# A Modeling Application for GHG Fluxes Estimates in Betel Nuts Plantations in Taiwan
## 4 Discussion  
In this study, the application of a VPM model turned out to be advantageous for a tropical cultivar such as betel nuts, inasmuch these kinds of models take advantages of additional spectral bands available from advanced optical sensors. They need input data such as the enhanced vegetation index (EVI [34]), land surface water index (LSWI [10]), air temperature, and PAR. In tropical environments, where precipitation is the most important driving factor for plant growth, it is essential to use LSWI, which is sensitive to the total amount of liquid water in vegetation and its soil background [35]. Furthermore, the quantitative relations between the vegetation indices (EVI and NDVI) and the CO\({}_{2}\) flux data clearly demonstrated the improvement of EVI over NDVI, in terms of the phase and magnitude of photosynthesis [10]. Time series of EVI and LSWI may provide valuable insights into the processes (e.g., growing season length and water stress) that regulate forests and carbon exchange in cultivars. Another advantage of the proposed method is that LUE models have been frequently used and are based on a simple and practical conceptual algorithm [36], also permitting comparisons between different environments. Deepening this kind of research can help policy makers and companies to make production processes more sustainable as well as to find new horizons for business making. Strengthening the role of finance in an efficient economy that also achieves environmental and social objectives is one of the goals set in many international agreements. With an action plan on sustainable finance, which provides for the creation of a unified system to provide clarity and guidance on what to consider as sustainable and useful for mitigating climate change, a more sustainable and responsible society can be promoted as well as a low-carbon economy. Confidence in climate objectives and the use of sustainable finance to tackle climate change are fundamental. Bringing sustainable financial instruments closer to businesses, the private sector will contribute to raising global awareness of climate change. An international emissions trading system is an instrument featured in the Kyoto Protocol to the Framework Convention on Climate Change, designed to reduce emissions of greenhouse gases among major industrial countries. For example, Europe established, in 2003, an emission trading scheme (ETS) intended as a test designed to help its member states transition to a system that would lead to compliance with their Kyoto Protocol commitments. The ETS covers CO\({}_{2}\) emissions from big industrial entities in the electricity, heat, and energy-intensive sectors. Carbon prices vary in different ETS markets and across time [37]; however, they are about 5-17 US Dollars/ton CO\({}_{2}\). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Taiwan** & & & **Italy** & \\ \hline
**GPP** & **NEP** & **NEP** & **GPP** & **NEP** & **NEP** \\ (gC m\({}^{-2}\) month\({}^{-1}\)) & **(gC m\({}^{-2}\) month\({}^{-1}\))** & **(gC m\({}^{-2}\) month\({}^{-1}\))** & **(gC m\({}^{-2}\) month\({}^{-1}\))** & **(gC m\({}^{-2}\) month\({}^{-1}\))** \\ \hline
319.05 & 145.27 & 45 & 219.0 & 80.4 & 36 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: GPP and NEP mean values in Taiwan and Italy. Every single government could better enforce emission laws and requirements for big companies, requesting reports about emissions first, promoting projects to balance emissions that could involve local people in plantation management, increasing social welfare and richness in those country areas where there is greater poverty and fewer job opportunities. On the other side, big companies could use light use efficiency models to better understand, in preliminary design phases, the amount of carbon that could be absorbed by vegetation in sustainable projects.