Bark Characterisation of the Brazilian Hardwood Goupia glabra in Terms of Its Valorisation

Half of the Amazon Forest, which has a marked seasonality in rainfall, is susceptible to intense droughts caused by positive phases of the El Niño-Southern Oscillation (ENSO). Cedrela odorata L., sensitive to climate variations, emerges as a promising candidate for studies on how trees respond to climate change. Given the demand for its wood and the imperative for its protection in the Amazon Biome, applying the principles of environmental sustainability becomes crucial. This study characterizes local climatic variables near the Amazon River and assesses their impact, as well as the effect of ENSO, on the radial growth of Cedrela odorata using Pearson correlation analyses. Ring synchronization followed the standard methodology in dendrochronology, confirming common growth patterns and the formation of growth rings in C. odorata. Significant correlations with growth were noted concerning local climate, with negative associations for maximum and average temperatures and evapotranspiration, and a positive correlation with relative air humidity. ENSO exhibited a significant negative correlation with growth rings, indicating reduced growth during El Niño events. The species is notably sensitive to water availability, particularly at the onset of the growth period. The study concludes that the growth of C. odorata in the Óbidos-PA microregion responds to climate change.

The growing demand for products of forest origin in the middle north region of Mato Grosso, Brazil has been increasing the production of the genus eucalyptus. This study aimed to assess the deposition and decomposition rates of litter at the central plot areas of Eucalyptus urograndis (Clone H13) areas of three, five, seven and nine years of age. In five and seven-year areas, the interfaces (borders) eucalyptus–crop and eucalyptus–native forest, and further, native forest remnant areas were assessed. Litter collectors with 1 m² area were installed and the deposited material was collected monthly. For quantifying the decomposition rates, collections were carried out at 30, 60, 120, 180, 240, and 300 days after installing the decomposition bags. In the dry season, higher amounts of deposited litter were observed, with a greater representation of the leaf fraction. Bark fraction presents positive and negative correlations with wind speed and relative air humidity, respectively. The litter balance found indicates that even under a tropical climate, high deposition rates occur when compared to the litter decomposition of E. urograndis, allowing significant increases of litter in planted areas as the age increased.

Background. Forest fires generate several economic, social and environmental losses in native and planted forests. For the prevention and combat of forest fires it is important to know the behavior of fire in each environment potential for its development. This analysis depends on the direct measurement in the field of the parameters associated with the speed of propagation of the fire line and the length of the flames. The fire behavior is influenced by the interaction between meteorological and topographic conditions and plant residues (combustible material) inherent to the environment in which they occur. Objective. This paper evaluated of the fire behavior and microclimate in prescribed burnings performed at different times of the day, on the areas of 5.5-year-old Eucalyptus urograndis (clone H13), in the Cerrado Amazonia transition zone, Mato Grosso state, Brazil. Methodology. Prescribed burnings was carried out in eucalyptus/crop (EC), eucalyptus/eucalyptus (EE), and eucalyptus/forest (EF) interfaces from 8:00 to 16:00 (considering solar time), in subdivided plots with ten replications. We conducted characterizations of the combustible material - CM (density, moisture, and dry mass), meteorological variables (air temperature, relative air humidity, and wind speed/ direction), and fire behavior (flame length, fire spread rate, and fire intensity). Results. The EF interface showed the highest density, moisture, and herbaceous material. The changes in solar energy scattering represented by the zenith angle (Z) directly affected the meteorological variables, with a gradual increase in the interfaces EC, EE, and EF, respectively. Implications. The results obtained allow the definition of the best times to carry out burns prescribed in forest monocultures, optimizing the available resources (water, retardants, labor, among others) in the direct fight against forest fires. Conclusion. Diurnal evolution of Z affected the fire behavior; in addition, the greater solar radiation between 10:00 and 14:00 resulted in fire intensification in the environmental interfaces.