The recent recipient of two major awards, Craig D. Allen, a research ecologist with the U.S. Geological Survey Fort Collins Science Center, has loved trees since childhood. He is now considered an expert of world renown on the twin phenomena of forest changes and tree mortality resulting from climate warming and drought, and in 2010 was twice recognized for his scientific contributions...
Historical and Modern Disturbance Regimes, Stand Structures, and Landscape Dynamics in Piñon–Juniper Vegetation of the Western United States
Pinon–juniper is a major vegetation type in western North America. Effective management of these ecosystems has been hindered by inadequate understanding of 1) the variability in ecosystem structure and ecological processes that exists among the diverse combinations of pinons, junipers, and associated shrubs, herbs, and soil organisms; 2) the prehistoric and historic disturbance regimes; and 3) the mechanisms driving changes in vegetation structure and composition during the past 150 yr. This article summarizes what we know (and don’t know) about three fundamentally different kinds of pinon–juniper vegetation. Persistent woodlands are found where local soils, climate, and disturbance regimes are favorable for pinon, juniper, or a mix of both; fires have always been infrequent in these woodlands…
A conceptual framework for dryland aeolian sediment transport along the grassland–forest continuum: Effects of woody plant canopy cover and disturbance
Breshears, D.D., J.J. Whicker, C.B. Zou, J.P. Field, and C.D. Allen
Development and Publication of Vegetation and Soil Monitoring Protocols for Rocky Mountain Inventory and Monitoring Network of Parks
The Rocky Mountain Network (ROMN) invested several years cooperatively developing and evaluating an approach, methods, and pilot data for sampling vegetation and soil conditions in terrestrial ecosystems of the Rocky Mountain region. These measures are designed to serve as baseline indicators of range and woodland system conditions and trends, including wildlife habitat and ecosystem function and condition. Vegetation and soil sampling efforts continue to expand within the National Park Service (NPS) and other U.S. Federal agencies; this project was established to complete several important components of the NPS ROMN monitoring plan, including submission for review and publication. Collection of field data using the prescribed methods supported methods comparisons and power analyses, which in turn will guide selection and adaptation of protocols. FORT will coordinate review and revision of the methods based on experience gained during the pilot period. Specific objectives include (1) completing statistical analyses of pilot data to make a final comparison of proposed methods based on associated variance, accuracy, and precision of the estimates; (2) completing statistical analyses of power for trend and standard error of status estimates required for determining the target sample size; and (3) incorporating results of these analyses into the ROMN VCSS Protocol Narrative and Standard Operating Procedures. These methods can be adapted and applied to similar systems (interested parties may contact the task manager for consultation and/or participation). Additionally, plans for the future include establishment of a rangeland condition assessment using similar methods applied regionally across gradients of system drivers (important influences) to serve as a reference for landowners and managers across the region.