Elements of Ecological Restoration - exam 2
What are three specific reasons why a plan to restore the historical role of fire in forests around Flagstaff, Arizona, would not be appropriate for high-elevation forests in the northern Rocky Mountains?
-degree of departure from historical conditions due to fire suppression - fire regime would be high severity that only burns in long time periods apart (elevation)=> high severity regimes regenerate slower so would run out of fuels to burn. - species type would not match the allowance of that treatment type and would end up altering species.
What does it mean to have a "fuel-limited" fire regime; what is an example?
Fuel limited: regime with low resource activity like vegetation to inherently fuel fire which results in low fire activity. ex: desert or arctic tundra.
Ecological Resilience
Has change in ecosystem but may bounce back to a desirable condition unless crosses over threshold then would need more effort to be restored. Otherwise will remain in a degraded state. Think of ball on hill slope diagram.
Fire Intensity (include metric units)
I= Hwr. units: (Kw/m). amount of energy released in a given area. "Physical measure of the rate of energy released per unit fire line."
What are three general attributes of "frequent-fire" forests discussed by Professor Larson?
Low tree density • Old tree dominated • Large snags, logs • Fire-resistant spp. • Low surface fuels Mosaic pattern: • Individual Trees • Tree clumps—small, med, large • Openings: meadows w/in the forest
Primary Pine Defense
Primary (preformed, constitutive) = primary resin, monoterpenes (toxin) and other chemicals. 1st defense. this defense is always in place or in the tree incase something happens. physical. ex: like a castle with a mout and walls. ex: Mt. pine beetle burrowing into tree.
Explain the concept of forest productivity. How do insects and pathogens affect productivity?
Productivity is how efficient something is producing. the fullest potential of biomass being produced would 100% productivity, but insects and pathogens reduce the amount of productivity by allowing some parts of the forest to reduce. around 2/3's of the forests reductions are due to insects and pathogens which can be good and bad.
Rate of Spread (include metric units)
R= Heat flux/ Heat Sink. (m/s) How quickly fire is moving - heat flux: fuel load/ heat of combustion. heat sink: fuel bulk density, moisture content. ( if heat flux increases, R increases. if heat sink increases, R decreases)
How does the spatial pattern of trees within a forest affect ecosystem function? Provide two examples from class.
Spatial pattern can be achieved with ICO (Individual, Clump, Openings). Pattern can add diversity to ecosystem function. key driver of forest development into different regimes. Supports complex food webs and wildlife habitat. A driver towards resistance. ex: increase snow retention (continuing to have snow), and promote plant diversity and abundance.
Production Forestry
Uses agricultural and economic models as basis for management. Attempts to eliminate or evade natural disturbances. Seeks to optimize a single output, such as fiber or net revenue. Intentionally produces simplified, homogeneous, regulated systems.
Ecological Forestry
Uses ecological models as basis for management. Works with, and within the limits of, the natural disturbance regime. Seeks resilience and maintenance of many ecosystem services. Maintains & restores ecosystem complexity & spatial heterogeneity.
What is the primary reason fire activity (e.g., annual area burned) has increased over the past three decades across the western U.S.?
Widespread forest fire activity is strongly linked to warm/dry seasonal conditions, across multiple time scales. Fire suppression removes critical ecosystem functions and alters future fire behavior. Fuel accumulation across many low- and mid-elevation ecosystems exacerbates climate-driven trends. Increased human infrastructure results in more wildfire disasters
Describe three ways in which fire affects forest structure, composition, and function?
forest structure: fire can determine patterns of regeneration by frequency. this would thin trees and raise canopy height. Composition (type of fire makeup): frequent fires will favor thick bark species like ponderosa pines. Function: fires function is to cycle nutrients back into the ecosystem and specifically the soil.
Fire Severity
impacts on an ecosystem due to fire whether it be mortality or loss. high, mixed, and low severity.
Fire Hazard
potential fire behavior of a fuel complex, independent of fuel moisture. - Land use and fire suppression have increased fire hazard in some forest types - Fuels management can modify fire hazard, and have been shown to be effective in modifying fire behavior (esp. when including Rx fire)
Induced Pine Defense
secondary resin, lesion formation=> due to insect burrowing into bark, monoterpenes (toxin) and other chemicals. physical and chemical=> ramps up chemicals in resin. ex: when castle knows its being attacked and boils oil to throw at enemy. ex: 2nd type of resin created with more toxins/ chemicals and still sticky to encompass beetle.
What are the main drivers of forest resistance to fire, insect outbreaks, and drought?
diversity
Crown Fire (active and Passive)
fire that spreads among the crowns (tops) of trees. Active: those in which a solid flame develops in the crowns, but the surface and crown phases advance as a linked unit dependent on each other. passive: those in which trees torch as individuals, reinforcing the spread rate, but are not basically different from surface fires
Surface Fire
fire that spreads through low lying vegetation like fine herbaceous fuels and woody debris. (not litter or duff since that is ground fire)
At multiple scales, the presence of fire on Earth depends on what three factors?
- consumable resources. - atmospheric conditions. - ignitions.
Natural Disturbance
A disturbance the ecosystem had evolved with. exposed to it multiple times. (unnatural disturbance is a disturbance that they cant recover from because they hadn't been exposed to it before and have not evolved with it)
Poikilotherm
An organism whose body temperature changes with its surrounding environment.
What are three goals (of the five discussed in class) of restoration in frequent-fire forests?
Consuming surface fuels - Thinning small trees & fire-sensitive species - Maintaining high live crown base - Limiting connectivity of canopy fuels - Creating patchy regeneration opportunities
What does it mean to have a "climate-limited" fire regime; what is an example?
Climate limited: regime with high resource activity but not the right weather environment to allow fire to occur. ex: tropical rainforest where there are plenty of fuels but the environment is to moist to allow fire to ignite/ sustain.
ICO Method
Clump ID Algorithm. "Individual Clumps and Openings." Spatial pattern of clump size. A way to make sure you don't remove trees in a uniform pattern that looks like a crop. Depending on the type of forest, this has more complex spatial pattern that is random in grouping to produce more processes.
What is the difference between fire intensity and fire severity?
Fire Intensity = I=Hwr. units: (Kw/m). amount of energy released in a given area. "Physical measure of the rate of energy released per unit fire line." Fire Severity = impacts on an ecosystem due to fire whether it be mortality or loss. high, mixed, and low severity.
Why is fire an important contemporary (modern) topic when considering forest restoration and forest management in western North America?
Fire suppression costs weigh into much of our budgets in government and are expensive. Also threatens many urban areas which has many people concerned and wanting to reduce fire rather than understand it as a natural process.
Describe the three basic fire regimes discussed in class, referencing the expected fire frequency, fire severity, and what limits fire in each fire regime.
Low, Mixed and High. Low: has high frequency but low severity and is limited by the amount of fuels that can be burned (generally limited by fuel). High: has low frequency but high severity with high mortality rate (generally limited by climate) Mixed: time scale can be both low or high frequency and severity, patchy and has some mortality. has regeneration but creates structural complexity.
Native Organism
Organism that occurs naturally in an area. evolved there. (can still be damaging or can be beneficial) ex: mountain pine beetle or spruce budworm to Northern Rockies
What are the options for restoring American chestnut? How would each of these options be carried out? Pick the option that you would use and explain why you chose it over the others.
do nothing, implement GMO (Wheat gene), cross breed with chinese, find best specimen of original american chestnut to breed. do nothing= allow species to come back on own or go extinct. GMO= produced in a lab and implemented into forest. Chinese cross breed= cross breed the american with chinese chestnut, already on 16th generation and is only 1/16th chinese (done in lab, would alter shape of tree as chinese is more shrub like). breed original= take 100% pure american chestnuts and breed in a lab till able to enter into forests and hope the best can resist the fungi but will likely be expensive, time consuming, and fail. I would choose GMOs since it would slightly alter the DNA but the structure of the trees would be the same, and then not alter the forest structure as well as resist the fungi.
Invasive Organism
exotic species that causes damage. Did not evolve with ecosystem. Highly virulent/damaging to native trees. Able to vastly alter ecosystems. Permanent once established. Often 'unmanageable'
Describe the differences between fire behavior and a fire regime, including the key variables used to describe each.
fire behavior looks at how individual fires react over time and space with rate of spread (amount consumed over time) and rate of intensity (how much is consumed and damaged/ energy released in an area). Fire regime is looking at multiple fires over long periods of time and similar/ multiple spatial areas. key variables for Behavior: rate of spread, fire intensity. Key variables for Regime: low, high, and mixed regimes with fire frequency, size, intensity and severity.
What are two human activities that have contributed to the degradation of frequent-fire forests in the West?
fire suppression, cattle grazing and logging
What is a primary goal of hazardous fuels reduction projects in forests? Describe a scenario when fuels reduction (a) is and (b) is not consistent with goals of restoring the historical role of fire in a forest ecosystem.
primary goal of hazardous fuels reduction projects in forests = alter fire behavior to improve effectiveness of fire suppression efforts and reduce fire severity. a) fuels reduction is consistent with goals of restoring the historical roles of low elevation ponderosa pine forest with a low severity burn rate and has a high frequency of burning. b) is not consistent with goals of restoring the historical role of fire when Rx burns or thinning are happening in a high severity fire regime of Doug Fir forest that is supposed to burn every 100yrs.
What are the requirements for mountain pine beetle populations to develop into an outbreak of epidemic levels? Once an outbreak is underway, there are two possible outcomes. What are these two possible outcomes and why are they different?
requirements for populations or mt pine beetle to become an outbreak= a forest that has the right size and age group of trees, have the correct species (pine, generally like Lodgepole), and have a trigger such as a drought. The two possible outcomes are= going to completion in forest like the beetles kill all the trees and then run out of food and starve. OR a rain occurs/ the forest becomes healthier and resists the beetles. Last 20ish yrs have had outbreaks 10x worse than in the past due to climate change heating up forests and not having cooler conditions.
Fire Regime
summarizes the characteristic patterns of fire and fire effects over broad spatial and temporal scale. The climate, ignitions and vegetation of an area over regions in decades/ centuries.