9-1A08
SNPLMA RESEARCH PROPOSAL ROUND 9
I. Title Page
Project title: Silvicultural Prescriptions to Restore Forest Health
Science Theme # 1: Effects of Wildfire and Fuel Treatments
Subtheme: Alternatives for Fuel Treatments
Team members: Dr. Patricia Manley (USFS Pacific Southwest Research Station [PSW]), Dr. Malcolm North (USFS
PSW), Dr. Dennis D. Murphy (University of Nevada, Reno)
Patricia Manley, Ph.D. (primary contact)
US Forest Service
1731 Research Park Dr.
Davis, CA 95618
530-759-1719 (ph)
530-747-0247 (fx)
pmanley@fs.fed.us
Malcolm North, Ph.D.
US Forest Service
1731 Research Park Dr.
Davis, CA 95618
530-754-7398 (ph)
530-747-0247 (fx)
mnorth@fs.fed.us
Dennis D. Murphy, Ph.D.
Department of Biology
University of Nevada
Reno, NV 89557
775-784-1303 (ph)
775-784-1302 (fx)
ddmurphy@biodiversity.unr.edu
Grants contact:
Bernadette Jaquint
bjaquint@fs.fed.us
ph: (510) 559-6309
fax: (510) 559-6440
Total funding requested: $381,200
In-kind contributions:
$185,000
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II. Proposal Narrative
a. Abstract
Many uncertainties exist in the effects and effectiveness of fuel treatment prescriptions being planned in the Lake
Tahoe basin on various forest health objectives. In the basin, forest health objectives include restoring a greater
proportion of the landscape to old forest conditions, restoring forest composition (e.g., greater predominance of
Jeffrey pine), structure (e.g., more open forest structure and multi-aged forests), conserving and restoring biological
diversity, and reducing the risk of catastrophic wildfire. The lack of information combined with the urgency to act is
potentially forming a perfect storm in the Lake Tahoe basin, where extensive treatments are planned over a short
period of time (5-10 years), thereby creating the opportunity for significant unforeseen negative ecological
consequences. Fuel treatments are typically designed to reduce crown bulk density and canopy contagion, resulting
in the remaining trees having a fairly regular spacing. Historical records indicate that forests with an active fire
regime had clustered tree spacing with gaps and heterogeneous understory plant cover. This study will design and
test a silvicultural prescription that leaves a clustered distribution of trees that more closely mimics historical
distributions while also reducing fuels to determine the benefits gained in ecological restoration and the sacrifices
made in altering fire behavior. It will also test the relative effects of the two prominent slash treatments: pile and
burn and mastication. We will examine the interaction of two overstory (regular canopy tree spacing [fire emphasis]
and clustered tree retention [restoration emphasis]) and two understory (mastication and pile and burn) treatments
and a control on measures of forest function (vegetation, soil properties, truffles), biological diversity (birds, small
mammals, ants, invertebrates), and habitat and prey for key wildlife species of special concern (Northern Goshawk
[Accipiter gentilis], California Spotted Owl [Stirx occidentalis], and American marten [Martes americana]). A
factorial design will be used to test overstory and understory treatment effects on forest functions, biological
diversity and select prey species. Sampling will use a Before-After-Control-Impact (BACI) design, with clustered
treatment (n = 4) and control (n = 1) sites. The cluster of five sites will be implemented within a similar set of
environmental conditions, and then replicated in at least 4 different locations, for a total of 20 sample sites.
b. Justification Statement
The elevated threat of high-intensity wildfire and poor forest health in the Lake Tahoe basin have resulted
in increased emphasis and funding to implement treatments designed to address these concerns. The urgency for
treating forest fuels has become more imperative as initial analyses indicate that global climate change may already
be increasing the length and severity of the western United State’s wildfire season (Westerling et al. 2006).
Extensive fuel treatments are in the process of being planned and implemented in the montane zone around the
basin, with 68,000 acres currently planned for treatment as outlined in the Lake Tahoe Multi-Jurisdictional Fuel
Reduction and Wildfire Prevention Strategy (Dec 2007; Fig. 1).
While there is a sense of urgency in treating Basin forests, for many of the proposed treatments we do not
their impact on ecological conditions, wildlife or their relative efficacy at reducing fire intensity. In the basin, forest
health objectives include restoring a greater proportion of the landscape to old forest conditions, restoring forest
composition (e.g., greater predominance of Jeffrey pine), structure (e.g., more open forest structure and multi-aged
forests), conserving and restoring biological diversity, and reducing the risk of catastrophic wildfire. Research has
not been able to keep pace with the need for greater understanding of treatment effects and effectiveness, despite the
growing recognition at national, regional, and local scales of the need to consider a spectrum of forest health
objectives in forest management practices, even in wildland-urban interface areas.
Current Sierra Nevada forest management, including the Lake Tahoe basin, is focused on parts of the
catastrophic wildfire prevention strategy: 1) intensive treatments in close proximity to urban development (Defense
zone) intended to achieve immediate fuels reduction; and 2) landscape strategies within ¼ mile of urban
developments (Threat zone) intended to reduce the potential of fire intensity and spread (Strategically Placed Area
Treatments [SPLATs] in the Threat zone; Finney 2001). Fire scientists have developed effective fire behavior
models that have been particularly valuable for optimizing and prioritizing fuels treatments to change fire behavior
(Stratton 2006; Ager et al. 2007; Finney et al. 2007); however, these models do not consider treatment effects on
forest restoration and biological diversity objectives. The lack of tested silvicultural treatments to meet the current
forest management challenges makes it virtually impossible to know how the extensive planned treatments will
affect forest health in light of the conservation and restoration mandates of the many land management and
regulatory agencies in the basin and the Lake Tahoe Restoration Act. Research is urgently needed to design, test,
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and provide information on forest treatment options that have a known range of effects on the suite of forest
conservation and restoration objectives that exist in the basin.
This study proposes to design and test a silvicultural prescription with a forest restoration emphasis that
strikes a balance between reducing the risk of crown fire and restoring forest structure and composition to conditions
more representative of what an intact fire regime would create and to which native species are adapted. It is now
generally understood that, historically, forests had more open understories and larger diameter trees than forests that
exist today. A less commonly highlighted feature of forests with an intact natural fire regime is the spatial
distribution of trees, which were more clumped and irregularly spaced compared to the forest structure that exists
today in the Lake Tahoe basin both as a result of previous forest practices (untreated) or following fuels reduction
(treated). This study will design a silvicultural prescription that leaves a clustered distribution of trees that more
closely mimics historical distributions while also reducing fuels to determine the benefits gained in ecological
restoration and the sacrifices made in altering fire behavior.
c. Background and problem statement
Land managers from five different agencies in the basin are actively reducing hazardous fuels primarily
with thinning (hand or mechanical treatments), followed by some form of slash treatment (pile and burn, or
mastication; Fig.1). Fuel reduction treatments in defense and threat zones typically target reductions in crown bulk
density and crown contagion, accomplished by reducing crown overlap through regularly spacing remaining trees.
Some research suggests, however, that this regular tree spacing is not typical of historic forest conditions nor is it the
habitat structure to which animal species have evolved and adapted in montane forests. In the Sierra Nevada,
historical data (Lieberg 1902, Bouldin 1999), narratives (Muir 1911) and reconstruction studies (Bonnickson and
Stone 1982, Minnich et al. 1995, Barbour et al. 2002, Taylor 2004, North et al. 2007) indicate that historically
montane mixed-conifer forests were highly clustered with groups of trees separated by sparsely treed or open gap
conditions. Tree clustering has many ecological effects, including promoting the regeneration of shade-intolerant
pine (York et al. 2003, North et al. 2004, Gray et al. 2005, York and Battles 2008), increasing plant diversity and
shrub cover (North et al. 2005), moderating surface and canopy microclimate conditions within the tree cluster
(Rambo and North in press), and providing a variety of microhabitat conditions for birds (Purcell and Stephens
2007) and small mammals (Innes et al. 2007, Meyer et al. 2007). In fire-suppressed forests, shrubs are often shaded
out (Nagel and Taylor 2005, North et al. 2005), reducing their size, abundance, and fruit/seed production in lowlight forest understories. Anecdotal narratives (Lieberg 1902, Muir 1911), forest reconstructions (Taylor 2004), and
historical plot maps (Eric Knapp, pers. communication) suggest that shrub cover in active-fire conditions was likely
to have been much higher than in current forests, mostly due to large shrub patches that occupied the gaps between
tree clusters.
Empirical studies of on-the-ground effects of fuels reduction treatments are few (van Wagtendonk, 1996;
Stephens, 1998; Pollet and Omi, 2002; Graham et al., 2004; Agee and Skinner 1995; Stephens and Moghaddas,
2005a; Murphy et al. 2008). A recent literature review of fuel treatment effects lead by PSW determined that the
effectiveness of fuels treatments currently being implemented in the basin, particularly combinations of different
thinning prescriptions and slash treatments on fuels and fire behavior and on forest restoration and biodiversity
conservation objectives, are virtually untested and unknown (Bigelow and Manley 2008, Manley et al. 2008). Fuels
treatments are likely to greatly affect habitat conditions for substantial numbers of native plant and animal species
for many decades after treatment,(e.g., Passovoy and Fule 2006). The reduction of overstory and understory tree
density and the more even spacing of overstory trees can result in potentially significant changes in habitat structure
for species that use both understory and overstory resources (George and Zack 2001). Dead wood is a critical
habitat element for wildlife (Bull 2002). Snags are often lost in thinning operations because of their potential hazard
to people during thinning and prescribed burn operations. Logs are often lost through post-harvest slash treatments
(Stephens and Moghaddas 2995b). Old-forest associated species are most at risk, including many species of
conservation concern in the basin, because their habitat requirements are closely linked to those being most altered
by fuel treatments. While these treatments are intended to address hazardous fuel accumulations, they may also
constitute the most disruptive habitat changes that have been faced by species of conservation concern (old-forest
associates such as California Spotted Owl, Northern Goshawk, and American marten) over the last century. We
need a better understanding of how to design treatments to retain habitat value for old-forest associated species.
A few studies of the effects of fuels treatments on fire behavior and small mammals have been conducted
in the Sierra Nevada (e.g., Stephens and Moghaddas 2005a, Monroe and Converse 2006, Amacher et al. 2008);
however their results have been equivocal (Converse et al. 2006). These studies have shown that individual species
respond to the changes in forest structure and composition created by standard fuel reduction treatments, but no
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consistent patterns of response emerged across studies or species. To date, there have been few studies focused on
multiple species responses and how treatments impact forest function, community dynamics, and ecosystem
services. Given the high social importance of ecosystem health in the Lake Tahoe basin, there is a heightened need
to understand thresholds of persistence of populations and community structure and dynamics. Further, small
mammals, and songbirds to a lesser degree, are the primary prey of multiple species of concern in the basin,
specifically the California Spotted Owl, Northern Goshawk, and American marten.
Canopy-associated species, such as Douglas squirrel and northern flying squirrel (Glaucomys sabrina),
have been found to be affected by specific types of changes in forest overstory and understory characteristics.
Northern flying squirrel is one of the few small mammal species for which many studies have been conducted in
various forest types in the western U.S., and they are clearly vulnerable to impacts from fuels treatments through
reductions in forest canopy, increased tree spacing, reductions in woody debris, and reductions in diversity or
biomass of understory plants, truffles, and lichen (e.g., Bull et al. 2004, Lehmkuhl et al. 2004, 2006, Meyer et al.
2005a, Meyer et al. 2007). Understory associates, such as shrews, voles, and mice, are most vulnerable to changes
in ground cover and truffle abundance (e.g., Meyer et al. 2005b), which can be highly altered on sites where
chipping or mastication has been performed. Although bird responses to fire and fuel treatments have been studied
to some degree in western forests (Pilliod et al. 2006), responses are variable. Specific responses of species of
concern in the basin are needed, especially given the potential vulnerability of small population sizes of a number of
old-forest associated species (e.g., Pileated Woodpecker [Dryocopus pileatus], Black-backed Woodpecker [Picoides
arcticus], Hermit Warbler [Dendroica occidentalis], northern flying squirrel, and habitat suitability and prey
populations for top carnivores (California Spotted Owl, Northern Goshawk, and American marten).
Post-harvest pile burning and mastication treatments generally produce significantly different understory
conditions relative to each other and to those created by frequent, low-intensity fires typical of the historical fire
regime. Slash treatments of any type typically result in reductions in downed wood, which is a critical habitat
element for many wildlife and invertebrate species (Bull 2002, Sanford et al. in prep). A recently completed study
of biological diversity in urban forests (Manley et al. 2006, 2007) showed that extremely high or low densities of
downed woody material can significantly change the composition and abundance of small mammals and ants.
Mastication is of particular concern, given that it commonly results in a reduction in logs and shrub cover, which are
important habitat elements for many small mammals and birds. Some birds (e.g., Robinson and Alexander 2002)
and small mammals (e.g., Coppeto et al. 2006, Innes et al. 2007) are closely associated with these habitat patches.
In the short-term absence of shrubs, thinning slash piles may provide some cover and habitat heterogeneity for
wildlife associated with diverse understory conditions.
Although investigations of fuel treatment effects have been mounting over the past several years in the
Sierra Nevada and the west (Pilliod et al. 2006), results are limited, and only one study has been initiated in the Lake
Tahoe basin. Our research team has been studying the effects of existing treatment prescriptions on plants and
animals, and preliminary results suggest that fuels treatments, particularly mechanical treatments and mastication
following standard prescriptions, can have substantial effects on old-forest associated species and biological
diversity (Murphy et al. 2008). Research directed at the design, testing, and delivery of a silvicultural prescription
that meets a balance of ecological and fire behavior objectives is needed greatly in the Lake Tahoe basin to ensure
that treatments across the landscape ultimately meet the spectrum of objectives that exist for forest health, including
the conservation of biological diversity and wildlife species of special concern.
d. Goals, objectives, and predictions
The goal of this study is to develop and test an alternative silvicultural prescription that is designed to
achieve the balance of objectives for forest health and biodiversity conservation that exist in the basin. Specifically,
the objectives of the study are three fold: 1) apply existing knowledge about historic forest conditions, forest
function, and biodiversity conservation to develop a silvicultural prescription that meets a balance of forest
management objectives (Restoration emphasis) by leaving a greater proportion of the understory intact and leaving
trees in a more clumped distribution within stands; and 2) compare the performance of the Restoration emphasis
prescription with that of the standard fuels reduction treatment prescribed for the defense zone (Fire emphasis); and
3) provide an interpretation of the direction, magnitude, and ecological significance of observed differences
associated with understory and overstory structure. We are also interested in the effects of prescribed fire as a tool
to meet forest management objectives. Given that most prescribed fire is used at the end of a sequence of forest
treatments, we have designed the experiment such that a comparison of burned and unburned sites can be
incorporated into the study at a later time as funding allows.
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This research study is designed to build on two important existing efforts. Dr. North and colleagues have
written a scientific paper that outlines the ecological perils of standard fuels reduction treatments in the Sierra
Nevada, and how to design prescriptions that avoid these perils while still reducing the risk of catastrophic wildfire
(North et al. 2008). This scientific paper serves as the foundation for our conceptual model for understanding the
potential effects of the different treatments biological diversity in the Restoration prescription that will be developed
for this study. Dr. Manley and Dr. Murphy are currently collaborating with colleagues to complete pre- and posttreatment sampling on fuels treatment sites on the west and east shores of the basin, the results of which informed
our experimental design and honed the field methods used in this project.
Informed by the composite projects in which the team is involved, we will examine the interaction of two
overstory (regular canopy tree spacing [fire emphasis] and clustered tree retention [restoration emphasis]) and two
understory (mastication and pile and burn) treatments and a control on measures of forest function (vegetation, soil
properties, truffles, ants), biological diversity (birds, small mammals, invertebrates, plants), and habitat and prey for
key wildlife species of special concern and interest (Northern Goshawk, California Spotted Owl, and American
marten). Our broad conceptual model is that regular canopy tree spacing will reduce microclimate and soil moisture
variability reducing food resources, while mastication will homogenize understory habitat reducing animal diversity
and abundance. Based on this model, our predictions are as follows:
1) There will be significantly lower bird, small mammal, and invertebrate diversity and reduced prey
populations in masticated than in pile and burn treatments.
2) Regularly spaced canopy trees will have significantly lower truffle abundance, invertebrate diversity, and
habitat value for old-forest associated species compared to clustered tree distributions
3) Clustered tree retention with pile and burn understory will have higher biological diversity, higher habitat
value for old-forest associated species, and retain greater forest function than any treatment including the
control.
e. Approach, methodology and location
The urgency of the information needs and the interdependent nature of the multiple objectives requires an
interdisciplinary science team with a depth of understanding of the individual sciences, an efficient integrated
research design, and collaborative analysis and product development. This study and research team offer the
greatest opportunity for research to contribute timely and robust results to informing the management of forests to
achieve the multiple and potentially conflicting critical management and restoration objectives.
The research team engaged here has a breadth and depth of expertise in forest ecology, long-term
knowledge and experience working in the basin, existing data to inform the development of prescriptions, and
established working relationships with management agencies and staff in the basin. The Restoration prescription
will be developed in concert with agency staff (foresters and biologists) to ensure that the prescription can be
implemented within the regulatory and fiscal framework in which agencies must operate to implement their forest
management activities. It will also attempt to strike the most advantageous balance between the reduction of the risk
of wildfire and the restoration forest structure and associated forest function, conservation of biological diversity,
and maintenance of habitat and prey for species of special concern (California Spotted Owl, Northern Goshawk, and
American marten). Detailed vegetation parameters form the foundation for evaluating treatment effects on wildfire
potential and, combined with soil moisture, can inform predictions about the long-term ecological trajectory of the
forests. The consequences for biological diversity and ecosystem services are poorly predicted based on vegetation
and soil conditions, thus direct measurements of plant, vertebrate, and invertebrate populations and communities are
needed to address the consequences of treatments to biological diversity and ecosystem resilience.
Sampling Design
A factorial design will be used to test the effects of overstory and understory treatment effects. The
overstory treatments will consist of the Restoration emphasis and Fire emphasis thinning prescriptions; the postharvest treatments will consist of pile-and-burn and mastication, for a total of four treatments. Sampling will use a
Before-After-Control-Impact (BACI) design, with clustered treatment (n = 4) and control (n = 1) sites. The cluster
of five sites – four treatments and one control – will be implemented within a similar set of environmental
conditions, and then replicated in at least 4 different locations, for a total of 20 sample sites. Data collection will
include detailed descriptions of the composition, structure, and abundance of vegetation, songbirds and
woodpeckers, small mammals, and ground-dwelling invertebrates. Treatments and control site conditions need to be
a minimum of 10 acres in size, such that All sites in a cluster will be sampled for each type of data within two weeks
of one another so the data reflect the same set of environmental influences (e.g., weather, plant phenology, human
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disturbance events). Clusters will be sampled two years before and two years after treatment for a total of four
sample years per cluster. It is expected that treatments among clusters will be staggered over a two to three year
period, given the myriad of factors that affect the timing of contracting and implementation. Every effort will be
made to complete pre and post-treatment sampling in as short a period as possible to expedite the delivery of results
to management.
Field Methods
Data will be collected within an integrated rectangular macro-plot that measures 150 x 330 m. The plot
lay-out and data collection parameters are designed to be compatible with our previous research on fuels reduction
treatments in the basin, and to be comparable with previous research conducted elsewhere in the Sierra Nevada.
Vegetation data collection will measure changes occurring at two scales; stand-level forest structure and
composition and microhabitat conditions. To quantify treatment effects on stand structure, we will measure all
mature trees with a diameter of >6” (15cm at DBH) within the macroplot. To sample microhabitat related to small
mammal occurrence, we will sample nine variables at all small mammal capture locations and an equal number of
random non-capture stations. At each location within a 12.6 m radius (0.05 ha) around the trap we will sample: (1)
species and total basal area of large (>50 cm dbh) trees, (2) species and total basal area of large (>50 cm dbh) snags,
(3) canopy closure (%), (4) total volume (m3/ha) of intact (decay classes 1-2) and heavily decayed logs (decay
classes 3-5), (5) litter depth (cm), (6) shrub cover (%) and species richness, (7) herbaceous plant cover (%), (8) char
height (at burned sites), and (9) aspect. Plots will be installed at 10 randomly selected trapping stations within each
macroplot, for a total sampling area of 1 ha (2.5 ac). In addition to the standard FIREMON measurements, we will
take digital hemispherical photographs at all grid sample stations to assess canopy closure (versus canopy cover [see
Jennings et al. 1999]), and measure direct and indirect light levels which are highly correlated with understory plant
cover and composition, and soil surface temperatures (North et al. 2005; Wayman and North 2007).
To assess changes in food chain dynamics, we will sample the abundance and diversity of truffles,
following established protocols (North et al. 1997). In brief, during peak fruiting (usually late June), we will place
a 4-m2 circular quadrat every 40 m in a 5 by 5 square grid centered on the small mammal sample grid at each study
site (total of 25 quadrats per sample location),. All collected truffles will be counted, placed in wax bags, dried for
24 hours at 60°C, weighed to the nearest 0.01 g, and identified to species following established methods (Meyer and
North 2005). We will use truffle collections to estimate frequency, biomass, and species richness of truffles in
treated and untreated stands.
In addition to sampling vegetation, we will also measure changes in soil moisture before and after
treatments at three depths (0-15 cm, 15-40 cm, and 40-70cm). No single measure can account for the ecological
effects of mechanical thinning on forest functions, but increases in soil moisture availability have been associated
with reducing drought stress and bark beetle mortality in leave trees (Smith et al. 2005, Fettig et al. 2007), increases
in the diversity and cover of understory plants (Wayman and North 2007) and below-ground truffles (Meyer and
North 2007), tree establishment and regeneration (Gray et al. 2005), higher soil invertebrate diversity (Marra and
Edmonds 2005), and greater soil respiration and microsite heterogeneity (Ma et al. 2005). In fire suppressed forests
with high stem densities, competition for snowmelt water can rapidly dry soils, limiting some ecosystem processes
(North and Rosenthal 2006). To avoid spatial variation and soil disturbance when sampling, we will use time
domain reflectometry (TDR, model 1502C, Tektronix Inc., Beaverton, OR) to measure volumetric water content
between stainless steel rods permanently installed in the soil. At 10 sample points in each plot, we will insert 3 pairs
of rods to measure each of the three depths following methods detailed in Gray and Spies (1995). We will sample
soil moisture immediately after snow melt (field capacity), one month later (beginning of the dry down), and than
every two weeks through the end of August (to assess available moisture duration).
Birds and small mammals are the primary focus of vertebrate sampling – they are directly affected by
treatments and have complementary sensitivities to the effects of fuels treatments. They also serve as the primary
prey for upper trophic level species of special concern in the basin: California Spotted Owl, Northern Goshawk, and
American marten. Small mammals are closely tied to the local conditions, they are highly dependent upon overstory
and understory vegetation, and they primarily are year-round residents. Birds are more mobile, but most species
have relatively narrow environmental conditions in which they can successfully breed, and they are also dependent
upon both overstory and understory conditions.
Live-trap sampling methods target small mammal species presence and abundance, with an emphasis on
tree squirrels. All required permits have already been obtained. A total of 72 live trap stations will be placed on a
6x12 grid at 30 meter intervals. This spacing represents a balance between encountering a sufficient number of
squirrel home ranges and obtaining a high enough recapture rate for chipmunks and mice to obtain reliable estimates
of density (e.g., Jones et al. 1996, Converse et al. 2004). One Tomahawk mounted in a tree and one extra-large
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Sherman trap are placed at each trap station (n = 144 traps total) and baited with a mixture of oats, bird seed, and
raisins. All animals are individually marked with ear tags (one in each ear), enabling calculations of population size
and turnover rates over time. Traps are open for 4 days and nights, and checked twice per day.
Bird point count stations will be located at each corner of the macroplot grid for a total of 4 count stations
with intervening transects. Sites will be sampled three times during the spring (late May to early July), with a 10
minute count conducted at each station, recording all individuals seen and heard within 10 m distance intervals
(Ralph et al. 1993). New species encountered along transects will also be recorded.
Invertebrate composition and relative abundance will be characterized with a grid of pitfall traps with the
same response design used in our previous studies. We will use a standard pitfall trapping method to quantify
invertebrate community characteristics because it provides rapid and repeatable results and unbiased samples of
ground-dwelling invertebrates within a survey area (Anderson 1990, Agosti et al. 2000). At each site, we will array
12 traps in a 40 x 40-m grid. We will place four traps, spaced 10-m apart, along each of three 40-m transects that are
oriented north-south and centered on the center point of each plot; the three transects are separated by 20 m
(Bestelmeyer and Wiens 1996, Anderson 1997). Pitfall traps consist of 6.5-cm diameter (120 ml) plastic cups with
approximately 25 ml of propylene glycol. Traps will be left open for 7 days and then contents will be collected.
Ants will be identified to species and the remaining invertebrates will be identified to morphospecies and placed in
functional groups (e.g., Mac Nalley et al. 2004).
Data Analysis
Vegetation variables generated will include composition, cover, richness, vertical structure, and horizontal
spacing. Tree data includes: species, trees ha-1, basal area ha-1, height to live crown base, canopy cover, crown bulk
density. Fuel load parameters include: fuel depth, litter and duff load, 1-hour, 10-hour, 100-hour, 1000-hour sound
and rotten timelag fuel loads, and total fuel load. These parameters provide data necessary to quantify the long-term
effectiveness in maintaining wildfire hazard reduction and for evaluating the short and long-term effects of
treatments on plant species diversity and ecosystem function.
For each time step (pre and post), fire behavior will be modeled under three fire weather conditions using
Fire Family Plus and Fuels Management Analyst (FMA). Analysis of variance (ANOVA) will be used to determine
if significant differences (p < 0.05) existed in variables for vegetation, fuel loads, fire behavior (rate of spread, fire
line intensity, flame length, torching index, crowning index), and fire effects (predicted tree mortality) for each
treatment type and after each treatment stage. If significant differences are detected, a Tukey-Kramer HSD test will
be performed to determine if there were significant differences between treatments. Parameters that have the
greatest influence on model outputs in the basin will be identified to inform future monitoring investments.
Vegetation composition and structure, along with soil moisture and primary environmental gradients (e.g.,
slope, aspect) will be analyzed relative to treatment variables the degree to which treatments help or hinder various
forest restoration objectives. Pre and post-treatment canopy closure and solar radiation above each sample point will
be estimated using digital photographs taken with a 180 degree fisheye lens. Black and white images will be taken
at dawn or dusk during cloudless sky conditions and analyzed using Gap Light Analyzer 2.0 software. TDR
measurements of soil moisture will use a Sierra-specific calibration (F3,146=2563.2, p<0.0001, R2=0.98) between
electric pulse velocity and soil moisture from similar soils at the Teakettle Experimental Forest (Zald et al. in
review): H2O = 10.8049 – (18.7982*1/V) + 10.2857*(1/V)2 – 1.0168*(1/V)3, where H2O=Volumetric soil moisture
(%), and V=TDR measured velocity of the electric pulse (mm/ns). Changes in soil moisture through time and
between treatments will be analyzed with repeated measures ANOVA.
Small mammal parameters will include species composition, richness, abundance, and turnover for all
species detected. Bird parameters will include composition, richness, and abundance across all species and
ecological groups. Bird and small mammal species that serve as primary prey for top carnivores of concern will be
analyzed individually and as a group to determine their response to treatments. Invertebrate sampling will result in a
description of species composition, species richness (number of species), and abundance (number of individuals) of
all ants, ant functional groups, and functional groupings across all well-sampled invertebrates.
Pre- and post-treatment conditions will be characterized for all response variables using simple descriptive
statistics. The identity of treatment clusters will be retained in all analyses of changes in conditions resulting from
treatment. Repeated measures analysis of variance will be used to compare pre and post treatment conditions. As
with analysis of fire behavior, if significant differences are detected, a Tukey-Kramer HSD test will be performed to
determine if there were significant differences between treatments. A logistic regression will be used to relate all
selected microhabitat variables to the occurrence of key old-forest associated species, such as northern flying
squirrels. For each significant parameter in the logistic regression model, we will calculate the odds ratios and their
confidence intervals based on Quasi-Newton estimation.
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We will use Akaike’s Information Criterion (AIC) to develop models of the association between sampled
species and forest conditions at each capture site. Models will be used to test influential factors associated with
various measures of diversity following fuel treatments. We will use a corrected AIC (AICc) for model selection,
since sample sizes may be small relative to the number of model parameters (Burnham and Anderson 2002). Once a
suitable model is selected, we will use logistic regression to relate all selected habitat variables to the occurrence of
each species (e.g., Meyer et al. 2007). For each significant parameter in the logistic regression model, we will
calculate the odds ratios and their confidence intervals based on Quasi-Newton estimation. Comparisons of
predictions based on the California Wildlife Habitat Relationships (CWHR) will also be generated and compared to
observed to quantify the accuracy and precision of CWHR predictions for fuel treatment effects analysis. We will
determine the potential impacts on species of special concern by assessing effects on habitat conditions based on
pre-existing habitat models. We will also conduct an analysis of the proposed P7 terrestrial indicators to determine
their response to the different fuel treatments.
f. Relationship of research to previous research, monitoring, and management
This research study is builds on the primary work on historical forest structure, biodiversity, forest
management, and landscape management, much of which has been conducted by the members of our research team.
As previously mentioned, Dr. North and colleagues have written a scientific paper that outlines the ecological perils
of standard fuels reduction treatments in the Sierra Nevada, and how to design prescriptions that avoid these perils
while still reducing the risk of catastrophic wildfire (North et al. 2008). This scientific paper has received extensive
scientific review, and serves as the foundation for our conceptual model for understanding the potential effects of
the different treatments biological diversity in the Restoration prescription that will be developed for this study. The
work of Dr. Alan Taylor (Taylor 2004) provides an invaluable piece of the foundation for the parameters of the
Restoration emphasis prescription, along with the findings of Manley et al. (2006) in their study of biodiversity in
urban forests, and forest ecology work conducted elsewhere in the Sierra Nevada (e.g., North et al. 2005). Dr.
Manley and Dr. Murphy are currently collaborating with colleagues to complete pre- and post-treatment sampling
on fuels treatment sites on the west and east shores of the basin (Murphy et al. 2008), the results of which informed
our experimental design, and validated key measures and associated sampling effort to used in this project. Dr.
North also is currently investigating fire frequency in riparian areas as a foundation for informing target forest
structure in riparian forest ecosystems based on their structure under a natural disturbance regime. This work will
help us interpret how clustered overstory trees and log piles (common in riparian forests) may influence riparian
wildlife communities. Finally, Dr. North is collaborating with Dr. Matt Hurteau to examine how different tree
species growing in solitary or grouped distributions may respond to changing climate conditions.
g. Strategy for engaging managers
Research team members have worked in the basin for over 10 years, and have established working
relationships with personnel in all Basin agencies. A close collaboration already exists between the science team
and the agencies involved in forest management in the basin. We understand the constraints under which agency
personnel must work to accomplish the important work of reducing the risk of wildfire in the basin, including
compliance with National Forest Management Act, National Environmental Policy Act, California Environmental
Quality Act, Nevada State Land environmental policies, and internal agency fiscal policy and prudence. We will
work directly with managers to design and implement this research study in a manner that is compatible with these
constraints yet yields valuable new information that would not other wise be generated to help managers meet the
complexity of forest management objectives. Specifically, we will engage foresters from multiple agencies in the
design of the Restoration treatment and rely on them to identify where and when treatments can be implemented on
the ground in accordance with environmental documents and procedures. Once the final design is in place, we will
continue to work in close contact with planners and formally call or meet twice per year with agency staff to ensure
that the research remains viable and on track. The research team will also provide presentations as requested to
individual agencies or multi-agency groups on the design, progress, and preliminary findings of the study as it
progresses. Important information exchanged at these meetings will include the type and location of treatments,
details of data collection, early results and their implications for the study and for management applications, and
steps the research team can take to improve and speed the application of results to management.
h. Description of deliverables
8
Deliverables will be in the form of quarterly reports tracking progress in the primary project activities,
interim reports that provide details on data collected and a summary of preliminary findings, a final report, a
minimum of three peer-reviewed publications, and multiple presentations at local and regional agency, public, and
scientific forums, including at least one national scientific meeting. In addition, we will develop a web page that
describes all aspects of the project, including pre- and post-treatment photos of sample sites and species being
detected during surveys.
Papers in peer-reviewed scientific journals: 1) Response of understory vegetation and ground-dwelling
invertebrates to fuel treatments designed to mimic historical forest structure; 2) Biological diversity and
estimated fire behavior responses to fuel treatments designed to mimic historical forest structure: can we
have it all?; 3) Effects of fuel reduction treatments on old-forest associated species: options for retaining
and restoring habitat value
Symposia, conference, workshop presentations: Lake Tahoe Science Symposium, Society for Conservation
Biology national meeting, Society of American Foresters national meeting, Local and regional forest
management and fire conferences
Progress and completion reports and presentations: Quarterly, annual progress, and final completion reports;
and annual presentations to staff and leadership at the primary agencies involved in forest management
(e.g., NDSL Nevada Tahoe Resource Team, US Forest Service LTBMU, California Tahoe Conservancy,
California State Parks)
Website: Information on the study background, objectives, study area, methods, results, conclusions, and
photos available on PSW-supported public web site for the project
III. Schedule of major milestones/deliverables
We expect the results of the study can directly inform the design and implementation of fuel treatments to
meet multiple ecological objectives, including forest restoration, wildlife conservation, and fire safety in the Lake
Tahoe basin. The specific parameters of the Restoration emphasis prescription can be developed soon after funding
is available. Assuming that funding arrives too late to begin data collection in 2009, the 2009 field season will be
used to collaborate with managers and select sites for sampling starting in 2010. Deliverables will be in the form of
the prescription, quarterly reports tracking progress in field data collection activities, annual reports, annual
meetings and presentations within the basin and at regional and national professional meetings. Written products
include a final report in 2011comparing pre- and post-treatment conditions of sites relative to treatments and at least
two peer-reviewed publications.
9
Milestone/Deliverables
Submit quarterly
progress reports
2009
Funding received
Start
Date
End
Date
1-Apr
Site selection
1-Jun
30-Aug
Site descriptions
1-Sep
1-Dec
1-May
15-Sep
1-Oct
15-Dec
15-Jan
15-Mar
15-Mar
1-May
1-May
15-Sep
1-Oct
15-Dec
15-Jan
15-Mar
15-Mar
1-May
1-May
15-Sep
Data entry and analysis
1-Oct
15-Dec
2013
Continue data analysis
15-Jan
15-May
15-May
15-Jul
15-May
15-Jul
15-Jul
15-Sep
2010
Field data collection
Data entry and analysis
2011
Prepare interim report
of findings
Present findings
Field data collection
Data entry and analysis
2012
Prepare interim report
of findings
Present findings
Field data collection
Present and discuss
findings
Prepare final report of
findings
Submit manuscript to
peer reviewed journal
Description
Submit brief progress report to Tahoe Science Program coordinator by the
1st of July, October, January, and April.
If funding is received in early April, then it may be possible to begin data
collection in 2009. If so, we will attempt to move the entire schedule for the
project up one year to start data collection in 2009. It is most likely,
however, that funding will arrive too late to accomplish the agency
coordination necessary to select sites and treatments prior to the need to start
data collection June 1.
Work with CTC, USFS, NDF, and CASP select sample sites, including
which treatments will be conducted at what sites.
Build a site database and populate it with relevant ecological information
available about each site available from remotely sensed data
Hire field crews and collect all pre-treatment field data as described in
methods (vegetation data at grid sites collected by USFS/UMT during the
same time period)
Enter all field data into project database and conduct simple summaries of
site characteristics.
Compile a summary of the results in a brief report intended to inform
management agencies
Offer to present progress and results to date to interested parties and local
symposium opportunities
Hire field crews and collect all 1st year post-treatment field data as
described in methods (vegetation data at grid sites collected by USFS/UMT
during the same time period)
Enter all field data into project database and conduct simple summaries of
observed changes resulting from treatments and control site variability.
Compile a summary of the results in a brief report intended to inform
management agencies
Offer to present progress and results to date to interested parties and local
symposium opportunities
Hire field crews and collect all 2nd year post-treatment field data as
described in methods (vegetation data at grid sites collected by USFS/UMT
during the same time period)
Enter all field data into project database and conduct simple summaries of
observed changes resulting from treatments and control site variability.
Conduct final analysis of relationships between burn intensity, treatment,
and biodiversity responses
Offer to present research results to interested parties and local symposium
opportunities
Final report with all results will be provided and made available to all
interested parties.
Prepare and submit manuscripts for publication
10
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11
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diversity within regional assemblages of birds and butterflies. J. Biogeography 31(6):917-929.
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California’s southern Sierra Nevada. Canadian Journal of Botany 83:1015-1020.
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thinned forest stands of the Sierra Nevada. American Midland Naturalist 157:202-211.
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abundance and consumption by Neotamias speciosus in the Sierra Nevada of California. Can. J. For. Res.
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pattern of old-growth western hemlock/Douglas-fir and mixed-conifer forest. Forest Science 50: 299-311.
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Sierran mixed-conifer understory communities. Plant Ecol. 177: 13-24.
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Southern Sierra Nevada, California. Forest Science 51(3): 266-275.
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treatments in a Sierran Mixed Conifer forest. Forest Ecology and Management.
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V. Figures
Figure 1. Proposed locations for fuels reduction treatments in the Lake Tahoe basin from the Tahoe MultiJurisdictional Fuel Reduction and Wildfire Prevention Strategy (Dec 2007).
14