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Forest Ecosystesm
Cusask- Midterm
Undergraduate 3

Additional Geography Flashcards




What are the paleo floristic realms?
Antartic, Australian, S. African, Boreal, neotropics, Paleotropics
What is a forest stand?
continuous group of trees growing, similar site conditions and constant structure
What is forest stand dynamics?
-Succession + Disturbance
-what happens after a forest gets disturbed.
What is canopy structure? How is is measured?
-Organization or spatial arrangement of a plant canopy, measured by LEAF AREA INDEX(LAI): which is ratio of total upper leaf structure of vegetation divided by surface area of land on which it grows.
What is a climograph? Holdridge life zones?
-climograph is a simple diagram quantifying aspexts of relationship between climate and vegetation types.(y-axis temperature & x-axis is precipitation)
-Holdridge: more advanced, includes evapotranspiration directly & from trees.
alpha diversity & beta diveristy?
-Alpha: biodiversity in a PARTICULAR AREA usually expressed as SPECIES RICHNESS of area. Count # of species in ecosystem.
-Beta: compares species diversity between ecosystems or along gradients. Count # of taxa unique to each ecosystem.
Systems Model for mechanistic model of forests
systems model is directed development/succession, an overall climax species to be obtained, disturbances are unnatural and hinder the process of succession & steady state. Used as a general picture of diverse complicated forests such as rainforests in which there are too many factors to calculate.
-Mechanistic model: takes into consideration disturbance as a natural factor. It works from the bottom up of biology/chemistry to soil sciences to ecological studies of the habitat, there is no steady state or climax species; this is better used for silviculture maintainence.
What are the main components of Biodiversity? (3 traditional & 2 new ones)
3- richness(3 of different species in given area), composition, evenness
2- interaction, ecosystem diversity

-greater biodiversity= greater resilience of ecosystem, more species to "absorb" or reduce effects, i.e. climate change(atleast one species able to adapt and fill niche)
What are some forest ecosystem functions and services?
-Cusack: "These are similar - forest services are essentially functions that we can put a value on, or a "price tag" - these are the forest functions that people are willing to pay for, and so are used as a conservation tool. For example, nitrogen fixation is a forest function, but most people wouldn't pay to keep the forest fixing nitrogen. Carbon storage is another forest function, and people are increasingly willing to pay for this."

-Function= production units of goods and services, i.e.- wood, grass for cattle, meat from animals, ecotourism, water/soil conservation & retention, CO2 sequestration, water purification.
-water purificatin, recycle nutrients, provide fertile soil.
Plant taxonomy! King David came over for "The good stuff"
-Kingdom, division, class, order, family, tribe, genus, species.
What are the gradients? IPEAL!
-Intercontinental: Gondwandaland & Laurasia
-Precipitation: annual rainfall
-Edaphic: Soil(parent material, pH nutrient availability, CHONPS)
What are novel ecosystems?
-Cusask: "Novel species assemblages result from invasive species coming into forests and mixing with the native species, so that the mixture of species did not evolve together."
-It is the globalization of biological resources; with increased transportation/mobilization of humans, allowed species to be transported far distances across formerly impermeable geographical barriers(mountains/oceans), allows for invasive species to interact with native ecosystems forming novel species assemblages.
What is functional diversity?
Functional diversity: the number of functional roles represented in an ecosystem
Main causes of species loss?
-Green house gases
-land use change
-species introduction
-In other words: Pollution, development and invasive species.
What are some ecosystem services?
-Soil fertility, timber/food/freshwater, climate regulation & natural pest control
What is primary growth & apical dominance?
-Upward growth of a single tree, branches growing outward, also includes root growth outwater (TREES NEVER STOP GROWING!)
-Apical dominance is main central stem of plant growing more strongly than other SIDE stems, grows upward toward sun.
What is primordia? budbreak? and shoot elongation?
Primordia: cell factories w/in bud tips
-Cusack= "The primordia is the general biological term for tissue where new cells form. The apical meristem is particular to trees, so this would be the specific name on trees for where the primordia are."
-budbreak: Cusack- "the official start of the
growing season, and marks the beginning of shoot elongation. This is the
"greening up" of the forest canopy, and is very responsive to
environmental cues. Some species have plasticity in bud break, and are
responding to climate change by having earlier bud break."
-Shoot elongation: 1st growth of the season seen as "bud break" triggered by environmental cues(day length/temp/moisture), usually from stored photosynthate, it preceeds leave development. In apical control it is a lateral growth.Shoot elongation: occurs as the primordial expand rapidly and develop new
stems, leaves, and accompanying lateral primary meristems (usually shoot
or flower buds); most elongation occurs when growing space is at its
maximum and the possibility of injury from frost, desiccation, or heat
damage is low
What is secondary growth?
-increase in tree girth
-Cambium(cell generation zone) develops inward into the xylem(heartwood) & phloem(innerbark); it also develops the defense and stresses.
-tropical rings less distinctly annual, based more on environmental conditions, measured by radiocarbon dating.
What is xylem and phloem?
-Xylem(means "wood"): "wood" tissue of tree, transports water and few nutrients upward in tree from roots throughout plant, replacing water from transpiration and photosynthesis. Heartwood/drywood- not all xylem is functioning, essentially dead wood that holds up tree in core; Sapwood- is active xylem

-Phloem(means "bark"): innermost layer of bark, living tissue that carries photosynthates(glucose)produced from leave photosynthesis to all other parts of plant, often the roots.
What is preformed growth? sustained growth? recurrent growth? terminal florescence growth? and aborted tip?
Preformed: fixed growth, conservative strategy, conditions of year before set next season, save photosynthate instead of using it for secondary growth, can still be effected(stunted) by some extreme conditions, conifers
-sustained growth: opportunistic, weaker apical dominance, broad leaf.
-Recurrent: grow some/store some, intermediate, multiple waves of preformed growth.
-Terminal flourescence: flowering structure on apical leader(flourescence), strong apical control, FOCUSED ON REPRODUCTION
What affects height growth?
-Trees always growing until they die.
-Primary growth
-related to site conditions- stunting shows conditions unfavorable.
-Young trees grow height slowly at first, have to develop leaves/roots, then they go through "Grand Growth" spurt.
Tree design problems and their solutions?
-Geotropism, trees always growing against gravity, require anchoring of taproots.
-Strength, trees need structural support for crown. Use celluse & lignin, the xylem heartwood that holds the structure together.
-Photosynthate: trees need enough energy to maintain all parts. They branch out for more sun, increase leaf area index(only limited by water/nutrients)
-Self-shading branches: higher branches cover lower ones, self-pruning occurs
-Water loss during photosynthesis: Fine roots gather water, stomata closes up during heat, leaf angles itself away from sun and develop waxy layers.
-Transportation throughout tree, foliar uptake of water(redwood + fog) vascular system(xylem/phloem) create highway up and down tree, cambien creates/expands the "secondary growth".
-Age & Injury: stored primordia cells for emergency rapid replacement shoots, good for silviculture to stimulate growth through disturbances/pruning.
Describe the priority and factors of photosynthate allocation
-Respiration always 1st!
-Primary growth usually second, starting with leaf and fine roots(temporal) and then height and reproduction(this can come earlier in certain species)
-leftovers go to secondary growth
-Defense is last unless diseases are prominent then it may be 2nd to respiration.
Tree ID- Global vs. Dichotomous approach
-Global: general characteristics to get family/genus identification(crown shape, trunk, leaf arrangement, scent)
-Dichotomous: decision key where every point you select moves you to next step, gets you to species level but may require reproductive parts; i.e. needle/broad leaf, fasicles/scales(needle)
-from CA book: crown shape, bark color/texture, leaf shape/arrangement.
Crown development, how does a tree maximize leaf exposure to sun?
-sun/shade leaves
-shade tolerance
-crown closure
-open growth
-side shade
-functional live crown
-Sun leaves: the outer leaves of tree, point upward toward sun
-Shade leaves: inner leaves, flat to sun rays for more exposre.
-shade tolerance: ability to grow in lowlight condtions(down to 1-3%) absorb the light flecks.
-Crown Closure: closure w/ emergent trees to maximize light growing space.(light only limitatin)
-Open growth: when no crown closure there must be a belowground limitation to growth.
-side shade: the disturbance of potential crowns to realized crowns due to crown overlap/shading.
-Functional live crown: all parts alive but only certain parts contribute to photosynthesis, others are "carbon sinks" and self-pruned, if part of crown lost, rush of growth created to help too much apical damage can cause death.
What is the mantra of tree growth(3)?
-ALL trees grow better on good sites
-SOME species grow so well they outcompete others
-Species are found where they can compete successfully, NOT where they grow best.
What are indicator species?
-Site specific species, native to ecosystems, represent larger species assemblages.
Species interactions:
mutualism: tree-microbe
competition: tree-tree
parasitism: tree-mistle toe?
What is competitive exclusion?
-states 2 species cannot survive together if competitng for same niche.
-relative competitiveness: poplar vs. pines, one is better at competing than other in 1 environment.
-Stochasticity: random chance; branch breaks killing seedling, or seedling dispersal.
What are the 4 components of Niche?
-life form
What are the environmental growth limitations on trees?
-light, temperature, oxygen, water, CO2 & nutrients.
-growing space, both light(above) and roots(below ground)
-Macro/micro nutrients: CHONPS- Carbon, hydrogen, Oxygen, Nitrogen, phosphorous, Sulfer. (also iron, manganese, potassium, chloride)
What is above ground and below ground growing space?
-Cusack: "Growing space is the amount of space that the available resources will
support. Aboveground, growing space is limited by sunlight. In theory
crowns should be able to fully close to maximize use of sunlight, or
aboveground growing space. The emergent trees is tropical forests increase
aboveground light growing space by increasing surface area exposed to
Belowground growing space is limited by water and nutrients. If there is
enough water and nutrients, then roots systems will fully close and take
up all the space. If there is not enough water, they will not close, and
the aboveground growth will also be limited, so belowground limitations
will prevent full crown closure. If there is enough water but not enough
nutrients, then you could have full root and crown closure, but you might
have stunted height growth because trees are investing more photosynthate
in expanding root systems to look for nutrients.
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