Limits...
Combining airborne laser scanning and Landsat data for statistical modeling of soil carbon and tree biomass in Tanzanian Miombo woodlands

View Article: PubMed Central - PubMed

ABSTRACT

Background: Soil carbon and biomass depletion can be used to identify and quantify degraded soils, and by using remote sensing, there is potential to map soil conditions over large areas. Landsat 8 Operational Land Imager satellite data and airborne laser scanning data were evaluated separately and in combination for modeling soil organic carbon, above ground tree biomass and below ground tree biomass. The test site is situated in the Liwale district in southeastern Tanzania and is dominated by Miombo woodlands. Tree data from 15 m radius field-surveyed plots and samples of soil carbon down to a depth of 30 cm were used as reference data for tree biomass and soil carbon estimations.

Results: Cross-validated plot level error (RMSE) for predicting soil organic carbon was 28% using only Landsat 8, 26% using laser only, and 23% for the combination of the two. The plot level error for above ground tree biomass was 66% when using only Landsat 8, 50% for laser and 49% for the combination of Landsat 8 and laser data. Results for below ground tree biomass were similar to above ground biomass. Additionally it was found that an early dry season satellite image was preferable for modelling biomass while images from later in the dry season were better for modelling soil carbon.

Conclusion: The results show that laser data is superior to Landsat 8 when predicting both soil carbon and biomass above and below ground in landscapes dominated by Miombo woodlands. Furthermore, the combination of laser data and Landsat data were marginally better than using laser data only.

Electronic supplementary material: The online version of this article (doi:10.1186/s13021-017-0076-y) contains supplementary material, which is available to authorized users.

No MeSH data available.


Around June, bush fires start to appear in the study area. Here illustrated in three Landsat 8 OLI images where black burnt areas clearly spread during July to September
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5392451&req=5

Fig4: Around June, bush fires start to appear in the study area. Here illustrated in three Landsat 8 OLI images where black burnt areas clearly spread during July to September

Mentions: The Miombo woodlands of Liwale are characterized by high tree species diversity including highly valuable timber species such as Brachystegia spp., Julbernardia spp. and Pterocarpus angolensis. According to the field sample survey conducted within the project, the study area consists of 61% forest or woodland, 14% grassland and 25% cultivated land. The definitions used are according to NAFORMA [31]. In the wooded areas human disturbances occur in the form of harvesting for timber, charcoal burning, honey collection and game hunting. Fire is also an important factor in the Miombo woodlands, underlined by the seasonality in precipitation which leaves the vegetation dry for several months. In the study area, the lack of cattle also leaves large amounts of grasses that dry and therefore are easily set alight (Fig. 4).Fig. 4


Combining airborne laser scanning and Landsat data for statistical modeling of soil carbon and tree biomass in Tanzanian Miombo woodlands
Around June, bush fires start to appear in the study area. Here illustrated in three Landsat 8 OLI images where black burnt areas clearly spread during July to September
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5392451&req=5

Fig4: Around June, bush fires start to appear in the study area. Here illustrated in three Landsat 8 OLI images where black burnt areas clearly spread during July to September
Mentions: The Miombo woodlands of Liwale are characterized by high tree species diversity including highly valuable timber species such as Brachystegia spp., Julbernardia spp. and Pterocarpus angolensis. According to the field sample survey conducted within the project, the study area consists of 61% forest or woodland, 14% grassland and 25% cultivated land. The definitions used are according to NAFORMA [31]. In the wooded areas human disturbances occur in the form of harvesting for timber, charcoal burning, honey collection and game hunting. Fire is also an important factor in the Miombo woodlands, underlined by the seasonality in precipitation which leaves the vegetation dry for several months. In the study area, the lack of cattle also leaves large amounts of grasses that dry and therefore are easily set alight (Fig. 4).Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

Background: Soil carbon and biomass depletion can be used to identify and quantify degraded soils, and by using remote sensing, there is potential to map soil conditions over large areas. Landsat 8 Operational Land Imager satellite data and airborne laser scanning data were evaluated separately and in combination for modeling soil organic carbon, above ground tree biomass and below ground tree biomass. The test site is situated in the Liwale district in southeastern Tanzania and is dominated by Miombo woodlands. Tree data from 15 m radius field-surveyed plots and samples of soil carbon down to a depth of 30 cm were used as reference data for tree biomass and soil carbon estimations.

Results: Cross-validated plot level error (RMSE) for predicting soil organic carbon was 28% using only Landsat 8, 26% using laser only, and 23% for the combination of the two. The plot level error for above ground tree biomass was 66% when using only Landsat 8, 50% for laser and 49% for the combination of Landsat 8 and laser data. Results for below ground tree biomass were similar to above ground biomass. Additionally it was found that an early dry season satellite image was preferable for modelling biomass while images from later in the dry season were better for modelling soil carbon.

Conclusion: The results show that laser data is superior to Landsat 8 when predicting both soil carbon and biomass above and below ground in landscapes dominated by Miombo woodlands. Furthermore, the combination of laser data and Landsat data were marginally better than using laser data only.

Electronic supplementary material: The online version of this article (doi:10.1186/s13021-017-0076-y) contains supplementary material, which is available to authorized users.

No MeSH data available.