Predição do tamanho de clareira em área de várzea sob regime de Manejo Florestal: estudo de caso na Reserva de Desenvolvimento Sustentável Mamirauá

Abstract

The objective of the study was to develop mathematical models capable of relating the size of forest clearings with dendrometric data and canopy morphometric characteristics, allowing to obtain knowledge for a better planning and estimation of the impacted area and thus contribute to the determination of the forest cover by the fall of the tree on the farm. This study was conducted in forest management areas of the Mamirauá Sustainable Development Reserve with an area of 1,124,000 hectares, located at the confluence of the Solimões and Japurá rivers, between the municipalities of Alvarães, Uarini, Maraã, Fonte Boa and Jutaí, state of Amazonas, located near the city of Tefé. The forest inventories were carried out between January and February of the years 2012, 2013 and 2014 by the community associations that develop the activities in their respective areas of forest management located in the Mamirauá RDS. The canopy morphometric data were collected in January 2018 and analyzed using Analysis of Variance, Pearson's Correlation Coefficient and Multiple Linear Regression Analysis. The tests showed that there is a significant difference between the clearings of species exploited in the forest management areas of the Mamirauá RDS, with Açacú (Hura crepitans) presenting higher values for a clearing area with 341.88 (m2) ± 99.09 (m2), DAP 136.83 (cm) ± 30.07 (cm), Height of 13.29 (m) ± 2.97 (m) and volume of 11.92 (m3) ± 4.9 (m3) for this species. The smaller clearings were caused by the species Louro inamuí (Ocotea cymbarum) with size in area of 193,94 (m2) ± 36,26 (m2) and for the species Castanharana (Lecythis pisonis Cambess.) With values in area of 164, 66 (m2) ± 19.97 (m2). The dendrometric (DAP and Height) and volume variables presented DAP (r = 0.85) and Volume correlation values (r = 0.697), showing a strong positive correlation with the clearing areas, indicating that the size of the clearing areas (m2) increased as individuals with higher DAP values and higher volume production (m3) are explored. The model that best fit and presented the best values according to the indicatives used as evaluation parameters was model 5, CL = -626.5439 + 6.6645.DAP -127.3025.G + 69.295.IS - 1,9302.IEV + 292,765. IA-4.3849.VSH, with a higher value of 0.9358 (R2Ajust), 7,000 (Cp mallows), 238.38 (AIC) and 19.7 (Syx%). It is possible to indicate for the prediction of clearing area the adjusted equation for model 7, CL = -134.5395 + 2.8028.DAP + 13.266.IS.