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Large Woody Debris Information in KRIS Big River 

KRIS Web Background Pages: Big Wood

The amount of large wood which has been removed from streams in the Big River area has not been quantified, as it has for parts of the Noyo River basin, but Stillwater Sciences conducted a review of what stream clearance reports could be obtained from California Department of Fish and Game files (Stillwater Sciences 1997) and generated a map of where, within the Noyo and Big River areas, large wood removal activities were believed to occur (see example below).  The Stillwater Sciences report compiles evidence that wood removal activities in the Mendocino coastal area have dramatically altered stream channels and available fish habitat.  The report includes, for example, an account that bed scouring of 10-20 ft occurred in some stream segments following large wood removal. (See Stream Clearance for more on this topic).

The image at left was taken was taken from the Fish and Aquatic Habitat view in the KRIS Big River Map project, and shows that large wood removal began in the 1950's and continued through the 1990s. CDF supplied the spatial data on wood removal which was generated by Stillwater Sciences from review of available wood removal documents in California Department of Fish and Game files. Documents by Mendocino Redwood Company and the USFS confirm that this map layer illustrates only a partial record of large wood removal in the Big River area.

The USFS' Redwood Sciences Laboratory has conducted two studies of large wood supply and recruitment in Caspar Creek.  O'Connor and Zeimer (1989) found that the stream had only remnant pieces of very large wood, and recruitment levels too low to provide natural recovery of channel conditions 80 years after logging.  Surfleet and Zeimer (1996) examined the North Fork Caspar Creek four years after second-growth logging with riparian buffer strips, and the South Fork Caspar Creek twenty-five years after logging without riparian buffer strips. They found that the South Fork Caspar Creek had less large wood in the channel and less recruitment potential.  Although not shown on the wood removal map, the South Fork Caspar Creek had been subjected to wood removal activities following logging.  Surfleet and Zeimer (1996) document the lasting effects of wood removal on large wood supply.

KRIS Big River contains two sets of data from large wood inventories.  The Mendocino Redwood Company (MRC) surveyed 44 segments from 28 streams within the Big River basin in 2000.  The surveys counted and measured all wood perceived to have any function for bed scour or fish habitat, but also categorized, as key pieces, those which surpassed minimum size requirements according to channel width.  The key piece criteria is similar, but not identical, to that described in Schuett-Hames et al. (1999).  MRC also recorded the type of wood and the occurrence of debris jams and smaller debris accumulations.

The chart at left shows that results of MRC wood counts in for surveyed reaches in the South Fork Big River subbasin.  Some surveyed reaches from smaller streams in the South Fork Big River contained up to 24 pieces of wood per 100 meters, but no reach had more than four key pieces and most had none.

	This chart shows the results of MRC wood measurements for the same South Fork Big River reaches.  Total wood density in tributaries of the South Fork ranged from 1-24 m3/100m, while key piece density ranged from 0-15 m3/100m.   Although key pieces provide a small percentage of total wood pieces, when present they provide a large percentage of wood volume.
	This chart shows the relative contributions to total wood density from four categories, including key pieces.  Non-key pieces have no minimum size, but were deemed to offer some habitat or bed scour function. Accumulations consist of 3-10 pieces of wood, and jams have greater than 10 pieces. While smaller wood may provide periodic cover and localized scour, key pieces commonly provide the structure which forms and maintains high quality pool habitat.
	This chart illustrates the proportional volumes of wood measured in South Fork Big River reaches by four categories of wood type. Substantial proportions of non-redwood species may be an indication of seral stage setbacks in combination with wood removal activities.  Non-redwood species may persist in the stream for only a fraction of the time that redwood does.

The other source of large wood data in KRIS Big River, comes from the Department of Fish and Game, and surveys of Hare Creek and Caspar Creek in 1999.  These DFG surveys follow the protocol outlined in the Salmonid Habitat Restoration Manual (CDFG 1998).  While this protocol somewhat resembles the standard level 1 protocol used in Washington (Schuett-Hames et al. 1999), it classifies wood size according to non-metric units and only two lengths (greater than or less than 20 feet).  Furthermore, it identifies the location of wood by simply within or above the bank-full channel.  In consequence, designation of key pieces is impossible, and comparison to regional data and the MRC data is difficult.

The chart at left shows results from an inventory of large wood in twelve 200 foot sampling reaches of Caspar Creek. The eight size categories for in-channel wood are displayed in eight different colors. The most abundant category is the small category containing wood 1-2 feet in diameter, and less than 20 feet in length. The five reaches from the downstream segment (Casp1) have considerably fewer pieces of wood than the seven reaches from the upstream segment (Casp2). Casp2 was subject to large wood placement during the year before inventory, but artificially placed pieces were not noted in the survey data.

This chart shows number pieces of large wood (>12 inches diameter) in two segments of Caspar Creek according to six location/status categories.  All within-channel wood is shown in blue and measures approximately 4 pieces/100 feet in both segments.  Recruitment potential for conifers, as indicated by the number of large trees on the flood-prone bank (dark green bars) is higher in the upstream segment.

Bilby, R.E. and Ward, J.W., 1989. Changes in characteristics and function of woody debris with increasing size of streams in western Washington, Transactions American Fisheries Society, 118: 368 – 378.

CA Department of Fish and Game. 1998. California Salmonid Stream Habitat Restoration Manual. Third Edition. Inland Fisheries Division. California Department of Fish and Game. Sacramento, CA. 495 p.

Holman, G. and W. Evans. 1964. Noyo River Stream Clearance Projects. California Department of Fish and Game. 12 p. 

Keithley, C. 1999. Evaluating Stream and Watershed Conditions in Northern California. Prepared for the California Department of Forestry, Fire and Resource Assessment Program. Sacramento, CA. 17 pp. 

Schuett-Hames, D., A.E. Pleus, J. Ward, M. Fox, and J. Light. 1999. TFW Monitoring Program method manual for the large woody debris survey. Prepared for the Washington State Dept. of Natural Resources under the Timber, Fish, and Wildlife Agreement. TFW-AM9-99-004. DNR #106. 66 pp.

Stillwater Sciences. 1997. A review of coho salmon life history to assess potentially limiting factors and the implications of historical removal of large woody debris in coastal Mendocino County. Prepared by Stillwater Sciences, Berkeley CA for Louisiana-Pacific Corporation, Wildlife and Fisheries Science Group, Forest Resources & Fiber Procurement Division. May 1997. 55 pp