Análise espaço-temporal da relação restauração florestal e paisagem local

Abstract

This research work aimed to monitor two areas in the process of forest restoration under total planting, with a primary difference in the influence of their surroundings, has a greater understanding of its dynamics and thus proposes better implementation and monitoring for areas under planting. The study was carried out in two areas undergoing forest restoration (ANA - non-adjacent area and AA - adjacent area), previously used for sugarcane cultivation, and a forest fragment considered as reference ecosystem (R). For landscape analysis, a buffer of 1 (one) km was performed, considering that the areas are about 2 (two) km away, avoiding overlap. Images were from RapidEye orbital platform dating from 12/03/2011 (before plantation), 8/9/2015 (approximately 4 years after plantation) and 10/09/2019 (approximately 8 years after plantation). Field data were collected between September and December 2017 for AA, ANA and R, and between September and November 2019 for AA and ANA. For this purpose, 60 permanent plots of 250 m² (10 x 25 m) were randomly distributed, with 20 plots in each area, and all arboreal individuals with circumference at breast height (cbh) ≥ 15 cm were measured and numbered with aluminum platelets. As for the assessment of natural regeneration, 25 m² (5 x 5 m) sub-plots were used in the upper left corner of each plot. Regarding classification, the AA landscape showed an increase of 91.1 ha of forest in eight years of plantation, it is noteworthy that its area is only 21.2 ha, thus, there was a contribution from the surroundings over 70 ha. Meanwhile, ANA showed an increase of 40.37 ha, this area may be presenting a slower restoration, however, apparently, there was fragmentation north of ANA between 2011 and 2015 and east between 2015 and 2019, reducing part of the forest cover to the surroundings of ANA. The adjacent one had a more efficient development, with an increase of 44 ha of core area in eight years, while the non-adjacent, 27 ha. The floristic composition was found to be similar between ANA and AA, in the two times intervals, however diverging from R. However, similarity between AA and R could be observed when comparing dispersion syndromes between areas. Regarding the absolute density in 2019, there was no significant difference between the areas, the canopy opening showed similarity between the adjacent and the fragment diverging from the non-adjacent. As for the composition of natural regeneration, R was not similar with any of the two areas at any time, however when comparing the grouping of plots between adults and regenerants, it is observed that the regenerants are closer to the similarity with the areas than the adults. It is important to mention that five late secondary species appeared in AA, one occurring only in 2017 (Eschweilera ovata), and four in 2019 (Aspidosperma spruceanum, Bixa orellana, Protium giganteum and Protium heptaphyllum) and only two appeared in ANA-2019 (Eschweilera ovata and Hymenaea courbaril). Regarding the number of individuals per height class, it is observed that AA has a better structure than ANA, as it has a higher occurrence of species in height classes II and III, both in quantitative and proportional terms. Analyzing the development of areas under restoration, it is understood that both areas under restoration are influenced by the surroundings and the surroundings by them.