Dendroecological testing of the pyroclimatic hypothesis in the central Great Basin, Nevada, USA

Franco Biondi,Jason Sibold,Leia P Jamieson,Scotty Strachan

doi:10.1890/es10-00068.1

Franco Biondi, Jason Sibold + Show 2 more

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https://doi.org/10.1890/es10-00068.1

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Journal: Ecosphere	Publication Date: Jan 1, 2011
Citations: 28	License type: cc-by

Affiliation: University of Nevada Reno, Colorado State University

Abstract

In the Great Basin region of western North America, records of past climate and wildfire variability are needed not only for fire use, but also for understanding the mechanisms behind the century-long expansion of pinon-juniper woodlands. The Mt. Irish area (Lincoln County, south-eastern Nevada) is a remote mountain ecosystem on the hydrographic boundary between the Great Basin and the Colorado River Basin. Non-scarred ponderosa pines (Pinus ponderosa C. Lawson var. scopulorum Engelm.) and single-needle pinyons (Pinus monophylla Torr. & Frem.) were used to develop a tree-ring reconstruction of drought (mean PDSI for May–July from NV Climate Division 3) from 1396 to 2003. A hypothetical fire regime was obtained from the PDSI reconstruction and from explicitly assumed relationships between climate and wildfire occurrence. A census of fire-scarred trees was then sampled at the study area, and crossdated fire-scar records were used to generate the fire history, independently of the pre-existing pyroclimatic m...

Highlights

Fire history studies play an important role in understanding how various factors, from natural to human, can affect wildfires, which are a major disturbance process in terrestrial ecosystems of western North America (Veblen et al 2003)
In the Great Basin of North America, relatively little information exists on ecosystem dynamics related to wildfire prior to Euro-American settlement, this factor has been linked to the century-long expansion of pinyon-juniper woodlands (Baker and Shinneman 2004)
The area we investigated is representative of several other mountain-top ecosystems in the Great Basin, where ponderosa pine is found in complex mixtures with elements of the more typical pinyon-juniper woodlands (Charlet 1996)

Summary

Introduction

Fire history studies play an important role in understanding how various factors, from natural (such as climate) to human (such as land-use patterns), can affect wildfires, which are a major disturbance process in terrestrial ecosystems of western North America (Veblen et al 2003). Forest environments that are characterized by low-intensity fire events, the primary source of information on long-term dynamics are firescarred trees, whose xylem ring patterns can provide seasonal to annual, spatially explicit records for long (.300 years) time periods (Veblen et al 2003). This has allowed quantitative analyses of changes in wildfire regime before and after Euro-American settlement In the Great Basin of North America, relatively little information exists on ecosystem dynamics related to wildfire prior to Euro-American settlement, this factor has been linked to the century-long expansion of pinyon-juniper woodlands (Baker and Shinneman 2004). There is still ample debate on the relative importance that changes in climate vs. human land use, such as the transition from Native American burning to Euro-American extinguishing, have had on the generally observed reduction of fire frequency in modern times (Betancourt et al 1993)

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