Description: Data represent yellow-cedar decline. The data were collected via aerial sketch mapping techniques and recorded on 1:250,000 USGS base maps from 500-3000 foot above ground level(AGL) observations. Survey coverage has been most intense for forests adjacent to shorelines and waterways. Data are collected, refined and updated on an annual basis. This data represent not one year's mortality but the cumulative effect seen from the air. For more information on this dataset, refer to the full report: https://www.fs.fed.us/pnw/pubs/pnw_gtr917.pdf
Copyright Text: Hennon, P. E., McKenzie, C. M., D'Amore, D., Wittwer, D. T., Mulvey, R. L., Lamb, M. S., Biles, F. E., and Cronn, R. C. (2016). A climate adaptation strategy for conservation and management of yellow-cedar in Alaska. https://www.fs.fed.us/pnw/pubs/pnw_gtr917.pdf
Description: The yellow-cedar distribution map that we developed is a major revision of the geographic occurrence of yellow-cedar in Alaska and throughout its range since publication of the Atlas of United States Trees (Little 1971). The new rangewide yellow-cedar map and the components used to build it are described in detail in section 1. The Alaska portion is outlined briefly here as it is the basis for the assessment of yellow-cedar habitat suitability and risk of decline presented in this section.
The rangewide distribution was developed at a resolution of 240 m, which is the common denominator for all input data sources. Yellow-cedar areas represented
in Prince William Sound and Glacier Bay National Park were derived by using “sketched polygon” methods from boat and aerial surveys. The 240-m rasterized data layer was applied in the respective zones of Glacier Bay, and northwestward for the yellow-cedar suitability/vulnerability predictions. There were either few or no forest inventory plots in these areas to inform a distribution model such as Ellenwood’s for these areas. The Ellenwood model’s 30-m forest parameter data are present only in the southeast Alaska subregion. Therefore, this new data layer (see following) is represented in an aggregated companion dataset at 240 m in order to include the Pacific Coast and south-central Alaska subregions of the Alaskan coastal forest. The Ellenwood 30-m-extent geographic information systems (GIS) layer for yellow-cedar represents the best available predictive source for areas in southeast Alaska south of Glacier Bay and the Haines area. This layer was produced for those pixels where the calculated probability was ≥50 percent; any single isolated pixels were removed and filled in. Those results were then buffered by two pixels and applied as representing yellow-cedar presence in the respective zones south of, but
not including, Glacier Bay and Haines for the yellow-cedar suitability/vulnerability
predictions.
More information is available in the full report: https://www.fs.fed.us/pnw/pubs/pnw_gtr917.pdf
Copyright Text: Hennon, P. E., McKenzie, C. M., D'Amore, D., Wittwer, D. T., Mulvey, R. L., Lamb, M. S., Biles, F. E., and Cronn, R. C. (2016). A climate adaptation strategy for conservation and management of yellow-cedar in Alaska. https://www.fs.fed.us/pnw/pubs/pnw_gtr917.pdf
Description: FHTET has completed the 2013 - 2027 National Insect and Disease Risk Map (2012 NIDRM); a nationwide strategic assessment and database of the potential hazard for tree mortality due to major forest insects and diseases. The goal of NIDRM is to summarize landscape-level patterns of potential insect and disease activity, consistent with the philosophy that science-based, transparent methods should be used to allocate pest-management resources across geographic regions and individual pest distributions. In other words: prioritize investment for areas where both hazard is significant and effective treatment can be efficiently implemented. As part of this analysis, host tree species were mapped nationwide. This dataset was created by combining all of the tree species together into a single layer for Alaskan forests. This has a lower tree-per-acre definition than other tree layers, so it shows a broader area of forest cover (including shrublands dominated by willow and alder).
Copyright Text: Krist et al. 2014. National Insect and Disease Forest Risk Assessment. USDA Forest Service Forest Health Technology Enterprise Team. FHTET-14-01. Ft Collins Colorado. Downloaded from https://www.fs.fed.us/foresthealth/technology/nidrm.shtml.