Use of Terrestrial Laser Scanner for Aboveground Biomass Estimation in a Seasonally Dry Tropical Forest

Structural parameters of vegetation and quantification of aboveground biomass (AGB) are important in forest monitoring to understand the vital cycle of ecosystems. This activity is even more challenging in seasonally dry tropical forests such as the Caatinga biome. The feasibility of using the terrestrial laser scanner (TLS) to measure structural parameters of plants and estimate aboveground biomass was investigated as an alternative to traditional methods. The study was conducted in an area of caatinga vegetation in the municipality of Petrolina, PE, Brazil, where three experimental subareas were selected to obtain measurements, cutting, and weighing of plants with a soil surface level diameter greater than 2.5 cm, totaling 97 plants. Scans were performed with the light detection and ranging (LiDAR) technology using TLS to obtain a three-dimensional point cloud. The correlation coefficient (r²) for plant height measured in the field and obtained by TLS was 0.80. The measures of trunk diameter at soil surface level and at heights of 40 and 130 cm showed r² of 0.79, 0.78, and 0.76, respectively. New exponential allometric equations were generated using input variables obtained in the field and point cloud TLS. These results demonstrate the feasibility and potential of using LiDAR-TLS in dry forests, such as caatinga vegetation. This emphasizes the need to deepen approaches, tools, and techniques using this technology throughout the year to detect variations due to senescence and, therefore, the carbon cycle.