Long-Term Persistence and Fire Resilience of Oak Shrubfields in Dry Conifer Forests of Northern New Mexico

Christopher H. Guiterman, Ellis Q. Margolis, Craig D. Allen, Donald Falk, Thomas Swetnam

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Extensive high-severity fires are creating large shrubfields in many dry conifer forests of the interior western USA, raising concerns about forest-to-shrub conversion. This study evaluates the role of disturbance in shrubfield formation, maintenance and succession in the Jemez Mountains, New Mexico. We compared the environmental conditions of extant Gambel oak (Quercus gambelii) shrubfields with adjoining dry conifer forests and used dendroecological methods to determine the multi-century fire history and successional dynamics of five of the largest shrubfields (76–340 ha). Across the study area, 349 shrubfields (5–368 ha) occur in similar topographic and climate settings as dry conifer forests. This suggests disturbance, rather than other biophysical factors, may explain their origins and persistence. Gambel oak ages and tree-ring fire scars in our sampled shrubfields indicate they historically (1664–1899) burned concurrently with adjoining conifer forests and have persisted for over 115 years in the absence of fire. Aerial imagery from 1935 confirmed almost no change in sampled shrubfield patch sizes or boundaries over the twentieth century. The largest shrubfield we identified is less than 4% the size of the largest conifer-depleted and substantially shrub-dominated area recently formed in the Jemez following extensive high-severity wildfires, indicating considerable departure from historical patterns and processes. Projected hotter droughts and increasingly large high-severity fires could trigger more forest-to-shrub transitions and maintain existing shrubfields, inhibiting conifer forest recovery. Restoration of surface fire regimes and associated historical forest structures likely could reduce the rate and patch size of dry conifer forests being converted to shrubfields.

Original languageEnglish (US)
Pages (from-to)1-17
Number of pages17
JournalEcosystems
DOIs
StateAccepted/In press - Oct 17 2017

Fingerprint

dry forests
coniferous forests
coniferous tree
Quercus
Fires
Quercus gambelii
persistence
fire severity
shrubs
shrub
patch size
fire scars
fire regime
Drought
growth rings
wildfires
Restoration
conifers
oak
disturbance

Keywords

  • alternative stable states
  • dry conifer ecosystems
  • fire-origin shrubfields
  • gambel oak
  • high-severity fire
  • metastability
  • tree rings

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Environmental Chemistry
  • Ecology

Cite this

Long-Term Persistence and Fire Resilience of Oak Shrubfields in Dry Conifer Forests of Northern New Mexico. / Guiterman, Christopher H.; Margolis, Ellis Q.; Allen, Craig D.; Falk, Donald; Swetnam, Thomas.

In: Ecosystems, 17.10.2017, p. 1-17.

Research output: Contribution to journalArticle

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