## 3 Results  
### The Full Harvard Forest NEE Record  
The full US-Ha1 NEE records are shown in Figure 1A for NEE, \(R_{coo}\), and GPP hourly values after filtering and gap-filling the full US-Ha1 record; biomass removal was negligible for the intervals analyzed. Figure 1B aggregates these variables as yearly sums identifying three main intervals with different NEE behavior. Up to 2003, the sequestration was approximately constant, with a yearly NEE mean (\(\overline{x}\)) of \(-\)703 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\) and an associated standard deviation (SD) of \(\pm\) 239 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\). The next six years (2004-2009) exhibited higher net sequestration with a peak in 2008, when the NEE \(\overline{x}\) and SD increased to \(-\)1658 \(\pm\) 414 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\), respectively. For the period 1992-2008, the \(\overline{x}\), SD were: \(-\)1007 and 563 gCO\({}_{2}\) m\({}^{-2}\)year\({}^{-1}\), respectively, with a trend of \(-\)86.8 gCO\({}_{2}\) m\({}^{-2}\)year\({}^{-1}\), R\({}^{2}\): 0.61. There was an abrupt decline in NEE in 2009-2011 to a value of \(-\)4.21 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\). Between 2012 and 2019, NEE became more unstable (\(\overline{x}=-\)1093 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\) + 472 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\)) than in previous periods but remained a net carbon sink. Over the whole term (1992-2019), the yearly mean carbon sequestration was \(-\)978 gCO\({}_{2}\)\(\pm\) 553 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\)[6]. NEE reached its minimum in 2010 (\(-\)4.21 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\)) and its maximum in 2008 (\(-\)2199 gCO\({}_{2}\) m\({}^{-2}\) year\({}^{-1}\)). Carbon uptake was distributed unevenly during the year, with sequestration during the forest growing season and emissions in the remaining weeks. NEE weekly sums for winter and summer accumulates carbon annually resulting in 27,101 gCO\({}_{2}\) m\({}^{-2}\) for the 1991 to 2019 period. Figure 1C shows soil respiration (R\({}_{s}\)) divided by Ecosystem Respiration (R\({}_{e}\)) yearly values (Brown) and total soil carbon measured in the top 15 cm of the mineral soil of the hardwood- (purple) and conifer- (grey) dominated plots in 1992 and 2013 from [6] to illustrate the coupling between diverse biological and financial indices for the US-Ha1 record. In Figure 1D we extrapolate the US-Ha1 data to a larger area (40,468 ha or 100,000 acres), based solely on numerical projection to illustrate potential project revenue with increasing land area, to pricing at the initial floor price for CARB of $10 and above the suggested social price of carbon of $25. The period 2009-2012 is highlighted with a grey bar to emphasize the change in ecosystem function across the indicators, for example, increased \(R_{co}\) and decrease in \(R_{s}/R_{e}\) shown in Figure 1B,C, respectively, and propagation of carbon loss to financial loss shown in Figure 1D. Figure 1: (**A**) Hourly NEE (blue), GPP (green), and \(R_{co}\) (orange) for the period 1992 to 2019. (**B**) Same as (**A**) shown as yearly sums. (**C**) Soil respiration (R\({}_{s}\)) divided by Ecosystem Respiration (R\({}_{e}\)) yearly values (Brown) and total soil carbon measured in the top 15 cm of the mineral soil of the hardwood- (purple) and conifer- (grey) dominated plots from [6].