Creek Vegetation
Contact Us ● Tanwaxreek Ecosystem ● Creek Crossings ● Volunteer Opportunities ● Links
Home ● Creek Info ● Creek Health ● Vegetation ● Fish ● Maps
| The upstream basin was deforested and converted to mostly agriculture and rural residential in the early part of the century. The lower part of the basin was not deforested until the 1960's and 1970's. The most apparent influence of past timber harvest was reduction of sources of large wood for in-stream habitat. Tanwax Creek now has less large wood in the stream than it did in the past, yet the shape of the channel in many places in the basin is substantially influenced by single and concentrated pieces of wood. |
| A large proportion of the pools are limited by lack of cover , as wood is generally in short supply. Wood and overhanging vegetation is critical for fish concealment. Bank habitat associated with overhanging vegetation is extensive in localized reaches. where available, undercut root wads, in-channel woody debris, and backwater and dammed pools provide over-wintering habitat. Habitat between pieces of gravel in the stream is limited by inherently high concentrations of fine sediments that fill in the gaps between the rocks. |
|
Several miles of logging roads cross the lower basin. This area has low gradient compared to other industrial logging areas in Western Washington, therefore logging roads do not present a major impact to fish habitat. Still, potential adverse impacts associated with logging roads should be evaluated and reversed. |
| With the advent of land clearing for agriculture and development came invasive plant species. Ground disturbance and sedimentation of streamside areas, especially in wetlands and lowland pastures, have led to an explosion of invasive plant species, include reed canary grass, thistle, and spirea. Reed canary grass appears to have most direct influence on the stream habitat. Dense stands have become established along significant portions of Tanwax Creek and its tributaries. The extensive riverine wetlands along the lower Tanwax are dominated by invasive reed canary grass. The smaller channels and off-channel areas of the primary tributaries have become effectively choked with nearly pure stands of reed canary grass. This has led to retention of both fine sediment and organic livestock waste. Subsequent effects on salmonids are largely unknown, but in come cases it appears to have effectively removed potential spring and fall spawning habitats. |