Whispering Firs Bog

Whispering Firs Bog was formed approximately 11,000 years ago. As the glacier receded, it scraped a depression on the north end of Vashon that would become the headwaters of Glen Acres Creek. The bowl was lined with glacial till, and so it would not drain. Eventually, sphagnum moss began to grow along the edges of the pool. The moss grew at its normal, incredibly slow rate of about a foot every 1,000 years. Today, the peat mass is estimated to be 11 feet deep based on sampling done by Vashon High School science students. NEXT

Stepping into the Bog is like stepping into a magical world, where everything is stunted like a bonsai garden. The Bog contains plants you won’t see anywhere else - dwarfed conifers, some of them 80 years old and standing only 8 feet high, stunted by the lack of nutrients in the water; the miniature and carnivorous sun dew plants, which lay in wait to catch tiny insects small enough to fit their traps; and things like Labrador tea and bog laurel. The peat mat itself bounces under your feet, as if this giant mass of plant matter was afloat – and it is. NEXT

Two decades ago, the Vashon Maury Land Trust was founded with the purchase of Whispering Firs Bog. It ranks as a King County Class-I wetland and is a distinctive and increasingly rare Puget Sound ecosystem. Whispering Firs Bog is one of only three preserved sphagnum bogs in all of lowland Puget Sound. NEXT

Whispering Firs Bog is extremely sensitive to development impacts. Any development in the drainage basin, and especially near the wetland, could endanger the health of the Bog. Soils introduced from clearing and construction and lawn creation can severely harm a peat bog – not to mention pet waste, the application of lawn or garden fertilizers, and the constant input of nitrogen from septic systems. Water runoff from cleared, paved and roofed areas are especially dangerous, as increased stormwater can increase the water level, make the water more alkaline, and add nutrients all at the same time. NEXT

The ancient pile of peat moss floats in its pool of water within a small drainage basin of about 30 acres. All of the water falling into that basin flows to the Bog – and as with much of life, water is the key. A sphagnum wetland requires a constant water level, a low level of nutrients (nitrogen) in the water, and water that is tannic (acidic). NEXT