Environmental values and fire hazard of eucalypt plantings

Meaghan Jenkins,Phil Zylstra,Luke Collins,Owen Price,Ross Bradstock,Trent Penman,Bronwyn Horsey

doi:10.1002/ecs2.1528

Meaghan Jenkins, Phil Zylstra + Show 5 more

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https://doi.org/10.1002/ecs2.1528

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Abstract

AbstractThe revegetation of cleared landscapes with woody plants (termed “environmental planting”) has the potential to sequester carbon (C), provide habitat, and increase biodiversity and connectivity. These environmental values are potentially offset by an increased fire hazard posed by revegetation. There is a need to understand the influence environmental planting has on landscape fire behavior and to determine how this changes as plantings age. This study examined how environmental values, regenerative capacity, fuel metrics, and potential fire behavior change with time since planting. We assessed 57 sites across the Albury‐Wodonga region (New South Wales, Australia). This included a range of environmental planting ages (4–40 yr time since planting), remnants, and pastures. Carbon storage increased with age of planting, with largest C stores found in remnants (105 tC/ha), while habitat complexity plateaued around 20 yr, with no significant difference between moderately aged plantings (14–20 yr), old plantings (>20 yr), and remnants. Modeled rate of fire spread was faster in pastures compared to environmental plantings and remnants. Flame height was slightly higher (0.5–1 m) in pastures than environmental plantings and remnants under a Very High Forest Fire Danger Index (FFDI), but this trend reversed under Extreme and Catastrophic conditions with flame heights greatest in environmental plantings and remnants albeit with slower rates of spread. This research highlights the importance of environmental plantings in the landscape in terms of C storage and environmental values and indicates the perceived hazard associated with rate of spread and flame height may not be justified at or less than Very High FFDI. However, at FFDI greater than Very High fire behavior may be significantly enhanced in environmental plantings and remnants. Further consideration needs to be given to the size and design of plantings and the type of species planted to fully develop an understanding of the complexities of fire risk. This study allows land managers to make informed decisions regarding the values and risks associated with revegetation of cleared landscapes with woody plants.

Highlights

The use of land to yield goods and services alters the structure and functioning of ecosystems, and how ecosystems interact with the atmosphere, with aquatic systems, and with surrounding land (Vitousek et al 1997)
Flame height was slightly higher (0.5–1 m) in pastures than environmental plantings and remnants under a Very High Forest Fire Danger Index (FFDI), but this trend reversed under Extreme and Catastrophic conditions with flame heights greatest in environmental plantings and remnants albeit with slower rates of spread
This research highlights the importance of environmental plantings in the landscape in terms of C storage and environmental values and indicates the perceived hazard associated with rate of spread and flame height may not be justified at or less than Very High FFDI

Summary

Introduction

The use of land to yield goods and services alters the structure and functioning of ecosystems, and how ecosystems interact with the atmosphere, with aquatic systems, and with surrounding land (Vitousek et al 1997). A review of habitat use by terrestrial fauna highlights the importance of maintaining a mosaic of habitats, as many species require multiple habitats to obtain different resources at different life stages (Law and Dickman 1998) Revegetation can provide this variety of habitats required for foraging, shelter, and nesting, and this is in part due to the development of structural complexity over time. We used both field surveys and modeling to assess how several measures of environmental value (i.e., aboveground C, habitat complexity, regenerative capacity of trees) and potential fire behavior (ROS, flame length) vary across a range of planting ages as well as adjacent pastures and remnants

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Literature Cited