NR 307 Dicus FInal 2019 Cal Poly exam with complete solutions

What 3 entities are necessary for combustion? oxygen, heat, and fuel 3 parts to fire? Photosynthesis -- Decay -- Combustion Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:02 / 0:15 Full screen Brainpower Read More Pre- Heating Pilot source like sun raises temp of fuels Dehydration drive extracts to the surface Pyrolisis degrades molecules to volatiles that support combustion Ignition Humans, Lightning, Volcanoes, and possibly meteorites Combustion 1. Burning of volatile gas 2. glowing or smoldering-- low heat, burns for a long time Extinction When the heat of vaporization is greater than the temperature of the fire Conduction The DIRECT transfer of heat from one substance to another substance that it is touching. Convection The transfer of heat by the movement of a gas Important for steep slopes and heavy wind events Radiation The transfer of heat by electromagnetic waves Ground Fuels All combustible materials lying beneath the surface Surface fuels Fuels that are close to the surface of the ground, such as grass, leaves, twigs, needles, small trees, logging slash, and low brush. Aerial fuels Fuels located more than 6 feet off the ground, usually part of or attached to trees. Timelag The rate at which dead fuel gains or loses moisture 1 hour fuels 0 - 1/4 inch diameter - 3-7% 10 hour fuels 1/4 - 1 inch diameter -7-10% moisture content 100 hour fuels 1 - 3 inches diameter - 10-15% 1000 hour fuels 3 - 8 inches diameter -- 20% grass fast burning, good horizontal continuity shrub high intensity, good horizontal continuity timber litter low intensity Timber-Understory Provides ladder to aerial crown fuels, low intensity, slash blowdown Temperature the angle of the sun on the hills or flatlands preheats fuels and lowers relative humidity amount of time the sun hits fuels Relative Humidity lowest at mid afternoon when the temps are the highest because high temperatures can hold the most moisture Winds Higher wind promotes fire intensity - supplies more oxygen -transfers heat to fuels by convection -takes away moisture -steeper the slope the faster and moe intense a fire burns north facing aspect carries heavier fuels higher moisture later curing South facing aspect lighter fuels lower moisture earlier curing chimney effect strong updrafts in drainage -rapid burnout and extreme intensity Saddles Where wind can funnel through and can cause extreme fire behavior Anatomy of a fire - pocket, finger, origin, flank, head, island, spot fire thick bark protects cambium from damage which allows nutrient transport to continue Most effective in areas with frequent low intensity fires -many pines, larch, and redwoods Branch Habitat rapid self pruning, decreases vertical continuity, common in shade intolerant species, Stand Habitat decreases horixontal continuity and decreases fuel common in ponderosa pines, Larch, Longleaf Pine Rapid Juvenile Growth if a fire comes up every fire years you better sprout up quickly Fire resistant foilage higher moisture content -- hardwoods typically have more moisture than conifers Rapid foilage decomposition reduces ignitions and rate of spread common in broadleafs with low levels of lignin Allelopathy The production of chemicals by plants that inhibit the growth of neighbouring plants that would support fire spread Deep Rooting Soil insulates heat-- common in Chapparal species Geophytes structures that are planted underground, housing underground storage systems, such as what is found in onions and potatoes-- effectively avoids fire Annuals basically grow during wet season to avoid fires entirely Recovery -sprouting back from trunks (adventitious buds) -sprouting from lignotubers (Chaparral) -Sprouting from roots distributed laterally -Sprouting from Rhizome (common in some grasses and herbs) - Colonizing after fire -early seed production -light wind borne seeds -serotinous cones -ability to survive extreme temps and drought Promoting Fire volatile gases and oils in shrubs facilitate fire flammable bark Heat Yield the heat of combustion corrected for various losses, mainly the presence of moisture in the fuel Low Elevation Deserts -Spring-summer-fall season -low RH -high temp Truncated if intervals are too long or short, plant and landscape turns into a new type Long Fire Interval greater than 70 years Fire Size Small= less than 25 acres (truncated is less than 2.5 acres discontinuous fuels) Medium= 25-2500 acres Large= greater than 2500 acres Multiple Patchiness Some low and some high patchiness Surface passive FIre 30% torching of the area Coring Lakes -annual layers of deposit -charcoal can indicate precsence of fire -pollen shows the plants present during fires Coring Trees -Even aged stand origination -shows release indicating when fire has rolled through because tree rings get larger due to abundance of resources Wedges give indication of tree age and tree history wihtout damaging tree -- quarter of the tree and 2 inch thickness Ignition Humans= more frequent but low intensity and smaller because natives knew when to start fires Fire Regimes Understory= Forests only because of need for timple litter-- low intensity and occur every 5-30 years Stand Replacement= any vegetation type and occurrence depends upon this, plentiful duff and downed wood--- kills aboveground Mixed Severity= Forests only because of the need for varied fuels and the history of fire along that gradient Nonfire= too much rain and moisture areas Primary Succesion where nothing lived before disturbance and this disturbance creates a new soil environment--glacier, lava, stream secondary succession where vegetation gone but soil is left intact-- more common type of succession Fire almost always drives ecosystem to a __________ stage of succession earlier Effects of lack of fire -Stand decreased biodiversity more vertical and horizontal continuity more duff and litter more bugs and cruds less resources for trees more risk to life and property Effects of lack of fire- landscape more homogeneity more water use= drought more emissions of CO DIsturbance Interactions Any event disrupting minimal structure to an ecosystem ex. fire, insects, diseases, drought recovery after fire involves_______ and _______ injury and regrowth _____________ and _______________ can sprout from stem and branches after fire Coast Live Oak and Coast Redwood _____________ almost exclusively regenerates in the western U.S. by sprouting Quaking Aspen Historically there have been more fires in a given mountain range on a lower elevation because... there are more people present and a longer fire season grasslands have a ____________ fire interval truncated short climate change is not likely to increase fire frequency and severity in.... Chaparral Scrublands Richard Minnich believes that fire suppression has had a significant effect on... chaparrals In general in the last 100 years, ___________ have increased at the expense of grasslands Pinyon juniper varying serotiny would be likely to be found in species with a ___________ large natural range do wildfires occur in non-fire regimes? yes In low elevation oak svannahs, do grasses start curing earlier or later than normal earlier size distribution of particulates -70% are less than 2.5 macrometers -20% between 2.5 and 10 macrometers -10% greater than 10 macrometers hydrocarbons have the biggest impact on human health fires have little effect on soil profiles after _______ in depth 3 cm litter and duff moisture is more or less important than moisture in mineral soil more important there is __________ soil moisture in lower layers after a fire and there is __________ soil moisture in upper layers after a fire higher and lower Add or remove terms