Estimativas do estoque de biomassa e carbono em um florestamento multiespecífico na região metropolitana de Maceió, AL

Abstract

ABSTRACT

The implementation of forests and their proper monitoring directly present an alternative for mitigating greenhouse gas (GHG) emissions and environmental degradation in general, since trees act as a carbon sink through the fixation of this element through photosynthesis. In view of the above, the present work aimed to quantify and evaluate the biomass and carbon stored in the arboreal stratum of the Arboretum de Alagoas, a forested area for 18 years with a plantation of high species diversity in the metropolitan region of Maceió. Therefore, a continuous forest inventory (IFC) was carried out in a sampling grid containing 88 plots of 400m2 each. The aboveground living biomass (B) was estimated by a pantropical allometric model, and then the Carbon Stock (EC) by the Intergovernmental Panel on Climate Change (IPCC) factor 0.47. The evaluation was performed by quantifying the Annual Periodic Increment (IPA) of these variables between two IFC measurements, and analyzed at the level of species, families, ecological groups and diameter classes. Conventional phytosociological parameters were also determined, in addition to the Carbon Importance Value (VIC), declaring that the species have a differentiated importance when storing carbon from the atmosphere. Finally, spectral data (Vegetation Indices – IVs) from a high spatial resolution image (3m) from the satellite (PlanetScope) were related via multiple regression with the inventoried biomass to obtain a model capable of predicting the B. Living biomass above ground was estimated in the first measurement at 73.7 Mg.ha-1and 80.9 Mg.ha-1in the secondmeasurement, whereas the carbon stock was 34.60 Mg.ha-1and 38.03 Mg .ha-1 , respectively. These values represent an IPA of biomass and total carbon of 4.3 and 2.0 Mg.ha-1 .year-1, respectively.The species that most contributed to the stocks were Bowdichia virgilioides, Anadenanthera sp.and Inga edulis, together representing 11.2 Mg.ha-1 of carbon. The most representative family wasFabaceae with more than 50% of all biomass and carbon stocked. Secondary species accounted for63,03% of the entire stock, in addition to which the largest share is provided by individuals withdiameters between 20 and 40 cm (52%). The species Bowdichia virgilioides, Handroanthus impetiginosus and Inga edulis were the ones that stood out in the study area for the VIC. The Normalized Difference Vegetation Index (NDVI) was the independent variable that presented the highest correlation with biomass (r = 0.70), having its insertion in the adjusted model, which presented average precision given by R2=0.50 and Syx = 31.68 Mg.ha-1 . It is concluded that the Alagoas Arboretum has estimates of biomass and carbon stocks below those observed in areas of more advanced stages, but a higher IPA, which can be classified as an area in the medium stage of natural succession and with advances for the stock. biomass in the area, given the accelerated growth of the vegetation, supported predominantly by individuals with average diameter in the area. The VIC proves to be useful in choosing species with the potential to accelerate forest production, thus also serving as an indicator for carbon quantification projects. Modeling with IVs proved to be very promising and satisfactory. However, more effort is needed to reduce the saturation point effects of the indices and thus ensure better and more accurate results for biomass and carbon estimates. Key Words: Recovery of Degraded Areas. Forest Measurement. Remote sensing.