Index

What is ecoSmart Design Software?
What is ecoSmart-Fire?
How does ecoSmart-Fire work?
Getting started
Step by step process
Reduce fire hazards by…
How do I…
- Create a lot
- Set lot orientation
- Add a house
- Add a garage
- Add pavement
- Add trees
- Move a tree
- Remove a tree
- Change size of a tree
- Raise a tree crown
- Add a second story
How do I know when I’m firesafe?
What this model will not do
What about buttons that don’t work?
Menu options
About

What is ecoSmart Design Software?

ecoSmart Design Software is a web-based program designed to evaluate trade-offs between different landscape practices on residential parcels. It is designed to be interactive, and allows you to re-configure your landscape and instantly see the impact on landscape water use and stormwater runoff (ecoSmart-Water), energy use for heating and cooling (ecoSmart-Energy), and fire safety (ecoSmart-Fire). ecoSmart-Fire, version 1.0 is completed and the other modules are under development.

What is ecoSmart-Fire?

ecoSmart-Fire is graphical software that allows you to interact with the program to visualize fire hazard effects of changing your landscape, such as moving a tree, replacing one tree with another, or raising tree crowns. It will answer the question: How will landscape changes affect my home’s fire hazard?

Some background…In the United States, 42 million homes are located in the wildland-urban interface. Landscaping on these properties directly influence the threat of loss in fires. Pre-fire actions by individuals responsible for the design and maintenance of these private properties can prevent disasters. Federal, state and local agencies have developed guidance for improving the fire safety of properties in the wildland-urban interface, but this general guidance may conflict with the desires of an owner for the appearance of the home exterior, use of the land, views, privacy, and wildlife habitat. ecoSmart-Fire is an interactive and flexible graphical-tool designed to assist residents identify ecoSmart-Fire choices while considering the ways to retain native fuels, irrigate the landscape, and insure privacy.

How does ecoSmart-Fire work?

ecoSmart-Fire is software for estimating the fire risk to a structure from nearby trees and other landscape vegetation. Version 1.0 incorporates a method to estimate the risk from fires through ignition by radiant heating.

Three principal factors are responsible for structure ignitions:

flame radiation
flame impingement – convection, and
firebrands (burning embers).

Radiation and convection involve the transfer of heat directly from the flame. Unlike radiation heat transfer, convection requires that the flames contact the structure. Firebrands involve the aerial transport of burning materials to a combustible fuel receptacle (structure roofing, open vents, etc.) from vegetation or other burning materials. Ignitions from radiation (given an exposed flammable surface) and from radiation heat transfer depend on two aspects of the flame: 1) the radiant heat flux to a combustible surface and, 2) the duration (length of time) of the radiant flux. The radiant heat flux depends on the flame size, flame-structure distance, and how much the combustible material of the structure is exposed to the flame. Whenever the flame length, 1-2 minutes in duration or more, is equal to or more than the separation of combustible vegetation from a structure, there is a high probability of structure ignition.

Of the possible modes of home ignition and destruction, the most is known about radiation. For example, radiative heating of a surface is additive; therefore, the radiative heat flux at a position on the surface, from two identical burning objects oriented similarly with respect to that position, is just twice that of one of them. In addition, radiation becomes a more dominant transport mechanism as fires become larger. Crown fires, which burn hot and spread rapidly, are well-known examples of fires where radiation is a dominant mode for fire spread. Therefore, this mode of ignition was selected to be the first to be quantified in the ecoSmart-Fire model. ecoSmart-Fire Version 1.0 incorporates a simple model of thermal radiation transport from trees to structures using exterior material ignition properties to assess the risk of ignition from landscape plantings. Altering the size and location of trees alters the fire risk to the structure.

To account for uncertainties that can exist in the characterizations of burning trees and ignition properties of exterior materials, as well as other factors, such as wind or fuel moisture content, the approach taken in ecoSmart-Fire is conservative. This is typical of all areas of engineering and design where “factors of safety” and conservative estimates of important information compensate for lack of exact knowledge. ecoSmart-Fire examines the “worst probable case scenario, to assess the vulnerability of a structure to fire.” It is well-known, for example, that the likelihood of ignition of a structure depends both on the magnitude of the incident radiative heat flux, and on the duration of this flux. In order for ecoSmart-Fire Version 1.0 to execute quickly, the effects of burning duration have been eliminated from the ignition model. Rather, each burning element (tree, shrub or other nearby structure) is assumed to be burning at its peak value simultaneously, and ignition of structure is assumed to occur if the value of the thermal radiative flux exceeds a critical value that depends on the exterior materials.

Since ecoSmart-Fire Version 1.0 has only implemented a model of ignition by thermal radiation, other important threats have been set aside for modeling and inclusion in later versions. Therefore, the approximations noted above represent limitations of Version 1.0. For example, ecoSmart-Fire Version 1.0 does not include the effects of ambient winds, burning brands and heat fluxes from nearby burning structures. Inclusion of these effects will require additional research, data, and development of a much more sophisticated mathematical model.

Even though many trees are used in the energy and hydrology sub-models of ecoSmart, fire data are available only from experiments with Scotch pine and Douglas fir trees at this time. These limited fire data have been used in ecoSmart-Fire Version 1.0 as though the data were appropriate for all tree species, with no experimental evidence currently that such extrapolations are valid. Therefore, predictions obtained in ecoSmart-Fire version 1.0 related to pine or fir trees have much more validity than those related to other trees.

The fire experiments conducted to measure burning characteristics of conifers, used cut dry trees. It is well known that low moisture content of trees, shrubs or other vegetation is critical to ignition and burning. In fact, high moisture content will prevent an individual tree from being ignited at all. The empirically derived formula from Babrauskas and Strauss, has been incorporated into ecoSmart-Fire Version 1.0 to help account for moisture-related effects in the burning vegetation model.

Although very limited as noted above, ecoSmart-Fire Version 1.0 is an important first step in providing a simple, but visually compelling, method to estimate the relative risk of home ignition from nearby burning trees. Given the present state of understanding of WUI fire, the manpower invested in developing and implementing a Web-based model, and the limitation on computer resources implied for such a Web-based model, ecoSmart-Fire Version 1.0 is probably the best model that could be constructed.

Getting started

Welcome to ecoSmart-Fire 1.0. This educational tool will help you visualize the fire hazard associated with different configurations of trees around your home. It does not include many of the complexities associated with structure ignition and fire spread, so it should not be used as the sole basis for landscape decisions. However, it is very useful for seeing how trees of different sizes and numbers influence fire hazard at different locations around your home.

To get started you will need to get measurements for your lot, trees and house.

Lot – Measure the length and width of your lot. This is most easily accomplished by pacing and recording the information on a piece of graph paper. Note which direction is north and estimate the percent slope you have, with 0% being flat and 90% vertical. If your lot is wider on one end than the other, measure both widths. If your lot is an irregular shape, come as close to a rectangle or pie shape as you can with the measurements. Also, take measurements of your driveway and sidewalks.
Trees – You will need to locate each tree on your lot. This will require two perpendicular measurements for each tree. The first will be to the nearest lot line and the second will be from your house or another lot line. To place a tree on the lot you will be asked to select the age or dbh (diameter at 4 ½ feet above ground) of the tree. If you select diameter you will need the following measurements: tree diameter, total tree height, and approximate width and height (distance from first limb to top) of the tree crown. Measure or estimate as close as you can.
House – Take measurements for your house and garage. Start with the largest rectangle or square portion as possible. Take separate measurements for the garage and each wing of the house. The house, garage and wings will all be added separately to the lot.

Step by step process

To find out how to ecoSmart-Fire your home is follow these steps:

When the web site window opens up you will see a smaller Lot Properties window. Select rectangle or trapezoid. Set your lot slope to the correct percentage. Set the length and width of your lot. Select the grid size you desire. And finally, set the default ground cover to the appropriate cover. Click OK.
To set lot orientation, click on Lot in the upper left hand corner. Click on Orientation and either select a basic orientation or use the button that allows you to set the exact orientation. Set orientation and click OK.
To add your house, click on Buildings in the upper left hand corner. Click on “add wing” in the drop down window. (There is no feature to add a house.) Set the length and width. Select the appropriate number of stories and check/uncheck air conditioned. Click OK and move your cursor to the lot. Position the house so it is in the proper location. Click the left mouse button to set it in place.
Click again on Buildings/add wing to add any additional wings to your house. Set the length and width. Check/uncheck air conditioned. Click OK and move your cursor to the lot. Position the wing so it is in the proper location. Click the left mouse button to set it in place. Repeat for all wings.
Click again on Buildings/add wing to add the garage. Set length and width. Check/uncheck air conditioned. Click OK. Drag garage in place.
Click on Lot/pavement to add driveway and sidewalks. Set length and width. Click OK and drag in place.
Click on Add Landscaping/trees to add trees to the parcel. Under Select Species, select the appropriate tree. Select age or dbh. If you chose age, set the correct age, click OK and drag your first tree to the proper location. Repeat until you have placed all of your trees. If you chose dbh, set the correct diameter, click OK and drag the tree to the proper location. Repeat until you have placed all trees.
If you want to be more precise with the dimensions of your trees, select dbh and then click on Advanced. Set tree Height, Crown Diameter, and Canopy Height to your exact measurements. Select Water Use. Click OK and drag trees in place. Repeat process for each tree. Continue until you have positioned all your trees. This completes the creation of your parcel. The color of the slider bar only provides you with an indication of how ecoSmart-Fire your home may be. If the bar is green you may be OK. If the bar is yellow there may be a few simple things you can do to change the color back to green. And if the bar is red your home is probably not ecoSmart-Fire, and you will need to take some more difficult and expensive steps to reduce the fire hazard. Do not rely on this program to predict the fire safety of your home. See a professional fire expert. The results you get with this computer tool are merely an indication of what might happen to your home in the event of a fire. Many other factors need to be considered when making fire hazard decisions like fire weather and neighboring parcels for example. Please seek further assistance if you are concerned.
You are now ready to experiment with various practices to reduce the fire hazards on your property. Remember that changes in vegetation result in changes in fire hazard. Go to Reduce Fire Hazards.

Reduce fire hazards by…

Removing a tree that is too close to the house – click on the tree you want to remove and drag it off the parcel. Click again.
Seeing how a tree will work in another location – click on the tree you want to move and drag it to the new location.
Removing and replace a tree – 1) click on desired tree and drag it off the parcel. Click again. 2) click on Add Landscaping/trees and change dbh. If you have selected the Advanced option, click on Advanced and repeat the process above for adding trees. Reposition the smaller tree in the same position as the one just removed.
Raising a tree crown – click on Add BMPs in the upper left hand corner and select crown raising. Set bottom of the canopy to the desired height. Set desired distance from the house. Click OK.

How do I…

Create a lot – In the Lot Properties window, select rectangle or trapezoid. Set your lot slope to the correct percentage. Set the length and width of your lot. Select the grid size you desire. And finally, set the default ground cover to the appropriate cover. Click OK.
Set lot orientation – Click on Lot in the upper left hand corner. Click on Orientation and either select a basic orientation or use the button that allows you to set the exact orientation. Set orientation and click OK.
Add a house – Click on Buildings in the upper left hand corner. Click on “add wing” in the drop down window. (There is no feature to add a house.) Set the length and width of the largest portion of the house that is square or rectangular. Select the appropriate number of stories and check/uncheck air conditioned. Click OK and move your cursor to the lot. Position this portion of the house so it is in the proper location. Click the left mouse button to set it in place. Click again on Buildings/add wing to add any additional wings to your house. Set the length and width. Check/uncheck air conditioned. Click OK and move your cursor to the lot. Position the wing so it is in the proper location. Click the left mouse button to set it in place. Repeat for all wings.
Add a garage – Click on Buildings/add wing. Set length and width. Check/uncheck air conditioned. Click OK. Drag garage in place.
Add pavement – Click on Lot/pavement to add driveway and sidewalks. Set length and width. Click OK and drag in place.
Add trees – Click on Add Landscaping/trees. Under Select Species, select the appropriate tree. Select age or dbh. If you chose age, set the correct age, click OK and drag your first tree to the proper location. Repeat until you have placed all of your trees. If you chose dbh, set the correct diameter, click OK and drag the tree to the proper location. Repeat until you have placed all trees. If you want to be more precise with the dimensions of your trees, select dbh and then click on Advanced. Set tree Height, Crown Diameter, and Canopy Height to your exact measurements. Select Water Use. Click OK and drag trees in place. Repeat process for each tree. Continue until you have positioned all your trees.
Move a tree – click on tree you want to move and drag it to the new location.
Remove a tree – click on tree you want to remove and drag it off the parcel. Click again.
Change size of a tree – 1) click on desired tree and drag it off the parcel. Click again. 2) click on Add Landscaping/trees and change dbh. If you have selected the Advanced option, click on Advanced and repeat the process above for adding trees. Reposition the larger/smaller tree in the same position as the one just removed.
Raise a tree crown – click on Add BMPs in the upper left hand corner and select crown raising. Set bottom of the canopy to the desired height. Set desired distance from the house. Click OK.
Add a second story – click on Buildings/add wing and select 2 stories. Click OK.

How do I know when I’m firesafe?

The color of the slider bar only provides you with an indication of how ecoSmart-Fire your home may be. If the bar is green you may be OK. If the bar is yellow there may be a few simple things you can do to change the color back to green like raising the crowns of trees within 20 or 30 feet of your house. But if the bar is red your home is probably not ecoSmart-Fire, and you will need to take more difficult and expensive steps to reduce the fire hazard, like removing trees. If your bar is not green you should find a qualified professional to help you determine which trees to prune or remove. Do not rely on this program to predict the fire safety of your home. See a professional fire expert. The results you get with this computer tool are merely an indication of what might happen to your home in the event of a fire. Many other factors need to be considered when making fire hazard decisions like fire weather and neighboring parcels for example. Please seek further assistance if you are concerned.

What this model will not do

This model does not calculate heat flux to the roof. Therefore, the slider bar changes color when a tree abuts or overhangs the roof. In general, fire planners seek to keep trees 10 feet or more away from structures and further from chimneys. Single unmaintained trees that overhang a structure pose a moderate threat, as wildfire can spread from the tree crown to the home. However, this fire hazard can be significantly reduced by raising the crown and thinning the canopy. Multiple trees pose more complex interactions, as each adds to fuel loading.
This model does not account for fire weather or severe slope. The model simulates thermal ignition only. Effects of winds and burning embers lofted by a crown fire have not been included in the model. During extreme fire weather (hot, dry and windy conditions) nearly as many homes are lost to embers as they are to direct thermal ignition from flames. In addition to developing and maintaining fuel treatment zones, it is highly important to build non-combustible structures, protect vents from embers and to install dual pane or tempered glass windows.
The building construction material feature has not been programmed for different building materials. This initial version was modeled for typical home construction. Building or retrofitting structures for fire safety is a critical step in protecting property from wildfire.
Fire spread from grass to shrubs to trees is not modeled. In reality, ground fuels can influence fire spread and behavior. Fires generally start in a receptive fuel such as grass, and spread to larger plants that overtop them through ladder fuels. Maintaining separation between grasses, shrubs, and trees, reduces fire hazard. For example, the separation distance between the top of shrubs and the bottom of tree crowns should be greater than two times the shrubs’ height.
The hazard posed by off-site structures, fences, wood piles, and trees are not included. When on-site fuel treatments alone fail to mitigate a fire hazard, off-site fuel treatment is needed.
The ability to prune a tree to remove deadwood and thin the crown is not provided. The driving force in fire behavior is the fine fuel, stems less than ¼-inch in diameter and foliage; these fine fuels carry the fire. Fuels larger than 1/4-inch contribute to fire intensity, but not necessarily to fire spread. Routine tree care to keep trees healthy and pruning to remove deadwood is critical to reducing fire hazard.
Ignition characteristics of different tree species and their fuel moisture values are omitted from the model. Little empirical data exist on the fire behavior of specific species, but it is available in other formats. Many fire departments have lists of species to exclude from fuel treatment zones due to their flammability. The UC Forest Products Lab list contains many species that pose hazards. The site is located at http://www.ucfpl.ucop.edu/I-Zone/XIV/vegetati.htm#Unfavorable Plants.
The model calculates radiation emitted from individual trees, and does not reflect synergistic effects of tree massings. Generally, a single specimen size tree when properly maintained (canopy raised, thinned of deadwood and meeting ANSI A300-1995 – Standard For Tree Care Operations, Tree, Shrub, And Other Woody Plant Maintenance) poses little hazard. However, when trees or shrubs are grouped, fire dynamics increase their heat flux more than their cumulative individual effect. The farther individual tree crowns are separated from one another, the less likely it is for an individual tree to burn. Generally, 20-feet of separation between mature tree canopies is recommended to eliminate crown fires.
Under Buildings, the deck feature has not yet been programmed to influence fire behavior. The pool feature is for use with the ecoSmart-Water component.
Under Add Landscaping, the tall grass, rock, bare dirt, and shrubs features have not been programmed to influence fire behavior.
The window and roof features are inoperative.
Under Add BMPs, the cistern, drywells and swales features are for use with the ecoSmart-Water component.

What about buttons that don’t work?

In addition to the limitations listed in What this model will not do, this first version has not been completely programmed to provide access to all of the features. The following buttons have not been programmed to function.

Buildings/construction
Buildings/walls
Buildings/roof
Buildings/window
BMPs/pruning
BMPs/crown reduction

Menu Options

LOT

Location – Currently set for Lake Tahoe
Description – Provides a summary of your selections for your lot properties: shape, length, width, slope, groundcover, and grid.
Weather/climate – Currently set for Lake Tahoe
Orientation – Allows you to set the compass-direction your lot faces.
Soil – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Water.
Pavement – Allows you to create rectangular-sized sections of pavement to be placed on your lot.

BUILDINGS

Add wing – Allows you to create rectangular-sized wings of your home, garage or out-buildings to be placed on your lot. Note: The main portion of you home is also considered a wing. Selections include: length, width, number of stories, and air conditioned.
Add window – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Energy.
Add deck – Allows you to create rectangular-sized sections of deck to be placed on your lot.
Construction – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Energy.
Walls – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Energy.
Roof – Currently inoperative

ADD LANDSCAPING

Pavement – Allows you to create rectangular-sized sections of pavement to be placed on your lot.
Lawn – Will automatically appear over your entire lot. You will need to add additional features to reduce the size of the lawn area.
Tall grass – Allows you to create rectangular-sized sections of tall grass to be placed on your lot. Tall grass is considered grass that is not regularly mowed.
Rock – Allows you to create rectangular-sized sections of rock cover to be placed on your lot. Rock is considered significant areas of naturally occurring rock outcrops or artificially placed rock and gravel.
Bare dirt – Allows you to create rectangular-sized sections of bare dirt to be placed on your lot.
Pool – Allows you to create a rectangular-sized pool to be placed on your lot.
Trees – Allows you to select your trees from a list of species and then chose one of two options to further define your trees – age or dbh. Dbh is defined as diameter of the tree at breast height or 4 ½ feet above ground. If you chose age, the program will automatically calculate dbh, height, crown diameter, crown height. Water usage will be set to medium. If you chose dbh, the program will automatically calculate age, height, crown diameter, crown height. Water usage will be set to medium. If you select the advanced option you can manually set height, crown, diameter, crown height, and water use for each of your trees.
Shrubs – Allows you to create rectangular-sized shrub masses to be placed on your lot.

ADD BMPs

Cisterns – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Water.
Dry well – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Water.
Swale – Inoperative for ecoSmart-Fire. Will be activated for ecoSmart-Water.
Trees – Same choices as Trees under ADD LANDSCAPING
Pruning – Currently inoperative
Crown raising - Allows you to simulate raising the bottom of tree crowns to see the effect on fire danger. Two selections need to be made: 1. the height to which you want to raise the bottom of the crowns, and 2. the distance from your home that all trees will have their crowns raised.
Crown reduction – Currently inoperative

TOOLS

Move reference point – Allows you to move the north arrow, or reference point, to a spot more convenient on your lot. By selecting Show distance to reference point you will be able to easily determine distances to various objects on your lot.
Orientation – Allows you to set the compass-direction your lot faces.
Add dimension line – Provides a ruler for easy reference.
Add text – Allows you to add words to your lot.
Show distance to reference point – Provides distances on x and y coordinates from the reference point.
Show legend – Will display all items, along with the number of each item, that you have been placed on your lot.

VIEW

Hide orientation
Hide pavement
Hide pool
Hide rock
Hide lawn
Hide tall grass
Hide bare dirt
Hide trees
Hide shrubs
Hide BMPs
Hide grid
Hide dimensions

HELP

Help
Index
About