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SINCE 1895

Abstract. Before settlement, tiny Yellow Island was exploited by Native Americans for camas and other food plants. Intentional burning kept ingrowth of conifers in check. In recent years the island has become valued for its meadows of wildflowers, but over time the meadows have become encroached by trees and large shrubs. Recent management efforts have begun to reduce such growth.

     One way to document changes in large vegetation is by historic photographs, maps and descriptions. This report introduces previously unappreciated historic documents from 1895 into this analysis of vegetation change of Yellow Island. Based on the new findings, removal of large trees and shrubs has restored the island's area of tree-cover to that of 1946 but not yet to the condition existing prior to settlement.


 pages about
forest history

The Presettlement Forest

Lost & Found Prairie

Impact of the Lime Industry

Late 19th-Century Landcover

Bigfoot's Forest (in prep)

Early Forest Composition


     Yellow Island, San Juan County, WA, is currently owned by The Nature Conservancy (TNC), who actively manages its vegetative land cover through restoration plantings, plant removal, and occasional prescribed burning in order to favor some species over others. In part, TNC's management efforts are informed by an understanding of the conditions and processes that existed prior to Euro-American settlement in the archipelago. It is well to recall that such non-native settlement of the San Juans began in earnest only after the General Land Office survey of 1874 (which omitted Yellow Island). Until the mid-1900s, settlement impact on Yellow Island was indirect, namely by cessation of native visitations. Present and historic conditions on Yellow Island were systematically studied by Agee and Dunwiddie (1984). They inventoried the plant communities, performed age analyses on trees, and documented evidence of past fires based on fire scars. Certain conclusions in that study about the sparseness of the pre-settlement forest were corroborated by a lone 1909 photograph from McConnell Island.

     Recently three unpublished images of Yellow Island, all dated 1895, were discovered and retrieved from the National Archives. They include a detailed land-cover map called a T-sheet and two associated photographs, which together constitute the earliest direct documentation of the island's large vegetation. These new images now assist in the on-going efforts to document and understand the vegetation dynamics on Yellow Island.


     T-2229 is one of fifteen manuscript topographic sheets from 1888-1897 covering all of the San Juan Islands (Fig. 1). They were prepared by J.J. Gilbert of the U.S. Coast and Geodetic Survey, based on plane-table surveying technology (Fig. 2). These exquisitely detailed documents represent the earliest systematic documentation of the topography, land-cover, and cultural features of the San Juans. Yellow Island appears on T-sheet #2229, which was drafted in 1895 (USC&GS, 1895a) (Fig. 3); the N-S axis is tilted 40° in order to fit the area of coverage onto a sheet of tracing fabric measuring 2.7 by 4.8 ft.

     T-sheets for the San Juans were never published or circulated, so they are little known today and their rich historic content has remained unexamined. Steps to gain broader accessibility began in 2000 when the original T-sheets of the San Juans were photocopied at full scale at the National Archives and Records Administration (NARA II) in College Park, MD. The retrieved hardcopies were then electronically scanned at 400 ppi and eventually posted on the World Wide Web (WSU, 2002). On the full-size T-sheet #2229 (Fig. 3) the 1800-ft long axis of Yellow Island measures about

2.25 in, and numerous topographical features are indicated. The island's intertidal character is depicted as rocky and sandy; and the distribution of offshore kelp beds is also indicated. Inland relief is marked by topographic lines at 20-ft intervals.At the island's highest point (about 60 ft) a dotted triangle indicates a triangulation station used in the survey; it is identified as Signal Goose. Another triangulation point at the NE point is not marked but is identified as Signal Yellow (Fig. 4). At such triangulation points braced poles were erected and typically 2-in holes were bored in the rock as lasting locators; the surveying crew likely passed some hours at these locations to make plane-table triangulations and to record and render observations. Signals Goose and Yellow would have afforded reasonable views of most of the vegetation on the island in 1895.

     In Figure 3, vegetative land cover is depicted by standard cartographic symbols: splays of upright ticks for grass, C-shaped marks for deciduous vegetation (usually meaning trees or large shrubs), and 5-lined stars for coniferous trees. These hand-drawn symbols may signify individual trees or clusters of such vegetation. Most of the ~23 symbols for conifers form an array coursing from SSW to NNE across the middle of the island; a cluster of three stars is located at the NE point and single stars are located near the western point and just north of Signal Goose. Most of the symbols for deciduous trees are scattered over the western half of the island.

     Along with his surveying activity that produced the T-sheets,  J.J. Gilbert also prepared hand-written narrative reports with each T-sheet, and some of those included landscape photographs or drawings. Two photographic images of Yellow Island printed by a brown bromide-process were pasted into the Descriptive Report for T-2229 (USC&GS,1895b).

     At NARA II in May, 2002, the original prints were electronically scanned at 300 ppi in black and white; the versions presented here have been digitally enhanced and sepia-tinted. The photographic negatives have not been located.
     The view point of one scene (Fig. 4) is from the surveyors' boat in Middle Channel between San Juan and Yellow Islands. A note indicates that the view is to the NE, but it is more likely ESE, in which case Shaw Island is the landmass in the background. The view point of the second photograph (Fig. 5a,b) is from Neck Point, Shaw Island, nearly a mile from Yellow Island, and is oriented WNW; San Juan Island and other marked islands lie in the background; it has been rephotographed (Fig. 5c and d).

    The two 7-inch wide photographic prints included with the narrative report for Yellow Island in the Descriptive Report for T-2229 are reproduced at slight reductions in Figures 4a and 5a. Signals Yellow and Goose are clearly indicated by braced white poles in Figure 4; Signal Yellow is barely discernible on the right in Figure 5. Image quality is sufficient, especially in the enlargements, to reveal that ~23 coniferous trees occupied the island in 1895; most were modest in stature, four or five were quite tall, and one was a tall snag. Shrubs and small trees are also indicated but cannot be clearly identified. A brief text entry (below) by J.J. Gilbert in Descriptive Report T-2229 supports impressions of the island's vegetation gained from the photographs and T-sheet:

"Yellow Island.­the westernmost of the Wasp Islands, and locally known as Goose Island, is rocky and rather sparcely (sic) covered with willow and other brush and a few scattering fir trees. Off the west end are several reefs, mostly covered at low tide. There is anchorage for a launch or other small craft on the north side of the spit at west end of island." (USC&GS, 1895b, p. 9; emphasis added).

     According to J.J. Gilbert's narrative description, the associated photographs, and the cartographic details of T-sheet #2229, the large vegetation of Yellow Island in 1895 was sparse, composed of both deciduous and coniferous forms, and located primarily near the center of the island. The recently rephotographed profile of the island from Shaw Island (Fig. 5c) illustrates some of the changes in large vegetation that have occurred over a span of 107 years. Compared to 1895, the average forest canopy (or "skyline") is now taller, the forest zone is broader and denser in terms of foliage and number of trees, and large spherical masses of opaque foliage indicative of deciduous forms are prominent today, at least facing the SE. The tallest trees in 1895 and 2002 are about the same height, but the number of tall trees is now greater. The tall snag a century ago and the solitary tall tree at the right in Figure 5b are no longer present.

Figure 6. Aerial photographs of Yellow Island from 1946 to 2006. Images are sized to correspond to Figure 3. N-S axis is vertical in (a), (b), and (d).

     Further insights into vegetation changes might benefit from comparisons with additional images, for example, from times between 1895 and the present. Figure 6a depicts vegetation on Yellow Island in 1946, which is a published aerial photograph in the soil survey for San Juan County (USDA, 1962); this published image is admittedly inferior in quality and somewhat obscured by overlays of soil polygons, their designations, and V-shaped symbols signifying rock outcrops.  Dark amorphous images of major vegetation are clearly confined to a swath across the island's middle. Efforts to obtain superior prints of this photograph or to locate its negative were unrewarded.

     Fairly recent aerial photographs, such as from the 1990 WDNR series (Fig. 6b) or the 1995 WDOE series (Fig. 6c), more clearly reveal the present-day distribution of vegetation. According to these images, large vegetation ­ meaning trees and shrubs ­ have expanded laterally from the narrower central swath seen in 1946. Quite recently (Fig. 6d), however, from the online source Digital Globe (see website), the zone occupied by large trees and shrubs has been reduced by aggressive management, that is tree removal.

Figure 7. Summary of zones occupied by major trees and shrubs from 1895 to 2006.

     A rough summary of vegetation changes from 1895 to the present is shown graphically in Figure 7, which is derived from data in Figures 3, and 6a-c. The sequence indicates that up to 1990 the area of forest coverage progressively doubled during each 50-year period by encroaching laterally into grassy meadows. These changes concur with the findings reported by Agee and Dunwiddie (1984). Since 1990, however, thanks to TNC's active management and removal of many trees, the zone occupied by trees has been reduced to the condition that existed in about 1946. Removal of even more trees may be required to restore the vegetation condition reported in the 1895 images, which are here reported for the first time.
Agee, J.K. and P.W. Dunwiddie (1984). Recent forest development on Yellow Island, San Juan County, WA. Can. J. Bot. 65: 2074-2080.

Digital Globe (2006). Online URL: www.
U.S. Coast and Geodetic Survey (1895a). Topographic Sheet No. 2229: Topography of Washington Sound, Wash. Orcas and Other Islands. Section XI, Sheet No. 8 (1:10,000).
National Archives and Records Administration, (Cartographic Division, Record Group 23), College Park, MD.
U.S. Coast and Geodetic Survey (1895b). Descriptive Report, Sheet No. 2229. Topography of Washington Sound (by J.J. Gilbert). National Archives and Records Administration, (Cartographic Division, Record Group 23), College Park, MD. 18 pp; 14 photographs.
U.S. Geological Service (1941). Aerial photographs of San Juan County, Washington (B&W; 1:34,000). (Symbol S, Rolls 1-5, Cans #2985-2989). National Archives and Records Administration, (Cartographic Division, Record Group 23), College Park, MD.
U.S. Department of Agriculture (1962). Soil Survey: San Juan County, Washington (by F.E. Schlots, et al.), 73 pp.

Washington State University (2002). See online URL:, select "Digital Collection," under "Northwest History" select "Early Washington Maps," and finally select
"Historic Maps of San Juan Islands (1887-1895)." By selecting an individual map from the index a thumbnail image will appear. Click on the thumbnail to view an intermediate-size image; to enlarge the image further, first scroll down to the bottom of the thunbnail and click "View Map Image" in order to zoom in for a closer look. Activate the zooming function by clicking on the specific area of map that interests you, but take note ­ at this stage whichever detail of the intermediate-size map is clicked will be the portion that is zoomed. Navigating laterally beyond the zoomed image is not possible, so to move to another zoomed area one must first backtrack to the intermediate image and activate another detail. In 2003 the same T-sheets (including their Descriptive Reports) were posted on another URL: ; when this page opens select a red button for the desired location, select "Original Scanned Image," and proceed as above to zoom into a selected portion of the image.
Washington Department of Ecology (1995). Shoreline Aerial Photographs: SNJ1362, 9/23/1995, 12:14:00 PM, Yellow Island (color; oblique). On-line URL:
Washington Department of Natural Resources (1990). Aerial photographs: San Juan County, Washington (B&W). Electronic files.
Washington Department of Natural Resources (2002) See online URL: adm/comm/nr02-54.htm



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