The St. Peter Sandstone of the American Midwest is presented today in textbooks as a simple and unproblematic example of “layer-cake geology.” The thesis of this paper is that the very simplicity of St. Peter Sandstone has made it challenging to characterize. In widely separated states, the sandstone appeared under different names. Several theories about how it formed began to circulate. The story of the St. Peter is not only the story of the assemblage of a stratigraphic unit over a vast area during three centuries, but also the role the study of the provenance of this unit played in the development of sedimentology in the early twentieth century, research that was made all the more challenging by its “simple” mineralogy. Indeed, the St. Peter has been controversial since it was first described.

Fire hazard is often mapped as a static conditional probability of fire characteristics’ occurrence. We developed a dynamic product for operational risk management to forecast the probability of occurrence of fire radiative power in the locally possible near-maximum fire intensity range. We applied standard machine learning techniques to remotely sensed data. We used a block maxima approach to sample the most extreme fire radiative power (FRP) MODIS retrievals in free-burning fuels for each fire season between 2001 and 2020 and associated weather, fuel, and topography features in northwestern south America. We used the random forest algorithm for both classification and regression, implementing the backward stepwise repression procedure. We solved the classification problem predicting the probability of occurrence of near-maximum wildfire intensity with 75% recall out-of-sample in ten annual test sets running time series cross validation, and 77% recall and 85% ROC-AUC out-of-sample in a twenty-fold cross-validation to gauge a realistic expectation of model performance in production. We solved the regression problem predicting FRP with 86% r² in-sample, but out-of-sample performance was unsatisfactory. Our model predicts well fatal and near-fatal incidents reported in Peru and Colombia out-of-sample in mountainous areas and unimodal fire regimes, the signal decays in bimodal fire regimes.

Nothofagus pumilio forests constitute the most economically important forest stand in southern Argentina and Chile. Total volume stocking and volumetric yield vary according to site quality, degree of occupation, growth stage and forest history of the stand. The objective of this work was to evaluate the stocking and the productive potential in quantity and quality of products for the sawmilling industry, using three harvesting systems (short logs, long logs and complete shafts) in the protection cut of a N. pumilio forest of site quality III in Tierra del Fuego (Argentina). The trials were conducted in an irregular mature forest with two strata and abundant regeneration (3.0 ha; RDI 93.8–113.4%). Total volumes varied between 726.5 and 850.3 m³∙ha^-1, with a volume/basal area ratio of 11.8 to 12.1 m³∙m^-2. The harvesting rates obtained were: 45.5% for complete logs, 21.3% for long logs and 22.4% for short logs. A model was used to estimate the timber volume for each system, where full shafts resulted in a significant increase in timber volume. Considering new alternatives in the planning of harvesting in forest management for N. pumilio forests, such as the system of complete shafts, allows obtaining higher harvesting rates, increasing the benefits for the forestry company and minimizing the damage to the forest, due to the shorter distance of the machinery in the forest harvesting.