How to Use This Soil Survey

Additional information about the Nation’s natural resources is available on the Natural Resources Conservation Service home page on the World Wide Web. The address is http://www.nrcs.usda.gov (click on “Technical Resources” ). This soil survey is a publication of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (formerly the Soil Conservation Service) has leadership for the Federal part of the National Cooperative Soil Survey.

Major fieldwork for this soil survey was completed in 1999 through 2001. Soil names and descriptions were approved in 2001. Unless otherwise indicated, statements in this publication refer to conditions in the survey area in 2001. This survey was made cooperatively by the Natural Resources Conservation Service and the National Park Service.

Soil maps in this survey may be copied without permission. Enlargement of these maps, however, could cause misunderstanding of the detail of mapping. If enlarged, maps do not show the small areas of contrasting soils that could have been shown at a larger scale.

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To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14th and Independence Avenue SW, Washington, DC 20250-9410, or call 202-720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.

1. Soils That Are on Uplands and Formed in Airfall-Deposited Ash and Pumice

2. Lapine-Steiger (ponderosa pine/fir)

3. Timbercrater-Llaorock-Castlecrest (mountain hemlock)

4. Timbercrater-Castlecrest-Llaorock (Shasta red fir) Soils That Are in Valleys and Formed in Ash and Pumice Flow Deposits of Ash, Pumice, and Cinders

5. Maklak-Collier (ponderosa pine/fir with lodgepole pine)

6. Castlecrest-Umak (mountain hemlock with lodgepole pine)

7. Unionpeak-Castlecrest (mountain hemlock)

8. Castlecrest (Shasta red fir) Soils That Are on Uplands and Formed in Airfall-Deposited Ash and Pumice Over Glacial Deposits

9. Lapine-Oatman

10. Grousehill Soils on Cinder Cones

11. Redcone-Cinder land Soils on Alpine Meadows With Intermingled Forests

12. Cleetwood-Llaorock-Dyarock Soils in Seeps and on Stream Terraces

13. Stirfry-Mariel-Anniecreek

I. Introduction

1. Anniecreek-Stirfry-Riverwash complex, 0 to 2 percent slopes

2. Badland, 50 to 100 percent slopes

3. Badland-Stirfry complex, 0 to 70 percent slopes

4. Castlecrest gravelly ashy sandy loam, 2 to 10 percent slopes

5. Castlecrest ashy loamy sand, dry, 0 to 15 percent slopes

6. Castlecrest ashy loamy sand, low, 0 to 7 percent slopes

7. Castlecrest gravelly ashy loamy sand, high elevation, 5 to 45 percent slopes

8. Castlecrest-Badland complex, 60 to 100 percent slopes

9. Castlecrest-Llaorock complex, 2 to 25 percent slopes

10. Castlecrest-Sunnotch complex, 5 to 45 percent slopes

11. Cleetwood very gravelly ashy loamy coarse sand, depressional, 0 to 7 percent slopes

12. Cleetwood-Castlecrest complex, dry, 10 to 30 percent slopes

13. Cleetwood-Castlecrest-Llaorock complex, 5 to 30 percent slopes

14. Cleetwood, thin surface-Cleetwood-Dyarock complex, 2 to 20 percent slopes

15. Cleetwood, thin surface-Llaorock-Cleetwood complex, 5 to 30 percent slopes

16. Cleetwood-Sunnotch-Castlecrest complex, high elevation, 15 to 30 percent slopes

17. Collier ashy loamy sand, 0 to 7 percent slopes

18. Collier ashy loamy sand, dry, 0 to 10 percent slopes

19. Collier very gravelly ashy loamy sand, low, 0 to 7 percent slopes

20. Collier-Badland complex, 60 to 100 percent slopes

21. Donegan very gravelly ashy sandy loam, 30 to 65 percent south slopes

22. Grousehill gravelly medial loam, 0 to 25 percent slopes

23. Grousehill-Llaorock complex, 5 to 35 percent slopes

24. Grousehill-Llaorock complex, dry, 0 to 30 percent slopes

25. Grousehill-Racing complex, 0 to 5 percent slopes

26. Lapine paragravelly ashy loamy coarse sand, 10 to 35 percent south slopes

27. Lapine paragravelly ashy loamy coarse sand, 35 to 55 percent south slopes

28. Lapine-Oatman complex, 5 to 30 percent slopes

29. Lapine-Oatman complex, 30 to 60 percent south slopes

30. Lapine-Rock outcrop-Wuksi complex, 30 to 70 percent south slopes

31. Lapine-Steiger-Wuksi complex, high elevation, 2 to 25 percent slopes

32. Lapine-Wuksi-Rock outcrop complex, 30 to 70 percent north slopes

33. Lava flows, 0 to 15 percent slopes

34. Llaorock-Castlecrest complex, 0 to 15 percent slopes

35. Llaorock-Castlecrest complex, 15 to 30 percent slopes

36. Llaorock-Castlecrest-Rock outcrop complex, 30 to 60 percent north slopes

37. Llaorock-Castlecrest-Rock outcrop complex, 30 to 60 percent south slopes

38. Llaorock-Rubble land-Rock outcrop complex, 60 to 90 percent north slopes

39. Llaorock-Rubble land-Rock outcrop complex, 60 to 90 percent south slopes

40. Llaorock-Timbercrater-Rubble land complex, dry, 60 to 90 percent south slopes

41. Maklak paragravelly ashy loamy sand, 0 to 10 percent slopes

42. Maklak paragravelly ashy loamy sand, low, 0 to 10 percent slopes

43. Maklak paragravelly ashy loamy sand, high precipitation, 0 to 10 percent slopes

44. Mariel-Stirfry complex, 0 to 3 percent slopes

45. Redcone-Cinder land complex, 30 to 60 percent south slopes

46. Redcone-Rock outcrop complex, 30 to 60 percent north slopes

47. Rock outcrop-Rubble land complex, 60 to 90 percent slopes

48. Stirfry mucky peat, 0 to 7 percent slopes

49. Stirfry-Grousehill complex, 0 to 10 percent slopes

50. Sunnotch gravelly ashy sandy loam, dry, 0 to 35 percent slopes

51. Sunnotch-Unionpeak complex, 15 to 35 percent slopes

52. Timbercrater paragravelly ashy loamy sand, dry, 25 to 60 percent north slopes

53. Timbercrater-Castlecrest complex, 0 to 10 percent slopes

54. Timbercrater-Castlecrest complex, dry, 2 to 15 percent slopes

55. Timbercrater-Castlecrest complex, dry, 15 to 30 percent south slopes

56. Timbercrater-Castlecrest-Llaorock complex, 10 to 30 percent south slopes

57. Timbercrater-Llaorock complex, 10 to 30 percent north slopes

58. Timbercrater-Llaorock complex, dry, 30 to 60 percent south slopes

59. Timbercrater-Llaorock complex, high elevation, 30 to 80 percent slopes

60. Timbercrater-Llaorock-Castlecrest complex, 30 to 60 percent slopes

61. Timbercrater-Sunnotch-Castlecrest complex, 0 to 10 percent slopes

62. Umak paragravelly ashy fine sandy loam, 0 to 7 percent slopes

63. Umak paragravelly ashy fine sandy loam, dry, 0 to 10 percent slopes

64. Umak paragravelly ashy fine sandy loam, low, 0 to 5 percent slopes

65. Unionpeak-Castlecrest complex, dry, 5 to 15 percent slopes

66. Unionpeak-Castlecrest-Llaorock complex, 15 to 30 percent slopes

67. Unionpeak-Castlecrest-Sunnotch complex, 0 to 15 percent slopes

68. Water

• Interpretive Ratings

•     Rating Class Terms

•     Numerical Ratings

• Ecological Sites

• Vegetation

•     Alpine Meadows with Intermingled Forests

•     Wetlands with Intermingled Forests

•     Whitebark Pine

•     Mountain Hemlock

•     Shasta Red Fir

•     Ponderosa Pine/Fir

•     Lodgepole Pine

•     Douglas Fir

• Rangeland

•     Plant Community Dynamics

•     Characteristics That Affect Management

• Wildlife Habitat

• Forest Productivity and Management

• Recreation

• Engineering

• Building Site Development

• Sanitary Facilities

I. Introduction

• Engineering Index Properties

• Physical Properties

• Chemical Properties

• Water Features

• Soil Features

• Anniecreek Series

• Castlecrest Series

• Cleetwood Series

• Collier Series

• Donegan Series

• Dyarock Series

• Grousehill Series

• Grousehill Taxadjunct

• Lapine Series

• Llaorock Series

• Maklak Series

• Mariel Series

• Oatman Series

• Racing Series

• Redcone Series

• Steiger Series

• Stirfry Series

• Stirfry Taxadjunct

• Sunnotch Series

• Timbercrater Series

• Umak Series

• Unionpeak Series

• Wuksi Series

• Time

• Climate

• Parent Material

• Relief

• Living Organisms

• Table 1.—Temperature and Precipitation

• Table 2.—Freeze Dates in Spring and Fall

• Table 3.—Growing Season

• Table 4.—Acreage and Proportionate Extent of the Soils

• Table 5.—Ecological Sites and Characteristic Plant Communities

• Table 6.—Forestland Overstory Characteristic Plant Communities

• Table 7.—Forestland Management

• Table 8.—Forestland Management

• Table 9.—Forestland Management

• Table 10.—Forestland Management

• Table 11.—Forestland Management

• Table 12.—Recreation

• Table 13.—Building Site Development

• Table 14.—Building Site Development

• Table 15.—Sanitary Facilities

• Table 16.—Sanitary Facilities

• Table 17.—Engineering Index Properties

• Table 18.—Physical Properties of the Soils

• Table 19.—Chemical Properties of the Soils

• Table 20.—Water Features

• Table 21.—Soil Features

• Table 22.—Classification of the Soils

Foreword

This soil survey contains information that affects land use planning in the park. It contains predictions of soil behavior for selected land uses. The survey also highlights soil limitations, improvements needed to overcome the limitations, and the impact of selected land uses on the environment.

This soil survey is designed for different users. Planners and engineers can use the survey to plan land use, select sites for construction, and identify special practices needed to ensure proper performance. Conservationists, teachers, students, and specialists in ecology, recreation, and wildlife management can use the survey to help them understand, protect, and enhance the environment.

The information in this report is intended to identify soil properties that are used in making various land use or land treatment decisions. Statements made in this report are intended to help the land users identify and reduce the effects of soil limitations on various land uses.

Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are shallow to bedrock. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations.

These and many other soil properties that affect land use are described in this soil survey. Broad areas of soils are shown on the general soil map. The location of each soil is shown on the detailed soil maps. Each soil in the park is described. Information on specific uses is given for each soil. Help in using this publication and additional information are available at the local office of the Natural Resources Conservation Service or the Cooperative Extension Service.

The lake is 7.0 to 9.5 kilometers (4.5 to 6.0 miles) wide, has 32 kilometers (20 miles) of shoreline, and has a surface area of 5,339 hectares (13,192 acres). At its deepest point, the lake is 592 meters (1,943 feet) deep, making it the deepest lake in the United States. The landscape surrounding the rim of the caldera slopes downward and outward toward the boundaries of the park and is covered by volcanic debris of various ages. Streams originating on the slopes of Mount Mazama form the headwaters of the Rogue River to the west or join the Klamath River drainage system to the south and east.

The rectangular park surrounding the lake comprises approximately 74,552 hectares (184,144 acres) and is characterized by varied topography that rises from 1,219 meters (4,000 feet) in Red Blanket Canyon in the southwestern corner of the park to 2,720 meters (8,926 feet) at the summit of Mount Scott. Other topographic high points are Union Peak, Hillman Peak, and Timber Crater. Numerous cinder cones are in the park; these were fed from vents radiating outward from Mount Mazama. Most of the park is heavily forested, but there are a number of ash- and pumice-covered, treeless flats. Sparse understory of trees or brush is in the mature forests, and most of the terrain is open and parklike. Where natural forest fires have occurred, there are thick stands of lodgepole pine, manzanita, and snowbrush. Steep-walled canyons along Annie, Castle, and Sun Creeks expose the thick deposits of ash and pumice and contribute to the ruggedness of the terrain.

This section provides general information about the park. It discusses history and development, geology, and climate.

Crater Lake National Park was established in 1902. It was “dedicated and set apart forever as a public park or pleasure ground for the benefit and enjoyment of the people of the United States” (16 USC 121). The act that established the park required that adequate measures be taken for the “preservation of the natural objects...the protection of the timber...the preservation of all kinds of game and fish.” The act required that the park be available, under regulations established by the U.S. Department of the Interior, for use by “scientists, excursionists, and pleasure seekers.”

Subsequent legislation, including the National Park Service Organic Act and the Redwood Act, emphasize the protection, preservation, and interpretation of the natural and historic objects, scenery, and wildlife of all national parks, including Crater Lake National Park. Park resources are to be managed in such a way as to maintain them in an unimpaired condition for the enjoyment of present and future generations.

The legislation enabling Crater Lake National Park also provides for visitor accommodations by stating that “restaurant and hotel keepers, upon application to the Secretary of the Interior, may be permitted by him to establish places of entertainment within the Crater Lake National Park for the accommodation of visitors, at places and under regulations fixed by the Secretary of the Interior, and not otherwise.”

The park is a vital element in a diverse regional recreation complex. Many people visit the park as part of a north-south trip to various parks and scenic areas in Oregon and northern California. Crater Lake has historically been the leading draw for visitors to southern Oregon. More than 500,000 people visit the park annually, most of which visit during the brief summer season. A greater number each year, however, are making use of the winter recreation potential of the park. Long snowy winters and mild short summers dominate the seasonal weather pattern at Crater Lake National Park. The park receives abundant snow in October through May. The average annual snowfall is about 500 inches. Generally, snow lingers in areas at the higher elevations throughout the summer. Crater Lake National Park is almost entirely surrounded by National forests and wilderness areas. The Winema National Forest borders the park on the south and east, the Umpqua National Forest is along the northern border, the Rogue River National Forest is along the western and southwestern borders, and the Sky Lakes Wilderness Area is along the southern border.

The southern entrance station at Mazama Village is 76 miles from Medford, Oregon, and 56 miles from Klamath Falls, Oregon, on State Highway 62. The park can be accessed from the north by State Highway 138. Both the south and north access roads lead to Rim Drive, a 33-mile roadway that circles the caldera rim with pullouts that provide scenic views of the lake. Winter access is maintained only from the southern entrance to the park headquarters in Munson Valley and up to Rim Village. Road closures, particularly between the headquarters and the rim, are common in winter because of frequent snowstorms.

Rim Village is on the southern side of the caldera rim. It is at an elevation of 2,164 meters (7,100 feet). It has been in operation year round since 1948, with limited services in winter. Seasonal interpretive activities are provided at a small visitor facility near the rim and at the Sinnott Memorial overlook. Sinnott Memorial is 25 feet below the rim on a precipitous cliff overlooking the lake. It is significant architecturally because it is constructed mostly of large, uncoursed rock that blends into the wall of the rim. The memorial offers visitors a spectacular view of Crater Lake and is an ideal place from which to study the lake and caldera. Seasonal hotel accommodations are available at Crater Lake Lodge. Food, gifts, a picnic area, geology talks (summer only), and interpretive exhibits also are available at Rim Village.

The headquarters of the park is about 3 miles south of Rim Village, in Munson Valley. The headquarters serves as the center for administration and maintenance of the park and for housing of the National Park Service employees. The Steel Information Center at the headquarters serves as a year-round interpretation and orientation focal point for visitors. The headquarters is in an historic complex of buildings with a designed landscape. This complex was constructed over a 15-year period beginning in 1926. The historic buildings at the headquarters and at Rim Village are listed in the National Register of Historic Places.

Mazama Village is about 7 miles south of Rim Village, and it is the primary overnight use area in summer. A campground, motel accommodations, food services, a gas station, a camper service store, shower and laundry facilities, interpretive walks, and evening campfire programs are provided at Mazama Village.

The Cleetwood area, on the northern side of the caldera rim, is accessed from Rim Drive. It is about 6 miles east of the north junction of Rim Drive and the north entrance road. From the parking lot at the Cleetwood area, a walking trail descends down the side of the caldera to the lake, a drop of 800 vertical feet. Commercial boat tours of the lake are available from this area. Naturalists from the National Park Service accompany the tours.

The park is in a complex geologic region of the Cascade Range, in Southern Oregon. Mount Mazama, which is about 400,000 years old, is one of the younger generation volcanoes in the Cascade Range (Bacon and others, 1997). Mount Mazama formed in an area of older andesitic volcanoes. The older generation volcanoes are represented in the park by the weathered remnants of Union Peak and Timber Crater. These volcanoes were active about 1.2 million years ago, and they have undergone extensive erosion by water and ice. The less resistant ash and breccia deposits of the upper portions of the volcanoes have been eroded away leaving a central spire that formed from the resistant rock of the core plug and the surrounding andesite lava flows.

Mount Mazama formed as a result of five closely spaced volcanic vents that produced a composite cone. Three volcanic vents are within the present-day caldera, and the other two are Mount Scott to the east and Williams Crater to the west. Regular eruptions of pumice, ashflows, and lava flows of andesite and dacite produced a peak reaching 10,000 to 12,000 feet in elevation. About 7,700 years ago, a major eruption covered much of Oregon and the rest of the Northwest with a layer of pumice and ash. Near the mountain, pyroclastic ash and cinder avalanches covered much of the flanks and nearby lowlands (Bacon and others, 1997). The massive eruption emptied the magma chamber under Mount Mazama, and the mountain collapsed. This collapse formed a caldera that is about 4,000 feet deep. The caldera has partially filled with water, creating the spectacular Crater Lake. Approximately 7,400 years ago, eruptions within the caldera formed several cones. One of these is called Wizard Island, which is visible above the lake.

The present landscape is dominated by the lakefilled caldera and the pumice- and ash-covered flanks of truncated Mount Mazama. Exposed in and around the caldera is andesitic and dacitic bedrock from previous eruptions. The ash, cinders, and pumice ejected from the mountain produced landscapes with characteristics related to the relative size and amount of these deposits. The initial eruption produced a plume of pumice and ash that covered a large portion of Oregon and the rest of the Northwest. The finer, sand-sized pumice and ash in the park is mainly on the drier part of the eastern flank of Timber Crater. This airfall material also produced thick accumulations of gravel-sized pumice to the north and east of Mount Mazama. The first pumice and ash pyroclastic flows, which traveled within the park and far beyond its boundaries, were mainly restricted to the valleys and the low-lying lava plains. These thick flows typically were dominated by cobble-sized pumice. Cross-sections of these flows can be seen in truncated stream terraces and roadcut embankments to the west of the park. During later eruptions, the ashflows were of smaller extent and were dominated by ash and cinders and a smaller percentage of pumice. These flows, on the outer flanks of the caldera, partially covered and filled in around the andesite and dacite bedrock (Williams, 1942). Today, the layered ashflows can be seen in the steep downcut canyonsides of Castle, Annie, Sand, and Sun Creeks.

Somewhat overshadowed by the effects of the volcanic eruptions is the long history of glaciation in the park. During the height of the Ice Age, large icecaps covered most the Cascade Range. Valley glaciers were on Mount Mazama throughout its pre-eruption history. Between eruptions, the mountain commonly had many valley glaciers. Slowly, large valleys were carved out by the glaciers. Some of these valleys were totally or partially filled in by tephra, particularly those on the northern side of Mount Mazama.

The cataclysmic eruption of Mount Mazama occurred during a period that was warmer than the present climate and in which the valley glaciers had retreated beyond the present caldera rim. The collapse of the mountain truncated the glacial valleys, and most of the glacial deposits in the valleys have been incorporated into or covered by eruption debris. Remnants of deposits from the icecaps remain, however, mainly in areas upwind of the airfall deposits and at elevations high enough to escape burial by the ashflows. These remnants lie to the west and south, near the border of the park. They consist of the oldest parent material in the park, the ice having receded about 15,000 to 25,000 years ago (Harris, 1988).

Detailed descriptions of ongoing geologic investigations within the park can be obtained from the Crater Lake Data Clearinghouse website maintained by the U.S. Geological Survey (Anonymous, 2000). (http://craterlake.wr.usgs.gov)

Prepared by the Natural Resources Conservation Service, National Water and Climate Center, Portland, Oregon.

The climate tables for this survey were created from data collected at the climate station at the headquarters of Crater Lake National Park, Oregon.

Thunderstorm days, relative humidity, percent sunshine, and wind information were estimated from data collected at the First Order station at Medford, Oregon, and from upper air data.

Table 1 gives data on temperature and precipitation for the park as recorded at Crater Lake in the period 1971 to 2000. Table 2 shows probable dates of the first freeze in fall and the last freeze in spring. Table 3 provides data on the length of the growing season. The extremes given in this section are for the entire period of record, which is 1931 to 2000.

In winter, the average temperature is 26.5 degrees F and the average daily minimum temperature is 18.4 degrees. The lowest temperature on record, which occurred at Crater Lake on January 21, 1962, was -21 degrees. In summer, the average temperature is 51.1 degrees and the average daily maximum temperature is 64.5 degrees. The highest temperature, which occurred at Crater Lake on August 8, 1981, was 90 degrees.

Growing degree days are shown in table 1. They are equivalent to “heat units.” During the month, growing degree days accumulate by the amount that the average temperature each day exceeds a base temperature (40 degrees). The normal monthly accumulation is used to schedule single or successive plantings of a crop between the last freeze in spring and the first freeze in fall.

The average annual precipitation is about 66.88 inches at the park headquarters. The average annual precipitation varies significantly across the park. Most of the western half of the park receives about 60 to 70 inches of precipitation annually. East of the rim, precipitation declines rapidly, with the northeastern corner of the park receiving only about 35 to 45 inches annually. Only about 2 inches, or 3 percent, of the annual total falls during the frost-free period in July and August. The frost-free season typically is only about 40 days, from mid-July to mid-August. The heaviest 1-day rainfall during the period of record was 7.3 inches on June 12, 1950. Thunderstorms occur on about 15 days each year, and most occur in May through August.

The average seasonal snowfall at the park headquarters is 482.7 inches, but it is higher along the rim. The average snowfall decreases to the northeast; the lowest amounts typically are in the northeastern corner of the park. The greatest snow depth at any one time during the period of record was 252 inches recorded on April 3, 1983. On an average, 234 days per year have at least 1 inch of snow on the ground

The heaviest 1-day snowfall on record is 37 inches recorded on February 28, 1971. Snowfall has been recorded in every month, and in some years snow has remained on the ground until August in the coolest, shaded areas.

The average relative humidity in midafternoon is about 40 percent. Humidity is highest at night, and the average at dawn is about 80 percent. The sun shines about 80 percent of the time possible in summer and about 45 percent of the time in winter. The prevailing wind is from the west. The average windspeed is highest, about 15 miles per hour, in winter and early in spring. The windspeed varies significantly, depending upon local topography. The windspeed is highest over exposed ridges, such as in the western and eastern high-lying areas of the rim.

This survey was made to provide information about the soils and miscellaneous areas in the park. The information includes a description of the soils and miscellaneous areas and their location and a discussion of their suitability, limitations, and management for specified uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of native plants; and the kinds of bedrock. They dug many holes to study the soil profile, which is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity.

The soils and miscellaneous areas in the park are in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the park. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the park and relating their position to specific segments of the landform, a soil scientist develops a concept or model of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape.

Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the park and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the park, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research.

While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses. Soil scientists interpret the data from these analyses and tests as well as the field observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Data are assembled from other sources, such as research information and field experience of specialists.

Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date.

After soil scientists located and identified the significant natural bodies of soil in the park, they drew the boundaries of these bodies on aerial photographs and identified each as a specific map unit. Aerial photographs show trees, buildings, roads, and rivers, all of which help in locating boundaries accurately.

The general soil map in this publication shows broad areas that have a distinctive pattern of soils, relief, and drainage. Each map unit on the general soil map is a unique natural landscape. Typically, it consists of one or more major soils or miscellaneous areas and some minor soils or miscellaneous areas. It is named for the major soils or miscellaneous areas. The components of one map unit can occur in another but in a different pattern.

The general soil map can be used to compare the suitability of large areas for general land uses. Areas of suitable soils can be identified on the map. Likewise, areas where the soils are not suitable can be identified.

Because of its small scale, the map is not suitable for detailed planning and management. The soils in any one map unit differ from place to place in slope, depth, drainage, and other characteristics that affect management.

Number of map units: 3

Percentage of park: 29 percent

Percentage of park: 7 percent

Location in park: Eastern side, primarily on the eastern flank of Timber Crater

Depth class: Very deep

Position on landscape: Pumice- and ash-mantled lava plains, hills, ridges, and cinder cones

Parent material: Pumice and ash

Elevation: 4,200 to 6,500 feet

Average annual precipitation: 25 to 50 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 10 to 50 days

Minor components: 10 percent Wuksi soils and 5 percent Rock outcrop

Present vegetation: Ponderosa pine, white fir, and lodgepole pine

Drainage class: Excessively drained

Permeability: Very rapid

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Very paragravelly ashy sand

Substratum texture: Extremely paragravelly ashy sand

Slope range: 2 to 70 percent

Drainage class: Somewhat excessively drained

Permeability: Rapid

Surface texture: Ashy loamy coarse sand

Subsoil texture: Paragravelly ashy loamy coarse sand

Substratum texture: Paragravelly ashy coarse sand

Slope range: 2 to 25 percent

Percentage of park: 17 percent

Location in park: Primarily north and east of Mount Mazama, downwind of the eruption

Depth class: Very deep

Position on landscape: Ridges, mountain flanks, and mountainsides

Slope range: 2 to 80 percent

Elevation: 5,500 to 8,900 feet

Average annual precipitation: 50 to 80 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 7 percent Rubble land, 3 percent Unionpeak soils, and 5 percent Rock outcrop

Present vegetation: Mountain hemlock, whitebark pine, and lodgepole pine

Drainage class: Excessively drained

Permeability: Very rapid

Parent material: Airfall deposits of pumice and ash

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Very paragravelly ashy loamy sand

Substratum texture: Extremely paragravelly ashy sand

Drainage class: Somewhat excessively drained

Permeability: Rapid

Parent material: Residuum and colluvium derived from andesite mixed with ash

Surface texture: Gravelly ashy sandy loam

Subsoil texture: Extremely stony medial sandy loam

Drainage class: Somewhat excessively drained

Permeability: Rapid

Parent material: Airfall deposits of pumice and ash

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Ashy coarse sand

Percentage of park: 5 percent

Location in park: Southeastern flank of Mount Mazama and nearby hills and cinder cones

Depth class: Very deep

Position on landscape: Ridges, mountain flanks, and mountainsides

Slope range: 2 to 80 percent

Elevation: 5,000 to 6,500 feet

Average annual precipitation: 40 to 60 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Rock outcrop

Present vegetation: Shasta red fir and lodgepole pine

Drainage class: Excessively drained

Permeability: Very rapid

Parent material: Airfall deposits of pumice and ash

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Very paragravelly ashy sand

Substratum texture: Extremely paragravelly ashy loamy sand

Drainage class: Somewhat excessively drained

Permeability: Rapid

Parent material: Airfall deposits of pumice and ash

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Ashy coarse sand

Drainage class: Somewhat excessively drained

Permeability: Rapid

Parent material: Residuum and colluvium derived from andesite mixed with ash

Surface texture: Gravelly ashy sandy loam

Subsoil texture: Extremely stony medial sandy loam

Number of map units: 4

Percentage of park: 42 percent

Percentage of park: 5 percent

Location in park: Lowlands and valleys, mainly near the eastern and southeastern boundaries

Depth class: Very deep

Position on landscape: Pumice flows and ashflows

Parent material: Pumice, ash, and cinders

Elevation: 4,000 to 6,000 feet

Average annual precipitation: 20 to 60 inches

Average annual air temperature: 38 to 44 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Lapine soils

Present vegetation: Ponderosa pine, white fir, and lodgepole pine

Drainage class: Excessively drained

Permeability: Very rapid

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Very paragravelly ashy loamy sand

Substratum texture: Extremely paragravelly ashy loamy sand

Slope range: 0 to 10 percent

Drainage class: Somewhat excessively drained

Permeability: Rapid

Surface texture: Ashy sandy loam

Subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Paragravelly ashy sand

Slope range: 0 to 80 percent

Percentage of park: 25 percent

Location in park: Lowlands and valleys near the northern, western, and southern boundaries

Crater Lake National Park, Oregon 19

Depth class: Very deep

Elevation: 4,500 to 7,500 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Timbercrater soils, 5 percent Unionpeak soils, 5 percent Sunnotch soils, and 5 percent Llaorock soils

Present vegetation: Mountain hemlock and lodgepole pine

Drainage class: Somewhat excessively drained

Permeability: Rapid

Position on landscape: Mountain flanks and mountainsides

Parent material: Ash and pumice

Surface and subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Ashy coarse sand and ashy sand

Slope range: 0 to 80 percent

Drainage class: Excessively drained

Permeability: Very rapid

Position on landscape: Pumice flows

Parent material: Pumice and ash

Surface texture: Paragravelly ashy fine sandy loam

Subsoil texture: Extremely paracobbly ashy loamy sand

Slope range: 0 to 10 percent

Percentage of park: 7 percent

Location in park: Along the northern, eastern, and southern flanks of the caldera rim

Drainage class: Somewhat excessively drained

Slope range: 0 to 35 percent

Elevation: 5,000 to 7,000 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 10 percent Sunnotch soils and 5 percent Rock outcrop

Present vegetation: Mountain hemlock and lodgepole pine

Depth class: Moderately deep to a duripan

Permeability: Rapid throughout the solum and moderately rapid in the weakly cemented duripan

Position on landscape: Ashflows

Parent material: Pumice, ash, andesite, and dacite

Surface texture: Ashy sandy loam

Subsoil texture: Gravelly ashy loamy sand

Depth class: Very deep

Permeability: Rapid

Position on landscape: Mountain flanks and mountainsides

Parent material: Pumice and ash

Surface and subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Ashy coarse sand and ashy sand

Percentage of park: 5 percent

Location in park: Eastern and southern valleys and lowlands

Slope range: 0 to 35 percent

Elevation: 5,000 to 6,500 feet

Average annual precipitation: 40 to 60 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 3 percent Cleetwood soils, 5 percent Sunnotch soils, and 7 percent Unionpeak soils

Present vegetation: Shasta red fir and lodgepole pine

Depth class: Very deep

Drainage class: Somewhat excessively drained Permeability: Rapid

Position on landscape: Mountain flanks and mountainsides

Parent material: Pumice and ash

Surface and subsoil texture: Paragravelly ashy loamy sand

Substratum texture: Ashy coarse sand and ashy sand

Number of map units: 2

Percentage of park: 10 percent

Percentage of park: 4 percent

Location in park: Southeastern corner 20 Soil Survey of

Slope range: 5 to 60 percent

Elevation: 4,300 to 6,000 feet

Average annual precipitation: 25 to 50 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 10 to 50 days

Minor components: 5 percent Collier soils

Present vegetation: White fir and ponderosa pine

Depth class: Very deep

Drainage class: Excessively drained

Permeability: Very rapid

Position on landscape: Pumice- and ash-mantled lava plains and hills

Parent material: Pumice and ash

Surface texture: Paragravelly ashy loamy sand

Subsoil texture: Paragravelly ashy loamy sand and very paragravelly ashy sand

Substratum texture: Extremely paragravelly ashy sand

Depth class: Deep to a duripan

Drainage class: Well drained

Permeability: Moderate

Position on landscape: Glaciated volcanic uplands

Parent material: Glacial deposits derived from andesite and mantled with ash

Surface texture: Gravelly medial sandy loam

Subsoil texture: Very gravelly medial sandy loam over extremely gravelly medial fine sandy loam

Percentage of park: 6 percent

Location in park: Uplands along the western boundary

Slope range: 0 to 35 percent

Elevation: 4,500 to 7,000 feet

Average annual precipitation: 45 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 10 to 35 days

Minor components: 10 percent Llaorock soils and 5 percent Timbercrater soils

Present vegetation: Mountain hemlock, Shasta red fir, Douglas fir, and lodgepole pine

Depth class: Moderately deep to a duripan

Drainage class: Moderately well drained

Permeability: Moderate

Position on landscape: Ridges and benches

Parent material: Ash over glacial till

Surface texture: Gravelly medial loam

Subsoil texture: Very cobbly medial loam

Number of map units: 1

Percentage of park: 3 percent

Percentage of park: 3 percent

Location in park: Cinder cones throughout park

Slope range: 30 to 60 percent

Elevation: 5,500 to 7,500 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Rock outcrop and 5 percent Timbercrater soils

Depth class: Moderately deep to a duripan

Drainage class: Somewhat excessively drained

Permeability: Rapid over moderate

Position on landscape: Cinder cones

Parent material: Cinders and ash

Surface texture: Very gravelly ashy sandy loam

Subsoil texture: Very gravelly ashy coarse sandy loam

Kind of rock: Andesite and basaltic andesite cinders

Number of map units: 1

Percentage of park: 15 percent

Percentage of park: 15 percent

Location in park: Alpine and subalpine meadows throughout park

Depth class: Very deep

Permeability: Rapid

Elevation: 5,700 to 8,000 feet

Average annual precipitation: 40 to 80 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Castlecrest soils, 3 percent Rock outcrop, and 2 percent Timbercrater soils

Present vegetation: Cleetwood—mountain buckwheat, western needlegrass, Shasta buckwheat, Newberry knotweed, mountain heath, and Hall’s sedge; Llaorock—mountain hemlock, whitebark pine, and Shasta red fir; Dyarock—Brewer’s sedge, bottlebrush squirreltail, Parry rush, and western needlegrass

Drainage class: Excessively drained

Position on landscape: Mountainsides and benches and valleys on mountains in the Pumice Desert

Parent material: Ash, and andesite and pumice fragments

Surface texture: Very gravelly ashy loamy coarse sand

Substratum texture: Ashy sand and ashy coarse sand

Drainage class: Somewhat excessively drained

Position on landscape: Ridges and backslopes of mountains

Parent material: Residuum and colluvium derived from andesite mixed with ash

Surface texture: Gravelly ashy sandy loam

Subsoil texture: Extremely stony medial sandy loam

Drainage class: Moderately well drained

Position on landscape: Swales and drainageways on mountains

Parent material: Ash, pumice, cinders, and andesite fragments

Surface texture: Very gravelly ashy loamy sand

Subsoil texture: Ashy loamy sand

Substratum texture: Gravelly ashy loamy coarse sand

Number of map units: 1

Percentage of park: 1 percent

Percentage of park: 1 percent

Location in park: Stream terraces, seeps flowing from canyonsides, and bogs scattered throughout park

Depth class: Very deep

Slope range: 0 to 15 percent

Elevation: 4,100 to 6,500 feet

Average annual precipitation: 25 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 5 percent Llaorock soils, 5 percent Grousehill soils, and 5 percent Riverwash

Present vegetation: Sphagnum moss, sedges, rushes, grasses, shrubs, and lodgepole pine

Drainage class: Very poorly drained

Permeability: Moderate

Position on landscape: Bogs in mountain basins

Parent material: Organic material

Surface texture: Mucky peak

Subsoil texture: Muck

Drainage class: Very poorly drained

Permeability: Moderately rapid

Position on landscape: Drainageways

Parent material: Mossy organic material over ash and pumice

Surface texture: Peat

Subsoil texture: Muck

Substratum texture: Gravelly ashy very coarse sand

Drainage class: Somewhat poorly drained

Permeability: Rapid

Position on landscape: Stream terraces

Parent material: Ash and pumice

Surface texture: Ashy fine sandy loam

Subsoil texture: Ashy sand

The map units delineated on the detailed soil maps in this survey represent the soils or miscellaneous areas in the park. The map unit descriptions in this section, along with the maps, can be used to determine the suitability and potential of a unit for specific uses. They also can be used to plan the management needed for those uses.

A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils.

Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. The contrasting components are mentioned in the map unit descriptions. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape.

The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas.

An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives the principal hazards and limitations to be considered in planning for specific uses.

Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement.

Soils of one series can differ in texture of the surface layer, slope, elevation, aspect, landscape position, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use, management, or interpretation. For example, Maklak paragravelly ashy loamy sand, 0 to 10 percent slopes, is a phase of the Maklak series.

Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes.

A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Llaorock-Castlecrest complex, 0 to 15 percent slopes, is an example.

General location: Stream terraces

Major land resource area (MLRA): 6

Elevation: 4,100 to 5,500 feet

Average annual precipitation: 25 to 40 inches

Average annual air temperature: 40 to 42 degrees F

Frost-free period: 10 to 50 days

Stirfry and similar soils: 20 percent

Riverwash: 15 percent

Minor components: 5 percent

Landform: Stream terrace

Geomorphic position: Stream terraces in narrow ravines

Parent material: Pumice and ash

Slope: 0 to 2 percent

Percentage of surface covered with stones and boulders: None

Restrictive features: None within a depth of 60 inches

Drainage class: Somewhat poorly drained

Permeability: Rapid

Flooding: Present (see table 20)

Water table: Present (see table 20)

Ponding: Not present

Available water capacity: About 7.2 inches

Ecological site: Forestland—(006XY706OR) Picea engelmannii/Alnus incana ssp. tenuifolia/Carex

Oi—0 to 4 inches; slightly decomposed plant material

A1—4 to 12 inches; ashy fine sandy loam

2A2—12 to 24 inches; very gravelly ashy sand

3Ab—24 to 32 inches; ashy fine sand

4Bg1—32 to 55 inches; ashy sand

5Bg2—55 to 71 inches; very gravelly ashy coarse sand

Landform: Stream terrace

Geomorphic position: Stream terraces and seeps in ravines

Parent material: Mossy organic material over ash and pumice

Slope: 0 to 2 percent

Percentage of surface covered with stones and boulders: None

Restrictive features: None within a depth of 60 inches

Depth to mineral soil: 40 to 60 inches

Drainage class: Very poorly drained

Permeability: Moderately rapid

Flooding: Not present

Water table: Present (see table 20)

Ponding: Not present

Available water capacity: About 8.5 inches

Ecological site: Rangeland—(003XY015OR) Meadow Fen 40-60 PZ

Oi—0 to 2 inches; peat

Oe—2 to 8 inches; mucky peat

Oa1—8 to 18 inches; muck

Oa2—18 to 51 inches; muck

2A—51 to 60 inches; gravelly ashy coarse sand

Landform: Stream terrace

Geomorphic position: Narrow flood plain

Parent material: Sandy and gravelly alluvium

Slope: 0 to 2 percent

Percentage of surface covered with stones and boulders: None

Restrictive features: None within a depth of 60 inches

Drainage class: Somewhat excessively drained

Flooding: Present (see table 20)

Water table: Present (see table 20)

Crater Lake National Park, Oregon 25

Percentage of map unit: 5 percent

Landform: Stream terrace

Geomorphic position: Seep and spring areas in narrow ravines

• Occasional flooding

• Dustiness if vegetation is removed

• Water erosion

• Frost hazard

• Wetness

• Wetness

• Organic soil material throughout profile

• Frost hazard

• Wetness

• Frequent flooding

• Rock fragments

• Water erosion

General location: Ravines in valleys

Major land resource area (MLRA): 3

Elevation: 4,000 to 6,000 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

Minor components: 20 percent

Landform: Ashflow

Geomorphic position: Nonvegetated ashflow deposits in valleys

Parent material: Ash, cinders, pumice, and andesite

Slope: 50 to 100 percent

Percentage of surface covered with stones and boulders: None

Restrictive features: None within a depth of 60 inches

Drainage class: Excessively drained

Percentage of map unit: 10 percent

Landform: Ashflow

Geomorphic position: Forested side slopes of ravines

Percentage of map unit: 5 percent

Landform: Drainageway

Geomorphic position: Base of side slopes of ravines, and narrow stream terraces

Percentage of map unit: 5 percent

Landform: Ashflow

Geomorphic position: Welded tuff outcroppings on side slopes of ravines

• Steep and unstable slopes

• Dustiness

• Wind erosion

• Water erosion

• Low water-holding capacity

General location: Ravines in valleys

Major land resource area (MLRA): 3

Elevation: 5,000 to 6,500 feet

Average annual precipitation: 30 to 60 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days