Characteristics and metrics of resilient forests in the Sierra de San Pedro Martir, Mexico

FOREST ECOLOGY AND MANAGEMENT

卷:482

Article

Murphy, Julia S.¹  York, Robert¹  Huerta, Hiram Rivera²  Stephens, Scott L.¹ 

[1] Univ Calif Berkeley, Dept Environm Sci Policy & Management, 130 Mulford Hall, Berkeley, CA 94720 USA

[2] Univ Autonoma Baja California, Fac Ciencias Marinas, Carretera Trasnpeninsular Ensenada Tijuana 3917, Ensenada 22860, Baja California, Mexico

关键词: Forest resilience;    Stand density index;    Wildfire;    Disturbance ecology;    Baja California;    Yellow pine;    Mixed conifer;   

DOI  :  10.1016/j.foreco.2020.118864

来源: Elsevier

【 摘 要 】

Ecological restoration of fire-excluded yellow pine-mixed conifer (YPMC) forests in the western US first requires the definition of desired future conditions. The Sierra de San Pedro Martir (SSPM) in Baja California has been used as a modern reference for other western US YPMC forests because it shares similar vegetation, soils, climate, and fire regimes, but is less impacted by logging and fire suppression. Our study re-visited a 14 ha SSPM watershed 16 years after it experienced a moderate severity fire preceded by four years of severe drought, in order to better understand resilient forests. We also provide a management-applicable metric for reference conditions by characterizing density and inter-tree competition using stand density index (SDI). We found no significant differences in forest structure between 2004 (1-yr post fire) and 2019 (16-yr post fire) periods, except for moderate and highly variable increases in duff and 1000-hr rotten fuel loads. Our exploration of SDI suggests that this watershed exists at extremely low levels of site occupancy and inter-tree competition relative to its potential. We concluded that, more than competition for resources, fire activity and large-scale climate fluctuations are the most important drivers of stand structure in the SSPM. This study demonstrates the importance of managing for very low tree densities as a component of resilience in YPMC forests.

【 授权许可】

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