Richard Burnham Lanman

Many governmental and non-governmental organizations are planting trees, often in developing countries where costs are lower, to offset carbon emissions in industrial countries and slow global warming. These efforts often fail to achieve carbon sequestration goals, frequently related to the selection of unsuitable planting sites, use of tree species with inadequate biomass or vulnerability to wildfire. Reforestation of the world’s tallest trees, which attain heights above 80 m and standing biomasses orders of magnitude greater than other trees, could optimize removal of atmospheric carbon. Wildfires have consumed almost 30% of California’s forests since 2000. To optimize carbon sequestration by tree planting in Santa Clara County, California, we selected coast redwoods, a tree species that is highly resilient to fire, rapidly accumulates the largest biomass of any tree in the world, has exceptional longevity, and is historically native to the westernmost portion of the county, where they support a unique ecosystem. Because historical redwoods range maps are conflicting, and because global warming may change the range of suitable habitat, we developed a machine learning model to determine optimal habitat available for reforestation. The optimal habitat identified included the current and known historical coast redwood forest and excluded lands with no historical records of redwoods, validating model accuracy. The opportunity to capture and store atmospheric carbon dioxide (CO ₂ ) is significant, as the model found 33,969 ha (131 mi ² ) of optimal redwood habitat, of which nearly 77% [26,051 ha (101 mi ² )] currently has no conifer cover. Restoring the historical coast redwood forest in this single county alone could sequester 2.3% of the entire State of California’s 2020 carbon emissions. Similar studies should be conducted in ocean-adjacent counties which likely have order of magnitude greater optimal coast redwood planting areas than inland Santa Clara County, with correspondingly greater potential carbon sequestration impacts.

Elk (Cervus canadensis) have been considered non-native to the Sierra Nevada mountain range of California and Nevada. However, elk have steadily increased their range southward from the Cascade Range into the northern Sierra Nevada over the last century. Recent reports also reveal Rocky Mountain elk moving northwards into the southern Sierra Nevada. Dispersals of lone bull elk from 2019–2022 have occurred to the central Sierra Nevada south of Lake Tahoe. These recent range expansions of elk herds and long-distance dispersals of individual elk raised questions about the possible historical presence of elk throughout this mountain range. Herein we conducted a broad investigation into historical newspaper accounts and other early explorer and naturalist observer records, museum specimens, Late Holocene zooarchaeological records, and indirect evidence including toponomastic references and Native American ethnographic and ethnolinguistic information. Taken in total, a variety of data sources suggest elk inhabited portions of the Sierra Nevada and the adjacent northwest Great Basin from the Late Holocene through historical times. Positive records were not numerous, suggesting that historically elk were not abundant, and nearly extirpated during the California Fur Rush of the early nineteenth century.

FULL RESEARCH ARTICLE Thomas Connor1,2, Thomas J. Batter2, Cristen O. Langner3, Jeff Cann4, Cynthia McColl5, and Richard B. Lanman5,6* 1 University of California, Berkeley, Department of Environmental Science, Policy, and Management, 130 Mullford Hall #3114, Berkeley, CA 94720, USA https://orcid.org/0000-0002-7630-51562 California Department of Fish and Wildlife, Wildlife Branch, Game Conservation Program, 1010 Riverside Parkway, West…

Molecular profiling of circulating tumor DNA (ctDNA) is a promising noninvasive tool. Here, next-generation sequencing (NGS) of blood-derived ctDNA was performed in patients with advanced colorectal cancer. We investigated ctDNA-derived genomic alterations, including potential actionability, concordance with tissue NGS, and serial dynamics in 78 patients with colorectal cancer using a clinical-grade NGS assay that detects single nucleotide variants (54–73 genes) and selected copy-number variants, fusions, and indels. Overall, 63 patients [80.8% (63/78)] harbored ctDNA alterations; 59 [75.6% (59/78)], ≥1 characterized alteration (variants of unknown significance excluded). All 59 patients had actionable alterations potentially targetable with FDA-approved drugs [on-label and/or off-label (N = 54) or with experimental drugs in clinical trials (additional five patients); University of California San Diego Molecular Tumor Board assessment]: 45, by OncoKB (http://oncokb.org/#/). The tissue and blood concordance rates for common specific alterations ranged from 62.3% to 86.9% (median = 5 months between tests). In serial samples from patients on anti-EGFR therapy, multiple emerging alterations in genes known to be involved in therapeutic resistance, including KRAS, NRAS, BRAF, EGFR, ERBB2, and MET were detected. In conclusion, over 80% of patients with stage IV colorectal cancer had detectable ctDNA, and the majority had potentially actionable alterations. Concordance between tissue and blood was between 62% and 87%, despite a median of 5 months between tests. Resistance alterations emerged on anti-EGFR therapy. Therefore, biopsy-free, noninvasive ctDNA analysis provides data relevant to the clinical setting. Importantly, sequential ctDNA analysis detects patterns of emerging resistance allowing for precision planning of future therapy.

Additional results for dual probe EGFR and ERBB2 FISH from Patients 9, 30 and 32.