Demonstrating the development and application of standing-tree carbon equations to improve the accuracy of forest cover carbon stock estimates in Thailand
Project title: To demonstrate the development and application of standing-tree carbon equations to improve the accuracy of forest cover carbon stock estimates in Thailand
Duration: January 2017–December 2018
Supervisory agency: Royal Forest Department, Bangkok, Thailand
Executing agency: Kasetsart University Faculty of Forestry, Bangkok, Thailand
Budget in USD (total/APFNet grant): 253,345/199,045
Target economy: Thailand
Location: Ngao Demonstration Forest, Lampang Province, Thailand
Focus Topics: Carbon stock accounting
Objectives: Provide accurate information on national forest carbon stocks to support informed sustainable forest management policy decision-making and balanced public debate on the benefits of forests in climate change mitigation; Develop and pilot-test accurate standing-tree carbon equations and their application to the preparation of a forest-cover carbon stock map in the Ngao Demonstration Forest, Lampang Province.
Expected outputs: Pilot-tested methodology to construct new tree carbon equations; Demonstration and application of tree carbon equations to prepare carbon stock forest cover maps; Action plan to construct and promote national standing-tree carbon equations; Project information and knowledge disseminated among stakeholders.
As economies all over the globe have committed to climate action by reducing or compensating for carbon emissions, it became clear that data on carbon is needed to ensure accurate reporting by each economy. It was recognized that carbon stored in forests needs to be properly accounted for as well as carbon emissions produced by energy production, transportation or the production of goods, etc. This is because forests can act as carbon sinks, often through forest restoration programmes, or that carbon emissions from deforestation should be part of an economy’s reported emissions.Thailand has reported to the United Nations Framework Convention on Climate Change (UNFCCC) for a number of years but there is still some uncertainty about the accuracy of national estimates of Thailand’s forest cover carbon stocks and limited knowledge of the best method to assess carbon stocks. This affects the quality with which Thailand can assess its own contributions to climate change. In January 2017, APFNet funded a project spearheaded by Kasetsart University Faculty of Forestry (KUFF) to develop a methodology for new standing-tree carbon equations that are expected to result in more accurate data about forest carbon stocks. A pilot map of forest cover carbon stocks in the Ngao Demonstration Forest in Lampang Province was developed. Using the methodology, a forest cover carbon stock map can be produced for the entire economy.
Project featured topics
Taking stock of Thailand’s forests
In 1992, researchers Pochai and Nanakorn developed local tree volume equations based on upper stem diameter measurements of standing trees. While a good tool at the time, those equations were developed for only one local area in northern Thailand using a small sample of trees. Additionally, only the diameter at breast height (DBH) of trees was used as an independent variable, while tree height – now the minimum standard for any volume equation – was simply not considered at all. Finally, sets of species were simply grouped together by tree family and wood density, thus potentially skewing the accuracy of the equations. Yet those equations were applied on a national scale. With the increasing importance of assessing carbon stocks accurately, these rough calculations needed to be updated. The new equations developed by Kasetsart University Faculty of Forestry incorporate both total height and DBH and were further refined by sampling the density of base tree cores. In this way, equations for major tree species groups, subdivided by wood density in evergreen, mixed-deciduous and dry dipterocarp forests, were developed. Subsequently, a focus group created a national action plan for the development of national standing-tree carbon equations for all the major species groups (more than ten groups).
Visualizing carbon stocks
Developing more accurate equations is a significant achievement but ensuring the new carbon estimates are actually used by policymakers is the next step. Tools that combine the more accurate data with geographic information systems (GIS) and remote sensing need to be employed to visualize the results. Policymakers need carbon stock maps that present the total carbon stored in a given forest. With such maps, government officials can make better informed policy decisions and have a visual tool that displays forest carbon stocks across the economy. Due to the limited focus of the project, it was not possible to create maps for all Thailand’s forests, as the equations only cover some of the major tree species groups. However, to demonstrate the potential of these tools, a pilot map of the Ngao Demonstration Forest in Lampang Province was developed using Landsat satellite data with a basic 30 x 30 m resolution on multi-spectral mode and one fine 15 x 15 m resolution on panchromatic mode, taking into account the area’s normalized difference vegetation index (NDVI) and various GIS data regression relationships between satellite data and ground data (collected during development of the equations).
Scaling it up
Towards the end of the project, a national workshop involving 40 participants from relevant government and private agencies was held to disseminate knowledge and get more national engagement to replace the old equations and maps. Using this new methodology to create more accurate carbon stock equations during future national forest inventories will help Thailand implement its strategic plan for sustainable forestry and meet national and international reporting commitments.