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94 Cards in this Set
- Front
- Back
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Change in local Temp in last century?
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warmer
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Change in local Precipitation in last century?
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none
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Hurricane intensity gradient from __ to __?
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SE to NW
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Modifiers of hurricane damage?
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Distance from shore and topography
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Cause of different effects of 1815 and 1938 hurricane?
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Amount of forest cover
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1815 hurricane land use and effect?
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most agricultural /w small wind-resistant trees
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1938 hurrican land use and effect?
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mostly forest with white pines
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Density =
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stems per 1000 hectares
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Relative Basal Area =
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area covered by truck of tree
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1938 hurricane effect on D and RB
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D almost to zero RB shot up
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Mound qualities
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high light
low water low N |
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Tops qualities
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low light
high net mineralization high nitrification |
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Pits qualities
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Average resource levels
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Overall blowdown effects
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less litterfall
more mineralization temporary burst of nitrification lit-Min-NIT no change in CO2, temp or moisture |
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Pest problems today vs past
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huge rise with settlement
vs. only one 5000 years ago with hemlock |
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Indian demographics pre-settlement
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pre: 40-65 million in americas
~3.5 million in north america ~75,000 in New England |
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Indian forest impact
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Fire to get animals
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Post-settlement movement pattern
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Rapid west-ward movement
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Percent forest over time
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dropped to min about 1850-60 at peak agriculture
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hardwoods are
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deciduous
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softwoods are
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conifers
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Land-use location: Hemlocks
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primary forests never cut down
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Land-use location: Red maple
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old unimproved pastures
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Land-use location: Oak-maple
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plowed fields and pastures
NOT continuously wooded sites |
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Qualities of Plowed that Never Plowed lack
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More Airation
More Manure Less Dense |
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Bulk Density: Plowed __ Unplowed
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Plowed > Unplowed
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% Carbon: Plowed __ Unplowed
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Plowed < Unplowed
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Mineralization/Nitrification greatest to least?
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Oak > Aspen > Pines
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Long-term impact of agriculture:
forest floor C cultivated __ woodlots |
cultivated < woodlots
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Long-term impact of agriculture:
mineral soil C: cultivated __ woodlots |
cultivated = woodlots
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Long-term impact of agriculture:
mineral soil N/P: pasture __ cultivated __ woodland |
pasture = cultivated > woodland
use of manure |
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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 |
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Long-term impact of agriculture:
highest rates of N cycling? |
cultivated
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mineralization control by current vegetation over past land use?
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hardwood deciduous > softwood conifer
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Nitrification strongly controlled
by __ Reason: |
former land-use
higher pH due to burning amended with manure |
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Describe land wildlife population change
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Wolf = down to zero replaced by coyote
Deer = down almost to zero then rebound Beaver = down to zero before others then reintroduced and rebound |
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bird wildlife change?
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depends on species: bobolink/meadowlark did best with least forest
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Effect of beavers
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Contribute up to 25% of plant richness in riparian zone
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Largest source of Nitrogen?
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!! Internal N Cycling !!
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Human activity effect on N?
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Doubled!
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Negative effect of N saturation
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N2O release
NO3 leach Essential cation loss Reduced prod and diversity Acidification water Eutrophication |
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4 stages of N addition
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0: pre saturation
1: N mineralization -> NPP increase 2: Ca:Al and Mg:N ratios decrease --> NPP & N also decrease 3: Nitrate leaching LOTS |
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CA:Al and Mg:N ratio
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linear decrease
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N Mineralization and NPP
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Linear increase -> hump curve growth -> hump curve decrease
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nitrification and leaching
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none, then fast growth with leaching overtaking nitrification
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Red pine vs Newer Mixed hardwood
soil nutrient availability? |
Surprisingly, red pine
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N addition effects:
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Both
+ foliar %N Pine + NO3 leaching + net nitrification Hardwood + net mineralization + productivity |
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Faster trip to saturation?
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Pine
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15N Results
Most retention? Forests overall? Greatest sinks? |
Hardwood retain more N than pine
Forests retain more N than expected Soil = greatest sink |
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N retention in soil NOT due to
MAYBE due to |
microbial immobilization
mycorrhizal assimilation or abiotic adsorption |
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OM =
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Organic Matter
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Functions of OM
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water holder, purifier, erosion control, plant structure
major source of world carbon and nitrogen |
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DIRT =
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Detritus Input Removal and Transfer
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Roots excluded via
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trenching
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Soil Incubations =
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CO2 replease
net N mineralization gross N flux |
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When is max respiration
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Time of highest temp
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Relationship between more/less litter and respiration?
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more litter, more respiration
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Q10
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Change in respiration per 10 degrees change in temp
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Root respiration calculation?
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Control - "no root" treatment
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highest/lowest Q10
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'Roots' at 4.5 / 'No inputs' at 2.3
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DOC=
max/min? |
Dissolved Organic Carbon
double litter max / O/A-less min |
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%C and %N
Organic soil? Mineral soil? |
Organic:
Max = double min = O/A-less Mineral: No effect |
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Fungi : Bacteria ratio?
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Fungi > Bacteria
~200 Harvard Forest |
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Photosynthesis in wet vs dry season?
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more photosynthesis during drought---time lag?
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Best TOTAL respiration estimator?
why? |
Eddy Covariance > Static chamber
SC doesn't count aboveground respiraiton |
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PnET Model?
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Predicts photosynthesis rates using relationship between foliar %N and Amax
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Levels of PnET model?
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PnET - Day = most basic
PnET - BGC = most complex full biogeochemistry cycling |
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Discussed use of PnET
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Examine interaction between N deposition change, CO2 and O3
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PnET +CO2?
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+NPP
++NCE |
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PnET +O3
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+NCE
+O3 <-- decreases effect of +NCE |
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+CO2 & N
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+NPP
+NCE |
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+CO2 & N & O3
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+NPP
+NCE less due to elevated O3 |
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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 |
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Current global forest cover vs past?
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50% of original
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Recover productivity, not necessarily biodiversity
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reclaimation
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re-establishing productivity but not necessarily all biodiversity
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rehabilitation
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bring back everything original
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restoration
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establishment of planted forest on non-forested land
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afforestation
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re-establishment of trees and under-story at site following removal
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reforestation
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long-leaf pine location
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southeast
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long-leaf pine old extent vs today
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38 million hectares -- 5% today
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long-leaf diversity
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high diversity -- 140 species plants/hectare
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Tropical dry forest extent past vs present
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used to be more than half, now 2% remain
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how to tell whether animal or wind dispersed seed?
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animal: small # old trees
wind: more even-age distribution |
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issue with cloud forests
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very slow recovery due to extremes between dry pastures cut into forest and wet forest that seedlings are accustomed to
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Northeastern US contribution to CO2 emissions?
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7th largest
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CO2 breakdown?
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35 transport
30 electric 35 residential/industrial/commercial |
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A1F1
B1 Effects of both? |
High emissions
Low emissions both predict climate change |
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migration of MA could be like?
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South carolina
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snow change?
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less slow--more winter precip though--but as rain
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snow-melt experiment effect on decomposition
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higher in short-term
no change in long-term |
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snow-melt experiment effect of warming on CO2 flux
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carbon release higher in heated plot, but increase decreases over time
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Microbial contribution in CO2 flux?
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~20%
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snow-melt experiment:
net mineralization? |
warming increases rates
with N less limiting |
