River Flows Are a Reliable Index of Forest Fire Risk in the Temperate Tasmanian Wilderness World Heritage Area, Australia

Abstract

Fire risk can be defined as the probability that a fire will spread across a landscape, that therefore determines the likely area burnt by a wildfire. Reliable monitoring of fire risk is essential for effective landscape management. Compilation of fire risk records enable identification of seasonal and inter-annual patterns and provide a baseline to evaluate the trajectories in response to climate change. Typically, fire risk is estimated from meteorological data. In regions with sparse meteorological station coverage environmental proxies provide important additional data source for estimating past and current fire risk. Here, we use a 60-year record of daily flows (ML day−1 past a fixed-point river gauge) from two rivers (Franklin and Davey) in the remote Tasmanian Wilderness World Heritage Area (TWWHA) to characterize seasonal patterns in fire risk in temperate Eucalyptus forests and rainforests. We show that river flows are strongly related to landscape soil moisture estimates derived from down-scaled re-analysis of meteorological data available since 1990. To identify river flow thresholds where forests are likely to burn, we relate river flows to known forest fires that have occurred in the previously defined ecohydrological domains that surround the Franklin and Davey catchments. Our analysis shows that the fire season in the TWWHA is centered on February (70% of all years below the median river flow threshold), with shoulders on December-January and March. Since 1954, forest fire can occur in at least one month for all but four summers in the ecohydrological domain that includes the Franklin catchment, and since 1964 fire could occur in at least one month in every summer in the ecohydrological domain that includes the Davey catchment. Our analysis shows that managers can use river flows as a simple index that indicates landscape-scale forest fire risk in the TWWHA.

Fire and geodiversity

“…A separate study found that fire-accelerated erosion rates contributed 8 and 6%, respectively, to long-term sediments yields in two lakes in the north-west USA (Swanson 1981). Similarly, in a simulated example, the compound impacts of wildfire and rainfall was shown to increase peak flows by up to six times when compared with events where wildfire was not present (Bowman and Williamson 2021).…”

Bushfires in Tasmania, Australia: An Introduction

“…This Special Issue touches on many issues central to understand how fire activity has changed across Tasmania through the Holocene [27], the impact and recovery of forest and shrub vegetation following recent fires [20,28], geographical patterns of lightning ignitions [29], fire severity patterns across forest-treeless vegetation boundaries [30], analysis of fire risk using soil moisture and river flow data [31], and the influence of a changing climate on dominant forest trees [32]. These articles highlight the complexity of fire management in Tasmania, especially associated with rapid changes driven by the Anthropocene.…”

A Highly Accurate Forest Fire Prediction Model Based on an Improved Dynamic Convolutional Neural Network

“…At present, research on forest fire risk detection based on ML mainly involves flame detection and smoke detection [17][18][19][20][21]. The forest fire risk monitoring methods proposed by most scholars are for specific scenes, with several problems that need to be solved.…”