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The methods detailed below are primarily field sampling procedures for quantifying fuel loads and generating Custom Fuel Models. The Canopy Bulk Density sampling procedure for Pitch Pine stands calculates Crowning Index (the windspeed necessary to sustain an active crown fire) for a given stand.
Martha's Vineyard Custom Fuel Models--We have generated nine custom fuel models for the fuels of Manuel F. Correllus State Forest at Martha's Vineyard. The nine models are for: 1) Pitch Pine untreated fuels, 2) Pitch Pine fuels thinned and then grazed by sheep, 3) Pitch Pine fuels thinned and mowed, 4) Oak Woodland fuels untreated, 5) Mowed Oak Woodland fuels, 6) Oak Woodland fuels mowed and grazed by sheep, 7) Scrub Oak untreated fuels, 8) Mowed Scrub Oak fuels, and 9) Scrub Oak fuels mowed and grazed by sheep.
View or download the models by clicking here (33KB Excel wkst).
Excel Workbooks for Sampling Methods--The file for each sampling method includes instructions, data calculation worksheets to generate inputs for BehavePlus Custom Fuel Models, and a sample field or lab sheet.
June 10, 2006: Corrections have been made to several of these worksheets, so please download the current versions below.
Sampling Method Data to BehavePlus Input Flowchart--A flow chart showing which sampling methods (Brown's Lines, 40x40s, or 1x1s) are used to generate which BehavePlus inputs. We hope it will be useful. Download it here (14KB pdf) .
BehavePlus2 Custom Fuel Modeling Exercise--Matthew Duveneck wrote a brief Custom Fuel Modeling Exercise for BehavePlus2. The exercise is meant to provide detailed instructions for simple custom fuel modeling. View or download it here (32KB Word doc).
As always, comments, questions, and suggestions are MOST appreciated. Please feel free to contact us!
Matthew Duveneck has put together an excel program and sampling protocols for calculating Canopy Bulk Density and Canopy Base Height in Pitch Pine stands based on stand inventory data. Notice: The current program is set up to handle only pitch pine trees up to 27 meters tall. In addition, calculations for stands of more than 1000 inventory trees will require copying and pasting calculation cells. Click here to download the excel workbook, which includes instructions and a sample fieldsheet.
1. Measure the following parameters for each live pitch pine greater than 4.5 feet in height within one or more 0.1 acre fixed radius plots (the radius of a 0.1 acre plot =37ft 3in):
2. When you have completed one plot, repeat step 1 for the next 0.1 acre plot until all plots within the stand have been sampled.
3. Enter data into the Canopy Bulk Density Excel file (download it here). Input is needed in the white cells. All other cells will be calculated for you. Under the Input_output tab, enter the plot size (decimal acres) in the upper left hand corner. Next, type the total number of plots that you sampled in the given stand.
4. Each tree sampled will represent a single row, beginning with row 6. Enter the site, plot number, date sampled, and treatment for one row. Then copy cells A6:D6 and paste them down to the appropriate number of cells (trees) per plot.
5. Fill in the dbh (cm), height (m), and dominance (d, c, i, s) for each tree within the plot. Repeat steps 3 and 4 for each plot sampled in the stand.
6. When all the trees are entered into the spreadsheet, the red cells at the top will indicate the stand's estimated Canopy Bulk Density in kg/m3 and Canopy Base Height in m. The calculations are based on predicting the vertical distribution of fuel and presenting maximum three-meter running mean of canopy weight as CBD. The CBH value is based on the lowest height at which at least 0.011 kg/m3 of available canopy fuels are present (Sando and Wick 1972).
8. To calculate plots from multiple stands or multiple treatment types, build and save separate excel files for each stand.
9. Next, use the Crowning Index Nomogram to calculate the windspeed needed to sustain active crowning. Based on the CBD calculated for your sample stand, draw a vertical line straight up from the CBD value on the X axis to reach the moisture condition curve of choice. From the moisture curve, draw a horizontal line to the left to the windspeed. Crowning Index is indicated at the point where the horizontal line crosses the Y axis.
The Crowning Index Nomogram is based on a zero percent slope and the standard moisture conditions. To calculate crowning index with a non-zero slope and/or custom surface fuel moisture conditions, use the fire behavior software NEXUS available from www.fire.org. NEXUS also calculates Torching Index (the windspeed needed to initiate crown fire) using the canopy base height parameter.
10. To simulate thinning a stand to determine changing CBD values, change the multiplier cell (green column H) from "1" to "0" for each tree-row you wish to simulate removing from the stand. This will adjust the CBD value based on the removal of those trees changed to zero.
Note: the following sampling methods are a combination of those used by Adam Mouw at Manuel F. Correllus State Forest , Dukes County, MA from 1996-1998 and those used at the David Sarnoff Preserve, Suffolk County, NY 2005. They will likely need to be adjusted to fit your sampling objectives. Please contact us with any questions.
1. 100' measuring tape
Selecting and locating a plot
1. select stands that approximate the dominant vegetation types of the Forest
Downed Woody Fuels Inventory
At each point:
1. look at the second hand of a watch. Sampling plane will extend 50 feet in a direction at which the second hand points multiplied by 6.
2. attach a measuring tape to a pin at the point
***Note: If you are sampling 40x40cm harvest plots and SO 1x1m plots for the same area, you do not need to count intersections of 1 or 10hr fuels in the Downed Woody Fuel inventory. You do still need to count intersections of 100 and 1000hr fuels (and measure the diameters of 1000hr fuels) and measure the fuel depths if you are going to create a custom fuel model. If you are not counting intersections of 1 or 10hr fuels, you may want to use a modified fieldsheet. Download it here.***
6. In the laboratory, enter all data into a template and calculate fuel loads and fuel depths. We have developed an excel workbook that will calculate fuel loads and depths for you from Brown's Lines Inventory data. Click here to view or download the workbook, which also contains instructions and a sample fieldsheet.
1. go-no-go gauge with increments that correspond to time lag classes
At ten randomly placed plots in each stand, harvest all fuel from 40 X 40 cm2 subplots:
1. Once a point is randomly located (e.g. by throwing an object over your shoulder), place a square frame of PVC pipe with internal dimensions of 40cm by 40cm flush on the litter surface.
3. Place all litter, including downed wood, in a separate bag. Do not collect the decaying humus layer.
4. Dry samples in a convection oven at 70° C for at least 72 hours (see notes, below)
6. Record weights to the nearest 0.1g on the lab sheet. Click here for a sample lab sheet. (pdf)
A few notes on drying bags:
When you come in from the field each day, it is important to place the bags in a dry place and off of the ground. If you have been transporting the paper bags in plastic garbage bags, you need to take them out of the plastic bags. If the bags stay in plastic or are stored on the ground and in a humid place, the contents (and the bags themselves) will likely rot and will not accurately represent fuel loads.
Dry samples in a convection oven at 70° C for at least 72 hours (3 days). Since ovens vary, check that the bags are completely dry and no longer losing moisture: take a few bags out of the oven, weigh each bag and all of its contents, and write the weight, time, and date on each bag. Return the bags to the oven and re-weigh the same bags after 2 or more hours. If the bags are ready, the weight should not have dropped more than a few tenths of a gram.
If you don't have enough time to sort and weigh all of the bags right away and you need to get more drying in the oven, you can label and place bags that have completely dried once (i.e. have been in the oven at least three days) in a dry place. When you have time to sort through the bags' contents, these bags will not need another 3 days in the oven. Our policy was to place them back in the oven for at least 2 hours, then check weights an hour later to see if they were still drying. In most cases, a 2-hour drying period is sufficient for this "second" dry.
Hints for sorting harvest bag contents:
Spread out a page of newspaper on a large table. Empty the contents (or a portion thereof, if the bag is very full) of one of the bags (e.g. live standing, herbs, dead standing, or litter) onto the paper and enter the identifying information from the paper bag onto the harvest biomass labsheet (pdf). Under item/species, you will probably put either "litter and downwood," "dead standing," or "live standing." Contents of "dead, downwood" bags need to be combined with the woody components from the "litter" bags.
Sort through the contents and separate out 1, 10, and 100hr wood. It is helpful to have somewhere to put these; shallow tupperwares or pie pans work well. It is not necessary to get every last bit of wood. In particular, if a piece of woody material does not weigh at least 0.1g, it does not need to be sorted from the litter. The sorting process, while time-consuming, should not be agonizingly slow.
When you have separated all of the woody material from non-woody, weigh each fuel item (1, 10, 100hr wood and leafy material) separately. It was helpful to us to put a shallow, open cardboard container onto the scale, tare/zero the scale, and then weigh the contents, but you can also weigh each dish and subtract the dish weight. You can pick up the corners of the newspaper to funnel leafy material into the weighing dish.
1. scrub oak go-no-go gauge with increments of 1/4 cm, up to 3 cm
It was necessary to sample scrub oak stems separately because their size and clumped distribution made sampling them on 40x40cm2 plots impractical.
Locate a subplot randomly (e.g. by throwing an object over your shoulder), and place a square frame of PVC pipe frame with internal dimensions of 1m x 1m flush on the litter surface
1. 100' measuring tapes, marked in feet and tenths on one side, meters on the other (2)
Selecting and locating a plot
1. select stands that approximate the dominant vegetation types of the Forest
1. Walk around 10m radius circle and record all species present and the strata in which they appear (grass and forbs, low shrub, high shrub, and canopy)
1. Record average height of each vegetation layer from a plot 0.6m in radius to the nearest 10cm.
2. Record the average height to the base of the live crown and total tree height to the nearest 5 ft.
4. Proceed to the next plot using the random-bearing method
© 2005 Kimberly Iwamoto. This is the Web site for the Joint Fire Science Program Northeast Barrens Fuels Demonstration Project. This site is hosted by the Department of Ecological Conservation, University of Massachusetts, Amherst. Produced and maintained by the lab of Dr. William A. Patterson III. Please contact us with questions or comments at firstname.lastname@example.org.