The minimum mapping unit for this project was .5 acre and the minimum
width for any mapped polygon was
approximately 30 feet.
Attribute:
Attribute_Label: ACAD_TEXT
A numerical field containing the unique user-assigned identification
number for each map polygon (it was called
ACAD_TEXT for reasons having to do with the ArcCAD GIS program). This
item serves as the principal "key" for
sorting database records and relating them to the map polygons. Due
to additions and deletions of polygons during the
map editing process, these ID numbers were not necessarily sequential.
Attribute:
Attribute_Label: POLY__
Some polygons have been divided by a river mile marker into two or
more parts. The sub-units of such a polygon are
designated by decimal numbers.
Attribute:
Attribute_Label: BANK__
Code 7000 = Mid-Channel
Code 8000 = Right Bank (facing downstream).
Code 9000 = Left Bank (facing downstream).
Attribute:
Attribute_Label: BANK
Indicates left or right bank.
Attribute:
Attribute_Label: R_MILE
Attribute:
Attribute_Label: USGS_QUAD
U. S. Geological Survey, 7.5 Minute Series Topographic Quadrangle
names.
Attribute:
Attribute_Label: AERIAL_PHO
Mendocino County, 1992 Aerial Photo Number, WAC Corporation, Eugene,
Oregon. Aerial photo copy
enlargements at 1:6000 scale, (original scale 1:31,680).
Attribute:
Attribute_Label: REACH
Code 000 = York Creek
Code 100 = Feliz Creek
Code 200 = Dooley Creek
Code 300 = Russian River, south of Hopland Hwy. 101 bridge
Code 400 = Morrison Creek
Code 500 = Ackerman Creek
Code 600 = Hensley Creek
Code 700 = Forsythe Creek
Code 800 = Robinson Creek
Code 900 = Russian River, north of Calpella
Attribute:
Attribute_Label: LANDUSE
Code O (Land Use) = Open Land (i.e., mainly unvegetated land that
is not presently in agricultural, industrial,
residential, commercial, transportation, or urban use, with <10%
cover by herbs, shrubs, and/or trees).
Code h (Land Cover) = areas (other than gravel bars or gravel pit
margins) in which open condition is clearly the result
of recent human disturbance by cutting, bulldozing, heavy vehicle
traffic, etc.
Code sc (Land Cover) = a gravel bar which has recently been "scraped"
or "skimmed" to obtain aggregate.
Code ot (Land Cover) = other
Code N (Land Use) = Non-Cultivated Vegetated Land (i.e., cultural,
semi-natural, or natural vegetation with >10%
cover by herbs, shrubs, and/or trees).
Code fs (Land Cover) = Forbs and Shrubs predominate, although scattered
small trees may be present. Use of this
category is restricted to relatively early successional vegetation
in habitats normally dominated by trees.
Code rf (Land Cover) = Riparian Forest, Woodland, and/or Scrub
Landuse: Natural - Non-Cultivated Vegetated Land (i.e., cultural,
semi-natural, or natural vegetation with >10% cover by
herbs, shrubs, and/or trees).
Landcover:
Forbs/Shrubs = Forbs and Shrubs predominate, although scattered small
trees may be present. Use of this category is
restricted to relatively early successional vegetation in habitats
normally dominated by trees.
Ripararian Forest = Riparian Forest, Woodland, and/or Scrub
Landuse: Open Land - (i.e., mainly unvegetated land that is not
presently in agricultural, industrial, residential, commercial,
transportation, or urban use, with <10% cover by herbs, shrubs,
and/or trees).
Landcover:
Human Disturbance = areas (other than gravel bars or gravel pit margins)
in which open condition is clearly the result of recent
human disturbance by cutting, bulldozing, heavy vehicle traffic, etc.
Scraped = a gravel bar which has recently been "scraped" or "skimmed" to obtain aggregate.
Attribute:
Attribute_Label: LANDCOVER
Code O (Land Use) = Open Land (i.e., mainly unvegetated land that
is not presently in agricultural, industrial,
residential, commercial, transportation, or urban use, with <10%
cover by herbs, shrubs, and/or trees).
Code h (Land Cover) = areas (other than gravel bars or gravel pit
margins) in which open condition is clearly the result
of recent human disturbance by cutting, bulldozing, heavy vehicle
traffic, etc.
Code sc (Land Cover) = a gravel bar which has recently been "scraped"
or "skimmed" to obtain aggregate.
Code ot (Land Cover) = other
Code N (Land Use) = Non-Cultivated Vegetated Land (i.e., cultural,
semi-natural, or natural vegetation with >10%
cover by herbs, shrubs, and/or trees).
Code fs (Land Cover) = Forbs and Shrubs predominate, although scattered
small trees may be present. Use of this
category is restricted to relatively early successional vegetation
in habitats normally dominated by trees.
Code rf (Land Cover) = Riparian Forest, Woodland, and/or Scrub
Landuse: Natural - Non-Cultivated Vegetated Land (i.e., cultural,
semi-natural, or natural vegetation with >10% cover by
herbs, shrubs, and/or trees).
Landcover:
Forbs/Shrubs = Forbs and Shrubs predominate, although scattered small
trees may be present. Use of this category is
restricted to relatively early successional vegetation in habitats
normally dominated by trees.
Ripararian Forest = Riparian Forest, Woodland, and/or Scrub
Landuse: Open Land - (i.e., mainly unvegetated land that is not
presently in agricultural, industrial, residential, commercial,
transportation, or urban use, with <10% cover by herbs, shrubs,
and/or trees).
Landcover:
Human Disturbance = areas (other than gravel bars or gravel pit margins)
in which open condition is clearly the result of recent
human disturbance by cutting, bulldozing, heavy vehicle traffic, etc.
Scraped = a gravel bar which has recently been "scraped" or "skimmed" to obtain aggregate.
Attribute:
Attribute_Label: WHR
The California Natural Diversity Data Base (CNDDB) and the Wildlife
Habitat Relationships (WHR) system are used
by the Department of Fish and Game to classify vegetation communities
and wildlife habitats throughout the state (see
Airola 1988; Holland 1986; Mayer and Laudenslayer 1988). In the present
study, CRP used both of these systems to
classify polygons, in addition to the land use/land cover classification
scheme presented above. The approximate
correspondences among these three classification systems is given
in the following table, for those land cover units that
may occur in the study area:
------------------------------------------------------------------------------------------------------------------
Land Cover Units Used in this Study, and Their Approximate Correspondence
to Units in the WHRHabitat Type and
CNDDB Natural Community Type Classification Systems1
------------------------------------------------------------------------------------------------------------------
Land Cover Units WHR WHR CNDDB
Used In This Study Codes Habitats Codes
------------------------------------------------------------------------------------------------------------------
Riparian Forest VRI Valley-Foothill Riparian 61400
Riparian Forest VRI Valley-Foothill Riparian 63400
Notes:
1CNDDB codes are generally based on R. F. Holland (1986), and R. F.
Holland's WHR-CNDDB correlations in the
"Crosswalk Table" on pp. 23-39 in Mayer and Laudenslayer
(1988). WHR Habitat names and codes are those listed
in Mayer and Laudenslayer (1988) and the California Department of
Fish and Game's WHR Computer Database
(version 5.0). Since the intention of the WHR system is to classify
major vegetative complexes at a scale sufficient to
predict wildlife habitat relationships, most of its categories are
at the association level of a vegetation classification or
higher. A WHR habitat is generally broader than a "natural Community"
type in the CNDDB system; i.e., a WHR
habitat often encompasses more than one CNDDB community type.
Where disturbance has removed a pre-existing tree cover and tree
species have not yet re-colonized a site to any
significant degree, the WHR system allows the coding of such units
as the "seedling stage" of a tree-dominated habitat.
In this project we preferred not to make assumptions regarding potential
vegetation development; all such units were
coded on the basis of their presently existing cover (e.g., "Open",
"Grassland", or "Forbs and Shrubs").
3All Grassland/Savanna cover units were assumed to be WHR Annual
Grassland, unless determined by ground truth to
be Perennial Grassland.
Attribute:
Attribute_Label: CNDDB
The California Natural Diversity Data Base (CNDDB) and the Wildlife
Habitat Relationships (WHR) system are used
by the Department of Fish and Game to classify vegetation communities
and wildlife habitats throughout the state (see
Airola 1988; Holland 1986; Mayer and Laudenslayer 1988). In the present
study, CRP used both of these systems to
classify polygons, in addition to the land use/land cover classification
scheme presented above. The approximate
correspondences among these three classification systems is given
in the following table, for those land cover units that
may occur in the study area:
------------------------------------------------------------------------------------------------------------------
Land Cover Units Used in this Study, and Their Approximate Correspondence
to Units in the WHRHabitat Type and
CNDDB Natural Community Type Classification Systems1
------------------------------------------------------------------------------------------------------------------
Land Cover Units WHR WHR CNDDB
Used In This Study Codes Habitats Codes
------------------------------------------------------------------------------------------------------------------
Riparian Forest VRI Valley-Foothill Riparian 61400
Riparian Forest VRI Valley-Foothill Riparian 63400
Notes:
1CNDDB codes are generally based on R. F. Holland (1986), and R. F.
Holland's WHR-CNDDB correlations in the
"Crosswalk Table" on pp. 23-39 in Mayer and Laudenslayer
(1988). WHR Habitat names and codes are those listed
in Mayer and Laudenslayer (1988) and the California Department of
Fish and Game's WHR Computer Database
(version 5.0). Since the intention of the WHR system is to classify
major vegetative complexes at a scale sufficient to
predict wildlife habitat relationships, most of its categories are
at the association level of a vegetation classification or
higher. A WHR habitat is generally broader than a "natural Community"
type in the CNDDB system; i.e., a WHR
habitat often encompasses more than one CNDDB community type.
Where disturbance has removed a pre-existing tree cover and tree
species have not yet re-colonized a site to any
significant degree, the WHR system allows the coding of such units
as the "seedling stage" of a tree-dominated habitat.
In this project we preferred not to make assumptions regarding potential
vegetation development; all such units were
coded on the basis of their presently existing cover (e.g., "Open",
"Grassland", or "Forbs and Shrubs").
3All Grassland/Savanna cover units were assumed to be WHR Annual
Grassland, unless determined by ground truth to
be Perennial Grassland.
Attribute:
Attribute_Label: LANDFORM
Main Stem River Channel
Code I = Immediate Bank: a narrow bank which makes an abrupt transition
between the wetted channel and the upper
terrace, with no intervening in-channel terrace or gravel bar.
Code Tc = In-Channel Terrace: areas of intermediate elevation located
between a gravel bar and the outer channel
bank/upper terrrace. In-channel terraces may be in various stages
of hummock formation, or they may be
more-or-less level if the hummocks have already coalesced.
Code P = Point Bar or Alternate Bar: gravel bars formed at bends in
a stream's thalweg that follow bends in the stream
channel are called point bars; bars formed where there is a meandering
thalweg within a straight stream
channel are called alternate bars. There is a gradation between the
two types of bars which often makes them
difficult to distinguish; they are therefore lumped together here.
Code Wc = Wetted channel: that portion of the river's main
channel (or a back channel connected to the main channel) in which
surface water is visible.
Code M = Mid-Channel Island, or emergent "riffle bar"
Immediate Bank: a narrow bank which makes an abrupt transition between
the wetted channel and the upper terrace, with no
intervening in-channel terrace or gravel bar.
Point Bar or Alternate Bar: gravel bars formed at bends in a stream's
thalweg that follow bends in the stream channel are
called point bars; bars formed where there is a meandering thalweg
within a straight stream channel are called alternate bars.
There is a gradation between the two types of bars which often makes
them difficult to distinguish; they are therefore lumped
together here.
In-Channel Terrace: areas of intermediate elevation located between
a gravel bar and the outer channel bank/upper terrrace.
In-channel terraces may be in various stages of hummock formation,
or they may be more-or-less level if the hummocks have
already coalesced.
Mid-Channel Island: emergent "riffle bar".
Attribute:
Attribute_Label: CANOPY
Canopy closure as estimated from aerial photos
("Photo-Closure") was classified into three categories:
Code L = Low; from "10"% (i.e., 5-15%) up to "40"%
(i.e., 35-45%)
Code M = Medium; from > "40"% up to "70"% (i.e.,
65-75%)
Code H = High; from > "70"% up to 100%
Note: The standard WHR system uses four classes for percent canopy
closure (i.e., 10-24%, 25-39%, 40-59%,
60-100%). In the present project it was not feasible to distinguish
such narrowly-defined categories because of the
less-than-optimum quality of the available aerial photos; we therefore
used the three broad classes defined above. In
effect our scheme combined the first two WHR categories ("Sparse"
and "Open") into a single class, while retaining
classes similar to the WHR's "Moderate" and "Dense"
categories.
Note: Our class boundaries for percent canopy closure were deliberately
"fuzzy"; i.e., instead of a class boundary being
a single percentage value, our threshold criteria spanned a range
of values. The dividing line between canopy closure
classes was drawn by eye where there was a "noticeable change"
in canopy density that fell within these ranges on the
photos; the actual location of the line was therefore a matter of
the judgement of the photo-interpreter. According to
Thompson (1987) a similar procedure is used by USGS to produce vegetation
cover information on 7.5 minute quad
maps.
Attribute:
Attribute_Label: COVER
A rough visual estimate of the percentage of ground surface within
the entire polygon covered by vegetation of any type.
Codes and categories for cover followed Northen's terminology (Northen
1991; 1992):
Code u = "unvegetated" (<10% cover)
Code s = "sparsely vegetated" (11% - 50% cover)
Code c = "well vegetated" (> 50% cover)
Attribute:
Attribute_Label: CROWN_SZ
We used 1:2,400-scale aerial photos and ground-truthing to classify
vegetation in terms of the average crown diameter
of overstory trees. However, we modified the criteria of the WHR system
(Mayer and Laudenslayer 1988) by
dropping the "multi-layered" class (because it combines
layering and cover criteria rather than just tree size), and
lumping the remaining five WHR classes into three categories, as follows:
Code A = Seedling to Sapling size (<15'; WHR codes 1 and 2)
Code B = Pole to Small size (15'-45'; WHR codes 3 and 4)
Code C = Medium to Large size (>45'; WHR code 5)
Note: The use of these three broad size classes was a deliberate
tradeoff, intended to improve the classification
accuracy by accepting some loss of precision.
Note: The WHR system assumes that there is a consistent relationship
between crown diameter and dbh which can be
applied to all species of conifers on the one hand and all species
of hardwoods on the other. No doubt this is an
over-simplification, but it enables the user of the WHR system to
obtain a rough estimate of average tree dbh from
aerial photos in areas or time periods for which ground truth data
may be unavailable.
The table below gives the correspondences among size class, conifer
crown diameter, hardwood crown diameter, and
dbh class that are assumed in the WHR system (Mayer and Laudenslayer
1988). Also shown are the actual sizes of
tree crown images as they appear on aerial photos at the scales which
were used in this project:
-------------------------------------------------------------------------------------------------------------------------
WHR WHR WHR WHR WHR Hdwood Crown Hdwood Crown
Code Size Conifer Hardwood dbh Diam. on 1:6,000 Diam. on 1:2,400
Class Crown Diam. Crown Diam. Class Aerial Photos Aerial Photos
-------------------------------------------------------------------------------------------------------------------------
1 Seedling n/a n/a < 1" n/a n/a
2 Sapling n/a < 15' 1-6" < 0.8 mm < 1.9 mm
3 Pole < 12' 15-30' 6-11" 0.8 - 1.5 mm 1.9 - 3.8 mm
4 Small 12-24' 30-45' 11-24" 1.5 - 2.3 mm 3.8 - 5.7 mm
5 Med/Large > 24' > 45' > 24" > 2.3 mm > 5.7 mm
------------------------------------------------------------------------------------------------------------------
Attribute:
Attribute_Label: AV_DBH
Attribute:
Attribute_Label: SUC_STATUS