossGrowth_BG - (
        tfi.DOMCO2Emission + tfi.DOMCH4Emssion + tfi.DOMCOEmission),
    0.0)

df["Net Biome Productivity (NBP)"] = (
    tfi.GrossGrowth_AG + tfi.GrossGrowth_BG - (
        tfi.BioCO2Emission + tfi.BioCH4Emission + tfi.BioCOEmission +
        tfi.DOMCO2Emission + tfi.DOMCH4Emssion + tfi.DOMCOEmission +
        tfi.SoftProduction + tfi.HardProduction + tfi.DOMProduction))

There are some slightly different definitions in the literature, but the implementation here seems unclear. In some definitions there is essentially no different between NBP and NEP. Other definitions include emissions from abiotic disturbance in NBP, but not in NEP, where NEP is then gross primary production minus respiration (heterotrophic and autotrophic).

My specific questions are:

1. What does the condition tfi.DistTypeID == 0 imply for NEP. What disturbance types is NEP limited to?
2. What are bio emissions (tfi.BioCO2Emission + tfi.BioCH4Emission + tfi.BioCOEmission), and how do they differ from DOM emissions? Why are bio emissions included in NEP, but not NBP?