soil factors influencing moisture & productivity fir/docs/cb vernon... · soil factors...
TRANSCRIPT
Soil factors influencing
moisture & productivity:
Overview, soil descriptions, and
landscape processes
Chuck Bulmer and Brian Wallace
21 April 2017 Dry Belt Fir workshop, Vernon
“advancing management of multiple values in the dry belt fir, and
maintaining dry belt fir stands over the long term””
Outline • Soils of the Dry Fir Forests in the
Okanagan • physiography, geological origin, parent
materials, soil development
• Sources of information • Soils of BC website distribution
• Soil Information Finder Tool
• Other mapping efforts
• Perspectives on changing
information needs
Dry fir: • Elevations to ca
900m in the north
and as high as
1200+ in the south
• Mostly confined to
the valley walls and
plateau edges in the
north, and up on to
the plateau in the
south
Vernon area: • Elevations up to ca
800-1200m in the
north and as high as
1200+ in the south
• Higher on south
facing slopes
Steep slopes: • Slope in degrees
• Many parts of area
with the dry fir
forests are along
the walls of the
Okanagan Valley
Geology: • Mosaic of rock
types, not related to
topography
• Residual soil
materials and
colluvium inherit
rock characteristics
• ‘Local’ glacial tills
retain similarity
• Transported valley
sediments - no
Soil texture and plant
available water
Parent
material: • Tills on the plateau
• Water-deposited
materials in the
valley bottom
• Colluvium on the
slopes
• Rock, organics in
lesser amounts
Soil types: • Grass land soils in
the valley; south
aspect
• Forest soils in
uplands: Brunisols
and Luvisols,
depends on texture
• Poorly drained soils
(Gleysol) and fresh
deposits (Regosol)
close to the rivers
The effect of aspect S:
Chernozem Brunisol
Kelowna
area: • Elevations a bit
higher than Vernon
• Mostly confined to
the valley walls in
the north, and up on
to the plateau in the
south
Steep slopes: • Slope in degrees
• Many parts of area
with the dry fir
forests are along
the walls of the
Okanagan Valley
Geology: • Mosaic of rock
types, not related to
topography
• Residual soil
materials and
colluvium inherit
rock characteristics
• ‘Local’ glacial tills
retain similarity
• Transported valley
sediments - no
Parent
material: • Tills on the plateau
• Water-deposited
materials in the
valley bottom
• Colluvium on the
slopes
• Rock, organics in
lesser amounts
Soil types: • Grass land soils in
the valley; south
aspect
• Forest soils in
uplands: Brunisols
and Luvisols,
depends on texture
• Poorly drained soils
(Gleysol) and fresh
deposits (Regosol)
close to the rivers
Dry fir: • Elevations to ca
800m in the north
and as high as
1200+ in the south
• Mostly confined to
the valley walls in
the north, and up on
to the plateau in the
south
Steep slopes: • Slope in degrees
• Especially near
Keremeos the valley
sides are very steep
Geology: • Mosaic of rock
types, not related to
topography
• Residual soil
materials and
colluvium inherit
rock characteristics
• ‘Local’ glacial tills
retain similarity
• Transported valley
sediments - no
Parent
material: • Tills on the plateau
• Water-deposited
materials in the
valley bottom
• Colluvium on the
slopes
• Rock, organics in
lesser amounts
Soil types: • Grass land soils in
the valley; south
aspect
• Forest soils in
uplands: Brunisols
and Luvisols,
depends on texture
• Poorly drained soils
(Gleysol) and fresh
deposits (Regosol)
close to the rivers
Sources of
soil info: • Search “soils info
BC”
• http://www.env.gov.bc.ca/e
sd/distdata/ecosystems/
(kmz files for google earth)
• Soil Information Finder
tool Web mapping
Deepa Filatow MoE Kelowna
View soil data in Google Earth:
View soil data in Google Earth:
View soil data in SIFT:
View soil data in SIFT:
View soil data in SIFT:
Sources
25 m soil map
for the
Okanagan Basin
Scott Smith
Ag Agri-Food
Canada,
Summerland
Erosion and
redistribution • Erosion is an
ongoing process,
but operates slowly
in vegetated soils
• Greatly accelerated
after fire, when soil
is exposed
• Dry landscapes can
experience severe
soil loss
Erosion and redistribution • There is only a thin veneer of soil over many
hillslopes in the Okanagan landscape
Conclusions • Diverse origins and ecosystems
have created different soils
• Soil texture is connected to geology
/ rock type.
• Aspect affects water balance and
vegetation outcomes
• Steep slopes are common
• Ongoing redistribution of soil
materials through landscape
evolution
• Water, solar energy, drive important
processes of productivity
Extras
Soil Water Balance Inputs = snow and rain
Outputs =
• evaporation
• transpiration
• runoff
• storage
More water loss from
transpiration?
• Fine textured (clay) soils allow greater water movement
toward the surface from deeper layers.
• It takes about 15 days with little rain to dry the top 5 to 10
cm of an exposed mineral surface to the permanent wilting
point.
• If there is no vegetation, the soil at the 15 to 20 cm depth
will still be moist.
Spittlehouse and Stathers. 1990. Seedling microclimate.
Soil water dynamics after harvest
Frost and tree seedlings
• Radiation frost occurs on calm, clear nights when the ground
surface cools to <0°C. Bare soil reduces this risk while grassy
vegetation increases the risk.
• Advection frost occurs when cool air flows or is blown
(advected) onto a site.
• Radiation and advection frosts often occur at the same time.
Perspective: • Need to use
information to
keep it ‘alive’
• Knowledge
may not ever
really be
‘lost’, it may
just need to
be refreshed
• Experience
• Competition for moisture between grass and tree
seedlings
• Intensity of site prep and the timing of seedling
planting after harvest will likely influence the success
of the new forest
Conclusions