Fuel Classes in Conifer Forests of Southwest Sichuan, China, and Their Implications for Fire Susceptibility

San Wang,Shukui Niu

doi:10.3390/f7030052

Abstract

The fuel characteristics that influence the initiation and spread of wildfires were measured in Keteleeria fortune forest (FT1), Pinus yunnanensis forest (FT2), P. yunnanensis and Platycladus orientalis (L.) Franco mixed forest (FT3), P. yunnanensis Franch and K. fortunei (Murr.) Carr mixed forest (FT4), Tsuga chinensis forest (FT5), and P. orientalis forest (FT6) in southwest Sichuan Province, China. We compared vertical distributions of four fuel classes (active fuel, fine fuel, medium fuel and thick fuel) in the same vertical strata and in different spatial layers, and analyzed the fire potential (surface fire, passive and active crown fires) of the six forest types (FT). We then classified the six forest types into different groups depending on their wildfire potential. By using the pattern of forest wildfire types that burnt the most number of forests, we identified four fire susceptibility groups. The first two groups had the lowest susceptibility of active crown fires but they differed in the proportion of surface and passive crown fires. The third group was positioned in the middle between types with low and extremely high fire susceptibility; while the fourth group had the highest susceptibility of active crown fires. The results of this study will not only contribute to the prediction of fire behavior, but also will be invaluable for use in forestry management.

Highlights

Wildfire is a primary source of natural disturbance in forest ecosystems, and it plays an important role in determining the landscape structure and plant community composition
We described each forest type with statistics on surface fuel horizontal continuity, canopy closure, and fuel horizontal and vertical continuity
Our results indicated that the distribution and structure of four fuel classes, the total loading and fire potential differed among the six forest types

Summary

Introduction

Wildfire is a primary source of natural disturbance in forest ecosystems, and it plays an important role in determining the landscape structure and plant community composition. The shrub and small trees stratum act as a “ladder fuel” that forms a continuous ladder fuel from the surface fuel up to the canopy fuel, which can turn low-intensity surface fires into severe canopy fires, potentially resulting in active crown fires [2,3]. Fire susceptibility is determined by the distribution, type and continuity of fuel [6]. Forest managers are expressing a growing interest in proactively reducing an area’s susceptibility to fires, yet fires remain responsible for a large proportion of the annual area burned in fire-prone ecosystems. Our knowledge of wildfire prevention and its relationship with forest type is lacking [7,8,9]

Objectives

Methods

Results

Discussion

Conclusion