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Long-term persistence and fire resilience of oak shrubfields in dry conifer forests of northern New Mexico

Ecosystems

By:
, ORCID iD , ORCID iD , , and
https://doi.org/10.1007/s10021-017-0192-2

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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.

Study Area

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Long-term persistence and fire resilience of oak shrubfields in dry conifer forests of northern New Mexico
Series title:
Ecosystems
DOI:
10.1007/s10021-017-0192-2
Edition:
Online First
Year Published:
2017
Language:
English
Publisher:
Springer
Contributing office(s):
Fort Collins Science Center
Country:
United States
State:
New Mexico
Other Geospatial:
Jemez Mountains