Culebra Range of the Sangre de Cristo Mountains, Colorado. Sample Collection: Ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), Bristlecone pine (Pinus aristate), and Limber pine (Pinus flexilis) living in lower and upper montane slopes of the Culebra Range (~Latitude 37˚N, ~Longitude -105˚W WGS84). The Fire-Climate-Human NGGDPP archive collection was obtained in two separate field campaigns. 1) CSU/USFS-led Bar-NI Fire History (Huckaby and Fornwalt, 2001). Sixty-six fire scar cross-sections were collected using a hand saw or chain saw from living, standing dead, and remnant wood at Bar-NI Ranch (37.15°N, -105.02°W). 2) USGS-led fire history (Brice and Kehrwald, 2023). Twenty-two fire scar cross-sections were collected using a hand saw or chain saw from living, standing dead, and remnant wood at Trinchera Ranch (37.41°N, -105.37°W). Samples were processed following standard dendrochronological methods, including sample surface preparation and visual cross-dating. The annual ring-widths were measured to 0.001mm precision from the digital imagery using Coorecorder measuring software. Visual crossdating was verified statistically using the ring-width measurements in the program COFECHA v.6.06P. Measurement data are not available for cross-sections with tree-growth complacency or hypersensitivity precluding robust statistical crossdating. Ring-width analysis results of these collections have not been published. These tree cross-sections now require preservation. Currently, the physical samples are too large to share outside the project location. To overcome this challenge, 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 dataset includes processed tree ring data from avalanche paths throughout Colorado, USA. The data were processed in three distinct phases that resulted in this dataset: collection, processing, and avalanche signal analysis. This dataset consists of samples from 1188 cross-sections and increment cores from 1023 individual trees within 24 avalanche paths across the region. From these samples 4135 probable avalanche related growth disturbances were identified.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Fire. The data include parameters of fire history|tree ring with a geographic location of New Mexico, United States Of America. The time period coverage is from 396 to -40 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

These data were compiled for research pertaining to the effects of stand density on growth rates in semi-arid forests. Increasing heat and aridity in coming decades is expected to negatively impact tree growth and threaten forest sustainability in dry areas. Maintaining low stand density has the potential to mitigate the negative effects of increasingly severe droughts by minimizing competitive intensity. By inspecting growth rates and the climate and soil moisture conditions that drive these growth rates we can understand better the positive effects of reducing stand density and the specific dynamics that are beneficial to growth.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Fire. The data include parameters of fire history|tree ring with a geographic location of New Mexico, United States Of America. The time period coverage is from 377 to 8 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Fire. The data include parameters of fire history|tree ring with a geographic location of Colorado, United States Of America. The time period coverage is from 821 to -46 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Fire. The data include parameters of fire history|tree ring with a geographic location of California, United States Of America. The time period coverage is from 450 to -47 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

This dataset contains two phases of research. The first dataset includes several variables that were sampled across aspen stands in the Santa Rosa, Ruby, and Jarbidge mountain ranges (Great Basin, Northern Nevada, USA) in 2010 and 2011. Across 101 aspen sites, several plot-level attributes were collected (e.g. elevation, slope, aspen stand type). For each plot, data describing live trees (both those less than 7.5 cm diameter and those greater than/equal to 7.5 cm) are included, such as species, diameter, and age. The data set also includes information for dead trees greater than/equal to 7.5 cm diameter (e.g. species, location, diameter). The second dataset includes tree ring measurements (for live trees greater than/equal to 7.5 cm diameter) and monthly climate data for a subset of sites (n = 20) that were included in the first phase. For this subset of 20 sites, we analyzed the relationship between tree ring width measurements and climate variables. The climate variables represent monthly total precipitation, average temperature, and climatic moisture index values by year for the period of record.