Susan J. Smith - Academia.edu (original) (raw)

Papers by Susan J. Smith

Quaternary Research, 2002

Analysis of a buried deposit in the Diamond Valley of southern California has revealed well-prese... more Analysis of a buried deposit in the Diamond Valley of southern California has revealed well-preserved pollen, wood, and diatom remains. Accelerator mass spectrometry dates of 41,200±2100 and 41,490±1380 14C yr B.P. place this deposit in marine isotope stage 3. Diatoms suggest a shallow lacustrine environment. Pollen data suggest that several plant communities were present near the site, with grassland, scrub, chaparral, forest, and riparian communities represented. Comparison with modern pollen suggests similarities with montane forests in the nearby San Bernardino and San Jacinto ranges, indicating vegetation lowering by at least 900 m elevation and temperatures 4°–5°C cooler than today. An increase in high-elevation conifer pollen documents climatic cooling near the profile top. Early-profile diatoms are typical of warm water with high alkalinity and conductivity, whereas later diatoms suggest a higher flow regime and input of cooler water into the system. We suggest that the sequ...

Nature, 2011

In this Letter, the affiliations for authors Jaime Toney, Julianna Fessenden and Giday WoldeGabri... more In this Letter, the affiliations for authors Jaime Toney, Julianna Fessenden and Giday WoldeGabriel were listed incorrectly. The correct affiliations for all authors are as shown here.

Madroño, 2008

A long-term history of water table fluctuations, from alternating periods of drought and abundant... more A long-term history of water table fluctuations, from alternating periods of drought and abundant precipitation, can be preserved in the stratigraphy of wetland sediments. We examined the middle to late Holocene history of vegetation and climate change from a small wetland on the Modoc Plateau in Shasta County, northeastern California. This site is at a transition between the Great Basin and the Californian Floristic Provinces, and the paleoecological record from Flycatcher Basin exhibits affinities to both. Although the sedimentary record extends back to ca. 8300 cal yr BP, organic sediment did not form until ca. 4500 cal yr BP, indicating that water was probably absent in the basin during the middle Holocene. Pollen and plant macrofossils deposited after 4500 cal yr BP suggests a mixed conifer-Quercus forest grew around Flycatcher Basin. Charcoal is abundant in these sediments, indicating periodic forest fire. Distinctly modern forests developed by about 2200 cal yr BP, when Pinus became the dominant conifer with Quercus, in a more closed forest, perhaps with more frequent fire. The record from Flycatcher Basin provides no evidence for change in the boundaries between the Great Basin and California (Cascadian) floristic provinces during the period of record. The late Holocene is interpreted as a generally increasingly mesic sequence, with a long-term increase in groundwater recharge, yet interspersed by extended drought during the last 2000 yr. Extended droughts occurred from ca.

Journal of Archaeological Science, 2008

Credible interpretation of pollen recovered from archaeological sites hinges upon understanding h... more Credible interpretation of pollen recovered from archaeological sites hinges upon understanding how pollen becomes deposited by both the environment and human behavior. The environmental role has been studied to some extent, but how the activities of people have formed the pollen assemblages at archaeological sites is usually just assumed rather than considered explicitly. Moreover, the complexity involved in the interaction between human behavior and pollen ecology is seldom considered. An archaeological case study of grinding tool pollen washes highlights the ambiguities of standard practice because the results confound common assumptions about pollen washes. A series of experimental seed and grinding tool washes designed to test the relationships between the processing of seeds and the deposition of pollen help explain why, for most situations, artifact pollen washes do not provide direct or even faithful records of plant processing. These results highlight the need for further experimental research with pollen so that we are warranted in making behavioral inferences from palynology. This conclusion is easily extended to other microbotanical data classes that archaeologists regularly employ.

Forest Ecology and Management, 2010

The frequency and intensity of ecosystem disturbance, including outbreaks of forest insects and f... more The frequency and intensity of ecosystem disturbance, including outbreaks of forest insects and forest fires, is expected to increase in the future as a result of higher temperatures and prolonged drought. While many studies have concentrated on the future climatic impacts on fire, little is known about the impact of future climate on insect infestation. Paleoecological techniques are important in this regard in identifying the potential relationships between climate and insect outbreaks in the past, as a predictive tool for the future. We examine a high-resolution 20th century record of spruce beetle (Dendroctonus rufipennis) infestation from a small, subalpine lake, comparing the paleoecological record to the historical and treering record of the event. An extensive spruce beetle outbreak occurred in northwestern Colorado during the 1940s and 1950s, causing widespread mortality of mature Picea engelmannii. Pollen analysis of this period documents the decline of Picea and its replacement locally by Abies lasiocarpa, paralleling age and composition studies of modern forest stands in the region. This study is a proof of concept that, when applied to longer sedimentary records, could produce a detailed record of infestation for the Late Holocene or older time periods. This information will be useful to forest managers in efforts to plan for the effects of D. rufipennis infestations, and subsequent succession within high elevation conifer forests.

The Water Canyon Paleoindian site near Socorro, New Mexico is directly associated with an extensi... more The Water Canyon Paleoindian site near Socorro, New Mexico is directly associated with an extensive buried wet meadow deposit. While extant across the Pleistocene – Holocene transition and into the middle Holocene, this landscape-scale deposit arguably represented a persistent, regional wetland resource, not only for plants and animals, but Paleoindian groups as well. Today it represents an important proxy data archive for environmental, climatic and archaeological reconstruction. Our recent research efforts at the site have focused largely on the period from 8300 to 9600 radiocarbon years ago, and have generated dated pollen profiles, stable carbon isotope data sets, charcoal species identifications and both faunal and macrobotanical remains. These findings provide us with provocative glimpses into the environment, climate, bison ecology, and human diet during Late Paleoindian times.

Quaternary Research, 2002

Analysis of a buried deposit in the Diamond Valley of southern California has revealed well-prese... more Analysis of a buried deposit in the Diamond Valley of southern California has revealed well-preserved pollen, wood, and diatom remains. Accelerator mass spectrometry dates of 41,200±2100 and 41,490±1380 14C yr B.P. place this deposit in marine isotope stage 3. Diatoms suggest a shallow lacustrine environment. Pollen data suggest that several plant communities were present near the site, with grassland, scrub, chaparral, forest, and riparian communities represented. Comparison with modern pollen suggests similarities with montane forests in the nearby San Bernardino and San Jacinto ranges, indicating vegetation lowering by at least 900 m elevation and temperatures 4°–5°C cooler than today. An increase in high-elevation conifer pollen documents climatic cooling near the profile top. Early-profile diatoms are typical of warm water with high alkalinity and conductivity, whereas later diatoms suggest a higher flow regime and input of cooler water into the system. We suggest that the sequ...

Nature, 2011

In this Letter, the affiliations for authors Jaime Toney, Julianna Fessenden and Giday WoldeGabri... more In this Letter, the affiliations for authors Jaime Toney, Julianna Fessenden and Giday WoldeGabriel were listed incorrectly. The correct affiliations for all authors are as shown here.

Madroño, 2008

A long-term history of water table fluctuations, from alternating periods of drought and abundant... more A long-term history of water table fluctuations, from alternating periods of drought and abundant precipitation, can be preserved in the stratigraphy of wetland sediments. We examined the middle to late Holocene history of vegetation and climate change from a small wetland on the Modoc Plateau in Shasta County, northeastern California. This site is at a transition between the Great Basin and the Californian Floristic Provinces, and the paleoecological record from Flycatcher Basin exhibits affinities to both. Although the sedimentary record extends back to ca. 8300 cal yr BP, organic sediment did not form until ca. 4500 cal yr BP, indicating that water was probably absent in the basin during the middle Holocene. Pollen and plant macrofossils deposited after 4500 cal yr BP suggests a mixed conifer-Quercus forest grew around Flycatcher Basin. Charcoal is abundant in these sediments, indicating periodic forest fire. Distinctly modern forests developed by about 2200 cal yr BP, when Pinus became the dominant conifer with Quercus, in a more closed forest, perhaps with more frequent fire. The record from Flycatcher Basin provides no evidence for change in the boundaries between the Great Basin and California (Cascadian) floristic provinces during the period of record. The late Holocene is interpreted as a generally increasingly mesic sequence, with a long-term increase in groundwater recharge, yet interspersed by extended drought during the last 2000 yr. Extended droughts occurred from ca.

Journal of Archaeological Science, 2008

Credible interpretation of pollen recovered from archaeological sites hinges upon understanding h... more Credible interpretation of pollen recovered from archaeological sites hinges upon understanding how pollen becomes deposited by both the environment and human behavior. The environmental role has been studied to some extent, but how the activities of people have formed the pollen assemblages at archaeological sites is usually just assumed rather than considered explicitly. Moreover, the complexity involved in the interaction between human behavior and pollen ecology is seldom considered. An archaeological case study of grinding tool pollen washes highlights the ambiguities of standard practice because the results confound common assumptions about pollen washes. A series of experimental seed and grinding tool washes designed to test the relationships between the processing of seeds and the deposition of pollen help explain why, for most situations, artifact pollen washes do not provide direct or even faithful records of plant processing. These results highlight the need for further experimental research with pollen so that we are warranted in making behavioral inferences from palynology. This conclusion is easily extended to other microbotanical data classes that archaeologists regularly employ.

Forest Ecology and Management, 2010

The frequency and intensity of ecosystem disturbance, including outbreaks of forest insects and f... more The frequency and intensity of ecosystem disturbance, including outbreaks of forest insects and forest fires, is expected to increase in the future as a result of higher temperatures and prolonged drought. While many studies have concentrated on the future climatic impacts on fire, little is known about the impact of future climate on insect infestation. Paleoecological techniques are important in this regard in identifying the potential relationships between climate and insect outbreaks in the past, as a predictive tool for the future. We examine a high-resolution 20th century record of spruce beetle (Dendroctonus rufipennis) infestation from a small, subalpine lake, comparing the paleoecological record to the historical and treering record of the event. An extensive spruce beetle outbreak occurred in northwestern Colorado during the 1940s and 1950s, causing widespread mortality of mature Picea engelmannii. Pollen analysis of this period documents the decline of Picea and its replacement locally by Abies lasiocarpa, paralleling age and composition studies of modern forest stands in the region. This study is a proof of concept that, when applied to longer sedimentary records, could produce a detailed record of infestation for the Late Holocene or older time periods. This information will be useful to forest managers in efforts to plan for the effects of D. rufipennis infestations, and subsequent succession within high elevation conifer forests.

The Water Canyon Paleoindian site near Socorro, New Mexico is directly associated with an extensi... more The Water Canyon Paleoindian site near Socorro, New Mexico is directly associated with an extensive buried wet meadow deposit. While extant across the Pleistocene – Holocene transition and into the middle Holocene, this landscape-scale deposit arguably represented a persistent, regional wetland resource, not only for plants and animals, but Paleoindian groups as well. Today it represents an important proxy data archive for environmental, climatic and archaeological reconstruction. Our recent research efforts at the site have focused largely on the period from 8300 to 9600 radiocarbon years ago, and have generated dated pollen profiles, stable carbon isotope data sets, charcoal species identifications and both faunal and macrobotanical remains. These findings provide us with provocative glimpses into the environment, climate, bison ecology, and human diet during Late Paleoindian times.