Soils of the - Agriculture and Agri-Food Canada

BURWELL SOILS (BW)
Location and Extent :
Burwell soils occur on the lower and middle mountain slopes, mostly in the Coas t
Range. There are about 460 ha of pure map units and an additional 3330 ha of soil complexes dominated b y
Burwell soils . The complexes are mostly with Strachan and Cannell soils .
Topography and Elevation :
The topography of Burwell soils is very steeply to steeply sloping with slop e
gradients varying between 20 and 70 percent . The soils often occupy either slightly depressional or concave
positions in the landscape . Elevations range between 150 and 700 m above sea level .
Parent Material and Texture :
Burwell soils have developed from moderately coarse-textured glacial til l
deposits modified somewhat by colluvial action in the upper part . Surface and subsurface textures are usuall y
sandy loam or gravelly sandy loam and contain numerous stones and some boulders . The subsoil (below abou t
100 cm) is dense, compact, stony, strongly cemented gravelly sandy loam or sometimes, gravelly loamy sand .
Soil Moisture Characteristics :
Burwell soils are imperfectly drained . They are rapidly to moderatel y
pervious in the upper part but this abruptly becomes slow in the cemented subsoil . Persistent, lateral, telluri c
seepage above the dense, cemented subsoil layers is usual and during periods of high rainfall, the seepag e
commonly comes to the surface in shallow, intermittent drainage-ways .
General Soil Description : The surface of Burwell soils consists of between 10 and 20 cm of organic fores t
litter, the lower half of which is black, well-decomposed and amorphous . Underlying this is a gray, leached ,
sandy layer usually varying from 2 to 5 cm in thickness but sometimes being absent . In turn, this is underlain b y
a sandy to gravelly, friable, moderately porous, dark reddish brown zone about 75 cm thick containing a few ,
hard, spherical concretions, some reddish or yellowish mottles and between 8 and 15 percent organic matter .
Abruptly underlying for about 75 cm is a dense, hard, compact, strongly cemented, massive to coarsely plat y
layer which is olive-gray to grayish-brown in color. It is sandy to gravelly in texture and contains common ,
reddish or yellowish mottles . A well developed zone of organic matter accumulation (derived mainly fro m
decayed roots) is usually present immediately above the cemented layer . Below depths of about 160 cm th e
cemented layer grades to gray and olive-gray, compact, massive, unweathered glacial till soil parent material .
Soil reaction is extremely to very strongly acid in the upper 150 cm then gradually changes to medium acid a t
greater depths . Soil classification is Duric Ferro-Humic Podzol.
Commonly Associated Soils : Strachan, Cascade, Cannell and Eunice soils commonly occur in soi l
complexes with Burwell soils or occupy adjacent map polygons . Strachan and Cascade soils differ fro m
Burwell soils by being well or moderately well drained, rather than imperfectly drained . Cascade soils also
contain a proportion of silty, eolian material in the upper soil layers . Cannell soils differ by being underlain b y
bedrock within 1 m of the surface while Eunice soils consist of 10 cm or more of organic forest litter over bedrock .
Vegetation :
The vegetation on Burwell soils is dominantly coniferous, mainly western hemlock, western re d
cedar and coast Douglas-fir; various ericaceous shrubs and ferns form the understory . Rooting is generall y
unrestricted to about 100 cm depth but is severely limited below that by the dense, cemented soil layers .
General Land Use Comments :
(1) Burwell soils are not suitable for agricultural or urban purpose s
because of excessive slopes and stoniness . (2) Forest productivity is high . Limited plot data indicates growth o f
western hemlock and western red cedar is about 12 to 15 m 3 /ha/yr. During harvest, special care is required t o
prevent surface erosion and to control seepage into road cuts and ditches . Slumping of steep cut slopes i s
probable .
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