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Rapidly Eroding Piñon–Juniper Woodlands in New Mexico
Author(s) -
Hastings Brian K.,
Smith Freeman M.,
Jacobs Brian F.
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.1290a
Subject(s) - juniper , woodland , slash (logging) , herbaceous plant , watershed , erosion , forestry , sediment , environmental science , geography , agroforestry , hydrology (agriculture) , agronomy , ecology , geology , biology , paleontology , geotechnical engineering , machine learning , computer science
The piñon ( Pinus edulis Engelm.)–juniper [ Juniperus monosperma (Engelm.) Sarg.] woodlands of Bandelier National Monument are experiencing accelerated erosion. Earlier studies suggest that causes of these rapidly eroding woodlands are related to an unprecedented rapid transition of ponderosa pine ( Pinus ponderosa C. Lawson) savanna to piñon–juniper woodlands as a result of cumulative historical effects of overgrazing, fire suppression, and severe drought. To study the effectiveness of slash treatment in reducing accelerated erosion, we used sediment check dams to quantify sediment yield from twelve paired microwatersheds (300–1100 m 2 ) within an existing paired watershed study. Six of the twelve microwatersheds were located in a 41‐ha (treatment) watershed with scattered slash treatment, whereas six microwatersheds were located in an adjacent 35‐ha untreated (control) watershed. The primary purpose of our research was to quantify the rates of sediment yield between the treated and control microwatersheds. Sediment yield was measured from 15 individual storms during the months of June–September (2000 and 2001). In response to slash treatment, mean seasonal sediment yield for 2000 equaled 2.99 Mg/ha in the control vs. 0.03 Mg/ha in the treatment and 2.07 Mg/ha in the control vs. 0.07 Mg/ha in the treatment in 2001. The practice of slash treatment demonstrates efficacy in reducing erosion in degraded piñon–juniper woodlands by encouraging herbaceous recovery. Our data show that slash treatment increases total ground cover (slash and herbaceous growth) beyond a potential erosion threshold. Restored piñon–juniper woodlands, as the result of slash treatment, provide a forest structure similar to pre‐grazing and pre‐fire suppression conditions and decrease catastrophic fire hazard.