The interaction of fire and mankind: Introduction

'Interesting' or 'boring': Modifying the implicit association task to measure implicit fire interest in an adolescent community sample

The efficacy of explicit measures in assessing fire interest is often compromised by social desirability biases, presenting a challenge for early intervention programs aimed at preventing firesetting behaviour. The current study aimed to validate a novel fire interest Implicit Association Task (IAT), as a more reliable measure of implicit fire interest in adolescents. An Australian community adolescent sample of 85 participants, aged 10-17 (M = 13.65, SD = 1.81), completed a series of questionnaires, and the novel fire interest IAT. Based on self-reports, participants were classified as firelighters (n = 52) or non-firelighters (n = 33). IAT outcomes revealed an inclination towards associating "fire" with "interesting." Notably, firelighters, compared to non-firelighters, performed significantly quicker during hypothesis-consistent trials of the IAT where fire-images were paired with interesting-words. Moreover, a weak correlation emerged between the speed of responses in these hypothesis-consistent IAT trials and self-reported fire interest. This investigation is one of the few that examined the efficacy of implicit measures of fire interest and is the first to do so using a modified IAT. With continued refinement, the fire interest IAT could be successfully used to assist with early intervention programs aimed at preventing child firesetting behaviour. PsychINFO Code: 3230.

Paleo-Wildfires and Their Paleoclimatic Effects in Early Permian Coal in the Southern North China Basin

Paleo-wildfires can help elucidate the transition trends of Earth from "icehouse" to "greenhouse," thereby allowing us to forecast the current changes associated with wildfires of this era. In this study, the early Permian Shanxi Formation in the Pingdingshan coalfield, located south of the North China Basin, was selected as a study site. Based on data on inertinite content, inertinite reflectance, nine polycyclic aromatic hydrocarbons (PAHs), paleo-wildfires, and their paleoclimate effect during the early Permian coal formation were systematically analyzed. The inertinite content in coal in the study area ranged from 9.76 to 29.65%, with an average of 19.32%. Meanwhile, the average inertinite reflectance values ranged from 2.41-4.74%, with an average of 2.75%. PAHs in the study area were mainly tricyclic and tetracyclic; the contents of fluorene, phenanthrene, pyrene, bypyrene, benzo[b]fluoranthene, and benzo[e]pyrene were higher than those of other PAHs in the same stratum. The total concentration of PAHs varied widely between layers (3601-21,894 ng/g). The presence of paleo-wildfires was confirmed by the contents of inertinite and PAHs. It can be concluded that paleo-wildfires in the study area were dominated by surface fires at low and medium temperatures based on the combustion equation. The oxygen content in the paleo-atmosphere of the Early Permian Shanxi Formation in the study area was 24.29%, which provided the necessary conditions for the occurrence of wildfires.

The discovery of fire by humans: a long and convoluted process

Numbers of animal species react to the natural phenomenon of fire, but only humans have learnt to control it and to make it at will. Natural fires caused overwhelmingly by lightning are highly evident on many landscapes. Birds such as hawks, and some other predators, are alert to opportunities to catch animals including invertebrates disturbed by such fires and similar benefits are likely to underlie the first human involvements with fires. Early hominins would undoubtedly have been aware of such fires, as are savanna chimpanzees in the present. Rather than as an event, the discovery of fire use may be seen as a set of processes happening over the long term. Eventually, fire became embedded in human behaviour, so that it is involved in almost all advanced technologies. Fire has also influenced human biology, assisting in providing the high-quality diet which has fuelled the increase in brain size through the Pleistocene. Direct evidence of early fire in archaeology remains rare, but from 1.5 Ma onward surprising numbers of sites preserve some evidence of burnt material. By the Middle Pleistocene, recognizable hearths demonstrate a social and economic focus on many sites. The evidence of archaeological sites has to be evaluated against postulates of biological models such as the ‘cooking hypothesis' or the ‘social brain’, and questions of social cooperation and the origins of language. Although much remains to be worked out, it is plain that fire control has had a major impact in the course of human evolution.

This article is part of the themed issue ‘The interaction of fire and mankind’.

Fire effects on soils: the human dimension

Soils are among the most valuable non-renewable resources on the Earth. They support natural vegetation and human agro-ecosystems, represent the largest terrestrial organic carbon stock, and act as stores and filters for water. Mankind has impacted on soils from its early days in many different ways, with burning being the first human perturbation at landscape scales. Fire has long been used as a tool to fertilize soils and control plant growth, but it can also substantially change vegetation, enhance soil erosion and even cause desertification of previously productive areas. Indeed fire is now regarded by some as the seventh soil-forming factor. Here we explore the effects of fire on soils as influenced by human interference. Human-induced fires have shaped our landscape for thousands of years and they are currently the most common fires in many parts of the world. We first give an overview of fire effect on soils and then focus specifically on (i) how traditional land-use practices involving fire, such as slash-and-burn or vegetation clearing, have affected and still are affecting soils; (ii) the effects of more modern uses of fire, such as fuel reduction or ecological burns, on soils; and (iii) the ongoing and potential future effects on soils of the complex interactions between human-induced land cover changes, climate warming and fire dynamics.This article is part of the themed issue 'The interaction of fire and mankind'.