HMU polygons were delineated into broad land cover types based on high resolution orthophotos, flown in 2009, provided by The City of Everett. A ground field reconnaissance was then conducted where forest condition attributes were observed and entered into a database. Collected attributes include forest health variables which indicate the presence of low vigor, mechanical tree failure, root rot, mistletoe, and bare soil. Other fields hold the species and size class of the dominant, secondary and tertiary overstory species, tree stocking, regeneration species, groundcover, and the prevalence (from most common to fifth-most common) of invasive species. For the tree-iage analysis, each HMU was assigned a value (High, Medium, or Low) for current tree composition and for the level of invasive species present. Adjustments to HMU boundaries were also made by the field surveyor.

The field data was edited for completeness and accuracy. The field data table was joined to the revised HMU polygon feature class. A tree-iage matrix threat value from 1 to 9 was calculated. Matrix value 98 = open water, and 99 = hardscape or landscape.

The dataset is stored as an ESRI personal geodatabase. Lookup tables describing attribute data are contained in the geodatabase.

The assessment was performed in October 2012 under contract to Forterra by International Forestry Consultants, Inc., a subsidiary of American Forest Management, Inc.