Boreal Forest: Soil-Vegetation Interactions Flashcards
___ trees are first to colonize an area, then ___ arrive
deciduous trees
conifers
soil characteristics affect the soil ___ and ___ stores that determine the resulting floristic community
moisture
nutrients
soil particles have a ___ charge, so ___ ions like __ become ‘affixed to the soil particle
Plants must __ or find a way to get these cations if they want them
negative
positively
calcium
exchange
pedosphere=
soil conditions
the pedosphere is affected by 4 other ‘spheres’:
These all change with location!
biosphere (organisms)
hydrosphere (water)
lithosphere (parent material/ earth)
atmosphere (air- energy/ gas exchange)
**
4 main components of boreal forest
- physical template
- slope
- elevation - Climate
- clouds, sun, temp, precipitation - Biota
- fire
- insect outbreaks
- forest structure - Soil
- soil temp/ permafrost
- soil moisture
- nutrient availability
- forest floor organic layer
black spruce and tamarack will be found in areas with ___ soils (hydric), and ___ active layer and a ___ organic layer
gleysols (waterlogged)
thin
thick
White spruce, birch, aspen, and firs will be found in ___ sites with ___ active and organic layers
mesic (flowing moisture)
medium
Jack pine thrives in ___ sites with ____ soil where there’s a ___ active layer and ___ organic layer
xeric
podzols (dry and sandy)
thick (or no permafrost)
thin
Which 4 factors drive the community segregation in the boreal forest
moisture
soil
active layer
organic layer
why is there a thin active layer in podzols??
not much organic material stays at the surface because water goes through and take it with it (sandy particles allow water too flow through rapidly)
Soil is composed of:
25% ___
25%___
45%___
5%____
25% air
25% water
45% mineral particles
5% organic matter
What’s one way humans are directly changing the soils?
we compress soils with roads etc= changes the open spaces and makes it less permeable (less air and water can get in)
List the following in order from largest to smallest particle size
silt
clay
sand
gravel
which one carries the least nutrient availability?
Which one has a negative charge & retention of cations?
gravel
sand
silt
clay
sand
clay
____ hold the greatest volume of water b/c of ___ ratio. Is this water avail to plants?
clay
SA
not available to plants because clay holds it very strongly
field capacity=
content of water remaining in soil a few days after being wetted and free drainage nearly ends
at the ___ ___, water is still available, but it’s strongly attached to soil, so not very accessible to plants
wilting point
the mosaic pattern of forests in boreal region is related to ___ patterns
- ___ in wet areas
- ___ in dry areas
drainage
spruce
poplars
Why does soil have layers?
If there’s no ___ there’s no layers
the aging of the materials present on the surface (they leech downward)
leeching eg in tropical forests
What are the 6 soil horizons?
- O horizon (humus)
- A horizon (topsoil)
- E Horizon (eluviation layer- movement of particles downward)
- B Horizon (subsoil)- illuviation layer ie movement into horizon
- C horizon (regolith)
- R horizon (bedrock)
Podzolization=
downward transport of Fe and Al in conjunction with organic matter from the A and E horizons to the B horizon
The __ horizon is lighter in color because the minerals have been leeched out, and the ___ horizon is darker because more minerals including oxidized iron (brown/red)
E
B
Soil development and formation process:
1
2
3
4
- additions (eg organic matter falling from trees)
- losses (eg leeching or eluviation, or erosion)
- translocations= eluviation or illuviation
- transformations (chemical eg oxidations/ reduction)
___ layer = taking away –>
___ –>
___ layer= bringing to
eluviation
translocation
illuviation
What are the 6 main soil types of the boreal forest?
- Podzolic (found w Jack Pine)
- Brunisolic= young/ poorly developed soil
- Luvisolic= post-glacial retreat (lots f clay and silt)
- Cryosolic- permafrost soil
- Gleysolic= wetland soil
- Organic = wetland soil
___ soil is dominant in boreal regions
It has __ parent materials and low ___ status because there’s lots of ___
podzolic
acidic
nutrient
leeching
t/f
brunisolic soil always has horizons
false
young soils= less weathering so layers are less prominent
becomes more layered with age
Lucisolic soils are __colored, __ horizons that develop in cool and ___ forested areas
They have __ soil due to ___ leaving behind silt and clay
light
eluvial
wet
loam
glaciation
cryosolic soil has poor ___ because poor ___ through frozen soil
horizons
leeching
As permafrost melts, ___ soils will become ___ soild
cryosolic
brunisolic
Gleysolic soil is found in areas with modest ___ and high ___ ___
They have periodic __ conditions
drainage
water tables
anoxic
what are the 2 types of bunisolic soils?
Eutric brunisols= dominate cooler high and mid-boreal regions
Malanic brunisols= in milder moist climates
Organic order soils are common in ___ and have extremally __ parent material
They’re very vulnerable to ___ b/c they desiccate in dry years
wetlands
acidic
fire
Soil and vegtation development is a function of
- ___ material
-
- ____ relief
- ____(biogeography)
-___
parent
climate
topographic relief
organisms
humans
Why is the mosaic boreal forest reflective of soil conditions?
- soil was there first
- also b/c vegetation influences soil (eg open vs closed canopy)
