Forest Ecosystem Pattern and Processes Forest Distribution

1
Forest Ecosystem Pattern and Processes Forest
Distribution
Forests are major ecosystems across world
https//www.uwsp.edu/natres/nres743/images/T2/dist
ribution.jpg
2
Long-term US Vegetation Changes
Note changes in forest distribution!! Why??
http//www.innovations-report.com/bilder_neu/27416
_vegetation_type.jpg
3
US Forest Land Percentages
Forested area is not the same as it was in 1600
yet demand continues to increase, and pressures
on forests mount
http//www.usgcrp.gov/usgcrp/Library/nationalasses
sment/overviewforests.htm
4
Biome distribution
Distribution of biomes related to temperature and
precipitation
Note Wet and Hot v. Dry and Cold (or Hot)
http//www.globalchange.umich.edu/globalchange1/cu
rrent/lectures/kling/ecosystem/ecosystem.html
5
U.S. Forest Distribution
Note predominance in Eastern US less in Midwest
and SW Why?
http//www.usgcrp.gov/usgcrp/Library/nationalasses
sment/overviewforests.htm
6
Dominant Forest Types, 1960-1990
Note forest types relation to temperature and
moisture
http//www.usgcrp.gov/usgcrp/Library/nationalasses
sment/overviewforests.htm
7
Dominant Forest Types Projected Scenarios due
to climate change
Species will respond to altered temperature and
moisture
But, will the right soils be in the right place??
http//www.usgcrp.gov/usgcrp/Library/nationalasses
sment/overviewforests.htm
8
Individual Species Distribution
Tree species ranges limited by temperature,
moisture, (and soil requirements)
Digital Representations of Tree Species Range
Maps from "Atlas of United States Trees" by
Elbert L. Little, Jr. (and other publications)
To see ranges of other species
http//climchange.cr.usgs.gov/data/atlas/little/
9
What is Photosynthesis?

• Process by which plants, some bacteria, and some
  protistans use the energy from sunlight to
  produce sugar
• Cellular respiration converts energy into ATP -
  "fuel" used by all living things
• Conversion of unusable sunlight energy into
  usable chemical energy is associated with the
  actions of the green pigment chlorophyll
• Most of the time, the photosynthetic process uses
  water and releases the oxygen
• Overall reaction of this process
• 6H2O 6CO2 ----------gt C6H12O6 6O2

10
Photosynthesis
(Shorthand for any number of complex C structures)
11
Photosynthesis - Photophosphorylation
ADP (adenosinediphosphate)
ATP (adenosine triphosphate)
NADP (nicotinamid adenosine di phosphate) (an
enzyme)
What are requirements of photosynthesis?
How are those requirements met?
www.emc.maricopa.edu
12
Photosynthesis Leaf Diagram
http//www.caribbeanedu.com/kewl/science/science04
d.asp
13
Photosynthetic Light Response Curve
Photosynthetic Light Response Curve - At light
levels above a certain point (light saturation),
most plants do not have increased net carbon
gain. Note the Light Compensation Point.
http//ecology.botany.ufl.edu/ecologyf02/Primarypr
oduction.html
14
Sun v. Shade Leaves
Note difference in Photosynthesis rate at low
light
Sun Leaves
Shade Leaves
Note difference in Max Photosynthesis rate
Plants are usually adapted to growth in direct
sunlight or shaded conditions. Similar
differences are observed among the leaves of
large trees those leaves that develop under the
shade of other leaves are anatomically and
metabolically different from those that grow on
exposed canopy surfaces. Shade-type leaves
typically are thinner, have more surface area,
and contain more chlorophyll than those of sun
leaves. As a result, shade-leaves (curve B) often
are more efficient in harvesting sunlight at low
light levels remember, the slope of the line
observed under low light conditions is a measure
of photosynthetic efficiency. However, sun-leaves
(curve A) display a higher light saturation point
and maximum rate of photosynthesis.
http//www.marietta.edu/spilatrs/biol103/photolab
/physfacs.html
15
Photosynthetic Profile Diagram
Higher Photosynthesis rate in sun leaf areas
Photosynthetic profile diagram for the Wind River
Canopy (WA) Crane site. Values listed are
photosynthetic capacity on a projected leaf area
basis for fully-induced leaves determined using
an LI-6400 photosynthesis system. Units are in
µmol C m-2 s-1, sample size is 3-5
individuals/site/species, based on measurements
made during Sept. 1996.
http//nigec.ucdavis.edu/publications/ar/annual99/
western/WRWinner0.html
16
Photosynthesis vs. Air Temperature
Air temperature influences the energy balance of
the plant canopy through the convective heat
transfer to the plant leaves and bodies High
temperatures can reduce enzyme efficiency,
therefore reducing photosynthessis
Photosynthesis activity vs. light and air
temperature conditions (tomato culture)(Kamenev,
1975).
http//geoheat.oit.edu/images/bulletin/bull18-1/fi
g36-3.gif
17
Photosynthesis vs. Temperature CO2
Although not considered a stress, the effects of
elevated levels of carbon dioxide on
photosynthesis represent another area of interest
to our group.  Fossil fuel burning is
increasing the levels of carbon dioxide in the
environment, with consequent effects on the
global climate.  Because Rubisco (an enzyme)
has a low affinity for carbon dioxide,
photosynthesis should increase as atmospheric
levels of carbon dioxide rise, increasing
productivity and converting some of the excess
carbon dioxide into biomass.   However, the
actual increase that occurs is generally lower
than predicted. 
http//www.wcrl.ars.usda.gov/programs/physbiochem/
pbresearch.html
18
Photosynthesis (CO2 vs. H2O Trade)
CO2 enters and water exits through leaf
stoma Water required for photosynthesis Water
lost during opening of stoma
http//ecology.botany.ufl.edu/ecologyf02/Primarypr
oduction.html
19
Forest Hydrologic Cycle
www.knockouthomeinspections.com
20
Net Primary Production
Gross PP total energy assimilated by
photosynthesis. Net PP accumulation of energy
into plant biomass - ie, plant growth and
reproduction (not including maintenance ie-
respiration)
http//ecology.botany.ufl.edu/ecologyf02/Primarypr
oduction.html
21
NPP vs. AET
Spatial variation in global NPP related to
temperature and precipitation, which can be
approximated by a single variable, actual
evapotranspiration (AET) Factors such as soil
types and textures and plant functional types can
influence the relationship between NPP and AET
http//www.colorado.edu/eeb/courses/4140bowman/lec
tures/4140-22.html
22
Nutrients in Forest Ecosystems
Table 1. Features of the major nutrient cycles

http//www2.dekker.com/sdek/143572177-31923825/abs
tractdbenccontenta713571811words
23
Nitrogen Cycle - Processes
Ammonification
Plant Uptake
http//www.physicalgeography.net/fundamentals/9s.h
tml
24
Nitrogen Cycle - Rates
3
20
Note!!! Human N addition natural addition!
120 (fertilizers and N-fixing crops)
36
200
Ammonification
Plant Uptake
1200
Fluxes in units of 1012 g N/yr
http//www.physicalgeography.net/fundamentals/9s.h
tml
25
Nutrient Mineralization and Immobilization
Mineralization - the release of organically bound
nutrients in an inorganic form usable to
organisms and/or plants
Organic N NH4
NO3
Ammonification
Nitrification
Mineralization
Immobilization - the conversion of an element
from the inorganic to the organic form
unavailable to plants
http//soils.tfrec.wsu.edu/mg/cycling.htm
26
Decomposition vs. Temperature
Letters different sites
Lower temperature less decomposition, more mass
remaining
Controls on litter decomposition The 21 sites
covered a broad range of conditions from the wet
(yearly precipitation 1783 mm), mild (9.3oC mean
annual temperature) Douglas-fir and western
hemlock forested sites in the pacific cordilleran
ecoclimatic region (SHL, PMC) to the dry (266
mm), cold (-9.8oC), black spruce forested sites
in the subarctic (GI1, INU). Across all litter
types, annual temperature was the best single
climate predictor tested (r2.316 all data 0.722
sitemean), inclusion of annual precipitation
improved the fit (r20.378 all data 0.865
sitemean)
http//www.pfc.forestry.ca/climate/cidet/controls_
e.html
27
Decomposition Chemistry (e.g., Lignin)
Letters different litter
More lignin less decomposition, more mass
remaining
Figure 7. All litters, Third year remaining mass
versus Klason Lignin N. Of all litter quality
measures the ratio of Klason lignin to total
N gave the best fit (r2 0.265 all data 0.738
typemean) though regressions differed with wood
blocks excluded.
http//www.pfc.forestry.ca/climate/cidet/controls_
e.html
28
Ecosystem Model
http//www.hubbardbrook.org/research/images/budget
.gi
29
Soil Horizons I
The Ailey series consists of soils that are deep
or very deep to a dense layer. These well
drained, slowly permeable soils formed in sandy
and loamy marine sediments on uplands, mostly in
the upper Coastal Plain. Slopes are 0 to 25
percent
To see horizons of other soil types
http//www.mo15.nrcs.usda.gov/features/gallery/gal
lery.html
30
Soil Horizons II
O Horizon - The top, organic layer of soil, made
up mostly of leaf litter and humus (decomposed
OM).A Horizon Topsoil layer found below O and
above E. Seeds germinate and plant roots grow in
this dark-colored layer. It is made up of humus
(decomposed OM) mixed with mineral particles.E
Horizon - This eluviation (leaching) layer is
light in color and found beneath A and above B.
It is made up mostly of sand and silt, having
lost most of its minerals and clay as water drips
through the soil (in the process of
eluviation).B Horizon - Also called the subsoil
- this layer is beneath E and above C. It
contains clay and mineral deposits (like Fe, Al
oxides, and calcium carbonate) that it receives
from layers above it when mineralized water drips
from the soil above. B can be very thick and can
be broken down into multiple layers within the
horizon. C Horizon - Also called regolith the
layer beneath B and above R. It consists of
slightly broken-up bedrock. Plant roots do not
penetrate into this layer very little OM is
found in this layer.R Horizon - The unweathered
rock (bedrock) layer that is beneath all the
other layers.
http//www.enchantedlearning.com/geology/soil/soil
layers.GIF
31
Determining Soil Layers Rollover Image
Can you identify possible horizons in this soil
profile?Roll your mouse over the image above to
see horizon lines.
Can you identify possible horizons in this soil
profile?Roll your mouse over the image above to
see horizon lines.
Can you identify possible horizons in this soil
profile?Roll your mouse over the image above to
see horizon lines.
Go to the website to view the image first without
the lines and then with the lines
http//www.learner.org/channel/courses/essential/e
arthspace/session1/closer1.html
32
Different Soils Different Forest Ecosystems
http//www.geography.btinternet.co.uk/ecosystems.h
tm
33
Ecosystem Development (Primary Succession)

• Begins with soil formation
• Generally slow, many 1000s years (e.g. post
  glaciation
• Early, mid-, late successional species

http//www.geo.arizona.edu/Antevs/nats104/00lect20
.html
34
Ecosystem Development (Secondary Succession)
-Reestablishment after disturbance -Faster than
primary succession 200 years (why?)
http//www.geo.arizona.edu/Antevs/nats104/00lect20
.html