Dendrochronological collections during the career of USGS emeritus, Paul Carrara: Douglas-fir (Pseudotsuga menziesii), Black cottonwood (Populus trichocarpa), Spruce (Picea), Shore pine (Pinus contorta contorta), Willow (Salix), Bristlecone pine (Pinus aristate), Engelmann spruce (Picea engelmannii), Aspen (Populus tremuloides), and Limber pine (Pinus flexilis) collections from western North America. The Carrara NGGDPP archive collection is comprised of fifty-two cross-sections obtains for studies of glacial, avalanche, and vegetative histories from Alaska, Montana, and Colorado. Samples were processed following standard dendrochronological methods, including sample surface preparation and annual ring assignment. These tree cross-sections now require preservation. We used high resolution digital photography to capture images of each sample using a system custom designed for digitizing tree rings. Digital images obtained for this archive can then be stored and used by researchers, communities and teachers and students at all education levels.

Dendrochronological collections during the career of USGS emeritus, Paul Carrara: Douglas-fir (Pseudotsuga menziesii), Black cottonwood (Populus trichocarpa), Spruce (Picea), Shore pine (Pinus contorta contorta), Willow (Salix), Bristlecone pine (Pinus aristate), Engelmann spruce (Picea engelmannii), Aspen (Populus tremuloides), and Limber pine (Pinus flexilis) collections from western North America. The Carrara NGGDPP archive collection is comprised of fifty-two cross-sections obtains for studies of glacial, avalanche, and vegetative histories from Alaska, Montana, and Colorado. Samples were processed following standard dendrochronological methods, including sample surface preparation and annual ring assignment. These tree cross-sections now require preservation. We used high resolution digital photography to capture images of each sample using a system custom designed for digitizing tree rings. Digital images obtained for this archive can then be stored and used by researchers, communities and teachers and students at all education levels.

Dendrochronological collections during the career of USGS emeritus, Paul Carrara: Douglas-fir (Pseudotsuga menziesii), Black cottonwood (Populus trichocarpa), Spruce (Picea), Shore pine (Pinus contorta contorta), Willow (Salix), Bristlecone pine (Pinus aristate), Engelmann spruce (Picea engelmannii), Aspen (Populus tremuloides), and Limber pine (Pinus flexilis) collections from western North America. The Carrara NGGDPP archive collection is comprised of fifty-two cross-sections obtains for studies of glacial, avalanche, and vegetative histories from Alaska, Montana, and Colorado. Samples were processed following standard dendrochronological methods, including sample surface preparation and annual ring assignment. These tree cross-sections now require preservation. We used high resolution digital photography to capture images of each sample using a system custom designed for digitizing tree rings. Digital images obtained for this archive can then be stored and used by researchers, communities and teachers and students at all education levels.

This data release is tree-ring data near Columbine Lake and surrounding region, Grand County, Colorado (Latitude 40.27˚ N, Longitude -105.83˚ E NAD83). Re-collection of four existing tree-ring sites (Hot Sulphur Springs Psuedotsuga menziessii (HSU), Lexan Creek Picea engelmannii (LCU), Monarch Lake Pinus ponderosa (MLU), and Vasquez Mountain Psuedotsuga menziessii (VMU)) was conducted to update data to the most recent years possible and to maximize data overlap with instrumental records and with historical records of fire occurrence. At the time of collection, initial climate-growth relationships were assessed in a network of previously collected tree-ring sites (collected between 1987 and 2003) to determine which sites expressed the strongest climate signal. Climate-growth relationships were then determined anew on each site chronology to visualize how and when trees in the network are responding to climate inputs. High-resolution environmental information from tree rings overlaps with historic and century-scale drought and fire occurrence (Buechling and Baker, 2004). Tree rings are accurately dated to the year, and they provide synoptic-scale climate information and local-scale fire history when multiple site chronologies are used. The tree-ring archive is capable of producing multiple proxies that reflect climate-growth relationships to better understand precipitation form and dynamics in the context of comprehensive long-term winter-spring precipitation reconstructions (Stahle et al. 2003; Torbenson et al. 2016; Chavardes et al. 2020; Coulthard et al. 2021). Tree-ring proxies also reflect distinct physiological "tree-growth mechanisms related to topographic and climatic site conditions. They provide unique information that may be used in combination to refine our understanding of environmental change at Columbine Lake and assess high-resolution environmental pre-conditioning and past occurrence of wildfire similar in scale and/or severity to wildfire in the historic record. Columbine Lake is located at the western boundary of Rocky Mountain National Park near the town of Grand Lake in Grand County, Colorado. It is within the head waters region of the Colorado River, one of the largest river basins in the western United States and a critical water resource for agriculture, municipalities, and ecosystems in seven states and Mexico. To the west of RMNP, the 2020 East Troublesome fire burned directly over the Columbine Lake area destroying 555 structures, killing two people, and expanding into portions of RMNP. The fire is a stark immediate reminder of the potential scale and impact of severe wildfire in the Colorado River headwaters. Low severity frequent surface fires that are dependent on extreme drought, as well as infrequent stand-replacing fires in less drought prone forests, are believed to be crucial elements influencing the vegetation in the region (Romme and Despain, 1989; Renkin and Despain, 1992; Buechling and Baker, 2004; Kipfmueller and Baker, 2000). However, there is a significant concern that if temperatures continue to increase with climate change, and droughts become more frequent and severe, the probability of large and destructive fires will also increase. Climate-fire nuances revealed in previous studies illustrate that the relationships between drought and wildfire in forests is more complex than a simple connection between aridity and fire ignition and merit investigation at multiple space and time scales (Littell et al. 2016). While drought primarily drives fire frequency and intensity in Colorado forests, seasonal drought may disproportionately precondition forests for fire in the region (Sherriff et al. 2001). Annual-scale measures of drought may mask the seasonal precipitation connection. However, to our knowledge, no systematic evaluation of the interrelationship of climate and fire has been conducted in the headwaters region of the Upper Colorado River basin using long-term paleo records. Work

This data release is tree-ring data near Columbine Lake and surrounding region, Grand County, Colorado (Latitude 40.27˚ N, Longitude -105.83˚ E NAD83). Re-collection of four existing tree-ring sites (Hot Sulphur Springs Psuedotsuga menziessii (HSU), Lexan Creek Picea engelmannii (LCU), Monarch Lake Pinus ponderosa (MLU), and Vasquez Mountain Psuedotsuga menziessii (VMU)) was conducted to update data to the most recent years possible and to maximize data overlap with instrumental records and with historical records of fire occurrence. At the time of collection, initial climate-growth relationships were assessed in a network of previously collected tree-ring sites (collected between 1987 and 2003) to determine which sites expressed the strongest climate signal. Climate-growth relationships were then determined anew on each site chronology to visualize how and when trees in the network are responding to climate inputs. High-resolution environmental information from tree rings overlaps with historic and century-scale drought and fire occurrence (Buechling and Baker, 2004). Tree rings are accurately dated to the year, and they provide synoptic-scale climate information and local-scale fire history when multiple site chronologies are used. The tree-ring archive is capable of producing multiple proxies that reflect climate-growth relationships to better understand precipitation form and dynamics in the context of comprehensive long-term winter-spring precipitation reconstructions (Stahle et al. 2003; Torbenson et al. 2016; Chavardes et al. 2020; Coulthard et al. 2021). Tree-ring proxies also reflect distinct physiological "tree-growth mechanisms related to topographic and climatic site conditions. They provide unique information that may be used in combination to refine our understanding of environmental change at Columbine Lake and assess high-resolution environmental pre-conditioning and past occurrence of wildfire similar in scale and/or severity to wildfire in the historic record. Columbine Lake is located at the western boundary of Rocky Mountain National Park near the town of Grand Lake in Grand County, Colorado. It is within the head waters region of the Colorado River, one of the largest river basins in the western United States and a critical water resource for agriculture, municipalities, and ecosystems in seven states and Mexico. To the west of RMNP, the 2020 East Troublesome fire burned directly over the Columbine Lake area destroying 555 structures, killing two people, and expanding into portions of RMNP. The fire is a stark immediate reminder of the potential scale and impact of severe wildfire in the Colorado River headwaters. Low severity frequent surface fires that are dependent on extreme drought, as well as infrequent stand-replacing fires in less drought prone forests, are believed to be crucial elements influencing the vegetation in the region (Romme and Despain, 1989; Renkin and Despain, 1992; Buechling and Baker, 2004; Kipfmueller and Baker, 2000). However, there is a significant concern that if temperatures continue to increase with climate change, and droughts become more frequent and severe, the probability of large and destructive fires will also increase. Climate-fire nuances revealed in previous studies illustrate that the relationships between drought and wildfire in forests is more complex than a simple connection between aridity and fire ignition and merit investigation at multiple space and time scales (Littell et al. 2016). While drought primarily drives fire frequency and intensity in Colorado forests, seasonal drought may disproportionately precondition forests for fire in the region (Sherriff et al. 2001). Annual-scale measures of drought may mask the seasonal precipitation connection. However, to our knowledge, no systematic evaluation of the interrelationship of climate and fire has been conducted in the headwaters region of the Upper Colorado River basin using long-term paleo records. Work

Nothophaeocryptopus gaeumannii is a common native, endophytic fungus of Douglas-fir foliage, which causes Swiss needle cast, an important foliage disease that is considered a threat to Douglas-fir plantations in Oregon. Disease expression is influenced by fungal fruiting bodies (pseudothecia), which plug the stomata and inhibit gas exchange. We measured foliar retention and the density of pseudothecia occluding stomates across 2- to 5-year-old needles from upper, middle and lower canopy positions of mature trees at three sites in the Oregon Coast Range and two sites in the western Oregon Cascade Mountains. This dataset is associated with the following publication: Shaw, D.C., G. Ritóková, Y. Lan, D.B. Mainwaring, A. Russo, R. Comeleo, S. Navarro, D. Norlander, and B. Smith. Persistence of the Swiss Needle Cast Outbreak in Oregon Coastal Douglas-fir, and New Insights from Research and Monitoring. JOURNAL OF FORESTRY. Society of American Foresters, Bethesda, MD, USA, 119(4): 407-421, (2021).

Swiss needle cast foliar retention metrics. This dataset is associated with the following publication: Lan, Y., D.C. Shaw, E. Lee, and P. Beedlow. Distribution of a foliage disease fungus within canopies of mature Douglas-fir in western Oregon. Frontiers in Forests and Global Change. Frontiers, Lausanne, SWITZERLAND, 5: 743039, (2022).

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