## 3 Methods and Data
### Estimating CO\({}_{2}\) Sequestration from the Forests of Japan  
Estimation of the sequestration from Japanese forests was obtained by utilizing the two data sets described above (_i.e._, the volume map and land cover map), along with an additional data set of forest inventory data provided by two Prefectural Governments and the precipitation data published by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) of Japan. CO\({}_{2}\) sequestration per unit area data published by the Tochigi Prefectural Government was used to estimate the sequestration values not only for each forest type but also for each tree age. This was achieved by transforming the volume map into ages among the different forest types, referring to the volume-tree age relationship data provided by the Oita Prefectural Government. The precipitation data were also used to help discriminate between growth rates for each region, which is an important step, because even with the same stem volume, the forests' per unit areas could have different tree ages due to local site productivity [37]. The stem volume-age relationship data provided by the Oita Prefectural Government is based on observations made on ground-level plots at multiple sites within Oita Prefecture. The curves were averaged for each growth region and computed as high, moderate and low growth rate areas. Each location within the study area that lies on a matching growth-rate region was determined to have a particular growth curve for that forest; the tree age conversion is based on that curve. To differentiate the growth rate of the study area, a relationship analysis was made using the precipitation data along with the total volume of growth made between the two periods of time. The sugi (cedar) and kunugi \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Landsat OLI Data Sets**} & \multicolumn{3}{c}{**Landsat OLI Data Sets**} \\ \hline
**Region** & **Path** & **Row** & **Date** & **Region** & **Path** & **Row** & **Date** \\ \hline \multirow{4}{*}{Kyushu Yamaguchi} & 112 & 36 & 2 May 2014 & & 106 & 33 & 8 May 2014 \\  & 112 & 37 & 13 April 2013 & & 107 & 31 & 29 April 2014 \\  & 112 & 38 & 13 April 2013 & & 107 & 32 & 19 October 2013 \\  & 113 & 37 & 23 April 2014 & & 107 & 33 & 17 September 2013 \\  & 113 & 38 & 29 October 2013 & & 108 & 31 & 20 April 2014 \\ \hline \multirow{4}{*}{Chugoku Shikoku Kansai} & 110 & 36 & 17 March 2014 & & 108 & 32 & 4 June 2013 \\  & 110 & 37 & 17 March 2014 & & 108 & 33 & 4 June 2014 \\  & 111 & 35 & 24 May 2013 & & 108 & 34 & 4 June 2014 \\  & 111 & 36 & 24 May 2013 & & 105 & 30 & 2 June 2014 \\  & 111 & 37 & 11 May 2014 & & 106 & 29 & 25 June 2014 \\  & 112 & 35 & 19 August 2013 & & 106 & 30 & 25 June 2014 \\ \hline \multirow{4}{*}{Chubu Chubu} & 108 & 35 & 7 August 2013 & & 106 & 31 & 28 October 2013 \\  & 108 & 36 & 7 August 2013 & & 107 & 29 & 19 October 2013 \\  & 109 & 35 & 14 August 2013 & & 107 & 30 & 19 October 2013 \\  & 109 & 36 & 14 August 2013 & & 108 & 28 & 10 October 2013 \\  & 109 & 37 & 17 October 2013 & & 108 & 29 & 10 October 2013 \\  & 110 & 35 & 17 May 2013 & & 108 & 30 & 10 October 2013 \\ \hline \multirow{4}{*}{Kanto} & 107 & 34 & 17 September 2013 & & & & \\  & 107 & 35 & 17 September 2013 & & & & \\ \cline{1-1}  & 107 & 36 & 17 September 2013 & & & & \\ \cline{1-1}  & 109 & 34 & 14 August 2013 & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Specification of the Landsat Imagery used. (sawtooth oak) data were used as representative of the coniferous and deciduous broadleaf forests, respectively. Unfortunately, there is a lack of data for the evergreen broadleaf forests, so the growth rate is considered only for the first two classes. Here, the precipitation data were used to determine whether precipitation would be one of the limiting factors for forest growth.