Western lily is primarily hummingbird pollinated-- it has non-spreading stamens and yellow or yellow-green tepal centers surrounded by deep red (Schultz 1989). In areas where the hummingbirds migrate before the flowers bloom, insects pollinate Lilium occidentale. The plant reproduces primarily by seed or by bulb scales (Schultz 1989). It does not form large colonies as some other lilies do, as its rhizomatous bulb does not branch (Vollmer 1939).Young seedlings are extremely vulnerable to desiccation (drying out), and the lily responds to dry years with low emergence (Imper, 1997). Grazing by deer and small mammals increases in dry years, leading to lower reproductive success and adult survival (Imper 1997).Western lily occupies a fairly specific ecological niche. It grows under the protection of small shrubs, but with nearby direct sunlight (Schultz, 1989). Lilium occidentale may require the small shrubs as mechanical support for their tall flowering stems and heavy flowers. However, it is shaded out by greater than 50% canopy cover or shrubs that are higher than 6ft (2m). Occasional fire or salt spray from the nearby ocean may play a large role in suppressing the growth of forest or dense shrubs (Schultz 1989). The salt spray can damage the L. occidentale leaves and flowers, but it is effective in suppressing the surrounding vegetation. After six successive years of spruce removal at one site, flowering of western lily increased by 2000% within only two years (Imper 1997). Current research and management practices are aimed at finding the most effective and cost efficient method of brush and tree removal. The Western lily grows in two major types of soils: 1) Deep, organic peat that is saturated for most of the year and 2) mineral-based soils derived from Cenozoic age or older parent material. These tend to be acidic, poorly drained, and have a clay """"hard pan"""" or shallow cemented iron pan within 60 cm of the surface (Imper 1997). Invading trees not only shade out the western lily, but they change the hydrology of the land as well. Their deep roots can penetrate the hard pan causing the land to drain.Grazing is a threat to Lilium occidentale because it limits reproductive potential. Exclusion of grazing at one site lead to an immediate increase in both flowering and fruit production by more than 300%. However grazing also may help to maintain the open habitat that the lily requires by suppressing vegetation succession. Most surviving populations in Oregon have a long grazing history (Imper 1997). Most damage by cattle occurs by trampling rather than actual consumption. If the Western lily is eaten, it is often a consequence of consuming nearby vegetation, and only the top portion of the shoot is eaten. Deer on the other hand, selectively graze on the lily, often removing the entire shoot (Imper 1997). Impact of cattle is often temporary, since the plant is not completely destroyed by trampling or light grazing. The loss of reproductive success may be offset by the maintenance of habitat that the cattle grazing provides (Imper 1997). Concentrations of seedlings are often found near cattle rest areas or pathways. Lily seeds can pass through cattle intact, and germinate in the feces. They may contribute to the spread of lilies in this way, and also by creating suitable habitat in once unoccupied areas (Imper 1997).Habitat may have been maintained by periodic burning by Native Americans (USFWS 1998). Natives burned their village areas both for security reasons and to cultivate plants. It is known that Lilium columbianum bulbs were eaten and were actively cultivated by regular burning, digging bulbs, and digging leaves under. Flowering plants were marked with stakes so that the bulbs could be dug in the fall (Gunther 1973). It is hypothesized that L. occidentale was used in a similar manner.