Rocky Butte (previously known as Mowich Illahee and Wiberg Butte) is an extinct
cinder cone
A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...
butte
__NOTOC__
In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and tablelands. The word ''butte'' comes from a French word mea ...
in
Portland
Portland most commonly refers to:
* Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States
* Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
,
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
,
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. It is also part of the
Boring Lava Field
The Boring Lava Field (also known as the Boring Volcanic Field) is a Plio-Pleistocene volcanic field with cinder cones, small shield volcanoes, and lava flows in the northern Willamette Valley of the U.S. state of Oregon and adjacent southwest ...
, a group of volcanic vents and lava flows throughout Oregon and
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered on ...
state. The volcano erupted between 285,000 and 500,000 years ago.
As part of the Boring Lava Field, Rocky Butte is considered an outlier of the
Cascade Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...
. It was produced by the
subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
of the oceanic
Juan de Fuca tectonic plate under the
North American tectonic plate; it is the core remnant of
intrusive rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''Igneous intrusion, intrusions'', such as batholiths, dike (geology), dikes, Sill (geology), sills, laccoliths, and volcanic necks.I ...
from kilate
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
volcano. The Butte has a
calc-alkaline
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic mag ...
composition and consists of
basaltic andesite
Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...
with
olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
phenocryst
300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter ...
s.
Historically, the mountain was the home of the Rocky Butte Jail, Judson Baptist College, and
Hill Military Academy
Hill Military Academy was a private, College preparatory military academy in Portland in the U.S. state of Oregon. Opened in 1901, it was a leading military boarding school in the Pacific Northwest. Originally located in Northwest Portland, it late ...
, as well as an extensive
Works Progress Administration
The Works Progress Administration (WPA; renamed in 1939 as the Work Projects Administration) was an American New Deal agency that employed millions of jobseekers (mostly men who were not formally educated) to carry out public works projects, i ...
construction project; it is also the site of a still functioning but decommissioned
airway beacon
An airway beacon (US) or aerial lighthouse (UK and Europe) was a rotating light assembly mounted atop a tower. These were once used extensively in the United States for visual navigation by airplane pilots along a specified airway corridor. ...
,
Portland Bible College
Portland Bible College (PBC) is a four-year Bible college in Portland, Oregon, United States that offers theological and church ministry degrees. It was founded in 1967 and is associated with Mannahouse Church, which is associated with Ministe ...
, and a campus for the City Bible Church. The slopes of Rocky Butte currently support Joseph Wood Hill Park and the Rocky Butte Natural Area, which includes a wide variety of flora and fauna and supports rich forest
stand
Stand or The Stand may refer to:
* To assume the upright position of standing
* Forest stand, a group of trees
* Area of seating in a stadium, such as bleachers
* Stand (cricket), a relationship between two players
* Stand (drill pipe), 2 or 3 ...
s. Located next to
Interstate 205
Interstate 205 may refer to either of two unconnected Interstate Highways in the United States, both of which are related to Interstate 5
* Interstate 205 (California), a connector in the San Francisco Bay Area
* Interstate 205 (Oregon–Washingt ...
, the Butte is a popular destination for hiking, climbing, and seeing mountains from its summit viewpoint.
Geography
![Downtown from Rocky Butte](https://upload.wikimedia.org/wikipedia/commons/8/86/Downtown_from_Rocky_Butte.jpg)
Rocky Butte lies in the northeast part of
Portland
Portland most commonly refers to:
* Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States
* Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
within the city limits, in
Multnomah County
Multnomah County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the county's population was 815,428. Multnomah County is part of the Portland–Vancouver– Hillsboro, OR–WA Metropolitan Statistical Area. Thou ...
, part of the U. S. state of
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
. It is one of the few smaller volcanic cones within or near Portland, along with Mount Tabor, Kelly Butte, and Powell Butte. According to the
U.S. National Geodetic Survey
The National Geodetic Survey (NGS) is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications ...
, Rocky Butte has an elevation of .
It is surrounded on almost all sides by the Portland Delta.
With a variable topography, the Portland area ranges from river valley floors to
terrace
Terrace may refer to:
Landforms and construction
* Fluvial terrace, a natural, flat surface that borders and lies above the floodplain of a stream or river
* Terrace, a street suffix
* Terrace, the portion of a lot between the public sidewalk a ...
s reaching elevations of . The
Willamette Valley
The Willamette Valley ( ) is a long valley in Oregon, in the Pacific Northwest region of the United States. The Willamette River flows the entire length of the valley and is surrounded by mountains on three sides: the Cascade Range to the east, ...
is separated within by hills reaching heights more than , and it is also physically separated from the lower
Columbia River
The Columbia River (Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, C ...
valley. The Columbia River flows west from the eastern Portland region, merging with the Willamette near Portland before moving north. Tributaries for the Willamette include the Pudding, Molalla, Tualatin, Abernethy, and Clackamas Rivers, while the Washougal and Sandy Rivers mark notable tributaries for the Columbia River. The Columbia River has significantly shaped the geology of the area.
Portland's climate is moderate, with long growing seasons, moderate rainfail, mild winters, and warm, dry summer seasons. The area typically does not experience frost, with more than 200 frost-free days annually. Temperature can vary widely, reaching a historic maximum of , though the usual July maximum is below , and the average minimum for January is above . Yearly, precipitation averages between in most river valleys, with a mean of from 1871 through 1952. It shows variability, however, with a historic low of at Portland in 1929 and a maximum of in 1882. More than 75 percent of this precipitation occurs between October and March; July and August mark the driest months with means below , while November, December, and January represent the wettest with averages greater than .
Prevailing winds
In meteorology, prevailing wind in a region of the Earth's surface is a surface wind that blows predominantly from a particular direction. The dominant winds are the trends in direction of wind with the highest speed over a particular point on ...
originate from the south during winter and from the northwest during the summer season, with the exception of prevailing winds at the mouth of the Columbia River Gorge, where winds predominantly move to the east. The southern winds have the highest velocities of the three, only rarely occurring with potentially destructive force.
Geology
![Boring lava allen map](https://upload.wikimedia.org/wikipedia/commons/9/9c/Boring_lava_allen_map.png)
There are a number of volcanic centers within a radius of
Troutdale and more than 32 vents within a radius of Kelly Butte. Mostly small
cinder cone
A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...
vents, these volcanoes also include some larger
lava dome
In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...
s from
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...
es at Mount Sylvania, Highland Butte, and Larch Mountain. Known as the
Boring Lava Field
The Boring Lava Field (also known as the Boring Volcanic Field) is a Plio-Pleistocene volcanic field with cinder cones, small shield volcanoes, and lava flows in the northern Willamette Valley of the U.S. state of Oregon and adjacent southwest ...
, this cluster includes more than 80 known small vents and associated lava flows, with more volcanic deposits likely present.
[ The Global Volcanism Program reports that the field includes somewhere between 32 and 50 shield volcanoes and cinder cones, with many vents concentrated northwest of the town of Boring.]
Considered an outlier of the Cascade Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...
, the Boring Lava Field lies about [ to the west of the major Cascade crest. It marks one of five volcanic fields along the ]Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
Cascade arc, along with Indian Heaven
Indian Heaven is a volcanic field in Skamania County in the state of Washington, in the United States. Midway between Mount St. Helens and Mount Adams, the field dates from the Pleistocene to the early Holocene epoch. It trends north to south ...
, Tumalo in Oregon, the Mount Bachelor
Mount Bachelor, formerly named Bachelor Butte, is a dormant stratovolcano atop a shield volcano in the Cascade Volcanic Arc and the Cascade Range of central Oregon. Named Mount Bachelor because it stands apart from the nearby Three Sisters, it ...
chain, and Caribou in California. Like the Cascade Range, the Boring field was also generated by the subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
of the oceanic Juan de Fuca tectonic plate under the North American tectonic plate, but it has a different tectonic position, with its eruptive activity more likely related to tectonic rift
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics.
Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...
ing throughout the region.[ The Boring Lava Field has erupted material derived from hot mantle magma, and the subducting Juan de Fuca plate may be as shallow as in depth at their location.
Many volcanic features in the Portland Basin area were destroyed by the Missoula Floods (also known as the Bretz or Ice Age Floods), which took place between 21,000 and 15,000 years ago and probably destroyed small cinder cones (including those made from ]tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
) and maar
A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...
craters, burying them under up to of silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...
from slack water
Slack water is a short period in a body of tidal water when the water is completely unstressed, and there is no movement either way in the tidal stream, and which occurs before the direction of the tidal stream reverses. Slack water can be estim ...
. Volcanic vents with either extensive eruptions of lava flows or volcanic plug
A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if rising volatile-charged mag ...
s that filled their vents survived, including Rocky Butte, Prune Hill, and Beacon Rock. However, the upstream side of Rocky Butte was heavily eroded by the flooding.
Rocky Butte is a prominent, but isolated hill, with two volcanic vents. It is the core remnant of intrusive rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''Igneous intrusion, intrusions'', such as batholiths, dike (geology), dikes, Sill (geology), sills, laccoliths, and volcanic necks.I ...
from a heavily eroded
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust, and then sediment transport, tra ...
, late Pleistocene volcano that erupted basaltic andesite
Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...
. Like many other vents in the Boring Lava Field, Rocky Butte consists of basaltic andesite with olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
phenocryst
300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter ...
s, and it has a calc-alkalic
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic mag ...
composition. This basaltic andesite can be observed in exposures that extend from its summit park area to the roads below, as well as in a sill (a sheet of intrusive rock wedged between older layers of sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
, beds of volcanic lava, or tuff, or along the direction of layering
Layering has evolved as a common means of vegetative propagation of numerous species in natural environments. Layering is also utilized by horticulturists to propagate desirable plants.
Natural layering typically occurs when a branch touches ...
in metamorphic rock
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...
) between layers of fluvial
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...
gravel from the Troutdale Formation on the Butte's eastern slope, within a flow scarp. Vug
A vug, vugh, or vugg (
) is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity (folding and faulting) are partially filled by quartz, cal ...
cavities were identified from rock in the historic quarry on the eastern side of Rocky Butte by scientists from the United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
, including optically positive hornblende
Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks ...
(also known as pargasite
Pargasite is a complex inosilicate mineral of the amphibole group with formula NaCa2(Mg4Al)(Si6Al2)O22(OH)2.
It was first described for an occurrence in Pargas, Finland in 1814 and named for the locality.
It occurs in high temperature regional ...
) with a pale brown color. They exhibit prismatic cleavage and extend for a few millimeters in length. Other minerals identified were dark green, pyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
crystals with 70 percent hedenbergite
Hedenbergite, Ca Fe Si2 O6, is the iron rich end member of the pyroxene group having a monoclinic crystal system. The mineral is extremely rarely found as a pure substance, and usually has to be synthesized in a lab. It was named in 1819 after M ...
and 30 percent diopside
Diopside is a monoclinic pyroxene mineral with composition . It forms complete solid solution series with hedenbergite () and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull ...
; white aggregates of tridymite
Tridymite is a high-temperature polymorph of silica and usually occurs as minute tabular white or colorless pseudo-hexagonal crystals, or scales, in cavities in felsic volcanic rocks. Its chemical formula is Si O2. Tridymite was first described ...
; brown, granular olivine crystals with 80 percent forsterite
Forsterite (Mg2SiO4; commonly abbreviated as Fo; also known as white olivine) is the magnesium-rich end-member of the olivine solid solution series. It is isomorphous with the iron-rich end-member, fayalite. Forsterite crystallizes in the orthor ...
and 20 percent fayalite
Fayalite (, commonly abbreviated to Fa) is the iron-rich end-member of the olivine solid-solution series. In common with all minerals in the olivine group, fayalite crystallizes in the orthorhombic system (space group ''Pbnm'') with cell para ...
; and tiny black, hexagonal plates of hematite
Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...
with beveled edges. These minerals constitute a rare combination, and Trimble (1963) was unable to explain why free silica tridymite would be found together with low silica olivine.
The hill descends to meet the floodplain of the Columbia River, and at lower elevations, the mountain has cliffs on its northern and eastern sides. At the foot of Rocky Butte, there is a fosse (a ditch), which extends for before it opens toward the Columbia River to the north and divides to the south into two arms that run west and southwest. This depression has a width of less than and an average depth between . There is another terrace, with a height of , which sits next to Rocky Butte. It runs for to the west, with a descent of over that distance. To the south, this terrace also has a long depression near its base, which extends for from Rocky Butte. These features are likely the product of more than just erosional forces; Bretz (1925) argued that the fosse resulted from fluid eddies
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid beh ...
that pushed downward where currents interacted with the eastern side of Rocky Butte, and the terrace formed from accumulation of deposits in water under the blockage.
Eruptive history
Evarts et al. (2009) assign Rocky Butte an age younger than 500,000 years. One Argon–argon dating
Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer ...
experiment determined an age for Rocky Butte lava of 285,000 years ± 16,000 years ago, which matches the normal magnetic polarity for the lava deposits at the Butte. There is a magnetic anomaly
In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying ...
about northwest from Rocky Butte in Portland, but it is unlikely to be associated with the volcano or the Boring Lava Field in general. Local newspaper sources report that Rocky Butte is extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
.[
Trimble (1963) noted that an eruption at Rocky Butte covered a hill composed of Troutdale Formation rocks, which are exposed as conglomerate rock at a height of on Rocky Butte's western slope. The exposure of rock from the Troutdale Formation suggests that Rocky Butte erupted onto a topographically irregular surface and that this surface later underwent erosion.
]
Ecology
The moderate climate and ample precipitation of the region lead to rapid regrowth of vegetation on untended sites, which can hamper fieldwork in the area. Many forests that covered the area were partly cleared for agriculture, timber, or burials in the early 20th century. These cleared and burned land plots sustain rich stands of secondary forest
A secondary forest (or second-growth forest) is a forest or woodland area which has re-grown after a timber harvest or clearing for agriculture, until a long enough period has passed so that the effects of the disturbance are no longer evident. ...
, featuring gorse
''Ulex'' (commonly known as gorse, furze, or whin) is a genus of flowering plants in the family Fabaceae. The genus comprises about 20 species of thorny evergreen shrubs in the subfamily Faboideae of the pea family Fabaceae. The species are n ...
, huckleberry
Huckleberry is a name used in North America for several plants in the family Ericaceae, in two closely related genera: ''Vaccinium'' and ''Gaylussacia''. The huckleberry is the state fruit of Idaho.
Nomenclature
The name 'huckleberry' is a Nort ...
, nettle
{{redirect, Nettle
Nettle refers to plants with stinging hairs, particularly those of the genus ''Urtica''. It can also refer to plants which resemble ''Urtica'' species in appearance but do not have stinging hairs. Plants called "nettle" include ...
s, poison oak Poison oak refers to two plant species in the genus ''Toxicodendron,'' both of which can cause skin irritation:
*''Toxicodendron diversilobum'' or Western poison oak, found in western North America
*''Toxicodendron pubescens
''Toxicodendron pub ...
, salal
''Gaultheria shallon'' is an evergreen shrub in the heather family (Ericaceae), native to western North America. In English, it is known as salal, shallon, or (mainly in Britain) gaultheria.
Description
''Gaultheria shallon'' is tall, spra ...
, and blackberry
The blackberry is an edible fruit produced by many species in the genus ''Rubus'' in the family Rosaceae, hybrids among these species within the subgenus ''Rubus'', and hybrids between the subgenera ''Rubus'' and ''Idaeobatus''. The taxonomy of ...
. Myriad species of fern, as well as rapid-growth deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
trees like alder
Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...
and vine maple
''Acer circinatum'', the vine maple, is a species of maple native to western North America.
Description
It most commonly grows as a large shrub growing to around tall, but it will occasionally form a small to medium-sized tree, exceptionall ...
are also frequent. Forests support stands of Douglas fir
The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...
, western hemlock
''Tsuga heterophylla'', the western hemlock or western hemlock-spruce, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma ...
, western redcedar
''Thuja plicata'' is an evergreen coniferous tree in the cypress family Cupressaceae, native to western North America. Its common name is western redcedar (western red cedar in the UK), and it is also called Pacific redcedar, giant arborvitae, w ...
, Pacific dogwood
''Cornus nuttallii'', the Pacific dogwood, western dogwood, or mountain dogwood, is a species of dogwood tree native to western North America.
Description
It is a small to medium-sized deciduous tree, reaching tall, often with a canopy spre ...
, bigleaf maple
''Acer macrophyllum'', the bigleaf maple or Oregon maple, is a large deciduous tree in the genus '' Acer''.
It is native to western North America, mostly near the Pacific coast, from southernmost Alaska to southern California. Some stands are al ...
, Oregon ash
''Fraxinus latifolia'', the Oregon ash, is a member of the ash genus '' Fraxinus'', native to western North America.
Description
''Fraxinus latifolia'' is a medium-sized deciduous tree that can grow to heights of in height, with a trunk diame ...
, red alder
''Alnus rubra'', the red alder,
is a deciduous broadleaf tree native to western North America (Alaska, Yukon, British Columbia, Washington, Oregon, California, Idaho and Montana).
Description
Red alder is the largest species of alder in North A ...
, cascara buckthorn, Pacific madrone
''Arbutus menziesii'' or Pacific madrone (commonly madrone or madrona in the United States and arbutus in Canada), is a species of broadleaf evergreen tree in the family Ericaceae, native to the western coastal areas of North America, from Bri ...
, and Oregon white oak
''Quercus garryana'' is an oak tree species of the Pacific Northwest, with a range stretching from southern California to southwestern British Columbia. It is commonly known as the Oregon white oak or Oregon oak or, in Canada, the Garry oak. It ...
; within swamps and moist areas in creeks, the shrub Devil's club
Devil's club or devil's walking stick (''Oplopanax horridus'', Araliaceae; syn. ''Echinopanax horridus'', ''Fatsia horrida'') is a large understory shrub native to the rainforests of the Pacific Northwest, but also disjunct on islands in Lake S ...
can be observed. Other trees that sometimes dominate forest areas include black cottonwood
''Populus trichocarpa'', the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology.
De ...
. Forest communities have many additional shrubs including Indian plum, western hazel, and snowberry
''Symphoricarpos'', commonly known as the snowberry, waxberry, or ghostberry, is a small genus of about 15 species of deciduous shrubs in the honeysuckle family, Caprifoliaceae. With the exception of the Chinese coralberry, '' S. sinensis'', whi ...
. Ground layer plants include the herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of t ...
sword fern Sword fern is a common name for several ferns and may refer to:
*''Nephrolepis'', a tropical genus of ferns, especially:
**''Nephrolepis exaltata'', commonly cultivated as a houseplant, including the Boston fern
*''Polystichum'', a cosmopolitan gen ...
and stinging nettle
''Urtica dioica'', often known as common nettle, burn nettle, stinging nettle (although not all plants of this species sting) or nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae. Or ...
.
In contemporary times, clearing of forests for housing development has left about half of the Boring Lava region still forested. As a result, water quality has decreased due to higher sedimentation and turbidity, and flooding has gotten worse over time. Streams within the area are of either first or second order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
, with moderate to low flows and average gradients between 10 and 12 percent. Cool and clear, many sustain macroinvertebrates, and a smaller number support amphibians and fish. The Riparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
s in the Lava Field area host diverse species, and they are influenced by uplands that serve as migration connections for birds, mammals, reptiles, and some amphibians. Gravel bars extend to the west from Rocky Butte, creating barriers for a lowland
Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland.
Definitions
Upland and lowland are portions of ...
marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
.
The United States Fish and Wildlife Service
The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
provided a list of potentially threatened or endangered species in the Boring Lava area, calling them "sensitive" species. Among plant species, they determined the following species to be sensitive: white top aster
Aster or ASTER may refer to:
Biology
* ''Aster'' (genus), a genus of flowering plants
** List of ''Aster'' synonyms, other genera formerly included in ''Aster'' and still called asters in English
* Aster (cell biology), a cellular structure shap ...
, golden Indian paintbrush, tall bugbane, pale larkspur, peacock larkspur, Willamette daisy, water howellia, Bradshaw's lomatium, Kincaid's lupine, Howell's montia, Nelson's checkermallow, and Oregon sullivantia. For animal and marine life, northwestern pond turtles, Willow flycatcher
The willow flycatcher (''Empidonax traillii'') is a small insect-eating, neotropical migrant bird of the tyrant flycatcher family. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (inc ...
s, long-eared myotis
The long-eared myotis (''Myotis evotis'') is a species of vesper bat in the suborder Microchiroptera. It can be found in western Canada, the western United States, and Baja California in Mexico.
Description
The long-eared myotis is a pale brown ...
es, fringed myotises, long-legged myotis
The long-legged myotis (''Myotis volans'') is a species of vesper bat that can be found in western Canada, Mexico, and the western United States.
Description
''Myotis volans'' is a species of bat found in Order Chiroptera, Family Vespertillion ...
es, Yuma myotis
The Yuma myotis (''Myotis yumanensis'') is a species of vesper bat native to western North America.
Description
The Yuma myotis is a relatively small myotis, measuring in head-body length, with an average wingspan of and a weight of about . T ...
es, Pacific western big-eared bats, and northern red-legged frog
The northern red-legged frog (''Rana aurora'') is a species of amphibian, whose range is the coastal region stretching from southwest British Columbia to southern Mendocino County in Northern California, and is protected in Oregon and Californ ...
s have been identified as species of concern; pileated woodpecker
The pileated woodpecker (''Dryocopus pileatus'') is a large, mostly black woodpecker native to North America. An insectivore, it inhabits deciduous forests in eastern North America, the Great Lakes, the boreal forests of Canada, and parts of the ...
s, bald eagle
The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche as ...
s, cutthroat trout
The cutthroat trout is a fish species of the family Salmonidae native to cold-water tributaries of the Pacific Ocean, Rocky Mountains, and Great Basin in North America. As a member of the genus '' Oncorhynchus'', it is one of the Pacific tro ...
, and coho salmon
The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientific species name i ...
are also considered sensitive.
Human history
Mowitch Illihee, 'home of the deer', was the traditional hunting grounds for indigenous peoples.
At the summit of Rocky Butte, a rotating airway beacon
An airway beacon (US) or aerial lighthouse (UK and Europe) was a rotating light assembly mounted atop a tower. These were once used extensively in the United States for visual navigation by airplane pilots along a specified airway corridor. ...
was erected in 1929; though the beacon is still lit, it was officially decommissioned in the late 1960s.
During the 1930s, employees of the Works Progress Administration
The Works Progress Administration (WPA; renamed in 1939 as the Work Projects Administration) was an American New Deal agency that employed millions of jobseekers (mostly men who were not formally educated) to carry out public works projects, i ...
constructed a park at the summit, at an elevation of about . Called Joseph Wood Hill Park, it was built on Rocky Butte when Rocky Butte was known as Wiberg Butte. Rock from Rocky Butte's eastern slopes was used for the Multnomah County jail
A prison, also known as a jail, gaol (dated, standard English, Australian, and historically in Canada), penitentiary (American English and Canadian English), detention center (or detention centre outside the US), correction center, correc ...
building, and some were later used for renovation of the Historic Columbia River Highway
The Historic Columbia River Highway is an approximately scenic highway in the U.S. state of Oregon between Troutdale and The Dalles, built through the Columbia River Gorge between 1913 and 1922. As the first planned scenic roadway in the United ...
. There is a communications tower on the southern end of the volcano.
The Rocky Butte jail, completed in 1947, served as the major facility for male prisoners in Multnomah County, with a courtyard and recreation field. According to Rubin (1973), the Rocky Butte jail housed 320 inmates, but Houston, Gibbons, and Jones (1988) claimed that it often exceeded this limit. The jail also had a library, which was established in 1967 and housed 3,000 volumes. In general, the jail was known for being the subject of multiple grand jury investigations for security concerns, dirty conditions, access to drugs, violence, lack of organized programming, and most notably, during the 1960s and 1970s for severe overcrowding. Further attempts to replace the Rocky Butte jail were motivated by a successful escape in 1981 and a gun smuggling incident that resulted in an officer being shot in 1982. The Multnomah County Detention Center (MCDC) was built in downtown Portland after Rocky Butte Jail was demolished in 1984 to make way for Interstate 205
Interstate 205 may refer to either of two unconnected Interstate Highways in the United States, both of which are related to Interstate 5
* Interstate 205 (California), a connector in the San Francisco Bay Area
* Interstate 205 (Oregon–Washingt ...
. The Rocky Butte Jail and MCDC participated in a study on prisons, which was published in 1988 in the journal ''Crime & Delinquency
''Crime and Delinquency'' is a peer-reviewed academic journal that publishes papers in the field of Criminology. The journal's editor is Paul E. Tracy (University of Massachusetts Lowell). It has been in publication since 1955 and is currently pu ...
''.
In 1934, the Rocky Butte Scenic Drive Historic District was established. Built as part of a Works Progress Administration project[ that supported 25,000 employees in Portland, it was designed by the Multnomah County Road Department,] The drive reaches the summit of Rocky Butte to a viewpoint overlooking Portland. Workers used basalt from the Rocky Butte quarry to create retaining walls, and the finished project was designed to have a rustic style typical for public works projects of the time. WPA workers also built the park and a baroque staircase at the top of Rocky Butte, finishing construction in 1939. At its peak popularity in the 1940s, Rocky Butte had more than 4,000 cars visiting each day. Over time, the park had far fewer visitors and fell into disrepair. During the 1970s, the summit became a frequent site for teenage parties; excessive littering and graffiti
Graffiti (plural; singular ''graffiti'' or ''graffito'', the latter rarely used except in archeology) is art that is written, painted or drawn on a wall or other surface, usually without permission and within public view. Graffiti ranges from s ...
were commonplace. In the early 1990s, the Rocky Butte Preservation Society began cleaning up and restoring the park area and adding new amenities. Once of land were added and the Preservation Society took on an active maintenance role, the site was regraded, original plaques were reinstalled, and lawn areas, irrigation, red cinder walkways and additional trees, flowers, shrubs and grass were added to the park. The District was listed on the National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic v ...
in 1991. Other WPA projects included a tunnel in length at the southern end of Rocky Butte. Built between 1939 and 1941, it was constructed to improve access to scenic views on the Butte. The project took 16 months to complete, and workers used hand mining and drill and shoot methods to excavate layers of cinders and lava flows. The tunnel is curved because of the volcano's 5 degree grade. Rocky Butte basalt was used to build the Rocky Butte Tunnel as well as the nearby West Burnside and NW Cornell Road Tunnels, all of which were constructed by the mason R. Curcio and his crew. In total, the WPA's Rocky Butte project cost $500,000 to complete.
The Hill Military Academy
Hill Military Academy was a private, College preparatory military academy in Portland in the U.S. state of Oregon. Opened in 1901, it was a leading military boarding school in the Pacific Northwest. Originally located in Northwest Portland, it late ...
, a prominent military school in Portland, moved from the northwestern district of Portland to a campus on Rocky Butte in 1931. The campus covered on the northern side of the volcano. Ran by its founder, Joseph Wood Hill, it closed in 1959 after its enrollment had declined significantly, and the school was purchased by Judson Baptist College.[ Today, ]Portland Bible College
Portland Bible College (PBC) is a four-year Bible college in Portland, Oregon, United States that offers theological and church ministry degrees. It was founded in 1967 and is associated with Mannahouse Church, which is associated with Ministe ...
has a campus on Rocky Butte with offices and dormitory buildings, and The Grotto
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the m ...
, a famous Catholic shrine encompassing , lies adjacent to the volcano. Created in 1924, The Grotto has more than 200,000 visitors annually. It consists of two levels, which are separated by the cliff of Rocky Butte's northern face. On the upper level of the shrine is the Chapel of St. Anne, which sits on the northern side of Rocky Butte and offers views of the Columbia River and Mount St. Helens. Built in 1934, the Chapel also has a Peace Garden (finished in 1989) and a Meditation Chapel, which was completed in 1991. The City Bible Church also maintains a location at Rocky Butte, with services on Sunday mornings at 9:30 and 11:15 am as well as youth services on Wednesdays at 7 pm.
In 2000, Portland Police Bureau
The Portland Police Bureau (PPB), officially the Portland Bureau of Police, is the law enforcement agency of the city of Portland, the largest city in the U.S. state of Oregon. While oversight of Portland's bureaus shifts among the five City ...
Officer Mark Kruger placed a shrine to Nazi soldiers on public park property at Rocky Butte. When Kruger's past was discovered during 2003 lawsuits, Kruger removed the shrine. The shrine was stored in the city attorney's office by then-deputy Tracy Reeve, preventing their discovery during the lawsuits. Kruger remained on the force and was promoted to captain in 2009. Kruger admitted to wearing Nazi uniforms. The shrine's existence was discovered by internal affairs in 2010 after commissioner Dan Saltzman ordered an investigation. Kruger was disciplined and suspended for two weeks in 2010, but was not demoted or fired. Kruger continued to state that he was a history buff, not a Nazi. He remained on the force until his retirement.
In May 2018, government officials from the Oregon Department of Transportation
The Oregon Department of Transportation (ODOT) is a department of the state government of the U.S. state of Oregon responsible for systems of transportation. It was first established in 1969. It had been preceded by the Oregon State Highway Depar ...
began clearing belongings and debris from a long-standing homeless campsite at the eastern side of Rocky Butte, also posting eviction notices. A fire occurred near a homeless camp on the northern side of Rocky Butte in July 2018.
Recreation
Rocky Butte is part of the Rocky Butte Natural Area, encompassing of land on NE Rocky Butte Road. The summit of Rocky Butte is a Portland city park, Joseph Wood Hill Park, which covers . The park offers views of the Boring Lava Field, Mount St. Helens
Mount St. Helens (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit or Louwala-Clough to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United St ...
, and Mount Hood
Mount Hood is a potentially active stratovolcano in the Cascade Volcanic Arc. It was formed by a subduction zone on the Pacific coast and rests in the Pacific Northwest region of the United States. It is located about east-southeast of Portlan ...
. It lies in the throat of Rocky Butte's former volcanic vent on a bluff above the Hill Military Academy campus;[ this land was donated by Joseph Hill's sons.][ The park has red, crushed stone pathways, a stone wall, and a stone pedestal adorned with a metal plague bearing Joseph Wood Hill's image looking to the west.][ Rocky Butte is a popular location for seeing mountains.] In 2017, the Portland Parks & Recreation
Portland Parks & Recreation (PP&R) is a Bureau of the City of Portland, Oregon that manages the city parks, natural areas, recreational facilities, gardens, and trails. The properties, which occupy a total of more than . The bureau employs a total ...
bureau proposed to clear trees and invasive species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...
in the park to allow better views of downtown Portland, Mount Hood, and Mount St. Helens, planting 400 low-growth trees and 5,200 shrubs in their place.[ A man was killed after falling from the summit viewpoint in May 2015.]
Rocky Butte does not have a well-defined trail system. There are a number of climber and biker trails made by civilians on the base and lower parts of the mountain, as well as climbing paths near the summit, which are unfenced and can be unsafe. A walking path described by L. O. Foster (2013) starts from NE 92nd Avenue and Skidmore Street and runs for each way, lasting 1.5 to 2 hours. This trail passes the Rocky Butte Tunnel, the site for the Hill Military Academy, and the beacon. Dogs can be unleashed on the trails, but have to be kept on a leash at Joseph Wood Hill Park.
Rocky Butte is also a popular climbing destination in the Portland area, having been developed by climbers during the 1970s and 1980s. Many of its routes are top-roped, but some top anchors are missing from its routes, so daisy chain straps are recommended. The climbing routes are not suitable for dogs or children. Some of the most popular climbs are on the section known as Video Bluff. Rocky Butte provides a variety of climbs including cracks, dihedrals, slab
Slab or SLAB may refer to:
Physical materials
* Concrete slab, a flat concrete plate used in construction
* Stone slab, a flat stone used in construction
* Slab (casting), a length of metal
* Slab (geology), that portion of a tectonic plate that i ...
, vertical, and overhanging face routes.
References
Sources
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External links
Rocky Butte Preservation Society
Rocky Butte Scenic Drive Historic District
at PortlandMaps
NRHP Registration Form, 1991
*
{{Volcanoes of Oregon , state=collapsed
Buttes of Oregon
Cascade Volcanoes
Cinder cones of the United States
Geography of Portland, Oregon
Landforms of Multnomah County, Oregon
Madison South, Portland, Oregon
Mountains of Oregon
Parks in Portland, Oregon
Subduction volcanoes
Volcanoes of Multnomah County, Oregon
Volcanoes of Oregon