225 Critical Zone Science: Intersection of Processes Linked to Geomorphology, Ecology, Fire and Climate (Posters)

This session welcomes interdisciplinary studies that investigate the rates and processes of soil development, regolith formation, carbon storage and the role of ecological and/or hydrologic feedbacks in shaping the landscape (both past and present).

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Exploring the Role of Climate Change on Western Juniper Establishment Rates in a Southwestern Idaho Watershed

Paper number: 225-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The expansion of western juniper (Juniperus occidentalis) across sagebrush steppe communities across the Pacific Northwest raises concerns about potential impacts on ecosystem dynamics in rangelands. Using a combination of remote sensing and field sampling from the Reynolds Creek Experimental Watershed (RCEW) in southwestern Idaho, we evaluate decadal patterns of western juniper establishment to inform future management strategies. We collected juniper tree cores, heights, and canopy diameters and used these metrics to develop a remote sensing model for estimating tree age in order to determine the rate of expansion of western juniper within a southwestern Idaho watershed. Using a combination of 77 tree ages established from tree cores and juniper characteristics from remote sensing, we developed a tree-age model which estimated the ages of >3,600 western juniper. We chose the climate variables of focus for this study a priori based on a prior literature review, and identified cooler spring and summer temperatures and increased winter and spring precipitation. Our results show increased current year spring precipitation was most influential on western juniper expansion in our study area. Future climate model predictions indicate spring precipitation in the Pacific Northwest will likely increase, which can suggest continued expansion of western juniper in rangelands in the future. This study informs land managers of future landscape dynamics in rangelands under a changing climate and improves our ability to track western juniper expansion across large spatial scales.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412875

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