By using overview information, you can usually restrict the
Level 1 field survey to a smaller portion of the watershed
than the initial study area.
The objectives of the Level 1 assessment are:
to confirm or revise the nature, location and extent of
forest harvest impacts on riparian habitat
to provide field data for use in prescription development
to provide a preliminary list of restoration options for
sites with impaired riparian functions
to provide sufficient information to identify and prioritize
impaired sites for Level 2 assessments and prescriptions.
The Level 1 assessment refines and builds upon the initial
information from the overview assessment in identifying impaired
riparian sites within the watershed. It does so by collecting
further qualitative and quantitative information in field
surveys. It also provides preliminary recommendations for
restoration opportunities and prioritizes sites for the Level
2 assessment and prescription phase.
Scope of the Level 1 Assessment
The Level 1 riparian assessment is a field-based activity
to survey current habitat conditions in selected riparian
locations. It examines priority sites and evaluates the
riparian level of functioning within those sites.
In particular, a site's level of functioning is based on
its ability to supply the basic riparian functions of:
LWD (especially from coniferous trees, which are more decay
resistant), CWD and SOD
stream bank and channel stability
wildlife and general biodiversity attributes.
The level of functioning will be evaluated within a classification
of low, moderate or high functionality. The Level 1 assessment
uses several features to characterize riparian habitat conditions
and identify priority sites for potential restoration. Habitat
features of particular importance are:
overstorey vegetation characteristics (tree species, densities
and heights, % cover)
understorey vegetation characteristics (shrub, herb and moss
species, % cover and height)
soil properties (horizon depths, textures, % coarse fragments)
indicators of disturbances (e.g., slides, culverts, flooding)
site gradient and aspect
stream gradient and width.
To evaluate habitat conditions, the Level 1 assessment compares
the values of the above habitat features within the reach
to expected values in mature or old-growth forests. However,
little in the way of published diagnostic data exists and,
therefore, many of the evaluations will be based on general
expected values at various successional stages of the riparian
forest. For example, at the pole-sapling structural stage
one would quite clearly evaluate provision of LWD as low
(i.e., low functionality).
The field survey collects quantitative and qualitative information
on the above features. Methods to obtain these data are described
Steps in the Level 1 Assessment
The steps in the Level 1 assessment are:
Develop a field visitation plan based on overview assessment
recommendations and considering field logistics such as access
and worker safety considerations.
Assemble field survey equipment:
field note book
plant identification field guides
measuring tools (e.g., tape, surveyors tape, foldable metre
stick, surveyers rod, range finder)
cable marked at 3.99 and 11.28 m (these sizes are used to
provide a tree stems/ha count)
tree corer (increment bore; medium size)
plant and soil sample bags
GPS unit (if available)
camera and film
small white board and pen to identify location in photographs
safety clothing (foot and head gear).
Gather and evaluate field data following the instructions
for Form 2
confirm boundaries of priority riparian areas
select representative plot locations
gather quantitative data on site conditions, including overstorey
and understorey vegetation from representative locations
gather descriptive data on soils, site disturbances and any
other features that may influence site assessment and prescription
evaluate level of functioning within each polygon (high,
moderate or low).
Identify priority sites recommended for the Level 2 assessment
and prescription phase. As with the outcome from the overview
phase, priorities are based on level of expected benefit
to the watershed and where the likelihood of success is high.
List or discuss possible restoration options for sites that
are likely candidates for restoration projects. Typical harvested
riparian sites and treatment scenarios are provided in Figure
Figure 4. Examples of stand types that provide
opportunities for riparian restoration and some options for
Level 1 Assessment Field Form Instructions
Use the following instructions to enter data in the Level
1 assessment field data form, Form
2 (see completed form
example in Appendix 7).
1. Preliminary Information
Polygon #: Transfer the polygon number from the overview
assessment Form 1. All polygons should receive a unique
Plot #: A minimum of one plot per polygon needs to be completed.
SSt: Stand structure (SSt) within an RVT, previously identified
during the overview assessment, should be confirmed in the
field. Classification should include one of the following:
INIT - initial succession (bare ground or early herbs)
SH - shrub herb
PS - pole sapling
YF - young forest
MF - mature forest
OF - old forest.
Also include whether the stand structure is deciduous tree
dominated (d) (>75% tree cover); coniferous dominated
(c) (>75% tree cover); or mixed (m) deciduous-coniferous
trees (neither deciduous nor coniferous tree species account
for >75% cover).
Creek name: Transfer from the overview assessment Form
or distinguish as either the official name of the stream
being surveyed as listed in the Gazetteer
of Canada for British Columbia, or a local name.
Reach #: Transfer from the overview assessment Form 1, and
refine if necessary. Delineating reaches is optional if doing
only a riparian assessment, but should be consistent with
reaches assigned if concurrently completing a fish habitat
assessment or channel assessment.
Location: Record a concise description of the geographic
location of the RVT surveyed referring to permanent or named
features (e.g., 30 m upstream from main logging bridge).
Creek aspect: The compass direction (N, S, E, W) the creek
BEC zone: To determine the biogeoclimatic ecosystem classification
(BEC) zone, refer to a BEC map. The maps provide an initial
identification of the biogeoclimatic unit for a particular
area, and may be all that is necessary if the area falls
well within a map polygon.
Nonetheless, it should always be verified during
the field visit. The BEC zone should be one of the following:
AT - Alpine Tundra
BG - Bunchgrass
BWBS - Boreal White and Black Spruce
CDF - Coastal Douglas-fir
CWH - Coastal Western Hemlock
ESSF - Engelmann Spruce-Subalpine Fir
ICH - Interior Cedar-Hemlock
IDF - Interior Douglas-fir
MH - Mountain Hemlock
MS - Montane Spruce
PP - Ponderosa Pine
SBPS - Sub-Boreal Pine Spruce
SBS - Sub-Boreal Spruce
SWB - Spruce-Willow-Birch.
(For detailed descriptions of BEC zones, refer to Appendix
Air photo: Transfer from the overview assessment Form
or record the flightline and air photo number that depicts
the stream reach or sampling site (year of flight should
be automatically included as part of the air photo number).
RVT slope: Use a clinometer or Abney level to measure the
slope of the RVT. The slope can be measuring by looking from
the edge of the streambank at right angles to the stream,
out to the edge of the RVT.
Stream gradient: Use a clinometer or Abney level to measure
the gradient of the stream (+ 0.5%) adjacent to the plot.
Mark the surveyor's rod at the eye level of the measurer.
The rod man holds the surveyor's rod vertical at the far
boundary of the habitat unit while the measurer sights the
clinometer on this mark to make the gradient measurement.
Map: Transfer from the overview assessment Form
1, or record
index number of the NTS (1:50 000 scale) or BCGS (1:20 000
scale) map that depicts the downstream boundary of the stream
reach or sampling site.
UTM: Using NTS maps or a GPS unit, record the UTM (Universal
Transverse Mercator) number that identifies the location
of the downstream boundary of the sampling site (e.g., 10.6975.58984).
Plot radius/Plot multiplier: Plots are created by measuring
out a specific length (plot radius) from a centre point and
surveying in a circle around the centre point (Figure 5).
Plots should be large enough to tally an average of six
live dominant trees per
plot over the RVT, and they should be
representative of the RVT. There are two standard lengths
to measure based on the stem density within the plot. Use
a 3.99 m radius in young
stands, for older less
dense stands, use 11.28
m instead. These radii are used since they can
be conveniently multiplied to calculate stems per hectare.
For a plot radius of 3.99 m, multiply by 200 (Figure 5).
For a plot radius of 11.28 m, multiply by 25. For a plot
radius of 5.64 m, used in some forest inventory activities,
multiply trees counted within plot by 100 (i.e., a circle
of 5.64 m radius is equal to 100 m2 area).
Figure 5. Example of a 3.99 m radius field
plot (submitted by V. Poulin, V. Poulin and Assoc., Vancouver).
Wb (bankfull channel width): Measure the bankfull channel
width (Wb) in metres at a representative site as the horizontal
distance perpendicular to the channel from rooted terrestrial
vegetation to rooted terrestrial vegetation on opposite sides
of the stream (often simply called channel width).
Stream width measurements should not be made near (within
approx. 20 m) of stream crossings, at unusually wide or narrow
points, or in areas of atypically low gradient such as marshy
or swampy areas, beaver ponds, or other impoundments. Do
not include vegetated islands or bars. If multiple channels
are separated by vegetated islands, sum the separate bankfull
channel width measurements. Include unvegetated gravel bars
in the bankfull channel width measurement. Refer to WRP Technical
Circular 8 for more explanation if needed, or the appropriate
Stream characteristics such as channel width and stream
gradient can be used to give an indication of the potential
value of fish habitat within the general area of the riparian
field site (lower gradient streams are usually more valuable
than high gradient streams), and help prioritize sites for
Code stream class: Transfer from the overview assessment
1, or on the basis of previous definitions (Table
classify your stream as S1 to S6. We recommend that the riparian
assessment procedure focus on S1-S3 stream classes unless
specifically designated otherwise by the contracting agency.
RMA, RRZ and RMZ: Based on the stream classification (S1-S6)
(or lake or wetland), record the width of the RMA, RMZ and
RRZ (see earlier definitions, Table 2).
Year of harvest: Transfer record (if any) of last harvest
or restocking from the overview assessment Form
1, and if
necessary refine based on field observations. A tree coring
device can help provide site specific data.
For the purposes of this form, overstorey refers to all deciduous
and coniferous tree species identified within a plot, regardless
of size or age.
Layer: Layers of the overstorey are based
on the diameter of the trunk at breast height (dbh). The layers are:
1a: > 22 cm (mature trees)
1b: 12.6-21.9 cm (mature trees)
2: 7.5-12.5 cm (poles)
3: 0.1-7.4 cm (saplings)
4: trees shorter than dbh (<1.3 m, regeneration layer).
Tree species stem tally: As species are identified, mark
in the species code and the number of trees for each species
in each layer within your chosen plot. There is room on the
form for six species. See Glossary for tree species codes
(e.g., Hw - western hemlock, Dr - red alder).
Total SPH: Stems per hectare (sph). Since it is impractical
in riparian assessment to survey an entire hectare of vegetation,
smaller plots are surveyed and hectare density is extrapolated.
This number is calculated by summing
species tallied within
each layer and multiplying by the plot multiplier.
For a plot radius of 3.99 m:
layer 1a: (3 Hw + 1Cw) × 200 (plot multiplier) = 800
(also see Figure 5).
This number is used to calculate relative presence and abundance
of the various species in each layer, and additionally to
measure future sources of large woody debris (LWD). Sum coniferous
and deciduous species separately.
Dominant species: Record the most abundant species for each
layer as the dominant species.
Species hgt (height), DBH: Once the dominant species has
been determined, select a representative example within the
plot and record its height (visual estimate in m) and dbh
The understorey is made up of species of shrubs, herbs and
mosses. These are important indicators of site specific
growing conditions, most typically related to soil moisture
and nutrient conditions, and are commonly used to help
establish the provincial BEC site series classifications.
Layer: Layers of the understorey are
based on average height and can be divided up as follows:
Tall shrub: >2 m
Short shrub: <2 m
Herbs: predominant herbaceous (non-woody) growth
Moss: predominant moss species present on ground.
% cover: As it is not practical nor useful to do stem counts
for the understorey, per cent cover is used as a measure
of abundance. Estimate the amount of foliar coverage of a
particular species within a given layer. For assistance in
estimating cover, refer to the companion charts in Figure
6. It is not necessary that all the species of a layer add
up to 100% cover.
Figure 6. Comparison charts for estimation
of foliage cover (after Luttmerding et al. 1990)
Species: There are no official species codes for shrubs,
herbs and mosses. Instead, fill in the field form with either
the latin or common name, or an acceptable abbreviation of
the names. For example, salmonberry, Rubus
commonly abbreviated as "Rusp;" (if using abbreviations,
be sure to include the full names of the species on the field
form). Record the three most abundant species in each layer.
Should you wish to record the presence of more than three
species, record them in the Comments section. If a species
is unknown and cannot be quickly identified in the field,
state whether it is a grass, forb, aquatic plant or moss
under species column, and take a sample for identification
later in the office or lab.
Height: Enter the height in metres to the nearest 0.1 m.
Mean height of dominant shrub layer: Estimate the average
height of the understorey layer with the greatest total cover.
4. Plot Summary
Total % cover: Estimate the total per cent cover for both
the overstorey and the understorey.
Total SPH: Sum the total stems per hectare (sph) for only
layers 1a and 1b.
Snags are any standing dead trees and are valuable as wildlife
trees and potential LWD (see BC classification of wildlife
trees in Appendix 6).
Total/Plot: Add up all snags over 5 m in height within the
DBH range: Estimate in centimetres the range in diameter
(at dbh) of all snags over 5 m in height.
Species: Where it is still possible to identify the snags
by species, record it. Otherwise, distinguish between coniferous
and deciduous trees.
% LWD: Estimate the per cent of snags within the plot that
may ultimately function as LWD (i.e., the percentage that
is close enough to fall into the stream within the next 10
years - approximately).
Total/ha: Multiply the total snags per plot by the plot
multiplier to calculate total snags per hectare.
6. Disturbance Indicators
Make note (yes or no) of the presence of any of the following
disturbance indicators within an RVT:
||Other (e.g., herbicide)
C (comment): If a more detailed explanation of disturbances
is desired, assign a number in the comment box and include
a corresponding description in the comments section at the
bottom of the form (referring back to the same number, e.g.,
C1, C2, C3).
7. Soil Horizons
Soil horizon can be defined as a layer of soil that is distinguished
from adjacent layers by characteristic physical properties
such as structure, colour or texture. Humus is the organic
layer at the top that consists of decomposing plant material.
A horizons are surface mineral horizons, and consist of
two types. Ae horizons indicate strong leaching of organic
matter and nutrients from upper mineral soil and are associated
with nutrient-poor to nutrient-medium soils. Ah horizons
indicate an accumulation of humus in the surface mineral
soil, and are generally associated with nutrient-rich soils.
Ae horizons are light greyish coloured (lighter than underlying
soil) while Ah horizons are dark brown coloured (darker
than underlying soil). (Refer to Appendix
4 for additional
Horizon: Classify as humus, Ae or Ah.
Depth: Measure and record the average thickness of each
soil layer in cm.
Texture (mineral layers only): To help identify soil type,
crush a small handful of soil in the hand, and remove coarse
fragments (particles greater than 2 mm in diameter). Gradually
add water to the soil and work into a putty (not too moist
or dry). Categorize the texture as either clay, silt or sand
based on the following features:
Clay - feels smooth and very sticky,
Silt - feels slippery or soapy,
Sand - feels grainy
% coarse fragments (mineral layers only): Per cent coarse
fragments can be determined through estimating per cent by
volume of mineral soil fragments greater than 2 mm
8. Level of Functioning
Levels can be briefly described as follows:
Low (L) - riparian vegetation functioning poorly, improvement
Medium (M) - functioning moderately, improvement may help
High(H) - functioning well, improvement
These can be assessed by visually estimating the current
extent of riparian functioning based on the potential level.
The level for each ecological function will vary according
to the structural stage of the vegetation (Table 3).
Table 3. Potential level of riparian functioning
Surface sediment filtering
Bank & channel stability
M - H
L - M
L - M
M - H
L - H
aSmall organic debris (e.g., leaf litter, twigs, falling
Criteria for determining level of functioning (adapted from
McLennan and Johnson 1997):
LWD/CWD: The primary factors for considering the level of
functioning for LWD/CWD are the number of sph of the overstorey
vegetation, the effective distance of potential LWD from
stream, and the species of potential LWD.
To assess sph for LWD (Table 4), consider only coniferous
tree species since their resistance to decay is much greater
than that of deciduous species. The exception would be when
assessing areas where coniferous species are naturally rare
Table 4. Assessing stems per hectare (sph) for potential
level of LWD functioning
1a >22 cm
50 - 150
1b 12.6-21.9 cm
50 - 100
2 7.5-12.5 cm
75 - 200
3 0.1-7.4 cm
200 - 400
4 <1.3 m height
300 - 600
The effective distance for LWD is considered to be a slope
distance of 25 m in BC coastal regions and 15 m in the interior.
SOD: For a general assessment of SOD, three factors should
be considered. First, assess height
distance of the
vegetation from the stream. The taller the vegetation,
the further it can be from the stream and still be effective
as SOD (Table 5).
Table 5. Effective distance for SOD and stream shading function
Secondly, deciduous leaf litter is higher in nutrients,
produced in larger quantities, and easier to decompose and
digest than needle litter. Therefore, SOD
which is deciduous
in origin will
be of higher
that which is
However, coniferous needles are shed year-round and therefore
provide continuous supply of nutrients.
Lastly, the amount of cover will affect SOD input
into the stream. The more cover (regardless of tree/shrub, deciduous/coniferous,
mature/early structural stage), the higher the input of SOD
relative to little or no cover.
With these three factors in mind, determine the level of
SOD functioning as either low, medium or high.
Stream shading: As with SOD, the
height and distance of vegetation from the stream (as described in Table 5), and
amount of cover
should be considered
for level of
functioning. In addition, the stream class, the BEC zone,
elevation and the aspect of the stream segment are important
factors for assessing stream shade.
Stream shading is likely to have the highest impact on streams
which are small in size, south facing in aspect, and located
in the dryer and warm BEC zones BG, IDF, PP, ICH and CDF.
Surface sediment filtering: The ability of
the riparian area to intercept surface sediment deposition
factors: extent of vegetation cover, slope, micro-topography
sediment sources. For example, minimal ground cover, high
RVT slopes (>35%) and relatively smooth micro-topography
will reduce the surface sediment filtering capacity at
Bank and channel stability: Observe the amount of vegetative
cover on the streambanks, and whether the banks are bare,
undercut or actively eroding. Decide whether the streambanks
in the area of your RVT are stable or unstable. If unstable,
indicate whether of low or moderate functioning level.
Observe the channel size and patterns, and
the channel substrate materials. Try to evaluate whether
the channel is stable,
degrading. If either aggrading or degrading indicate whether
of low or moderate functioning level. Refer
to figures in
WRP Technical Circular 7, Channel Conditions and Prescriptions
Assessment, or the Channel
Assessment Procedures Guidebook to
assist in this evaluation. In cases where it is too difficult
to assess (requiring input from a hydraulic
specialist), indicate by placing a "u" (unknown)
in the space provided.
Photos: Photo documentation (roll and frame number) should
be included in the field form for easy reference. Ideally,
two photos should be taken per plot, one of the RVT vegetation
and the second of the soil pit. Include a measure of scale
in each photo, for example, include a person or surveying
rod in the RVT photo, and include an tape measure in the
soil pit photo.
Other comments: The comments section can be used to explain
any disturbance indicators in greater detail as well as any
general comments on the site. In addition, since one plot
per RVT in most cases does not fully describe a site, walk-through
the RVT and make note of any additional tree species that
were not included in the plot, and any other observations
that might affect the outcome of the Level 1 assessment.
Finally, where possible, compare the functioning in the
harvested sites to similar variables in adjacent mature forest,
or old-growth forest sites.
Proper Functioning Condition
There are additional tools that can be used in the Level
1 field assessment stage. One method is the proper functioning
condition (PFC) checklist-style assessment of the U.S.
Bureau of Land Management (Prichard et al., 1998a, 1998b).
This method requires a stream hydrologist, soils specialist,
fish habitat biologist and riparian vegetation specialist
to walk the stream together and make on-site evaluations
based on their professional judgment (see Appendix
sample questions). Some of the terminology used in the
Code guide (e.g., desired future condition), are incorporated
in Figure 3 (see earlier in text). To effectively use this
method, consult the complete documentation of the Code
method and the supporting scientific references.
Level 1 Data Summary
After completion of field data collection and function evaluation,
return to the office and summarize the data. The summary
review of the field visits
refinement of mapping materials
tabulation of comparative data
discussion of the results
preliminary list of possible restoration activities per dysfunctional
recommended priority locations to proceed to the Level 2
assessment and restoration prescriptions stage.
Level 1 Summary Form Instructions
Once data has been collected from the field sites, it is
advisable to compare the sites to determine which are the
best candidates to recommend for Level 2 assessment and prescription.
This form (Form
3) is intended to make summaries and direct
comparisons easier (also see sample of completed form in
Reach no.: Identify the reach number (if simultaneously
conducting fish habitat or channel conditions assessments).
Transfer number from Forms 1 and 2.
Polygon no. and area (ha): Record the polygon number and
calculated area based on the overview assessment and confirmed
in the field visit. The area estimates (in hectares) can
be quite crude since we are not yet at the prescription phase.
For example, one can obtain a rough area measure by placing
a grid system over the air photo polygons and counting the
number of squares (of known area) from the grid which cover
the polygon area. From the number of squares and based on
knowing the scale of the air photo, one can use an appropriate
conversion to obtain polygon area.
RVT no.: First determine the riparian vegetation type (RVT)
labels (next column) and for each unique label, assign a
number. If there are two sites that have the same label,
they should also have the same RVT number.
An RVT label is created based on the stand structure and
the overstorey species composition. Stand structure is identified
in the first component. Composition makes up the second component
and is determined by identifying the dominant species from
the field form, with layer 1a and 1b. Where lower overstorey
layers of seedlings and saplings are important and data are
available, they will be the third component of the label.
If a species is less than 20% volume in its layer, it can
be included in brackets (Table 6).
Table 6. Examples of RVT labels (adapted from McLennan and
||A deciduous (d) pole sapling (PS) stand, 20-40 years
old dominated by red alder (Dr) with scattered Sitka
spruce (Ss) (<20%) in the overstorey; understorey
has significant stocking of Hw and Ss.
||A coniferous (c) pole sapling stand 20-40 years old
where red alder (Dr) is a minor component (<20%) and
western hemlock (Hw) and western redcedar (Cw) are dominant.
||A low (ls) shrub (SH) regeneration stand between 1
and 20 years old where red alder (Dr) is a minor component
(<20%) and western hemlock (Hw) and western redcedar
(Cw) are dominant.
||A coniferous (c) dominated mature forest (MF) stand
of Sitka spruce (Ss), western hemlock (Hw), and western
RVT labels can also be designed whereby fewer tree species
are part of the label, and instead, understorey vegetation
species (shrubs and herbs) are added. Shrubs and herbs are
indicators of site specific growing conditions and thus good
Level of functioning can be summarized by assigning numbers
to the low, medium and high designations on the field form.
For example, low becomes 1, medium - 3, high - 5. The numbers
for each of the categories for a polygon can then be added
in the Summation column. This method allows comparison of
each individual category and overall level of functioning
for different sites.
Because of regional and site variations, it may be
appropriate to assign stronger weightings to different functions,
for example LWD and stream bank stability may be more important
functions at some sites than provision of SOD or surface
sediment filtering. It will be left to the judgment of those
carrying out the assessment to use the system that suits
their project best (most appropriate tool) such as retaining
the existing ranking from Form
(L,M,H categories from the
field data form), or creating their own weighting system.
Disturbance indicators: Record here any disturbance indicators
that were noted during the site visit, particularly those
that may affect future restoration efforts (e.g., site prone
Priority and recommendations: The summary form for Level
1 is intended as a tool to compare the various RVTs that
were field assessed and to determine which of those require
the more detailed assessment and prescription development
at Level 2.
For all sites for which restoration is a possibility, prioritize
them for Level 2 activities, as high priority (H), medium
(M), or low priority (L), based on benefit to the resource
or watershed, and on factors such as accessibility, field
logistics and costs. At the bottom right hand corner of Form
3 you can sum the total area (in hectares) for the three
Output from the Level 1 Assessment
Output from the Level 1 assessment includes the following:
a brief discussion of methods used in the Level 1 assessment
mapping and map overlays of RVTs in study area
identification of known or suspected impaired polygons
a discussion of impairments and restoration options, desired
future conditions; limitations to restoration;
recommended sites for the Level 2 phase.
In some cases the recommendation may be that no further assessment
is required. Reasons not to proceed with Level 2 for a given
the site is currently functioning well (stream banks and
channels are stable, there is diverse mature vegetation that
offers adequate LWD/CWD, shading, sediment filtering and
the site is too prone to disturbance such as flooding, or
for other reasons cannot support restoration efforts and
success is unlikely.