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Updated: Jun 29, 2026
09:04
Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands
Published on: August 29, 2019
Mapping "old" vs. "young" piñon-juniper stands with a predictive topo-climatic model
B F Jacobs1, W H Romme, C D Allen
1Graduate Degree Program in Ecology and Department of Forest, Rangeland, and Watershed Stewardship, Colorado State University, Fort Collins, Colorado 80523, USA. brian_jacobs@nps.gov
Summary
Piñon-juniper woodlands in the Southwest are often seen as invasive, but this study distinguishes older, pre-settlement stands from younger ones. Findings highlight soil moisture and landforms as key factors in the distribution of these important historical ecosystems.
Area of Science:
- Ecology and ecological modeling
- Rangeland management and restoration
- Historical vegetation dynamics
Background:
- Piñon-juniper woodlands in the southwestern US are often perceived as expanding and invasive due to historic grazing.
- Current management focuses on forage production and hazard fuels, with restoration as a stated objective.
- The ecological value and extent of pre-settlement piñon-juniper communities are poorly understood.
Purpose of the Study:
- To differentiate between older, pre-Euro-American settlement piñon-juniper stands and younger, post-settlement stands.
- To model and map the distribution of these historical woodland types.
- To understand the ecological factors influencing the distribution of old-growth versus young piñon-juniper.
Main Methods:
- Developed a diagnostic key to distinguish between 'older' (pre-1850) and 'younger' (post-1850) piñon-juniper stands.
- Utilized predictive modeling and mapping techniques in north-central New Mexico.
- Analyzed the relationship between stand age and environmental factors like soil moisture, landform, and soil deposition.
Main Results:
- Soil moisture emerged as a primary factor in the distribution of older versus younger piñon-juniper stands.
- Older stands are typically found at higher elevations on skeletal soils, while younger stands (often one-seed juniper) favor lower, more productive areas.
- Presettlement woodlands occupied a distinct ecological niche defined by moisture, landform, and depositional patterns.
Conclusions:
- The historical extent and ecological distinctiveness of presettlement piñon-juniper woodlands are significant.
- Understanding these historical dynamics is crucial for effective rangeland restoration and management.
- Predictive modeling and mapping can support land management decisions regarding piñon-juniper ecosystems.
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