Forest Ecology Exam 2

Front 1

nutrient concentration are greater for what kind of tissue

Back 1

more metabolic active tissue

Front 2

order these in terms of nutrient content: foliage, new stem wood, fine roots old stem wood, new twigs, old branches

Back 2

foliage > fine roots > new twigs > old branches > new stem wood > old stem wood

Front 3

which leaf habit has greater concentration of nutrients

Back 3

deciduous > conifers (evergreen)

Front 4

temperate or tropical systems have more nutrients available in forests

Back 4

temperate > tropical

Front 5

which nutrient is most important for healthy forest

Back 5

nitrogen

Front 6

nutrients inputs into the ecosystem come from:

Back 6

weathering, mineralization and atmospheric inputs

Front 7

atmospheric inputs

Back 7

wet deposition, dry deposition and sea spray (geographically specific)

Front 8

wet deposition

Back 8

acid rain, any nutrient contained in precipitation, N and S moderate in industrial areas, S high in volcanic areas, P extremely low

Front 9

dry deposition

Back 9

particles suspended in the air and then deposited, base cations high in dry agriculture areas

Front 10

sea spray

Back 10

Na Cl and MgSO4 from oceans

Front 11

weathering

Back 11

minerals in earth's crust put under high pressure and temperature and formed rocked which are now subject to weathering

Front 12

physical weathering

Back 12

degradation of rock due to climatic factors (freeze/thaw) or biological activity (tree roots)

Front 13

chemical weathering

Back 13

dissolution of mineral when it reacts with water or other liquid

Front 14

rates of weathering and input of nutrients is controlled by:

Back 14

climate (higher temps means higher weathering) and parent material

Front 15

Ca and Mg come from which type of parent material?

Back 15

carbonates (limestone)

Front 16

mineralization

Back 16

the conversion of any type of organic material or transformation to inorganic forms of nutrients

Front 17

does weathering release N?

Back 17

no

Front 18

release of nutrients in organic matter is controlled by what ratio

Back 18

C : nutrient

Front 19

redfield ratio

Back 19

C : N : P

Front 20

a higher redfield ratio means

Back 20

lower rate of decompostion (decomposers have the lowest C:N, which makes sense because they decompose so fast)

Front 21

why does the use of woody chips as fertilizer or top organic layer bad for plants?

Back 21

this is because the C:N ratio is so high and will decompose very slowly

Front 22

nitrogen fixation

Back 22

the conversion of atmospheric N to organic N by several types of bacteria and blue green algae

Front 23

why is the symbiosis of plants and nitrogen fixing bacteria important?

Back 23

the symbiosis of these two things allows for a higher nitrogen fixation rate for the plants, meaning they can uptake more N which is the most limiting nutrient usually to plants

Front 24

factors influencing N fixation

Back 24

lower pH decreases N fixation, low soil oxygen (most fixers are aerobic), micronutrient deficiencies, temperature is optimal at 30-35 C, and soil moisute optimum is near field capacity

Front 25

effect of N available

Back 25

increase N availability greatly

Front 26

Nutrient outputs or losses

Back 26

leaching, erosion and gaseous losses

Front 27

leaching

Back 27

movement of nutrients below the rooting zone and into the subsoil. For every anion lost a valuable cation must accompany it to maintain soil neutrality. function of anion production and anion mobility

Front 28

why are anions lost to leaching?

Back 28

trees usually are unable to take up a great amount of anions meaning they will just leach down the soil

Front 29

processes that form anions

Back 29

nitrification, organic acids, bicarbonate formation, chloride input from sea spray, weathering

Front 30

erosion

Back 30

important in poorly managed forest areas, losses can exceed 200 kg N/ha/yr, more common in agriculture systems because no canopy cover or litter,

Front 31

denitrification

Back 31

conversion of NO3 to N2 by facultative anaerobic heterotrophs

Front 32

requirements for denitrification

Back 32

anaerobic soil, NO3 supply, warm soil (occurs in swamps, feed lots and ag soils)

Front 33

volatilization

Back 33

gaseous loss of a substance to the atmosphere

Front 34

three major processes responsible for nutrient uptake

Back 34

root growth, mass flow, diffusion

Front 35

mass flow

Back 35

nutrients flows in the water toward the plant root

Front 36

diffusion

Back 36

nutrient moves along concentrations gradient of high to low conc. in root

Front 37

rate limiting step of nutrient uptake?

Back 37

fine root growth and amount of mycorrhizae speed up process but the rate limiting step is getting the nutrient close enough to roots for uptake

Front 38

retranslocation

Back 38

removal of nutrients from senescing/dying tissue

Front 39

retranslocation is influenced by:

Back 39

tissue type, nutrient type, nutrient availability and leaf habit

Front 40

retranslocation tissue type

Back 40

foliage > wood

Front 41

retranslocation which nutrient

Back 41

N, P, S , Mg in pools, nutrients part of structure no moved ( Ca), energy costs to break down storage forms of nutrients to allow movement

Front 42

retranslocation nutrient availability

Back 42

deciduous does more retranslocating than evergreen, have more labial pool of nutrients, 80- 90% N removed from leaves

Front 43

ecological advantages of retranslocation

Back 43

greater nutrient use efficiency (amount of organic matter per unit nutrient used), prevents loss of nutrients to forest floor, decreases litter quality, independence from soil supply of nutrients

Front 44

detritus

Back 44

dead leaves, dead roots; anything plant sheds

Front 45

litterfall : detritus production

Back 45

litterfall nutrient content greater in deciduous than evergreen forests, litterfall N by region, indicator of nutrient availability

Front 46

fine roots : detritus production

Back 46

nutrients from fine root and mychorrizae turnover can equal or exceed litterfall nutrient input, important for underground nutrient pools

Front 47

herbivory : detritus production

Back 47

usually low, insect feces high in nutrients, bison feces high in nutrients as well (that's why you see fertile praries)

Front 48

impacts on nutrient cycling

Back 48

fire, harvesting, fertilization and management

Front 49

fire : nutrient cycling

Back 49

can cause volatilization

Front 50

harvesting : nutrient cycling

Back 50

type of harvest, time of year

Front 51

management

Back 51

N-fixing plants, tap roots, plant selection, symbionts

Front 52

decomposition

Back 52

process of physical and chemical breakdown of organic matter

Front 53

soil contains how much more carbon than the atmospher

Back 53

twice as much

Front 54

producers

Back 54

derive energy from sunlight and they return organic matter to the forest floor

Front 55

consumers

Back 55

get energy from consumption of plants, death is their fare and do respiration

Front 56

decomposers

Back 56

fauna, soil flora

Front 57

fauna decomposers

Back 57

macrofauna- moles, shrews, mice; other fauna-arthropods (ants, centipedes,crayfish) do fragmenting; annelids 80% of total soil fauna, fragmenting (worms); nematodes- which are on the forest floor

Front 58

soil flora decomposers

Back 58

protoza- abundant and breakdown soil organic matter; bacteria- aerobic heterotrophs (key decomposers), aerobic soils and actinomycetes (similar to fungi); fungi- most prevalent in litter, better adapted to acidic soils and is a key decomposer

Front 59

two steps of decomposition

Back 59

fragmentation (physical) and oxidation of organic matter (chemical)- results in the production of humus and mineralization of nutrients from organic matter

Front 60

estimating decomposition

Back 60

k=-ln(1-fraction mass loss)/time

Front 61

which biome has the highest decompostion rate? lowest?

Back 61

tropical forests, tundra

Front 62

order these in decomposition rate

Back 62

foliage>fine roots> twigs> stems

Front 63

methods of estimating decomposition

Back 63

litterfall/forest floor ratios; litterbags/weight loss; changes in specific gravity; CO2 evolution

Front 64

litterfall/forest floor ratio estimating decomposition

Back 64

main assumption: inputs and outputs are at a steady state

Front 65

litterbags/weight loss estimating decomposition

Back 65

leave bags in certain area for long amount of time and see how much the content decays:

k=(-ln(1-mass loss))/t

Front 66

mineralization

Back 66

minerals get released before all of organic material is decomposed

Front 67

what do fungi immobilize?

Back 67

P and N

Front 68

specific gravity estimating decomposition

Back 68

used usually for measuring wt loss in coarse woody debris (logs)

WL=(Volume after time t x SG after time t) - (Volume initially x SG initially)

Front 69

CO2 evolution estimating decomposition

Back 69

microbes performing decomposition release carbon dioxide in the process; have to remember to factor out root respiration though and have to do in aerobic conditions

Front 70

three major factors influencing decomposition

Back 70

climatic variables, litter quality, surface are:volume ratio

Front 71

climatic variables affecting decomposition

Back 71

temperature- decomposition is proportional to temp

moisture- best decomposition rates typically around field capacity

evapotranspiration-great predictor of decomposition at global scale

oxygen- most decomposers are aerobic or faculatative aerobic

Front 72

litter quality affecting decomposition

Back 72

nitrogen- redfield ratio controls decomposition rate, low ratio implies high decay rate

lignin- very resistant to decay, yields almost no net energy gain, some fungi have ligninases

Front 73

fungi go after what types of sources first and then what in organic matter

Back 73

starches and sugars and then go lignin last

Front 74

surface are : volume ratio affecting decomposition

Back 74

high ratio with smaller pieces

Front 75

in low litter quality you would expect to see not enough nutrients? or nutrients being lost? high quality?

Back 75

low litter quality you would expect to see a nutrient deficiency

high litter quality you would expect to see nutrients being lost because plants cannot uptake them fast enough

Front 76

humus

Back 76

highly decompsed organic matter

decompostion of humus becomes slower and slower over time

Front 77

turnover rate of humus?

Back 77

100's of years

Front 78

who is most to blame for organic matter being lost to the atmosphere/

Back 78

farmers

Front 79

is it harder or easier to build up soil organic material or break it down?

Back 79

its a lot easier to break down soil organic matter than to build it back up

Front 80

production ecology

Back 80

the production and allocation of organic matter by plants and animals. Egler was the first important production ecologist

Front 81

biomass

Back 81

the quantity or amount of organic matter per unit area; about 50% carbon

Front 82

production

Back 82

the rate of increase of organic matter per unit area per time

Front 83

levels of study for production ecology

Back 83

cellular/leaf-photosynthes

tree/plant- all tree components, includes yield for agri crops

ecosystem- photoautotrophs, hetertrophs and consumers

ladnscape to regional-flux towers and aircraft w/ CO2 sensors

global-terrestrial, aquatic, atmospheric

Front 84

estimation of biomass

Back 84

area harvest, mean tree approach, allometry

Front 85

area harvest estimating biomass

Back 85

most appropriate fro smaller vegetation such as for crops and grasslands; measure area and weight

Front 86

mean tree approach estimating biomass

Back 86

biomass of area based on the diameter breast height of average trees, calculated as average, good for even-aged forests

Front 87

allometry estimating biomass

Back 87

survey stand/plot, get ranges of diameter breast height, select most representative trees, weigh wet biomass components and get ratio to dry weight

biomass increases exponentially with diameter

Front 88

factors influencing above ground biomass

Back 88

stand age. climate, water availability, nutrient availability and leaf habit

Front 89

stand age influencing biomass

Back 89

biomass increases with age, above and below ground

Front 90

climate influencing biomass

Back 90

more favorable climate, increased biomass

Front 91

water availability influencing biomass

Back 91

foliage mass/LAI proportional to water availability

Front 92

nutrient availability influencing biomass

Back 92

biomass is related to limiting nutrients

fertilization increases biomass as long as water availability is sufficient

Front 93

leaf habit influencing biomass

Back 93

evergreen have greater foliage mass b/c of their retaining abilities

Front 94

estimating below ground biomass

Back 94

coarse roots, fine roots

Front 95

coarse root estimation of biomass

Back 95

use allometric relations, follows same trends of aboveground biomass

use high pressure water, dynamite or machinery to get to roots

Front 96

fine root estimation of biomass

Back 96

use metal core to take out of ground and separate out of soil and weigh

also use minirhizotrons; use of caerams to monitor root growth

Front 97

factors influencing belowground biomass

Back 97

stand age, nutrient availability, water availability, leaf habit

Front 98

stand age affect on belowground biomass

Back 98

coarse root biomass increases with stand age

fine root biomass reaches a max around canopy closure and stays the same

Front 99

nutrient availability affecting belowground biomass

Back 99

more fine roots on nutrient poor sites becasue need to get more nutrients

Front 100

water availability affecting belowground biomass

Back 100

fine root biomass inversely related to water content

Front 101

effect of leaf-habit belowground biomass

Back 101

in general evergreen trees allocate or support more fine roots than deciduous trees

Front 102

gross primary production

Back 102

total amount of carbon assimilated by plants per unit area and time

almost always positive

very difficult to measure

Front 103

net primary production

Back 103

net amount of carbon assimilated by plants per unit are and time

NPP=GPP-autotrophic respiration

always positive

Front 104

carbon allocation

Back 104

refers to the priority in which photosynthate is partitioned in the plant

Front 105

net primary production estimation

Back 105

repeated plot harvest

allometry and repeated stem measurements

Front 106

NPP also =

Back 106

change stem + change branch + change foliage (must account for losses to herbivory)

Front 107

net ecosystem productivity

Back 107

measure of the change of the total organic matter (living and dead) in the ecosystem per unit area and time

really is the amount of change or the total amount of carbon assimilated minus the loss of respiration from plants and mircobes

Front 108

equations for net ecosystem productivity

Back 108

NEP = GPP - autotrophic respiration - heterotrophic respiration

NEP= NPP - heterotrophic respiration

Front 109

if NEP is postive the terrestrial ecosystem is a C sink or source?

Back 109

sink

Front 110

fators affecting carbon allocation

Back 110

nutrient availability, water availability, leaf habit

Front 111

nutrient availability affecting C allocation

Back 111

fine root biomass is inversely related to the limiting nutrient in the stand (N or P)

Front 112

water availability affecting C allocation

Back 112

inversere relationship between water and belowground net primary production

Front 113

leaf habit affecting C allocation

Back 113

conifers allocate more C to fine roots than deciduous

Front 114

what sets the max LAI a plant can support?

Back 114

site water balance sets the max amount of LAI a site can support

Front 115

factors affecting autotrophic respiration

Back 115

temperature and biomass allocation

Front 116

autotrophic respiration comprises what percentage of GPP?

Back 116

40%

Front 117

production efficiency

Back 117

amount of C produced per unit leaf area or foliage mass

NPP/LAI

Front 118

does NPP increase at the same rate as LAI

Back 118

no

Front 119

why production efficiency decreases with LAI?

Back 119

net photosynthetic rate can only increase to a certain point (light saturation point)

light attenuation decreases exponentially through the canopy thus much of the leaf mass operates between the light compensation and light saturation points

Front 120

factors influencing production efficiency

Back 120

light-positive relationship

water- positve asymptotic relationship

nutrient availability- positive asymptotic relationship

Front 121

Net ecosystem production (NEP)

Back 121

=NPP-Respiration of heterotrophs

measure of the change of total organic matter per unit area and time

Front 122

factors influencing net ecosystem production

Back 122

climate and disturbance

Front 123

is the ecosystem a C-sink or source when NEP is positive?

Back 123

sink

Front 124

site productivity

Back 124

the potential of a site to produce one or more natural resources

ex: wood, wildlife, water

take into account sustainability and multiple resources

Front 125

direct measurement of site productivity

Back 125

no way to directly measure the site productivity when considering the amount of time, money and people needed to do so

Front 126

ways to measure site productivity

Back 126

remote sensing, ecosystem process models, environmental relationships/factors, habitat typing, ecological site classification, understory species, overstory tree species, site index

Front 127

site index

Back 127

forest measurement to indirectly estimate site quality

based on height of dominant and co-dominant trees based on some standard age (50 years typically)

Front 128

pros and cons of site index

Back 128

pros: easy and inexpensive, height growth is less sensitive than other measurements, very site dependent

cons: it is empirical, very site dependent, differs among species, requires trees growing in the site, cannot capture dynamic nature of tree growth

Front 129

overstory tree species - classification

Back 129

each species occupies its own niche

Front 130

pros and cons of overstory tree species - classification

Back 130

pros: allows for quick assumption about a given area

cons: this approach does not work well for species that are able to exist in a wide range of climate, very qualitative

Front 131

understory tree species - classification

Back 131

use of understory species to make classification of site

Front 132

pros and cons

Back 132

pros: more sensitive to microclimate differences, indicator species

cons: what about disturbance, influence of invasive species, qualitative

Front 133

ecological site classification

Back 133

primary means is through habitat typing

identified by distinct understory plant assemblages

natural vegetation to identify ecologically equivalent landscape units

Front 134

habitat typing classification

Back 134

relies on unique plant assemblages and soil- not single species

soils and topography are key drivers of vegetation composition and growth

Front 135

pros and cons of habitat typing

Back 135

pros: fairly easy, generally habitat types correlate to wildilfe habitat, management constraints and recreation potential, qualitative relationship to other ecosystem structural and functional characteristics, but must be established

cons: require good knowledge of flora, somewhat sensitive to disturbance, requires vegetation

cons: require

Front 136

environmental relationships/factors

Back 136

simple relationships between one or more variables and tree growth

Front 137

ecosystem process models

Back 137

based on biophysical and ecological principles

every physiological process model has some level of empiricism

Front 138

remote sensing

Back 138

NIR light / R light, can easily distinguish among major forest types, can detect disturbances, use radiation reflection

Front 139

life history

Back 139

the reproduction, growth and allocation characteristics of a species

Front 140

niche

Back 140

the physical or temporal space occupied by a species. life history oftern determines the niche. Often, an effective incasice species colonizes a spatial or temporal space not used effectively by natives

Front 141

R life history

Back 141

high rate of increase, allocate large amounts of energy to reproduction and have a lower competitive ability

Front 142

K life history

Back 142

allocate a large amount of energy to producing less offspring with a greater competitive ability

Front 143

R life classification

Back 143

rapid juvenile growth, early flowering, larger seed crops, shorter life span, high shoot/root ratio, nutrient cycling fast

Front 144

K life classification

Back 144

slower juvenile growth, delayed flowering, smaller seed crops, longer life span, low shoot/root ratio, nutrient cycling slow

Front 145

grime's life history model

Back 145

ruderals, competitors, strees tolerant

Front 146

ruderals

Back 146

high resource abundance, high disturbance frequency

forbs, short life span, large %NPP to reproduction, rapid max. growth rate, response to stress rapid reproduction

Front 147

competitors

Back 147

high resource abundant, low disturbance frequency

trees/shrubs, moderate to long life span, small %NPP goes to reproduction, rapid growth rate, responds to stress by shifting biomass allocation

Front 148

stress tolerant

Back 148

low resource availability, low disturbance frequency

forbs and lichens, long life span, small % of NPP goes to reproduction, slow growth rate, slow repsone to stress

Front 149

symbiotic relationship

Back 149

relationship between two organism in which both benefit or neither are negatively affected

Front 150

mutualism

Back 150

relationship between organisms in which both organisms benefit (ex. Mycorrhizae)

Front 151

commensalism

Back 151

relationship between two organisms in which one of the organisms benefits and the other is unaffected (ex. Mistletoe)

Front 152

antagonistic relationship

Back 152

interaction between two organisms in which at least one of the organisms is negatively affected

Front 153

three types of antagonistic relationships

Back 153

physical exploitation, antibiosis or chemical and competition

Front 154

antibiosis or allelopathy

Back 154

chemical interaction between life forms, fungi produces penicillin, plants have secondary compounds used for defense

ex. walnut tree produces juglone which inhibits the germination of other seedlings

Front 155

competition

Back 155

interaction among individuals for required resources that are commonly limiting

Front 156

intraspecific competition

Back 156

competition within the same species
generally does not alter community composition, but changes community structure

Front 157

interspecific competition

Back 157

competition among species, e.g. mixed hardwoods
-major factor for a change in species composition during succession

Front 158

physiological niche

Back 158

the environmental conditions in which a species can survive, grow and reproduce in isolation

Front 159

ecological niche

Back 159

the envrionmental conditions in which a species can survive, grow, and reproduce in competiton with other species

Front 160

aboveground competition

Back 160

more favorable carbon balance correlates well with the fitness or competitiveness of a individual or species
Architecture of tree can influence competitive status of plant
maintain a flexible branching pattern and produce foliage in areas where light is abundant

Front 161

belowground competition

Back 161

(1) faster access to the limiting resource (water and nutrients) (temporal dimension). E.g. rapid root growth.
(2) greater exploration of the soil resource (spatial dimension). E.g. greater allocation to fine roots and mycorrhizae
(3) use resources more efficiently and get by on less (physiological). E.g. retranslocation & greater biomass per unit nutrient used

Front 162

dominant

Back 162

trees with crowns extending above the general level of the canopy and receive full sunlight from the top and sides

Front 163

co-dominant

Back 163

trees with crowns forming the general canopy or slightly below, full sunlight from above only and moderate indirect light from the sides

Front 164

intermediate

Back 164

shorter than the twp above classes, crown may extend to the general canopy with only partial direct sunlight

Front 165

suppressed

Back 165

crown entirely below the general canopy with no direct sunlight.

Front 166

characteristics of shade tolerant plants

Back 166

have denser crowns, have slower growth rate, don't self prune, slower natural thinning, have greater needle longevity, respond to thinning more slowly, have more dense stands

Front 167

succession

Back 167

change in species compostion, structure and function following disturbance

function refers to nutrient cycling and water cycling

Front 168

sere

Back 168

stage in succession

Front 169

seral

Back 169

any stage of succession before the climax stage

Front 170

climax

Back 170

self-replacig sere that is relatively stable, implies equilibrium, self-replacing stuff that supposed to be there

Front 171

primary succession

Back 171

occurs on surface of terrain that was never vegetated, usually lacks soil development

from more intense disturbance

Front 172

secondary succession

Back 172

disturbance where soil was previously vegetated and soil is intact

Front 173

rate of succession influenced by

Back 173

disturbance intensity: lowere rate of succession for more intense disturbance

site fertility: decreased when site fertility is decreased

type of succession: slower for primary that for secondary

climate: slower in harsh v. mild conditions

Front 174

major factors of succession?

Back 174

autogenic: internal or endogenous

allogonic: external or exogenous

Front 175

autogenic

Back 175

occurs in years to maybe decades, modified by itself, internally driven, biophysical and biochemical changes less optimal for species that caused change and they're replaced by other species with life history characteristics better suited to the environment

Front 176

allogenic

Back 176

the physical environment changes and drives succession, often a result of geologic processes

Front 177

relay floristics: Clementsian model

Back 177

succession is composed of several to many discrete, predictable seral communities

the assembalge of species of each sere modify the habitat in such a way that they're a competitive disadvantage

Front 178

initial floristics: Eglers model

Back 178

succession is not predictable and driven by chance, in essence there is a sorting out of species

Front 179

linear succession direction

Back 179

proceeds to climax community and then the clock is reset

Front 180

cyclical succession direction

Back 180

patchwork of communities that replace themselves in cyclical sequence

Front 181

stages of stand development

Back 181

stand re-initiation, stem exclusion, understory re-initiation, old-growth

Front 182

3 hypotheses for NPP decline with age

Back 182

imbalance of respiring and photosynthetic biomass, nutrient immobilization and hydraulic constraint