Joint Fire Science / Red Mountain Mastication Study
» Fuels and Tree Mortality Data Collection
Measurements characterizing fuel conditions will be used to address our hypotheses and will also be used
in order to develop custom fuel models for mastication. These custom models will be used to compare
predicted fire behavior under a range of weather conditions and will be provided to managers in the
Subplot size and location: Four subplots will be randomly located in each 5 acre treatment
using ARC GIS. Subplots will not be placed near the edges of the treatment units, allowing for a 3 meter
buffer from the edge to reduce effects of treatment initiation. Based on an extensive fuels treatment
monitoring data set across three National Forests in the northern Sierra Nevada, this is the calculated
number of plots per stand needed to obtain mean estimates of surface fuel loadings within 20% and a
confidence level of 80%. Based on this sampling analysis, we concluded that six plots per stand are
optimal for treated stands that are variable natural stands. Our sites are more uniform, in a plantation
and therefore, we expect that four sub-plots will more than adequately capture variability within each
plot, especially since they will encompass a sample of 20% of the treated areas. Subplots will be 1,000
m2, as defined by a radius extending 17.85 m from the subplot center. Fuels data will be collected three
times: once before any treatments, once following all mechanical treatments, and once following
Crown Fuels: All living and dead trees will be tagged with sequentially numbered brass tags
nailed in at dbh prior to any treatments. For all live trees >15cm dbh, the following information will be
Tree damage will also be noted. For snags, information collected will be:
- tag number, species, dbh (cm)
- alive (y/n)
- height to live crown
- total tree height (m)
Following mastication and controlled burns the following will be collected:
- tag number
- total tree height
- decay class ( 1 thru 5 )
- height to live crown
- char height (on the bole)
- proportion of circumference of bole charred
- crown scorch height (foliage brown but not consumed)
- torch height (foliage consumed)
- tree status (dead or alive)
For smaller trees (2.5 to <15 cm dbh and > 1.37 m in height) and seedlings, a smaller circle will be
sampled that is centered at a random point along the perimeter of the subplot. A circle with a 8.92 m
radius will then be defined from this point. All pole size trees will be tagged with numbered brass tags
and the same set of information will be collected on these trees as from the trees that are >15 cm dbh.
Information on seedling and canopy cover will be collected from a 3.99 m radius circle centered at the
pole-tree plot center. In this area, the following information will be recorded: seedling species, alive
(y/n), height class (<15cm = 15, <30cm = 30, <60cm = 60, <100cm = 100, <200cm = 200, <300cm = 300, etc.).
Surface Fuels: Brown’s planer intercept method will be used to measure surface fuels (Brown
1974). From the subplot center, one 50 foot transect will be placed along a randomly selected bearing.
Beginning and ending of transects will be marked with rebar to ensure exact placement pre- and
post-treatment. Transects will be photographed, and the slope and bearing recorded.
Masticated Material, Litter and Duff Samples: No generalized fuel models for
masticated materials are currently available. In order to aid in estimating fuel loadings from
mastication bulk density samples will be taken. Two randomly located 30x30cm quadrats within each
treatment block will be collected. Litter, masticated material and duff layers will be separately
measured and collected. Samples will be floated to remove dirt and rock, placed in bags, air dried,
then oven-dried at 70oC for 48 hours and weighed. Equations will be derived to calculate masticated
material fuel loading based on depth.
Live Understory Fuels: Biomass of live understory fuels, including shrubs, forbs and
graminoids, will be estimated using Behave Fuel Subsystem NEWMDL program v 2.0 (Burgan and Rothermel
1984). Life form, density class, depth and cover are required inputs. A belt transect will be
established along the Brown’s planar intercept that is 50 feet long (same as intercept) and 1 meter wide.
Within that belt transect we will classify and record shrub, herb, and grass cover using cover classes
(1=0-5%, 2=6-25%, 3 =26-50%, 4= 51-75%, 5 = 76-95%, 6 = 96-100%), percent dead, and average height (cm),
and dominant species. The Burgan and Rothermel (1984) lifeform and density class will be assigned to
each understory component and fuel loading calculated according to their algorithms.
Tree Mortality: Post-burn mortality, and crown condition will be assessed by
measuring tree survival and crown condition in the subplots, at one year and two years following the
prescribed fire treatment. We will compare mortality and crown condition between masticated plots burned
with and without the mitigation treatment of pulling material away from the boles and root zone. In
addition, we will gather fire behavior data soil surface temperature maximums and duration near trees,
as described in the Fire Behavior section.