Carbon Stock Assessment Using Remote Sensing and Forest Inventory Data in Savannakhet, Lao PDR

Phutchard Vicharnakorn,Masahiko Nagai,Rajendra Shrestha,Abdul Salam,Somboon Kiratiprayoon

doi:10.3390/rs6065452

Phutchard Vicharnakorn, Masahiko Nagai + Show 3 more

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https://doi.org/10.3390/rs6065452

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Abstract

Savannakhet Province, Lao People’s Democratic Republic (PDR), is a small area that is connected to Thailand, other areas of Lao PDR, and Vietnam via road No. 9. This province has been increasingly affected by carbon dioxide (CO2) emitted from the transport corridors that have been developed across the region. To determine the effect of the CO2 increases caused by deforestation and emissions, the total above-ground biomass (AGB) and carbon stocks for different land-cover types were assessed. This study estimated the AGB and carbon stocks (t/ha) of vegetation and soil using standard sampling techniques and allometric equations. Overall, 81 plots, each measuring 1600 m2, were established to represent samples from dry evergreen forest (DEF), mixed deciduous forest (MDF), dry dipterocarp forest (DDF), disturbed forest (DF), and paddy fields (PFi). In each plot, the diameter at breast height (DBH) and height (H) of the overstory trees were measured. Soil samples (composite n = 2) were collected at depths of 0–30 cm. Soil carbon was assessed using the soil depth, soil bulk density, and carbon content. Remote sensing (RS; Landsat Thematic Mapper (TM) image) was used for land-cover classification and development of the AGB estimation model. The relationships between the AGB and RS data (e.g., single TM band, various vegetation indices (VIs), and elevation) were investigated using a multiple linear regression analysis. The results of the total carbon stock assessments from the ground data showed that the MDF site had the highest value, followed by the DEF, DDF, DF, and PFi sites. The RS data showed that the MDF site had the highest area coverage, followed by the DDF, PFi, DF, and DEF sites. The results indicated significant relationships between the AGB and RS data. The strongest correlation was found for the PFi site, followed by the MDF, DDF, DEF, and DF sites.

Highlights

Tropical forest lands are a natural forest type that is an important source of biodiversity, food, and carbon storage
A total of 197 species were found in the dry evergreen forest (DEF), mixed deciduous forest (MDF), and dry dipterocarp forest (DDF) sample sites (100, 91, and 105 species, respectively), and 38 species (21.2%) were found in all three forest types
A total of 23 species were found in the MDF and DDF sites, 7 species were found in the DEF and DDF sites, and 11 species were found in the DEF and MDF sites

Summary

Introduction

Tropical forest lands are a natural forest type that is an important source of biodiversity, food, and carbon storage. Tropical forests comprise the largest proportion of the world’s forests at 44% [1]; they contain one of the largest carbon pools and have a significant function in the global carbon cycle. Deforestation and forest degradation contribute 15%–20% of global carbon emissions, and most of this contribution comes from tropical regions. 60% of the carbon sequestered by forests is released back into the atmosphere via deforestation. Scientists have determined that tropical deforestation releases 1.5 Gt of carbon into the atmosphere each year [2]. Deforestation and forest degradation are the major sources of greenhouse gas (GHG) emissions in most tropical countries.

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