TY - JOUR
T1 - Reference conditions are influenced by the physical template and vary by forest type
T2 - A synthesis of Pinus ponderosa-dominated sites in the southwestern United States
AU - Rodman, Kyle C.
AU - Sánchez Meador, Andrew J.
AU - Moore, Margaret M.
AU - Huffman, David W.
N1 - Funding Information:
This project was made possible by several USDA grants (US Forest Service Rocky Mountain Research Station Joint Venture Agreement 28-JV7–939 and USDA-NRI (now AFRI) Grant 02-03807 ), and by financial and administrative support from the Northern Arizona University (NAU), the Ecological Restoration Institute , and NAU School of Forestry’s Mission Research Program . Lastly, we owe a debt of gratitude to the numerous research assistants involved in data collection and lab assistance over the course of this project. Without help from each of you, this would not have been possible. The authors would also like to thank Dr. Thomas Veblen and an anonymous reviewer for helpful feedback on a previous version of this manuscript.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/11/15
Y1 - 2017/11/15
N2 - Natural ranges of ecosystem variability (NRVs) describe the array of conditions and processes common to relatively intact or natural ecosystems, and are used to help land managers plan ecological restoration efforts and better understand ecosystem dynamics. In an effort to describe the variation in forest reference conditions and NRVs related to forest structure and spatial pattern across the American Southwest (Arizona and New Mexico, USA) prior to widespread fire exclusion (ca. late 1800s), we used historical inventory data and dendrochronology to reconstruct 33 Pinus ponderosa-dominated sites (0.8–3.2 ha in size) throughout the region. Though the historical stand densities, species compositions, tree spatial patterns, and modern increases in density varied widely among sites, site-level differences could partially be explained by abiotic factors and by forest type. Soil parent material and US Forest Service Terrestrial Ecosystem Units (TEUs) were important predictors of historical stand density, and species composition was a significant predictor of spatial pattern on our sites, with sites dominated by Pinus ponderosa and Quercus gambelii showing more distinct clustering of overstory trees. Reconstructed stand density (live trees ha−1) was also correlated with the proportion of trees found in groups. Lastly, the sites showing the smallest increases in stand density tended to be in the warmest, driest locations studied, suggesting that densities in these types of sites may be climatically limited and have changed comparatively less since the late 1800s.
AB - Natural ranges of ecosystem variability (NRVs) describe the array of conditions and processes common to relatively intact or natural ecosystems, and are used to help land managers plan ecological restoration efforts and better understand ecosystem dynamics. In an effort to describe the variation in forest reference conditions and NRVs related to forest structure and spatial pattern across the American Southwest (Arizona and New Mexico, USA) prior to widespread fire exclusion (ca. late 1800s), we used historical inventory data and dendrochronology to reconstruct 33 Pinus ponderosa-dominated sites (0.8–3.2 ha in size) throughout the region. Though the historical stand densities, species compositions, tree spatial patterns, and modern increases in density varied widely among sites, site-level differences could partially be explained by abiotic factors and by forest type. Soil parent material and US Forest Service Terrestrial Ecosystem Units (TEUs) were important predictors of historical stand density, and species composition was a significant predictor of spatial pattern on our sites, with sites dominated by Pinus ponderosa and Quercus gambelii showing more distinct clustering of overstory trees. Reconstructed stand density (live trees ha−1) was also correlated with the proportion of trees found in groups. Lastly, the sites showing the smallest increases in stand density tended to be in the warmest, driest locations studied, suggesting that densities in these types of sites may be climatically limited and have changed comparatively less since the late 1800s.
KW - Abiotic factors
KW - American Southwest
KW - Dendrochronology
KW - Historical reconstruction
KW - NRV
KW - Ponderosa pine
KW - Spatial ecology
KW - Species composition
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U2 - 10.1016/j.foreco.2017.09.012
DO - 10.1016/j.foreco.2017.09.012
M3 - Article
AN - SCOPUS:85029179549
SN - 0378-1127
VL - 404
SP - 316
EP - 329
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -