Lesson Plan by CB

Fire Ecology

State Standards to Meet:

Grade 8

·       Conflict and cooperation occur over space and resources.

·       Human activities can deliberately or inadvertently alter ecosystems and their resiliency.

Grade 7

·       Regions have different issues and perspectives.

·       Individual organisms with certain traits are more likely than others to survive and have offspring in a specific environment.

Grade 6

·       Human and physical systems vary and interact.

·       Organisms interact with each other and their environment in various ways that create a flow of energy and cycling of matter in an ecosystem.

·       Changes in environmental conditions can affect the survival of individual organisms, populations, and entire species.

·       Complex interrelationships exist between Earth’s structure and natural processes that over time are both constructive and destructive.

Grade 5

·       Earth’s surface changes constantly through a variety of processes and forces.

Goals:

·       Students will recognize the effects of fire on a montane forest.

·       Students will understand fire’s role in Colorado.

·       Students will identify fire mitigation techniques to make a Fire Wise Community.

·       Students will observe adaptations in different tree species.

·       Students will understand human’s role in fire and forest ecology.

Key Vocabulary:

Wildfire ecology: the study of linking the natural incidence of fire in an ecosystem and the ecological effects of this fire. 

Fire Mitigation: the act of removing fuels around structures to reduce the risk of creating fuel for wildfires.

Montane Forest: one of three biomes in Rocky Mountain National Park (the other two being sub alpine and tundra).  The Montane Forest exists at 5,500-9,000 feet.  It receives 25 inches or less of precipitation per year.

Succession: the gradual changes in structure, composition, and vegetation of a biotic community.  

Fire Wise Communities: a community or neighborhood that works together in creating defensible space, fire mitigation, and evacuation plans

Defensiible Space: the natural and landscaped area around a home or other structure that has been modified to reduce fire hazard. 

Fuel: anything that can start on fire like grasses, trees, fences, structures

Arson: the act of deliberately starting a fire.

Prescribed Burning: a tool used to restore and manage a forest.  Applying fire to an area over time recreating a natural forest with mixed-aged stands and diversity. 

Fire Containment: is used to describe a fire that is no longer growing and is contained.

Wildland-urban Interface (WUI): any area where man-made improvements are build close to, or within, natural terrain and flammable vegetation

Forest Stand: (or a stand of trees) a contiguous area that contains a number of trees that are relatively homogeneous or have a common set of characteristics.

Fire Suppression: the act of putting a fire out

Hydrophobic Soil:  soil that is unable to retain water.

Watershed: the area of land that drains to a particular point along a stream.

Rhizomatous roots: a modified stem of a plant that is found underground, often sending out roots and shoots to grow upwards

Serotinous: need an environmental trigger in order to release its seeds rather than spontaneously dispersing them

Equipment and Materials:

·       Cards for “Every Tree for Itself”

·       Trowel

·       Distilled water and dropper

·       Visual Aids

Lesson Plan:

I)      Introduction

A)   What is wildfire ecology?

i)      Fire Basics

a       Fire Triangle

B)   Wildfire History

i)      Local History

II)    Fire and Forest Cycles

A)   Montane Forests

i)      Adaptations

a       Ponderosa

b      Lodgepole

c       Aspen

B)   Succession

C)   Good vs. Bad Fire

i)      Effects on Soil

ii)    Effects on Watersheds

III)   Fire and Human Interaction

A)   WUI

B)   Fire Mitigation

Study Guide:

Introduction

What is wildfire ecology?

Fire has an important role in many ecosystems like grasslands, deserts, prairies, and forests.  Many different types of forests and plants rely on fire as part of their life cycles.  Fire promotes a healthy ecosystem by creating mixed-aged stands of trees.  Wildfire ecology is the study of linking the natural incidence of fire in an ecosystem and the ecological effects of this fire.  To understand wildfire ecology, it is important to first understand fire.

Fire needs three key components- heat, fuel, and oxygen.  Without any one of those three things, the fire will go out.  Heat is the energy that gets the fire started and is needed in order to keep a fire going.  There are many ways that a fire might start- either human or naturally caused.  Some human caused fires may start by an ignition of a car, failing to put a campfire out correctly, burning debris, or even deliberately starting a fire, which is called arson.  Naturally caused fires may be the result of lightning or volcanic activity.  Another component is fuel, which is anything that can start on fire.  Fuels may be grasses, limbs, trees, or any dried organic material.  Fuel could also be human-made structures like homes, fences, or structures.  The last component is oxygen.  In order to have a fire, a chemical process needs to occur that requires oxygen.  This oxygen is usually air and wind.  If it is windy during a wildfire, there is an ample amount of oxygen that fuels the fire to get really hot and spread quickly.  The change in heat and different air temperatures rising and falling in a wildfire results in fires creating their own winds that helps a fire sustain itself as long as fuel is available.  To put a fire out, the easiest of these three components to remove from the fire triangle would be fuel, which is why many wildfires are put out by creating fire breaks.

Wildfire History

Throughout history, there have been many different opinions of fire.  Is fire good or bad?  Fire can be very dangerous and scary when people and animals are at risk, but is it good for the forest itself?  Historically, in the United States the people’s public perception of fire is that it is very harmful to nature.  This view has changed drastically throughout history due to more knowledge and education about wildfires. We now know that many organisms have adapted to withstand fire and some organisms require fire for their life cycles.

In the United States, Native Americans used fire as a tool and would set fires deliberately for many reasons.  It may have been to reduce unwanted pests and to increase game animals such as buffalo, antelope, deer, rabbit, and some birds.  Other cultures around the world have used fire as a tool to clear forests and grasslands for farmland and a way to replenish the soil.  Once European settlers started creating towns in the wildlands of the United States, people began to become fearful of fire.  In 1905, Congress created the U.S. Forest Service to oversee the nation’s forestlands, and the agency’s leader promoted the control of fires and suppressing wildfires at all costs.  To protect forests, they thought at that time that suppressing fire and preventing forests from burning was the best way to do so.  In 1935, the Forest Service enacted the “10:00am Fire Control Policy”, which required that all wildfires on national land be put out by 10:00am the following morning.  That idea lasted until the 80’s when a large fire occurred in Yellowstone National Park.  After that event, forest ecologists stared to see that fire suppression lead to larger, hotter fires and suppressing fire was changing the makeup of forests. 

Yellowstone National Park has a similar ecological makeup to Rocky Mountain National Park.  There are many Aspen, Lodgepole Pines, and Douglas Fir.  Fire suppression allowed the forests to grow into same-aged stands and some forests were overgrown with undergrowth.  During the summer of 1988, a large fire burned more than 1 million acres of the park.  That summer was unusually dry and they had low runoff due to low amounts of snow the previous winter.  A dry summer and some lightning strikes resulted in fire that changed history.  Once the fires were started, high winds carried the fires quickly.  Some areas experienced high temperature fires resulting in damaged soils and blackened trees.  Approximately 793,000 of the National Park’s 2,221,800 acres were scorched by fire.  The wildlife in the area was greatly affected.  They found that 345 elk, 36 der, 12 moose, 9 bison, and 6 black bears died as a direct result of the fires.  Most of the animals were trapped as the fires invaded from all directions.  Many fish in the area were affected as well because of ash (ash sticking to their gills suffocating them) and from the fire retardant dropped on the streams.  The fire in Yellowstone National Park drastically changed public perception of fire, because they understood that this fire was larger and more devastating than normal wildfire due to suppression over the past decades.

Officials at other parks were influenced to reevaluate their wildfire policies.  Fire is now identified as a need in a wildland ecosystem and- more often than not- is now allowed to burn itself out unless it encroaches on people and structures.  The National Fire Policy now aims to improve ecosystem health and reduce fire hazards rather than fire suppression.

Fire and Forest Cycles

Montane Forest

As with most fires, plant growth was unusually lush in the years after the 1988 Yellowstone fires.  The ash from fire enriches the soil and fire opens up the forests and brings an abundance of sunlight creating ideal growing conditions for sun loving plants. Fire stimulates the growth of many forests species, including the native fireweed and many different trees. Fire is a necessary cyclical factor to having a healthy montane forest.  When fire comes through montane forests, it creates mixed-aged stands.  When fire comes through a healthy, mixed-aged stand it moves slowly and kills a few smaller trees and lets the larger ones continue living.  Forests that see more frequent, low intensity fires, is much healthier and the forest is less likely to burn again soon.  If the forest does reburn, they usually do so with a cooler, smaller flame with a less-damaging fire.   

Many plantlife found in the montane ecosystem (see Montane Ecology curriculum for more information) are used to fire, need fire, and have adapted to fire.  Some plants sprout again quickly after fire from existing roots.  For example, aspen stands grow back thicker and more vigorously after a fire because they love the sun and have rhizomatous roots. Rhizomatous roots means they have a modified stem that is found underground, often sending out roots and shoots to grow upwards. Lodgepole pines need fire for their lifecycle because they have serotinous cones, which mean that the cones need an environmental trigger to release its seeds rather than spontaneously dispersing them. In the case of lodgepole pine trees the environmental trigger needed is fire.  Within a few years after a fire, lodgepole pines will become visible among burned areas.  Ponderosa pines are also found in the montane forests and they have very thick bark to combat fires.

Ponderosa Pine Adaptations:

·       Extra thick bark to protect inner tree from high heat

·       Self-prunes lower branches, therefore fire cannot spread to upper branches and cause a crown fire

·       Lichen and moss typically do not grow on ponderosas, therefore less fuel to create crown fires

·       Seedlings prefer bare-mineral soil

·       Will colonize a site 1-2 years after a fire, shade tolerant

·       Thick bed of needles surrounds tree, suppressing grasses

Lodgepole Pine Adaptations:

·       Serotinous cones: cones are sealed with a resin that a fire will melt away once they reach a temperature of 120^oF, releasing seeds

·       Thin bark

·       Self-prunes lower branches

·       Most stands are usually the same age due to fire stimulating seedlings

Aspen Adaptations:

·       Seedlings prefer bare-mineral soil

·       Rhizomatous roots: extend up to 100 feet in adjacent areas.  If they are top-killed, their roots continue to have the ability to sucker and draw nutrients from living roots

·       Intolerant of shade and will dominate successively until they get shaded out

·       Thin bark has little heat resistance and is easily top-killed

·       They are self-thinning.  A healthy and mature stand can develop from dense sprouts.

·       Fuels are usually moister in aspen stands than in surrounding forest. Crown fires in coniferous forests often drop to the surface in aspen stands, or may extinguish after burning into them.

Succession

After fires, succession occurs.  Succession is the gradual changes in structure, composition, and vegetation of a biotic community.  After a fire, the first species to re-colonize will be those with seeds that are already present in the soil, those with seeds that are able to move into burned areas quickly, or rhizomatous roots.  These are generally fast-growing plants that require a lot of sunlight (like grasses or aspen trees).  Coniferous trees are often early successional species and are highly dependent on fire to allow them to have enough sunlight as seedlings.  As time passes, more slower-growing organisms grow.  These are usually more tolerant of shade.  Different species of organisms specialize in adapting to different stages of succession.  By having fires create different areas of succession, a greater number of species and diversity of organisms exists within a forest.

Good vs Bad Fire

Having different levels of growth in forests creates diversity that is necessary for a healthy forest and produces‘good’ fire.  A good fire is mild or moderate heat, stays close to the ground, and doesn’t move up trees to the canopy or crowns.  It takes out brush and small trees but leaves large fire-resistant trees intact. Fires occur naturally in pondersa pine forests in intervals of 10 years or less.  These fires are mild to moderate fires that generally do not reach the crowns of trees and leave most trees alive.  Many forests are not experiencing these natural cycles but face severe damage because of fire suppression and drought in previous decadse.  Fires in these overgrown forests result in crown fires that cause extensive tree deaths.  High intensity fires will burn into the crowns of the tallest trees and spread at very high temperatures.  When a forest burns frequently and has less plant litter, the fire stays at lower temperatures.Fire suppression may also lead to increased defoliation of the trees by insects, whose populations might otherwise be controlled by more regular fire occurences (Pine Beetle). In Colorado there’s a lot of plant litter because we are a desert and do not receive enough rain to help in decomposition.  Dead limbs and trees pile up over time because of this and the forests rely on fire to clean up those dead limbs and trees. 

Restoration ecology is the name given to an attempt to reverse or mitigate some of the changes that humans have caused to an ecosystem.  Prescribed burning is a tool used to restore and manage a forest.  Applying fire to an area over time recreates a natural forest with mixed-aged stands and diversity.  When a fire comes through after prescribed burned, it is a less intense fire.

When fires burn at extremely high temperatures (soil surface reaching 800^o C, 1472^o F), hydrophobic soils are created which is soil that is unable to retain water. Hydrophobic soil occurs when the plant roots exude a chemical into the soil that changes the soil composition and does not let it retain water. Soil composition is changed when condensation from the chemical reaction of burned organic materials leaves a waxy coating on soil particles.  Hydrophobic soil caused by high temperature fires may increase runoff and erosion from forested watersheds after wildfires.  Precipitation in a burned area may cause the ash and soil above the hydrophobic layer to become saturated resulting in mud slides. Overtime the soil is expected to return to normal, usually 1-6 years after the fire.  A watershed is the area of land that drains to a particular point along a stream. During this time, watersheds are greatly impacted by fire.

Fire and Human Interaction

Wildland-urban Interface

‘Good’ fires are a key component to forest cycles.  Wildfires in Colorado are a natural part of our ecosystem and help restore and maintain healthy forests, but risk occurs where wildland and urban areas meet. Wildland-urban interface (WUI) is any area where man-made improvements are built close to, or within, natural terrain and flammable vegetation, and where high potential for wildland fire exists. 

During the past few decades, population in the WUI has increased.  Homes, businesses, and subdivisions are being built on forested lands that have historically seen regular fires, and even need them to remain healthy.  To keep forests healthy and people safe, it is important that land managers and property owners work together.  Buildings and people’s property mitigated and firefighters are able to do their job safely in order to protect people and structures while still allowing fire to occur in the ecosystem.  Allowing natural fires to occur will help create a healthier forest and ulitmately reduce the risks associated with hot and uncontrollable fires.

Fire Mitigation

Many communities and neighborhoods are located in regions historically prone to frequent natural wildfires.  Living in the wildland areas requires more resourcefulness than living in urban areas.  It could take much longer for a fire engine to reach rural areas, and a small fire department can easily become overwhelmed during an escalating wildfire.  Planning ahead and taking actions to reduce risk can increase safety and protect homes.  Fire mitigation removes fuels around your house that can create increased heat and exposure to your home in the event of a wildland fire. It is important to create defensible space, which is the natural and landscaped area around a home or other structure that has been modified to reduce fire hazard. 

To create defensible space, it is important to look at the fuel around the structure.  Removing fuel is the best way to protect a structure.  There are different zones when creating defensible spaces.  The first zone is up to 15-30 feet away from the structure.  This zone needs to be very clear of fuels, such as flammable shrubs, pine needles, overhanging trees, and firewood.  Zone 2 is up to 100 feet away from the structure.  This space is a transitional area designed to lower the intensity of an encroaching fire.  Trees in this zone need to be thinned and spaced at least 10 feet away from each other at the crown of the tree.  It’s best to remove dead, dry organic materials in this zone to reduce fuels and to remove dead trees.  In zone 3, there is no specific width.  It should provide a gradual transition from zone 2 to areas further from the home that have other forest management objectives.  This zone should have diversity in tree size, age, and species.

Creating defensible space around structures reduces the risk of losing the structure to fire.  By discussing fire mitigation with neighbors, an entire community or neighborhood could be saved from fire.  An evacuation plan, fire mitigation of all properties, community meetings to discuss fire, and education will help everyone stay safe during wildfires, thus creating a fire wise community.

Key Questions:

1.     What adaptations do tree species in the montane forest have to withstand wildfire?

2.     What is succession?

3.     What is a WUI?

4.     How does wildfire affect watersheds?

5.     What are the negative impacts of wildfire?

6.     What are the positive impacts of wildfire?

7.     What are some fire mitigation techniques?

Activities:

·       Test Hydrophobic Soil (Water Drop Penetration Time Test)

WDPT test is based on the time it takes for a drop of distilled water to infiltrate into a sample of soil taken from a burned area.  Fill medicine dropper with distilled water.  Use a trowel to extract at least a 9cm column soil sample.  Try to keep the soil column intact.  Mark 3, 6, and 9 cm on the column.  Drop the distilled water at the three different spots, three times.  Record the average time for each point on soil sample. 

o   0-5 seconds means the soil has no water repellency

o   5-60 seconds means that soil is slightly hydrophobic

o   Longer than 60 seconds the soil is strongly water repellant

·       Every Tree for Itself

The object of this game is for the trees/students to gather as many squares as they can.  Explain that each colored square represents a tree requirement such as yellow-sun, blue-water, and green-nutrient (such as nitrogen). Have students create an historic ponderosa pine forest.

o   Distribute colored cards on the floor around the students so the squares are about 1-2 feet apart.

o   Give a signal to start the first round.  Have student trees reach with their branches (arms) to gather their requirements. Tell students that their feet are their roots and must remain planted at all times.  They are not allowed to slide or step.

o   Allow student trees to gather these requirements for one 30-second round. 

o   Throw in a black or red card, but don’t tell students what it represents.  After playing the round, tell them that the new color represents fire.  Anyone they can reach from where they stand is also on fire and they catch the other student trees on fire, and so forth. 

o   Different rounds can be different forests which include:

§  Place trees far apart to form an historic stand of ponderosa pines. How did the fire spread?

§  Put tree students in groups of 3-5 and have them fight for distributed resources.  Could they get enough requirements to live?

§  Fewer water cards distributed to show drought.

§  Fewer yellow cards distributed to show less sunlight for smaller growing trees.

·       Wildfire Tag

This game demonstrates how trees can be destroyed by fire, how they can be protected from fire, and how they grow back.

o   One student is the wildfire, four students are wildland firefighters and the rest of the students scatter and are trees

o   The wildland firefighters should gather around the wildfire in the middle of the group

o   The game starts when someone yells, “FIRE!” Then the wildfire runs to grab the hand of a tree.  When this happens, the tree becomes part of the wildfire, and the two of them run to grab another tree, thus the fire builds and spreads

o   At the same time, the wildland firefighters are creating fuel breaks by running to tag trees not yet burned and making them sit down.  They can only create fuel breaks from trees that have not been caught in the wildfire.

o   When the fire runs out of fuel, it burns out. (Wildfire students should drop their hands and stand still to illustrate that they are new trees).  Once again, there is a forest.