California Code of Regulations
Title 14 - Natural Resources
Division 1.5 - Department of Forestry and Fire Protection
Chapter 4 - Forest Practices
Subchapter 4 - Coast Forest District Rules
Article 2 - Ratings and Standards
Section 912.9 - Cumulative Impacts Assessment Checklist

a. Sediment Effects. Sediment-induced CWEs occur when earth materials transported by surface or mass wasting erosion enter a Watercourse or Watercourse system at separate locations and are then combined at a downstream location to produce a change in water quality or channel condition. The eroded materials can originate from the same or different Projects. Sediment is composed of both suspended and bedload material. Suspended sediment is usually the primary source of turbidity in forested watersheds, although suspended organic material also accounts for a proportion of the suspended load. Chronic turbidity can be an indicator of a Cumulative Impact when sources can be identified and linked to one or more Projects. Both turbidity and suspended sediment concentrations are subject to extreme inherent variability from region to region, storm to storm, and from year to year, dependent upon underlying geology and precipitation.

Potentially adverse Impacts are most likely to occur in the following locations and situations:

* Downstream areas of low Watercourse gradient where sediment from a new source may be deposited in addition to sediment derived from existing or other new sources.

* Immediately downstream from where sediment from a new source is combined with sediment from other new or existing sources and the combined amount of sediment exceeds the transport capacity of the Watercourse.

* Any location where sediment from new sources in combination with suspended sediment from existing or other new sources significantly increases turbidity, reduces the survival of fish or other aquatic organisms, or otherwise reduces the Quality of Waters used for domestic, agricultural, or other Beneficial Uses.

* Channels with relatively steep gradients which contain accumulated sediment and debris that can be mobilized by sudden new sediment inputs, such as debris flows, resulting in debris torrents and severe channel scouring.

Potentially significant adverse Impacts of cumulative sediment inputs may include:

* Increased treatment needs or reduced suitability for domestic, municipal, industrial, or agricultural water use.

* Direct mortality of fish and other aquatic Species.

* Impaired spawning and rearing habitat for salmonids or otherwise reduced viability of aquatic organisms, or disruption of aquatic habitats, and loss of Watercourse productivity caused by filling of pools and plugging or burying gravel.

* Accelerated channel filling (aggradation) resulting in loss of streamside vegetation and Watercourse migration that can cause accelerated bank erosion.

* Accelerated channel filling (aggradation) resulting in increased frequency and magnitude of overbank flooding.

* Accelerated filling of downstream reservoirs, navigable channels, water diversion and transport facilities, estuaries, and harbors.

* Channel scouring by debris flows and torrents.

* Nuisance to or reduction in water related recreational activities. Situations where sediment production potential is greatest include:

* Sites with high or extreme Erosion Hazard Ratings.

* Sites which are tractor logged on steep slopes.

* Unstable Areas.

b. Water Temperature Effects. Water temperature-related CWEs are changes in water chemistry or biological properties caused by the combination of solar-warmed water from two or more locations where natural cover has been removed (in contrast to an individual effect that results from Impacts along a single Class I or II Watercourse segment). Cumulative Impacts from water temperature are most likely to occur in the following situations:

* Where Class I or II Watercourse bottom materials are dark in color.

* Where water is shallow and has little underflow.

* Where removal of streamside Canopy results in substantial, additional solar exposure or increased contact with warm air at two or more locations along a Class I or II Watercourse.

* Where removal of streamside Canopy results in substantial, additional solar exposure or increased contact with warm air at two or more Class I or II Watercourses that are tributary to a larger Class I or II Watercourse.

* Where water temperature is near a biological threshold for specific Species.

Significant adverse Impacts of cumulative temperature increases include:

* Increases in the metabolic rate of aquatic Species.

* Direct increases in metabolic rate and/or reduction of dissolved oxygen levels, either of which can cause reduced vigor and death of sensitive fish and other sensitive aquatic organisms.

* Increased growth rates of microorganisms that deplete dissolved oxygen levels or increased disease potential for organisms.

* Class I or II Watercourse biology shifts toward warmer water ecosystems.

c. Organic Debris Effects. CWEs produced by organic debris can occur when logs, limbs, and other organic material are introduced into a Watercourse or Lake at two or more locations. Decomposition of this debris, particularly the smaller sized and less woody material, removes dissolved oxygen from the water and can cause Impacts similar to those resulting from increased water temperatures. Introduction of excessive small organic debris can also increase water acidity. Conversely, large organic debris is an important stabilizing agent in small to medium size, steep gradient channels. However, the sudden introduction of large, unstable volumes of debris (such as logs, chunks, and larger limbs produced during a logging operation) can obstruct and divert streamflow against erodible banks, block fish migration, and may cause debris torrents during periods of high flow. Additionally, removing streamside vegetation can reduce the natural, annual inputs of litter to the Watercourse. This can cause both a drop in food supply, and resultant productivity, and a change in types of food available for organisms that normally dominate the lower food chain of Watercourses with an overhanging or adjacent forest Canopy.

d. Chemical Contamination Effects. Potential sources of chemical CWEs include run-off from roads treated with oil or other dust-retarding materials, direct application or run-off from pesticide treatments, contamination by equipment fuels and oils, and the introduction of nutrients released during burning of Slash and Woody Debris or wildfire from two or more locations.

e. Peak Flow Effects. CWEs can be caused by management-induced peak flow increases in Watercourses during storm events. Peak flow increases may result from management activities that reduce rainfall interception (i.e., evaporation) and vegetative water use (i.e., transpiration), or produce openings where snow can accumulate, such as in clearcuts and on roads and Landings). While increases, if any, are likely to be small relative to pre-harvest peak flows, extensive Canopy removal over a short period of time on a watershed scale can increase peak flow Effects on streambank erosion, channel incision, and headward channel extension in erodible landscapes. The timing and concentration of flows affecting lower order Watercourse channel morphology can also be affected by the routing of runoff from roads, Landings, and skid trails. Peak flow Effects diminish with decreasing intensity of Canopy removal, increasing time since harvest, and during larger flow recurrence intervals.

a. Gravel Embedded -- Spaces between gravel filled with sand or finer sediments. Gravel are often in a tightly packed arrangement.

b. Pools Filled -- Former pools or apparent pool areas filled with sediments leaving few areas of deep or "quiet" water relative to Watercourse flow or size.

c. Aggrading -- Watercourse channels filled or filling with sediment that raises the channel bottom elevation. Pools will be absent or greatly diminished and gravel may be embedded or covered by finer sediments. Streamside vegetation may be partially or completely buried, and the Watercourse may be meandering or cutting into its banks above the level of the former streambed. Depositional areas in aggrading channels are often increasing in size and number.

d. Bank Cutting -- Can either be minor or severe and is indicated by areas of fresh, unvegetated soil or alluvium exposed along the Watercourse Banks, usually above the low-flow channel and often with a vertical or undercut face. Severe bank cutting is often associated with channels that are downcutting, which can lead to over-steepened banks, or aggrading, which can cause the channel to migrate against slopes that were previously above the high flow level of the Watercourse.

e. Bank Mass Wasting -- Channels with landslides directly entering the Watercourse system. Slide movement may be infrequent (single events) or frequent (continuing creep or periodic events).

f. Downcutting -- Incised Watercourse channels with relatively clean, uncluttered beds cut below the level of former streamside vegetation and with eroded, often undercut or vertical, banks.

g. Scoured -- Watercourse channels that have been stripped of gravel and finer bed materials by large flow events or debris torrents. Streamside vegetation has often been swept away, and the channel has a raw, eroded appearance.

h. Organic Debris -- Debris in the Watercourse can have either a positive or negative Impact depending on the amount and stability of the material. Some stable organic debris present in the Watercourse helps to form pools and retard sediment transport and downcutting in small to medium sized Watercourses with relatively steep gradients. Conversely, large accumulations of organic debris can block fish passage, block or divert Watercourse flow, or could be released as a debris flow.

i. Streamside Vegetation -- Streamside and adjoining vegetation provide shade or cover to the Watercourse, which may have an Impact on water temperature, and provide root systems that stabilize streambanks and floodplains and filter sediment from Flood Flows.

j. Recent Floods -- A recent high flow event that would be considered unusual in the Project area may have an Impacts on the current Watercourse condition.

a. Depth of surface litter.

b. Soil structure.

c. Soil organic matter content.

d. Presence and amount of coarse fragments in the soil.

e. Soil texture.

f. Soil moisture status.

Compaction Effects may be evaluated by considering the soil conditions, as listed above, at the time of harvesting activities and the proportion of the Project area subjected to compacting forces.

a. Pools and Riffles. Pools and riffles affect overall habitat quality and fish community Structure. Watercourses with little structural complexity offer poor habitat for fish communities as a whole, even though the channel may be stable. Structural complexity is often lower in Watercourses with low gradients, and filling of pools can reduce Watercourse productivity.

b. Large Woody Material. Large woody material in Watercourses play an important role in creating and maintaining habitat through the formation of pools. These pools comprise important feeding locations that provide maximum exposure to drifting food organisms in relatively quiet water. Removal of large woody material can reduce frequency and quality of pools.

c. Near-water Vegetation. Near-water vegetation provides many habitat benefits, including: shade, nutrients, vertical diversity, migration corridors, nesting, roosting, and escape. Recruitment of large woody material is also an important element in maintaining habitat quality.

a. Snags/Den Trees/Nest Trees: Snags, den trees, Nest Trees and their recruitment are required elements in the overall habitat needs of more than 160 wildlife Species. Many of these Species play a vital role in maintaining the overall health of Timberlands. Snags of greatest value are >16 in. dbh and 20 ft. in height. The degree of Snag recruitment over time may be considered. Den trees are partially live trees with elements of decay which provide wildlife habitat. Nest Trees have importance to birds classified as Sensitive Species.

b. Downed Large Woody Material: Large downed logs (particularly conifers) in the upland and near-water environment in all stages of decomposition provide an important habitat for many wildlife Species. Large woody material of greatest value consists of downed logs >16 in. diameter at the large end and >20 ft. in length.

c. Multistory Canopy: Upland multistoried canopies have a marked influence on the diversity and density of wildlife Species utilizing the area. More productive Timberland is generally of greater value and timber site capability may be considered as a factor in an assessment. The amount of upland multistoried Canopy may be evaluated by estimating the percent of the stand composed of two or more tree layers on an average per-acre basis.

Near-water multistoried canopies in Riparian zones that include conifer and hardwood tree Species provide an important element of structural diversity to the habitat requirements of wildlife. Near-water multistoried Canopy may be evaluated by estimating the percentage of ground covered by one or more Canopy strata, with more emphasis placed on shrub Species along Class III and IV Watercourses (14 CCR §§ 916.5, 936.5, or 956.5).

d. Road Density: Frequently traveled roads have a significant influence on wildlife use of otherwise suitable habitat. Declines in deer and bear use of areas adjacent to open roads are frequently noted. Road density influence on large mammal habitat may be evaluated by estimating the miles of roads, on a per-section basis, that are open to the public. This assessment can also account for the Effects of vegetation screening and the relative importance of an area to wildlife on a seasonal basis (e.g. winter range).

e. Hardwood Cover: Hardwoods are an important habitat component in Cumulative Impact assessment, because they often provide Snags, den trees, downed large woody material, multistory Canopy, cover, mast, late seral forest characteristics, and connectivity between habitats.

Hardwoods provide an important element of habitat diversity in the coniferous forest and are utilized as a source of food and/or cover by a large proportion of the state's bird and mammal Species. Productivity of deer and other Species has been directly related to mast crops.

Hardwood cover can be estimated using the Basal Area Per Acre provided by hardwoods of all Species.

f. Late Seral (Mature) Forest Characteristics:

Determination of the presence or absence of late seral (mature) forest characteristics provides a basis from which to begin an assessment of the influence of management on associated wildlife. These characteristics include large trees as part of a multilayered Canopy, large decadent trees, and the presence of large numbers of Snags and downed logs, all of which contribute to an increased level of stand decadence and complexity. Late seral forests may be evaluated by estimating the percentage of the land base within the Plan and the biological assessment area occupied by areas conforming to the following definitions:

* Forests not previously harvested that are at least 80 acres in size to maintain the effects of edge. This acreage is variable based on the degree of similarity in surrounding areas. The stand includes a multi-layered Canopy, two or more tree Species with several large coniferous trees per acre (smaller subdominant trees may be either conifers or hardwoods), large conifer Snags, and an abundance of large woody material.

* Previously harvested forests that are in many possible stages of succession and may include remnant patches of late seral forest which generally conform to the definition of unharvested forests but do not meet the acreage criteria.

g. Late Seral Habitat Continuity: The fragmentation and resultant isolation of late seral habitat types is one of the most significant factors influencing the sustainability of wildlife populations not adapted to edge environments.

This fragmentation may be evaluated by estimating the number of acres within the Project area, as well as the biological assessment area occupied by portions of or entire late seral stands at least 80 acres in size (considering the mitigating influence of adjacent and similar habitat, if applicable) and less than one mile apart, or connected by a corridor of similar habitat.

h. Special Habitat Elements:

Special habitat elements are specific physical and biological attributes of the landscape without which certain Species are not expected to be present or, if present, are at relatively low population numbers. The biological assessment area may contain special habitat or critical Functional elements that are not otherwise discussed within this Appendix (e.g., meadows that may be critical for fawning success of local deer population, etc...). Each Species may have several key limiting factors to consider during the assessment of Cumulative Impacts.

a. Inventory, growth, and harvest over a specified planning horizon

b. Projected forest carbon sequestration over the planning horizon

c. Timber Operation related emissions originating from logging equipment and transportation of logs to manufacturing facility

d. GHG emissions and storage associated with the production and life cycle of manufactured wood products.