Classification and Management of Aquatic, Riparian, and Wetland

364 Pages·2004·7.94 MB·English

United States Classification and Management of
Department of
Agriculture Aquatic, Riparian, and Wetland Sites
Forest Service on the National Forests of Eastern
Pacific Northwest Washington: Series Description
Research Station
General Technical Report
Bernard L. Kovalchik and Rodrick R. Clausnitzer
PNW-GTR-593
September 2004
The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of
multiple use management of the Nation’s forest resources for sustained yields of wood,
water, forage, wildlife, and recreation. Through forestry research, cooperation with the
States and private forest owners, and management of the National Forests and National
Grasslands, it strives—as directed by Congress—to provide increasingly greater service to
a growing Nation.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, gender, religion, age, disability,
political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases
apply to all programs.) Persons with disabilities who require alternative means for
communication of program information (Braille, large print, audiotape, etc.) should
contact USDA’s TARGET Center at [phone] (voice and TDD).
To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room
326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-
9410 or call [phone] (voice and TDD). USDA is an equal opportunity provider
and employer.
USDA is committed to making its information materials accessible to all USDA customers
and employees.
AUTHORS
Bernard L. Kovalchik is the area ecologist (retired), Area 2 Ecology Program,
Colville, Okanogan, and Wenatchee National Forests, Pacific Northwest Region.
Kovalchik was stationed at the Colville National Forest, 755 South Main Street,
Colville, WA 99114. Rodrick R. Clausnitzer is a forest botanist/plant ecolo-
gist, Okanogan-Wenatchee National Forests and the Area 2 Ecology Program,
Pacific Northwest Region. Clausnitzer is stationed at the Okanogan Valley Office,
Okanogan-Wenatchee National Forests, 1240 South Second Avenue, Okanogan,
WA 98840-9723.
Classification and Management of
Aquatic, Riparian, and Wetland Sites
on the National Forests of Eastern
Washington: Series Description
Bernard L. Kovalchik and Rodrick R. Clausnitzer
Published by:
U.S. Department of Agriculture, Forest Service
Pacific Northwest Research Station
General Technical Report PNW-GTR-593
September 2004
In cooperation with:
U.S. Department of Agriculture, Forest Service
Colville, Okanogan, and Wenatchee National Forests
ABSTRACT
Kovalchik, Bernard L.; Clausnitzer, Rodrick R. 2004. Classification and management
of aquatic, riparian, and wetland sites on the national forests of eastern Washington:
series descripton. Gen. Tech. Rep. PNW-GTR-593. Portland, OR: U.S. Department of
Agriculture, Forest Service, Pacific Northwest Research Station. 354 p. In cooperation
with: Pacific Northwest Region, Colville, Okanogan, and Wenatchee National Forests.
This is a classification of aquatic, wetland, and riparian series and plant associations
found within the Colville, Okanogan, and Wenatchee National Forests. It is based on the
potential vegetation occurring on lake and pond margins, wetland fens and bogs, and
fluvial surfaces along streams and rivers within Forest Service lands. Data used in the
classification were collected from 1,650 field plots sampled across the three forests. This
classification identifies 32 series separated into four physiognomic classes: coniferous
forests, deciduous forests, shrubs, and herbaceous vegetation. In addition, keys to the iden-
tification of 163 plant associations or community types are presented. The report includes
detailed descriptions of the physical environment, geomorphology, ecosystem function,
and management of each series. This classification supplements and expands information
presented in upland forest plant association classifications previously completed for the
three eastern Washington forests. It is a comprehensive summary of the aquatic, riparian,
and wetland series and contributes to the understanding of ecosystems and their manage-
ment in eastern Washington.
Keywords: Riparian, aquatic, wetland, vegetation classification, series description,
plant association, plant community, riparian vegetation, riparian ecosystems, eastern
Washington.
CONTENTS 59 USFWS Wetlands Classification
1 Introduction 59 Key to the Western Redcedar (Thuja plicata)
3 Methods Plant Associations
5 Classification Concepts and Terminology 63 Subalpine Fir Series (ABLA2)
7 The Physical Environment 63 Classification Database
12 Aquatic/Riparian/Wetland Classification 64 Vegetation Characteristics
13 Series Description Criteria 64 Physical Setting
14 Ecosystem Management 67 Ecosystem Management
15 Adjacent Series and Relationships to 71 Adjacent Series
Other Classifications 71 Relationships to Other Classifications
16 Keys for Field Identification 71 USFWS Wetlands Classification
16 Instructions for Using the Key 72 Key to the Subalpine Fir (Abies lasiocarpa)
17 Vegetative Key to the Major Vegetation Life Forms Plant Associations
17 Key to the Coniferous Forest Series 77 Engelmann Spruce Series (PIEN)
17 Key to the Deciduous Forest Series 78 Classification Database
18 Key to the Shrub Series 78 Vegetation Characteristics
18 Key to the Herbaceous Series 78 Physical Setting
81 Ecosystem Management
CONIFEROUS FOREST SERIES 85 Adjacent Series
19 Mountain Hemlock Series (TSME) 85 Relationships to Other Classifications
19 Classification Database 85 USFWS Wetlands Classification
20 Vegetation Characteristics 86 Key to the Engelmann Spruce (Picea engelmannii)
20 Physical Setting Plant Associations
22 Ecosystem Management 89 Grand Fir Series (ABGR)
25 Adjacent Series 89 Classification Database
25 Relationships to Other Classifications 90 Vegetation Characteristics
25 USFWS Wetlands Classification 90 Physical Setting
26 Key to the Mountain Hemlock (Tsuga mertensiana) 92 Ecosystem Management
Plant Associations 95 Adjacent Series
29 Pacific Silver Fir Series (ABAM) 95 Relationships to Other Classifications
29 Classification Database 95 USFWS Wetlands Classifications
30 Vegetation Characteristics 96 Key to the Grand Fir (Abies grandis) Plant Associations
30 Physical Setting 99 Miscellaneous Conifer Series and Plant Associations
32 Ecosystem Management 99 Physical Setting
35 Adjacent Series 100 Key to the Miscellaneous Conifer Series and
35 Relationships to Other Classifications Plant Associations
36 USFWS Wetlands Classification 101 Douglas-Fir Series (PSME)
36 Key to the Pacific Silver Fir (Abies amabilis) 101 Vegetation Characteristics
Plant Associations 101 Physical Setting
39 Western Hemlock Series (TSHE) 101 Ecosystem Management
39 Classification Database 102 Relationships to Other Classifications
40 Vegetation Characteristics 102 USFWS Wetlands Classification
40 Physical Setting 103 Subalpine Larch Series (LALY)
43 Ecosystem Management 103 Vegetation Characteristics
46 Adjacent Series 103 Physical Setting
46 Relationships to Other Classifications 103 Ecosystem Management
47 USFWS Wetlands Classification 104 Relationships to Other Classifications
47 Key to the Western Hemlock (Tsuga heterophylla) 104 USFWS Wetlands Classification
Plant Associations 105 Lodgepole Pine Series (PICO)
51 Western Redcedar Series (THPL)
52 Classification Database DECIDUOUS FOREST SERIES
52 Vegetation Characteristics 109 Quaking Aspen Series (POTR)
53 Physical Setting 109 Classification Database
55 Ecosystem Management 110 Vegetation Characteristics
58 Adjacent Series 110 Physical Setting
59 Relationships to Other Classifications 112 Ecosystem Management
116 Adjacent Series 167 USFWS Wetlands Classification
116 Relationships to Other Classifications 167 Key to the HEATH Plant Associations
116 USFWS Wetlands Classification 169 Vine Maple Series (ACCI)
116 Key to the Quaking Aspen (Populus tremuloides) 169 Classification Database
Plant Associations 170 Vegetation Characteristics
119 Black Cottonwood Series (POTR2) 170 Physical Setting
119 Classification Database 172 Ecosystem Management
120 Vegetation Characteristics 174 Adjacent Series
120 Physical Setting 175 Relationships to Other Classifications
123 Ecosystem Management 175 USFWS Wetlands Classification
126 Adjacent Series 175 Key to the Vine Maple (Acer circinatum)
126 Relationships to Other Classifications Plant Associations
127 USFWS Wetlands Classification 177 Sitka Alder Series (ALSI)
127 Key to the Black Cottonwood (Populus trichocarpa) 177 Classification Database
Plant Associations 178 Vegetation Characteristics
129 Miscellaneous Deciduous Tree Series and 178 Physical Setting
Plant Associations 181 Ecosystem Management
129 Physical Setting 183 Adjacent Series
130 Key to the Miscellaneous Deciduous Tree Series 183 Relationships to Other Classifications
131 Red Alder Series (ALRU) 183 USFWS Wetlands Classification
131 Vegetation Characteristics 184 Key to the Sitka Alder (Alnus sinuata)
131 Physical Setting Plant Associations
131 Ecosystem Management 187 Mountain Alder Series (ALIN)
132 Relationships to Other Classifications 187 Classification Database
132 USFWS Wetlands Classification 188 Vegetation Characteristics
133 Paper Birch Series (BEPA) 188 Physical Setting
133 Vegetation Characteristics 192 Ecosystem Management
133 Physical Setting 195 Adjacent Series
134 Ecosystem Management 195 Relationships to Other Classifications
134 Relationships to Other Classifications 196 USFWS Wetlands Classification
134 USFWS Wetlands Classification 196 Key to the Mountain Alder (Alnus incana)
135 Oregon White Oak Series (QUGA) Plant Associations
135 Vegetation Characteristics 201 Red-Osier Dogwood Series (COST)
135 Physical Setting 201 Classification Database
136 Ecosystem Management 202 Vegetation Characteristics
137 Relationships to Other Classifications 202 Physical Setting
137 USFWS Wetlands Classification 204 Ecosystem Management
137 Bigleaf Maple Series (ACMA) 208 Adjacent Series
208 Relationships to Other Classifications
SHRUB SERIES 208 USFWS Wetlands Classification
141 Willow Series (SALIX) 208 Key to the Red-Osier Dogwood (Cornus stolonifera)
141 Classification Database Plant Associations
142 Vegetation Characteristics 211 Douglas Spiraea Series (SPDO)
143 Physical Setting 211 Classification Database
148 Ecosystem Management 212 Vegetation Characteristics
154 Adjacent Series 212 Physical Setting
154 Relationships to Other Classifications 214 Ecosystem Management
154 USFWS Wetlands Classification 216 Adjacent Series
154 Key to the Willow (Salix) Plant Associations 216 Relationships to Other Classifications
161 Heath Series (HEATH) 217 USFWS Wetlands Classification
161 Classification Database 217 Key to the Douglas spiraea (Spiraea douglasii)
162 Vegetation Characteristics Plant Associations
162 Physical Setting 219 Miscellaneous Shrub Series and Plant Associations
164 Ecosystem Management 219 Physical Setting
167 Adjacent Series 220 Key to the Miscellaneous Shrub Series
167 Relationships to Other Classifications 221 Douglas Maple Series (ACGLD)
221 Vegetation Characteristics 269 USFWS Wetlands Classification
221 Physical Setting 270 Key to the FORB Plant Associations
221 Ecosystem Management 272 Metric and English Equivalents
222 Relationships to Other Classifications 272 Acknowledgments
222 USFWS Wetlands Classification 273 References
223 Devil’s Club Series (OPHO)
223 Vegetation Characteristics APPENDIXES
223 Physical Setting 291 Appendix A: Aquatic, Riparian, and Wetland Plant,
223 Ecosystem Management Animal, and Insect Species, and Diseases
224 Relationships to Other Classifications Mentioned in This Classification
224 USFWS Wetlands Classification 291 A-1: Aquatic, Riparian, and Wetland Plants
225 Salmonberry Series (RUSP) Listed by Scientific Name
225 Vegetation Characteristics 298 A-2: Aquatic, Riparian, and Wetland Plants
225 Physical Setting Listed by Common Name
225 Ecosystem Management 304 A-3: Insect Species Mentioned in This Classification
226 Relationships to Other Classifications 305 A-4: Diseases Mentioned in This Classification
226 USFWS Wetlands Classification 306 A-5: Wildlife Species Mentioned in This Classification
227 Shrubby Cinquefoil Series (POFR) 308 Appendix B: Management Information for Selected
227 Cascade Azalea Series (RHAL) Plant Species
227 Common Snowberry Series (SYAL) 308 B-1: Forage Palatability for Cattle, Sheep,
and Horses, Energy and Protein Value
HERBACEOUS SERIES 310 B-2: Thermal or Feeding Cover and Food Values for
231 AQUATIC Series Elk, Mule Deer, and White-Tailed Deer
232 Classification Database 311 B-3: Thermal or Feeding Cover Values for Upland
232 Vegetation Characteristics Game Birds, Waterfowl, Small Nongame Birds, and
233 Physical Setting Small Mammals
235 Ecosystem Management 312 B-4: Food Value or Degree of Use for Upland Game
237 Adjacent Series Birds, Waterfowl, Small Nongame Birds, and Small
237 Relationships to Other Classifications Mammals
237 USFWS Wetlands Classification 314 B-5: Potential Biomass Production, Erosion Control
238 Key to the AQUATIC Plant Associations Potential, Short-Term Revegetation Potential, and
241 MEADOW Series Long-Term Revegetation Potential
243 Classification Database 316 Appendix C: Productivity Information
243 Vegetation Characteristics 316 C-1a: Basal Area by Species by Series
245 Physical Setting 316 C-1b: Basal Area by Series
249 Ecosystem Management 317 C-2: Site Index (feet) by Species by Series
253 Adjacent Series 318 C-3: Down Log Attributes by Decomposition, Class,
254 Relationships to Other Classifications and Series
254 USFWS Wetlands Classification 321 C-4: Snag Attributes by Series
254 Key to the MEADOW Plant Associations 322 Appendix D: Occurrences of Threatened and Sensitive
254 Key to the Sedge (Carex) Plant Associations Species by Series
255 Key to the Nonsedge Plant Associations 323 Appendix E: Comparisons for Important Sedges (Carex)
263 FORB Series in Eastern Washington
264 Classification Database 326 Appendix F: Comparisons for Willow (SALIX) Species in
264 Vegetation Characteristics Eastern Washington
265 Physical Setting 329 Appendix G: Species Comparisons by Series
267 Ecosystem Management 344 Appendix H: Aquatic, Riparian, and Wetland Field Form
269 Adjacent Series 346 Glossary
269 Relationships to Other Classifications
PREFACE
There is tremendous diversity in the aquatic, wetland, The shrub-dominated series include the willow, heath,
and riparian ecosystems of eastern Washington. Bernard L. vine maple, Sitka alder, mountain alder, red-osier dogwood,
Kovalchik describes this variation at the series level in this Douglas spiraea, Douglas maple, devil’s club, salmonberry,
vegetation guide for national forest lands in Washington. shrubby cinquefoil, Cascade azalea, and common snowberry
Here “series” refers to the group of plant associations having series. Kovalchik presents these complex and dynamic sys-
the same climax species characterizing the dominant plant tems in a manner that facilitates good stewardship of these
cover. For example, the Pacific silver fir series is composed riparian/wetland resources. He identifies the environmental
of all plant associations potentially dominated by Pacific matrix supporting the 13 series and the management con-
silver fir at climax. The series is a level in the classifica- cerns that span the environmental variation in this diverse
tion hierarchy above the plant association level. This level is group.
useful in describing environmental conditions, community Herbaceous vegetation is described in the aquatic series,
composition, and management opportunities and limitations the meadow series, and the forb series. Unlike series within
at a scale broader than plant association descriptions. The the previous life-form groups (conifers, deciduous trees,
guide describes ecosystem diversity in a manner helpful to and shrubs), these three series of herbaceous vegetation do
resource managers with a fundamental understanding of not have a singular climax dominant (for example, Pacific
wetland ecology and vegetation. silver fir series). Rather, the series is named for recognizable
Included in this guide are series descriptions and keys to habitat (aquatic and meadow) or life form (forb). A vari-
hydrophytic vegetation dominated by conifers, deciduous ety of climax herbaceous species can dominate sites within
trees, shrubs, and herbaceous plants. The author describes each of these three series. The aquatic series includes all
the biotic and abiotic environments; the series distribution herbaceous plant associations supporting rooted vascular or
within the Colville, Okanogan, and Wenatchee National emergent vegetation that grows in deep water or in shallow
Forests; and ecosystem management of the series and its water along the shoreline of permanently standing water.
components. Plant association keys and association tables are Graminoids dominate sites classified in the meadow series;
presented for those who want additional information for site this complex series includes 24 plant associations. These
classification. Future classification efforts can build on this associations occur across a variety of habitats representing
framework and expand descriptions of the lower levels in the different environmental conditions of moisture, temperature,
classification taxonomy (plant associations). pH, aeration, and organic soil fraction. Five plant associa-
Kovalchik has expanded the work of other Area 2 plant tions with perennial forb dominance are found in the forb
ecologists in his treatment of the coniferous series; he de- series. The forb series includes all terrestrial riparian and
fines and describes those wetland and riparian sites dominat- wetland sites dominated by forbs; it does not include forb-
ed by mountain hemlock, Pacific silver fir, western hemlock, dominated sites in the aquatic series. The author’s treatment
western redcedar, subalpine fir, Engelmann spruce, grand of herbaceous vegetation has provided a simplified descrip-
fir, Douglas-fir, subalpine larch, and lodgepole pine. In addi- tion of the variation inherent in these diverse ecosystems
tion, he describes conifer types occupying moist sites adja- and helps resource specialists become familiar with the
cent to streams, rivers, lakes, and ponds that are transitional distribution and management of these types.
to upland vegetation described in earlier guides. The appendixes include information that both supple-
Vegetation dominated by deciduous trees is summarized ments and enhances the series descriptions. It has been a
in the descriptions of the quaking aspen, black cottonwood, rewarding experience working with Bud Kovalchik to finish
red alder, paper birch, Oregon white oak, and bigleaf maple this aquatic, wetland, and riparian classification guide. The
series. The author describes the composition, distribution, field sampling, synecological analyses, and draft document
and management of these important landscape elements in were his work; I have only assisted in the preparation of the
northeast Washington forests. He demonstrates that these final guide. Our hope is that the completed work is a valu-
series provide habitat diversity fundamental to maintaining able addition to the store of ecological information that will
wildlife, fish, and rare plant resources of the area, and he aid resource stewardship in northeastern Washington.
provides the framework for ecosystem management of these Rod Clausnitzer
types. July 2004
Introduction
Figure 1—Riparian and wetland ecosystems form a narrow interface between aquatic and upland ecosystems.
INTRODUCTION
This study presents a classification of (and management composition, and function throughout most of the United
options for) aquatic, wetland, and riparian series and plant States. Rehabilitation and restoration are currently high
associations occurring within the Colville, Okanogan, and priorities for the U.S. Department of Agriculture (USDA)
Wenatchee National Forests (NF) (fig. 1). Aquatic, wetland Forest Service (FS) and other agencies charged with manag-
and riparian ecosystems are only a small portion of the ing public land. To improve conditions, an understanding of
eastern Washington landscape. They are, however, dispro- wetland and riparian ecosystems is necessary. Classification
portionately important as habitats for plants and as sources of aquatic, riparian, and wetland series and their plant as-
of food, water, cover, and nesting habitat for animals (Crowe sociations provides a means of stratifying these ecosystems
and Clausnitzer 1997, Hansen et al. 1995, Kovalchik 1987). into recognizable and repeatable units that integrate potential
Vegetation production is generally higher in these ecosys- natural vegetation, soil characteristics, fluvial geomorphol-
tems than in nearby uplands, and their cool, moist micro- ogy, hydrology, and climate. This classification is integral
climate provides a contrasting habitat. These areas also to ecosystem management providing a common framework
are valued for human uses including recreation; livestock for communicating about wetland ecosystems among vari-
grazing; as a water supply for irrigation, mining opera- ous disciplines, and for planning management activities and
tions, and crop production; and as transportation corridors. analysis of their effects.
The structure and composition of riparian and wetland “Wetlands are areas that lie between terrestrial (upland)
systems influence the rate, amount, and timing for water, and aquatic systems and generally considered to be inundated
nutrients, organic debris, and inorganic materials that enter or saturated by surface or groundwater at a frequency and
lakes, ponds, streams, and rivers. The energy, and ultimate duration sufficient, under normal circumstances, to support a
amount, timing, and erosive power of floodwaters are influ- prevalence of vegetation typically adapted for life in saturated
enced by the soils, vegetation, and geomorphology of soil soil conditions” (Federal Interagency Committee for Wetland
surfaces (fluvial surfaces) within valley bottoms. Decades Delineation 1989). The U.S. Fish and Wildlife Service
of intensive use of riparian areas and other wetlands have (USFWS) wetlands classification (Cowardin et al. 1979) uses
caused substantial degradation of their ecological structure, the term “wetland vegetation” to describe “vegetation within
1
Classification and Management of Aquatic, Riparian, and Wetland Sites on the National Forests of Eastern Washington
or adjacent to, and hydrologically influenced by, streams, (Hemstrom and Franklin 1982), vegetation, soil, water, and
rivers, lakes, meadows, and seeps.” The term “riparian physical characteristics can usefully indicate plant responses
vegetation” is used specifically for vegetation located within to management, productivity potential, and future species
the valley of, and hydrologically influenced by, a stream or composition. Such a classification allows us to:
river. “Aquatic vegetation” grows in deeper, permanently • Plan management strategies—Evaluate resource
standing water in lakes and ponds (or in the sluggish back- condition, productivity, and responses to management.
waters of streams and rivers). • Communicate—Provide a common description of
These riparian and wetland zones form a narrow interface riparian conditions for various disciplines, record
between aquatic and terrestrial ecosystems. In the moun- successes or failures of management actions, and repeat
tainous regions of the Pacific Northwest (Kovalchik 1987, the successes.
Youngblood et al. 1985b), these water-oriented ecosystems
• Apply research—Provide a direct link between
are well defined by the presence of free, unbound water
research results and practical land management.
and are next to much drier upslope ecosystems. They occur
Recent classifications of series and plant associations
on a variety of sites, such as floodplains, bogs, marshes,
integrate potential natural vegetation, soil characteristics,
lakeshores, springs, and basins. Jurisdictional wetlands
fluvial geomorphology, hydrology, and climate (Crowe and
must (under current regulations) have three components:
Clausnitzer 1997, Diaz and Mellen 1996, Hansen et al. 1995,
wetland hydrology, hydric soils, and hydrophytic vegeta-
Kovalchik 1987). This classification follows their lead as
tion. The Natural Resources Conservation Service (NRCS)
it classifies aquatic, wetland, and riparian series and plant
has devised the list of soil types that qualify as hydric soils
associations (with some community types) occurring on
(USDA SCS 1987); the definitions of wetland hydrology
the Colville, Okanogan, and Wenatchee NFs.
are found in the Corps of Engineers Wetland Delineation
This classification covers all riparian and wetland sites
Manual (Environmental Laboratory 1987); and the USFWS
within the Colville, Wenatchee, and Okanogan NFs, as well
has prepared the list of hydrophytes and their degree of wet-
as a large tract of land on the west side of the Cascades
land affinity (USFWS 1996). Included are plant associations
between Washington Pass and the North Cascades National
occurring on fluvial surfaces in valley bottoms that may not
Park (fig. 2). It includes aquatic, riparian, wetland, and tran-
be classified as jurisdictional wetlands but that do function
sitional series and plant associations that (1) occur repeatedly
as “xeric” or “transitional” riparian or wetland areas (Crowe
in eastern Washington, (2) are large enough to be mapped
and Clausnitzer 1997, Kovalchik 1987). These fluvial surfac-
for project-level wildland management, and (3) have distinct
es usually are drier terraces and the adjacent toeslope. They
management differences.
also may include the transition to uplands that occurs at the
This classification supplements and expands information
margins of true wetlands.
presented in upland forest plant association classifications
Thus, typical riparian and wetland sites (as used in this
in eastern Washington (Lillybridge et al. 1995, Williams et
report) are composed of three distinct ecosystems (fig. 1)
al. 1995). It focuses on riparian and wetland ecosystems but
(Kovalchik 1987):
also includes aquatic ecosystems. Intermittent streams, dry
• Aquatic—The permanently flooded portion of the
draws, and other land features that may at times transport
riparian or wetland zone, which includes streams,
water are poorly represented in the classification, although
rivers, ponds or lakes.
they may support vegetation described by one of the series
• Riparian and wetland—The land next to water where
or plant associations. Seeps and springs support wetland
plants that are dependent on a perpetual source of
or riparian vegetation but were not sampled often. Small
water live.
portions of the NFs, such as parts of the eastern half of the
• Transitional or xeroriparian—Subirrigated sites lying
Tonasket Ranger District (RD) of the Okanogan NF and the
between riparian/wetland sites and upland. This
Table Mountain area of the Wenatchee NF, may have ripar-
ecosystem does not have true hydrophytic vegetation
ian zones in deteriorated condition. They are weakly rep-
such as sedges and willows, yet is uniquely different
resented in the database because of the lack of riparian and
from uplands.
wetland ecosystems in late-seral to climax ecological status.
The consistent occurrence of similar series and plant This study has been prepared to meet the following objec-
associations in these ecosystems can be used to stratify tives of the Pacific Northwest Region Ecology Program:
the landscape (Daubenmire 1976, Pfister et al. 1977). • Provide a useful classification of water-defined eco-
Although not all questions about a piece of land can be systems as a step toward completing the USDA Forest
answered by a series/plant association classification Service, Pacific Northwest Region classification
program.
2