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94 Cards in this Set

  • Front
  • Back
Change in local Temp in last century?
warmer
Change in local Precipitation in last century?
none
Hurricane intensity gradient from __ to __?
SE to NW
Modifiers of hurricane damage?
Distance from shore and topography
Cause of different effects of 1815 and 1938 hurricane?
Amount of forest cover
1815 hurricane land use and effect?
most agricultural /w small wind-resistant trees
1938 hurrican land use and effect?
mostly forest with white pines
Density =
stems per 1000 hectares
Relative Basal Area =
area covered by truck of tree
1938 hurricane effect on D and RB
D almost to zero RB shot up
Mound qualities
high light
low water
low N
Tops qualities
low light
high net mineralization
high nitrification
Pits qualities
Average resource levels
Overall blowdown effects
less litterfall
more mineralization
temporary burst of nitrification
lit-Min-NIT
no change in CO2, temp or moisture
Pest problems today vs past
huge rise with settlement
vs.
only one 5000 years ago with hemlock
Indian demographics pre-settlement
pre: 40-65 million in americas
~3.5 million in north america
~75,000 in New England
Indian forest impact
Fire to get animals
Post-settlement movement pattern
Rapid west-ward movement
Percent forest over time
dropped to min about 1850-60 at peak agriculture
hardwoods are
deciduous
softwoods are
conifers
Land-use location: Hemlocks
primary forests never cut down
Land-use location: Red maple
old unimproved pastures
Land-use location: Oak-maple
plowed fields and pastures

NOT continuously wooded sites
Qualities of Plowed that Never Plowed lack
More Airation
More Manure
Less Dense
Bulk Density: Plowed __ Unplowed
Plowed > Unplowed
% Carbon: Plowed __ Unplowed
Plowed < Unplowed
Mineralization/Nitrification greatest to least?
Oak > Aspen > Pines
Long-term impact of agriculture:
forest floor C
cultivated __ woodlots
cultivated < woodlots
Long-term impact of agriculture:
mineral soil C:
cultivated __ woodlots
cultivated = woodlots
Long-term impact of agriculture:
mineral soil N/P:
pasture __ cultivated __ woodland
pasture = cultivated > woodland

use of manure
Long-term impact of agriculture
C:N ratio
C:P ratio
N:P ratio
cultivated < pasture or woodlot
cultivated < pasture or woodlot
cultivated < pasture or woodlot
Long-term impact of agriculture:

highest rates of N cycling?
cultivated
mineralization control by current vegetation over past land use?
hardwood deciduous > softwood conifer
Nitrification strongly controlled
by __

Reason:
former land-use

higher pH due to burning
amended with manure
Describe land wildlife population change
Wolf = down to zero replaced by coyote
Deer = down almost to zero then rebound
Beaver = down to zero before others then reintroduced and rebound
bird wildlife change?
depends on species: bobolink/meadowlark did best with least forest
Effect of beavers
Contribute up to 25% of plant richness in riparian zone
Largest source of Nitrogen?
!! Internal N Cycling !!
Human activity effect on N?
Doubled!
Negative effect of N saturation
N2O release
NO3 leach
Essential cation loss
Reduced prod and diversity
Acidification water
Eutrophication
4 stages of N addition
0: pre saturation
1: N mineralization -> NPP increase
2: Ca:Al and Mg:N ratios decrease --> NPP & N also decrease
3: Nitrate leaching LOTS
CA:Al and Mg:N ratio
linear decrease
N Mineralization and NPP
Linear increase -> hump curve growth -> hump curve decrease
nitrification and leaching
none, then fast growth with leaching overtaking nitrification
Red pine vs Newer Mixed hardwood
soil nutrient availability?
Surprisingly, red pine
N addition effects:
Both
+ foliar %N
Pine
+ NO3 leaching
+ net nitrification
Hardwood
+ net mineralization
+ productivity
Faster trip to saturation?
Pine
15N Results
Most retention?
Forests overall?
Greatest sinks?
Hardwood retain more N than pine
Forests retain more N than expected
Soil = greatest sink
N retention in soil NOT due to

MAYBE due to
microbial immobilization

mycorrhizal assimilation or abiotic adsorption
OM =
Organic Matter
Functions of OM
water holder, purifier, erosion control, plant structure

major source of world carbon and nitrogen
DIRT =
Detritus Input Removal and Transfer
Roots excluded via
trenching
Soil Incubations =
CO2 replease
net N mineralization
gross N flux
When is max respiration
Time of highest temp
Relationship between more/less litter and respiration?
more litter, more respiration
Q10
Change in respiration per 10 degrees change in temp
Root respiration calculation?
Control - "no root" treatment
highest/lowest Q10
'Roots' at 4.5 / 'No inputs' at 2.3
DOC=
max/min?
Dissolved Organic Carbon
double litter max / O/A-less min
%C and %N
Organic soil?
Mineral soil?
Organic:
Max = double min = O/A-less
Mineral:
No effect
Fungi : Bacteria ratio?
Fungi > Bacteria

~200 Harvard Forest
Photosynthesis in wet vs dry season?
more photosynthesis during drought---time lag?
Best TOTAL respiration estimator?

why?
Eddy Covariance > Static chamber

SC doesn't count aboveground respiraiton
PnET Model?
Predicts photosynthesis rates using relationship between foliar %N and Amax
Levels of PnET model?
PnET - Day = most basic
PnET - BGC = most complex full biogeochemistry cycling
Discussed use of PnET
Examine interaction between N deposition change, CO2 and O3
PnET +CO2?
+NPP
++NCE
PnET +O3
+NCE
+O3 <-- decreases effect of +NCE
+CO2 & N
+NPP
+NCE
+CO2 & N & O3
+NPP
+NCE
less due to elevated O3
Effect of timber harvest compared to agriculture

why
NPP: Timber > Agriculture
NCE: Timber < Agriculture

lower intensity disturbance to soil less nutrient loss and more respiration, thus lower NCE
Current global forest cover vs past?
50% of original
Recover productivity, not necessarily biodiversity
reclaimation
re-establishing productivity but not necessarily all biodiversity
rehabilitation
bring back everything original
restoration
establishment of planted forest on non-forested land
afforestation
re-establishment of trees and under-story at site following removal
reforestation
long-leaf pine location
southeast
long-leaf pine old extent vs today
38 million hectares -- 5% today
long-leaf diversity
high diversity -- 140 species plants/hectare
Tropical dry forest extent past vs present
used to be more than half, now 2% remain
how to tell whether animal or wind dispersed seed?
animal: small # old trees
wind: more even-age distribution
issue with cloud forests
very slow recovery due to extremes between dry pastures cut into forest and wet forest that seedlings are accustomed to
Northeastern US contribution to CO2 emissions?
7th largest
CO2 breakdown?
35 transport
30 electric
35 residential/industrial/commercial
A1F1
B1

Effects of both?
High emissions
Low emissions

both predict climate change
migration of MA could be like?
South carolina
snow change?
less slow--more winter precip though--but as rain
snow-melt experiment effect on decomposition
higher in short-term
no change in long-term
snow-melt experiment effect of warming on CO2 flux
carbon release higher in heated plot, but increase decreases over time
Microbial contribution in CO2 flux?
~20%
snow-melt experiment:
net mineralization?
warming increases rates
with N less limiting