Wood Load - Unglaciated Confined Channels
(Information compiled by Dan Cadol)
Confined channel segments tend to have low wood loads because the steep channel gradients associated with confinement lead to high stream powers that effectively remove wood from the reach via transport or breakage. The wood that is retained generally exists in jams and in accumulations in low velocity zones, such as on the channel margins and sites of flow divergence.
Wood is recruited through natural mortality, mass movement, and avalanche deposits. The steep valley sides may increase wood delivery to the channel by increasing the ease of transport of wood from the hillslope to the channel.
Ponderosa pine and Douglas fir are the most common trees in the conifer forests below 2300 m elevation (riparian vegetation page link), and are expected to dominate the wood load. Hillslope aspect will exert a major control on tree distribution. At low elevations, north- facing slopes are significantly better than south-facing slopes at retaining moisture. Thus, north-facing slopes often support denser forest, whereas south-facing slopes are bare.
This process domain is likely to have been affected by human impacts such as tie drives. Such activities likely removed much of the wood that was present historically. Recovery of wood load in these channels is hampered by the high transport capacity, which removes most wood introduced to the channel.