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Linking old-growth forest composition, structure, fire history, climate and land-use in the mountains of northern México

Montaño, Citlali Cortés and Fule, Peter Z. and Falk, Donald A. and Villanueva-Díaz, José and Yocom Kent, Larissa L. (2012) Linking old-growth forest composition, structure, fire history, climate and land-use in the mountains of northern México. Ecosphere, 3 (11). ISSN 2150-8925


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Publisher’s or external URL: http://dx.doi.org/10.1890/ES12-00161.1


Old-growth forests are biologically and ecologically valuable systems that are disappearing worldwide at a rapid rate. México still holds large areas covered by temperate forests in the mountains of the Sierra Madre Occidental, but few of these retain old-growth characteristics. We studied four sites with remnant old-growth forests in Mesa de las Guacamayas, a site in the Sierra Madre Occidental in northwestern Chihuahua, to assess their composition, structure, and age characteristics. Overstory tree densities and basal areas at each site were based on measurements of all trees >1.3 m tall. The overstory was dominated by large Pinus durangensis, P. strobiformis, and Pseudotsuga menziesii (270-335 trees ha-1, basal area 24-42 m2 ha-1), with a subcanopy formed mostly of oaks. This species composition, combined with the lack of vertical structural development, and thus of fuel ladders, suggests that these forests are relatively resistant to severe wildfire. We evaluated forest attributes in the context of local fire regimes and regional climatic patterns, and found that frequent disturbance by surface fires has been part of the study sites' histories for at least 250 years. While climate was a driver of fire regimes historically in this mountain range, humans appear to have played a role in interruptions of the fire regime in the second half of the 20th century. Age distributions showed recruitment to the canopy over 250 years, while fires in the four sites recurred every 6-12 years. Temporary interruption of the fire regime in the mid-20th century at three sites was associated with increased tree establishment, especially by broadleaved species. One site had an uninterrupted fire regime and showed continuous tree establishment, consistent with the self-reinforcing role of frequent fire in regulating live and dead fuel loads. Remnant old-growth forests such as those we sampled are becoming increasingly rare in the Sierra Madre Occidental. The biodiversity and ecological processes that they support are highly threatened and their conservation must be made a priority in the U.S.-México borderlands.

Item Type: Article
Publisher’s Statement: Copyright by the Ecological Society of America, Citlali Cortés Montaño, Peter Z. Fulé, Donald A. Falk, José Villanueva-Díaz, and Larissa L. Yocom 2012. Linking old-growth forest composition, structure, fire history, climate and land-use in the mountains of northern México. Ecosphere 3:art106. http://dx.doi.org/10.1890/ES12-00161.1
ID number or DOI: 10.1890/ES12-00161.1
Keywords: Agricultural Economics (EE110); America; angiosperms; Animals; APEC countries; Biodiversity; Biological Resources (General) (PP700); Biological Resources (Plant) (PP720); Birds; canopy; chihuahua; Chordata; climate; conservation; Developing Countries; dicotyledons; Douglas fir; Drought; Ecology; Ecology (General) (ZZ330); environment; eukaryotes; Fagaceae; Fagales; Fires; Forest Fires (KK130); forests; Forests and Forest Trees (Biology and Ecology) (KK100); global carbon sinks; gymnosperms; Land Resources (PP300); land use; Latin America; leaf canopy; management; measurement; Meteorology and Climate (PP500); metrology; Mexico; Mountains; North America; oaks; OECD Countries; Old growth; old-growth forests; Pinaceae; pine-oak forests; pines; Pinopsida; Pinus; Pinus durangensis; Plants; Pseudotsuga; Pseudotsuga menziesii; Psittacidae; Psittaciformes; Quercus; recruitment; regimes; resistance; Rhynchopsitta; Rhynchopsitta pachyrhyncha; Sierra Madre Occidental; sites; southwestern united-states; Special Feature: Sustainability on the US/Mexico Border; Species diversity; Spermatophyta; Sustainability; Threshold Countries; Vertebrates; Wildfires
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QH Natural history
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > School of Forestry
Date Deposited: 01 Oct 2015 05:27
URI: http://openknowledge.nau.edu/id/eprint/648

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