## 2 Data and Methods
### FLUXNET Dataset
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & **Site Name** & **Abbreviation** & **Country/State** & **Latitude (\%)** & **Longitude (\%)** & **Forest Type** & **Year** & **Citation** \\ \hline Non-tropics & Plainch & DE-Hai & Germany & 51.079 & 10.452 & DB & 2001–2007 & [PERSON] _et al._[47] \\  & [PERSON] & DE-Tha & Germany & 50.964 & 13.567 & EN & 2001–2003 & [PERSON] _et al._[48] \\  & [PERSON] & DE-Wet & Germany & 50.454 & 11.458 & EN & 2002–2008 & [PERSON] _et al._[49] \\  & San Rosorse & IT-SRo & Italy & 43.730 & 10.287 & EN & 2001–2004 & [PERSON] _et al._[50] \\  & [PERSON] & NL-Loo & Netherlands & 52.168 & 5.744 & EN & 2001–2008 & [PERSON] _et al._[51] \\  & UCI-1964 burn site & CA-NS3 & Canada & 55.912 & –98.382 & EN & 2001–2005 & [PERSON] _et al._[52] \\  & UCI-1989 burn site & CA-NS6 & Canada & 55.917 & –98.964 & EN & 2001–2005 & [PERSON] _et al._[52] \\  & Howland Forest (west tower) & US-H02 & Maine, US & 45.209 & –68.747 & EN & 2001–2004 & [PERSON] _et al._[53] \\  & Morgan Monroe State Forest & US-MMS & Indiana, US & 39.323 & –86.413 & DB & 2001–2006 & [PERSON] _et al._[54] \\  & Missouri Ozark & US-M0z & Missouri, US & 38.744 & –92.200 & DB & 2004–2006 & [PERSON] _et al._[55] \\  & Metloulas Intermediate Pine & US-Me2 & Oregon, US & 44.452 & –121.557 & EN & 2002–2007 & [PERSON] _et al._[56] \\  & Metloulas First Young Pine & US-Me5 & Oregon, US & 44.437 & –121.567 & EN & 2001–2002 & [PERSON] _et al._[56] \\  & North Carolina Lobolly Pine & US-N2 & North Carolina, US & 35.803 & –76.668 & EN & 2005–2006 & [PERSON] _et al._[57] \\  & Niwot Ridge Forest & US-NR1 & Colorado, US & 40.033 & –105.546 & EN & 2001–2007 & [PERSON] _et al._[58] \\  & Mize & US-SP2 & Florida, US & 29.765 & –82.245 & EN & 2001–2004 & [PERSON] _et al._[59] \\  & Univ. of Mich. Biological Station & US-UMB & Michigan, US & 45.560 & –84.714 & DB & 2001–2006 & [PERSON] _et al._[60] \\  & Santraem Km83 Logged Forest & BR-Sa3 & Brazil & \(\sim\)3.018 & –54.971 & EB & 2001–2003 & [PERSON] _et al._[61] \\  & Bukit Soehnto & ID-Buk & Indonesia & -0.833 & 117.050 & EB & 2002 & [PERSON] _et al._[24] \\  & [PERSON] & ID-Pal & Indonesia & \(\sim\)2.345 & 114.036 & EB & 2002–2003 & [PERSON] _et al._[62] \\  & Mac Klong & TH-Mae & Thailand & 14.575 & 98.858 & DB & 2003–2004 & [PERSON] _et al._[24] \\  & Sakareat & TH-Sak & Thailand & 14.493 & 101.922 & EB & 2002–2003 & [PERSON] _et al._[24] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Site description of flux towers used in this study. Forest types are: deciduous broad leaf forest (DB), evergreen needleleaf forest (EN), and evergreen broad leaf forest (EB). Note that the years given in the table refer to the available data before applying the criteria described in Sections 2.1 and 2.2, and thus the actual number of years used in the analysis may be smaller. To assess the degree to which the selected FLUXNET sites were representative of the climatic range of the global forested regions, we first generated a 1982 to 2005 average global climatology of temperature and precipitation. We used the Climate Research Unit (CRU) TS3.1 dataset [63] and the MCD12C1 V005 [64] IGBP classification in 2001 (aggregated to a 0.5 degree resolution map by specifying the most frequent land cover in each pixel). We calculated the FLUXNET sites' annual mean temperature and precipitation during the flux measurement period and compared the two datasets in the temperature-precipitation domain following [PERSON] _et al._[65]. The selected sites ranged from -5 \({}^{\circ}\)C to 25 \({}^{\circ}\)C in mean annual temperature and from 200 mm/year to 2,300 mm/year in mean annual total precipitation, largely covering the climatic variability of global forested areas (Figure 2). Figure 1: Map of the flux tower sites used in this study. The data are from AmeriFlux in North America (**1**), CarboEurope in Europe (**2**), AmeriFlux in Brazil (**3**) and AsiaFlux in the Southeast Asia (**4**). Temperate deciduous forests are marked with gray symbols. Tropical forests are marked with white symbols.