Soils of the - Agriculture and Agri-Food Canada

SAYRES SOILS (S)
Location and Extent : Sayres soils are common at the higher elevations of the mountainous parts of the ma p
area . Although only 140 ha of pure map units are mapped, 27 800 ha of soil complexes dominated by Sayre s
soils also occur. The complexes are mostly with Dennett, Whonnock, Palisade, Golden Ears, Hollyburn ,
Strachan and Grouse soils .
Topography and Elevation : Sayres soils vary from steeply sloping or strongly rolling to extremely sloping o r
very hilly with slope gradients from 15 to Over 60 percent . Most commonly, however, gradients are between 4 0
and 60 percent. Elevations mostly lie between 650 and 1300 m above sea level .
Parent Material and Texture : Sayres soils have developed from moderately coarse textured, ston y
colluvium or glacial till that is between 10 cm and 100 cm thick and overlies bedrock . The organic forest litter o n
the soil surface is dominantly well-decomposed while the underlying mineral soil varies from mainly sandy loa m
or gravelly sandy loam to gravelly loamy sand . Numerous stones, cobbles and boulders are present .
Soil Moisture Characteristics : Sayres soils are moderately well to well drained . They are moderatel y
pervious and have high to moderate water holding capacity and moderate to slow surface runoff. Moderate t o
abundant telluric seepage occurs along the surface of the underlying bedrock during heavy rain or snowmelt ,
especially in areas where the bedrock is massive .
General Soil Description : Sayres soils generally have 15 cm or more of organic forest litter on the soi l
surface, most of which is well-decomposed, friable, matted and very dusky red to black in colour . The organi c
material is underlain by about 4 to 10 cm of gray, very friable, strongly leached, sandy material which, in turn, i s
underlain by a 20 to 50 cm thick zone of dark reddish brown to reddish-brown, friable to firm, weakly structured ,
sandy soil . Numerous gravel, stone, and cobble size particles are present and the organic matter content of th e
zone ranges from 10 to 20 percent . The zone is then abruptly underlain by bedrock, mostly granitic . A wel l
defined very dusky red root mat, from 2 to 10 cm thick is usually present immediately above the bedrock . Soi l
reaction ranges from extremely acid in the upper soil to very strongly acid above the underlying rock . Soi l
classification is Orthic Ferro-Humic Podzol:lithic phase .
Commonly Associated Soils : Dennett, Whonnock, Golden Ears, Palisade, Strachan, Hollyburn an d
Grouse soils all commonly occur in close association with Sayres soils, either occupying adjacent ma p
polygons or as part of soil complexes . Dennett soils differ from Sayres soils by consisting of 10 cm or more o f
organic forest litter over bedrock. Whonnock, Golden Ears, Palisade and Strachan soils are all more than 100 c m
deep, over bedrock and vary from Sayres soils in that respect . Additionally, Whonnock, Golden Ears an d
Strachan soils all have strongly cemented subsoils ; Whonnock soils are also imperfectly drained . Hollyburn an d
Grouse soils have soil depths over bedrock similar to Sayres soils . Hollyburn soils, however, do not contain th e
high levels of organic matter in the subsurface layers while Grouse soils are imperfectly drained and have a dar k
coloured surface mineral soil layer .
Vegetation : The natural forest on Sayres soils is mostly Pacific silver fir, mountain hemlock and yellow cedar ;
at the lower elevations, western hemlock and western red cedar also occur . Rooting is unimpeded down to th e
underlying bedrock . A well defined zone of root concentration (root mat) is usually present immediately above
the bedrock .
General Land Use Comments : (1) Sayres soils are unsuited for agriculture due to very steep slopes ,
stoniness, shallowness to bedrock and poor climatic conditions (very deep snow packs and short growin g
seasons) . (2) Urban or similar uses are also unsuited for reasons similar to those for agriculture . (3) Forest
growth is somewhat variable, ranging from moderate at the lower elevations where it is limited by shallow rootin g
depth and sometimes droughtiness, to poor at the higher elevations where adverse climatic conditions an d
shallow rooting depress growth . During forest harvesting care should be taken to prevent soil disturbance whic h
will either remove or further thin the already relatively shallow soil capping over bedrock . Data from a limite d
number of measured plots indicate Sayres soils have an annual productivity of wood of about 5 to 6 .5 m 3/ha . The
species considered are mountain hemlock, yellow cedar and Pacific silver fir .
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