Monitoring Plan for Vegetation Responses to 

Elk Management in Rocky Mountain National Park

By Linda C. Zeigenfuss, Therese Johnson, and Zachary Wiebe

Open-File Report 2011–1013

U.S. Department of the Interior

U.S. Geological Survey
ii

U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia 2011

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Suggested citation:

Zeigenfuss, L., Johnson, T., and Wiebe, Z., 2011, Monitoring plan for vegetation responses 

to elk management in Rocky Mountain National Park: U.S. Geological Survey Open-File Report 

2011–1013, 94 p., http://pubs.usgs.gov/of/2011/1013/.

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Contents 

Abstract .............................................................................................................................................................. 1

Introduction......................................................................................................................................................... 3

Methods.............................................................................................................................................................. 5

Selection of Monitoring Variables and Determination of Thresholds............................................................... 8

Design of Sampling Structure and Site Selection.......................................................................................... 10

Design of Monitoring Methods ...................................................................................................................... 12

Temporal Sampling Design........................................................................................................................... 15

Establishment of Monitoring Sites and Collection of Baseline Data .............................................................. 17

Baseline Condition............................................................................................................................................ 23

Aspen............................................................................................................................................................ 23

Willow ........................................................................................................................................................... 28

Upland .......................................................................................................................................................... 30

Retrospective Sample Size Tests ................................................................................................................. 30

Implementation of Monitoring ........................................................................................................................... 32

Monitoring of Existing Sites........................................................................................................................... 32

Data Summarization and Analysis ................................................................................................................ 34

Establishment of New Sites .......................................................................................................................... 36

Cost and Labor Considerations..................................................................................................................... 36

Material and Equipment Costs .................................................................................................................. 36

Labor Costs............................................................................................................................................... 37

Conclusion........................................................................................................................................................ 38

Acknowledgments ............................................................................................................................................ 38

References Cited.............................................................................................................................................. 39

Appendix 1: Rocky Mountain National Park Elk-Vegetation Monitoring Program Aspen Monitoring 

Protocol ............................................................................................................................................................ 41

Appendix 2: Rocky Mountain National Park Elk-Vegetation Monitoring Program Willow Monitoring 

Protocol ............................................................................................................................................................ 49

Appendix 3: Rocky Mountain National Park Elk-Vegetation Monitoring Program Upland Herbaceous Site 

Monitoring Protocol........................................................................................................................................... 66

Appendix 4: Rocky Mountain National Park Elk-Vegetation Monitoring Program Aspen Monitoring SiteEstablishment Protocol..................................................................................................................................... 77

Appendix 5: Rocky Mountain National Park Elk-Vegetation Monitoring Program Willow Monitoring SiteEstablishment Protocol..................................................................................................................................... 80

Appendix 6: Rocky Mountain National Park Elk-Vegetation Monitoring Program Upland Herbaceous SiteEstablishment Protocol..................................................................................................................................... 83

iii 

Appendix 7: Rocky Mountain National Park Elk-Vegetation Monitoring Program Willow Monitoring 

Offtake Calculation Protocol ............................................................................................................................. 86 
Figures

1. Map of the primary elk winter-range and core elk winter-range in Rocky Mountain National 

 Park, Colo.............................................................................................................................................6

2. Map of aspen, willow, and upland vegetation communities from which monitoring sites were 

 selected on elk winter-range in Rocky Mountain National Park, Colo..................................................7

3. An example of how random points were grouped into spatial “neighborhoods” for random 

 assignment to temporal sampling panels............................................................................................17

4. Locations of aspen-monitoring sites on elk winter-range in Rocky Mountain National Park, 

 Colo.....................................................................................................................................................19

5. Locations of willow-monitoring sites on elk winter-range in Rocky Mountain National Park, 

 Colo.....................................................................................................................................................20

6. Locations of upland vegetation monitoring sites on elk winter-range in Rocky Mountain 

 National Park, Colo.............................................................................................................................21

7. Examples of differing levels of aspen suckering and regeneration on elk winter-range of 

 Rocky Mountain National Park, Colo..................................................................................................24

8. Distribution of stems per acre in various aspen dbh classes on (a) core winter-range, 

 (b) non-core winter-range, and (c) Kawuneechee Valley monitoring sites in Rocky Mountain 

 National Park, Colo............................................................................................................................26

9. Distribution of stems among dbh classes from small, medium, and large stems in (a) core 

 winter-range, (b) non-core winter-range, and (c) Kawuneechee Valley aspen monitoring 

 sites in Rocky Mountain National Park, Colo.....................................................................................27

10. Degree of bark scarring on aspen trees on the elk winter-range of Rocky Mountain National 

 Park that was categorized as light, moderate, or heavy....................................................................28

11. Percentage of annual winter offtake (consumption) of herbaceous plants on upland sites on 

 the elk winter-range of Rocky Mountain National Park, Colo., 2007–2008.......................................31

12. Three alternative grazing-cage designs that might be used in Rocky Mountain National Park 

 monitoring program...........................................................................................................................37

Appendix Figures

1.1. Diagram of aspen-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

 monitoring program...........................................................................................................................41

2.1. Diagram of willow-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

 monitoring program...........................................................................................................................49

2.2. Diagram of layout of line-intercept plot used in the Rocky Mountain National Park elk-vegetation

 monitoring program...........................................................................................................................53

2.3. Diagram illustrating shoot-sampling protocol for a stem....................................................................55

3.1. Schematic of upland-vegetation-monitoring plot design....................................................................66

3.2. Schematic diagram of line-intercept method to measure upland shrub cover...................................69

4.1. Diagram of aspen-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

 monitoring program...........................................................................................................................79

5.1. Diagram of willow-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

 monitoring program...........................................................................................................................82

6.1. Photo of grazing cage design currently being used in elk-vegetation monitoring program...............84

iv
 Tables

 1. Vegetation types and their desired future conditions, indicator variables, and thresholds to be 

 used in implementing the Rocky Mountain National Park elk-vegetation monitoring plan...................9

 2. Sample design of elk-vegetation management monitoring program at Rocky Mountain 

 National Park, Colo.............................................................................................................................11

 3. Estimates of needed sample sizes to achieve powers of 0.9 and 0.95 to detect changes similar 

 to those observed in studies of willow growth in Rocky Mountain National Park 1994–1998............12

 4. Cost estimates to identify willow cover on the primary winter-range using remotely-sensed 

 imagery..............................................................................................................................................13

 5. Example of split–panel, serially alternating design used for sampling offtake in this monitoring 

 program..............................................................................................................................................16

 6. Matrix of suckering and regeneration observed on aspen-monitoring sites on the elk 

 winter-range of Rocky Mountain National Park, Colo.......................................................................23

 7. Baseline willow consumption measurements on the elk winter-range of Rocky Mountain 

 National Park, Colo., 2008–2009.......................................................................................................29

 8. Willow cover and height measurements on the elk winter-range of Rocky Mountain 

 National Park, Colo., 2008–2009.......................................................................................................29

 9. Mean winter herbaceous offtake on various upland vegetation types on elk winter-range in 

 Rocky Mountain National Park, Colo.................................................................................................31

 10. Sample-size tests using baseline data from upland and willow-monitoring sites in Rocky 

 Mountain National Park, Colo............................................................................................................32

 11. Projected labor requirements for annual and 5-year sampling periods for the Rocky Mountain 

 National Park elk-vegetation monitoring program..............................................................................33

 12. Summary of statistical analyses to be conducted as part of the Rocky Mountain National Park 

 elk-vegetation monitoring program....................................................................................................35

Appendix Tables

 1.1. Location information for aspen sites to be monitored every 5 years (2013, 2018, 2023, 2028) 

 as part of the Rocky Mountain National Park elk-vegetation monitoring program.............................45

 2.1. Schedule for site visits to upland-monitoring sites and location of site marker along transect 

 line and declination corrected bearing of the transect line.................................................................57

 2.2. Summary of locations, willow species, and sample sizes of shoots that should be collected 

 late each summer as part of the Rocky Mountain National Park elk-vegetation monitoring 

 program..............................................................................................................................................60

 3.1. Schedule for site visits to upland-monitoring sites and location of site marker along transect 

 line and declination-corrected bearing of the transect line.................................................................72

 3.2. Random-number table.......................................................................................................................74

 7-1. Example data for estimating stem-level browse offtake....................................................................88

v
Monitoring Plan for Vegetation Responses to 

Elk Management in Rocky Mountain National Park 

By Linda C. Zeigenfuss, Therese Johnson, and Zachary Wiebe 

Abstract 

Rocky Mountain National Park (RMNP) in north-central Colorado supports numerous 

species of wildlife, including several large ungulate species among which Rocky Mountain elk 

(Cervus elaphus) are the most abundant. Elk are native to RMNP but were extirpated from the 

area by the late 1800s. They were reintroduced to the area in 1913–1914, and the elk population 

in the park grew to the point that park staff actively managed the herd from 1944 until 1968. In 

1969, the active control of elk numbers was discontinued and replaced by natural regulation, and 

since then the herd has increased from approximately 500–600 animals to a high point ranging 

from 2,800 to 3,500 between 1997 and 2001. During this same period, there was an increase in 

the human population in the Estes Valley outside the park, which also provides elk range. 

In recent years, there has been growing concern over the condition of vegetation in the 

park and conflicts between elk and humans, both inside and outside the park. In response to these 

concerns, RMNP developed an Elk and Vegetation Management Plan/Environmental Impact 

Statement (EVMP/EIS) to evaluate the effects of a range of alternatives for managing elk and 

vegetation in the park. The purpose of the EVMP/EIS is to guide management actions in the park 

over a 20–yr (year) time period to reduce the impacts of elk on vegetation and restore, to the 

extent possible, the natural range of variability in the elk population and affected plant and 

animal communities. 

The EVMP outlines the desired future condition for three vegetation communities of 

concern where the majority of elk herbivory impacts are being observed: aspen, montane riparian 

willow, and upland herbaceous communities. Implementation of the EVMP aims to manage elk 

and vegetation on RMNP elk winter-range such that significant progress toward reaching these 

desired future conditions occurs over the 20-yr life of the plan. The management alternative that 

was selected relies on a variety of conservation tools including fencing, non-lethal redistribution 

of elk, use of various vegetation-restoration techniques, and lethal reduction of elk (culling). 

The EVMP incorporates the principle of adaptive management to assess the effectiveness 

of management actions. Use of adaptive management in the EVMP means that RMNP managers 

will adjust management actions as needed to successfully achieve the EVMP’s objectives. 

Determination of whether vegetation objectives are being achieved requires monitoring and 

evaluation of target vegetation communities. The objective of the work described in the current 

report was the design and implementation of a vegetation-monitoring program to help RMNP 

managers assess the effectiveness of their management actions and determine when and where to 

alter actions to achieve the EVMP’s vegetation objectives. This monitoring plan details the 

process of selecting variables to be monitored, overall sampling design and structure, site 

selection, data collection methods, and statistical analyses to be used to conduct this monitoring 
2 

program in conjunction with the EVMP. We report the baseline conditions observed at the time 

of establishment of monitoring sites. We include detailed field protocols for site establishment 

and data collection, as well as timetables for sampling so that RMNP staff will be able to 

continue monitoring the sites established during this implementation stage, and continue to add 

new sites when necessary, as the execution of the EVMP proceeds over the next 20 yrs. 
Introduction 

Rocky Mountain National Park (RMNP) encompasses nearly 108,000 ha (hectares) of 

high-elevation forest, shrublands, meadows, and alpine tundra and rocklands in north-central 

Colorado. The park supports numerous species of wildlife, including several large ungulate 

species. The most abundant ungulate species in the park is Rocky Mountain elk (Cervus 

elaphus). Elk are native to RMNP but were extirpated from the area by the late 1800s. They were 

reintroduced to the area in 1913–1914, and the elk population in the park grew to the point that 

park staff actively managed the herd (through the removal of animals) from 1944 until 1968. The 

herd was maintained at a population of 350–800 elk during this time. In 1969, the active control 

of elk numbers was discontinued and replaced by natural regulation, and since then the herd has 

increased from approximately 500–600 animals to a high point between 1997 and 2001, with 

annual estimates ranging from 2,800 to 3,500 (U.S. Department of the Interior, 2007). During 

this same period, there was an increase in the human population in the Estes Valley outside the 

park, which also provides elk range. 

The Rocky Mountain National Park/Estes Valley elk population migrates seasonally 

between high-elevation summer ranges and low-elevation winter-range where snow is less deep 

and forage more available in winter. The primary summer range includes subalpine and alpine 

areas within the park, as well as the Kawuneeche Valley on the west side of the park. Elk use 

summer range primarily during June, July, and August. In September, the majority of the elk 

herd typically begins to migrate to low-elevation winter-range in the Estes Valley on the east 

side of the park and adjacent areas outside the park, as well as areas further east. Elk typically 

return to the summer range beginning in May. 

In recent years, there has been growing concern over the condition of vegetation in the 

park and conflicts between elk and humans, both inside and outside the park. This has led to 

multiple research studies focused on the effects of elk herbivory on the elk winter-range both 

within and outside RMNP (Stevens, 1980; Baker and others, 1997; Berry and others, 1997; 

Suzuki and others, 1999; Zeigenfuss and others, 1999; Singer and Zeigenfuss, 2002; Kaye and 

others, 2003; R. Monello, T. Johnson, and R.G. Wright, National Park Service, unpublished 

report, 2005). In response to these concerns, RMNP developed an Elk and Vegetation 

Management Plan/Environmental Impact Statement (EVMP/EIS) to evaluate the effects of a 

range of alternatives for managing elk and vegetation in the park. The purpose of the EVMP/EIS 

is to guide management actions in the park over a 20–yr (year) time period to reduce the impacts 

of elk on vegetation and restore, to the extent possible, the natural range of variability in the elk 

population and affected plant and animal communities (U.S. Department of the Interior, 2007). 

After extensive involvement of the public, as well as of other agencies and entities responsible 

for managing wildlife and habitat outside the park, the final EVMP/EIS was published in 

December 2007. A Record of Decision was issued on February 15, 2008. 

The vegetation objectives of the EVMP/EIS are to restore and/or maintain the natural 

range of variation in vegetation conditions on the elk range, to the extent possible (U.S. 

Department of the Interior, 2007). This includes: 

 preventing loss of aspen (Populus tremuloides) clones within high elk-use areas; 

 restoration and maintenance of sustainable montane riparian willow (Salix spp.) as 

indicated by: 

o increasing montane riparian willow cover within suitable willow habitat on the 

primary winter-range; 

3 
o maintaining or improving the condition of riparian and upland willow on the 

primary summer range; 

 reducing the level of elk grazing on herbaceous vegetation. 

The plan outlines the desired future condition for each of these identified vegetation 

types. The desired future condition of aspen on the primary winter-range and in the Kawunechee 

Valley is an increase in aspen regeneration such that at least 45 percent of stands develop a 

regeneration cohort within each decade. This will be reflected in a higher diversity of age classes 

so that the distribution of stem diameter at breast height (dbh) reflects many (approximately 75 

percent) small-diameter stems, some (approximately 20 percent) medium-diameter stems, and 

few (approximately 5 percent) large-diameter stems. The desired long-term future condition of 

riparian montane willow is up to 70 percent willow cover within suitable willow habitat. The 

EVMP acknowledges that this level of recovery can’t be accomplished within the 20-year 

timeframe of the plan, but calls for an annual progressive increase in willow cover on the elk 

range to at least 10 percent greater than baseline conditions over 20 years, indicating progress 

toward the desired future condition. The plan also calls for an increase in the amount of willow 

that reaches a height beyond the reach of elk browsing, with average height increasing to at least 

20 percent greater than baseline conditions over the 20-yr life of the plan. The plan seeks to 

reduce the level of elk grazing on herbaceous vegetation and identifies maintenance in the 

diversity of grazing levels as the desired future condition for upland herbaceous vegetation, so 

that not all areas are heavily grazed. 

The management alternative that was selected relies on a variety of conservation tools 

including fencing, non-lethal redistribution of elk, use of various vegetation-restoration 

techniques, and lethal reduction of elk (culling). This alternative was selected because it best 

meets the Park’s general management objectives for protecting Park resources while being 

consistent with the Park’s purpose, mission, and goals (U.S. Department of the Interior, 2008). 

The selected alternative calls for the gradual lethal reduction of elk to achieve a population size 

that is at the upper end of the population’s natural range of variation (1,600–2,100 elk, with 600–

800 wintering inside the park and 1,000–1,300 wintering outside the park). Up to 65 ha (160 

acres) of aspen on the winter-range and in the Kawuneechee Valley, up to 105 ha (260 acres) of 

willow on the winter-range, and up to 73 ha (180 acres) of willow in the Kawuneechee Valley 

will be fenced to protect vegetation and promote habitat recovery. These areas were selected 

because they include areas most extensively impacted by elk herbivory and are subject to high 

concentrations of elk. Vegetation restoration will include the use of methods such as prescribed 

burning, mechanical treatments, and planting willow. Aversive conditioning (rubber bullets, 

cracker shot) and herding will also be used to help redistribute elk as needed. 

The EVMP incorporates the principle of adaptive management to assess the effectiveness 

of management actions. Use of adaptive management in the EVMP means that RMNP managers 

will adjust management actions as needed to successfully achieve the EVMP’s objectives. 

Determination of whether vegetation objectives are being achieved requires monitoring and 

evaluation of target vegetation-communities. The park needs established monitoring locations, 

adequate sample sizes, and tested and cost-effective methods to monitor the response of key 

vegetation communities to management actions. The objective of the work described in this 

report was to design and begin implementation of a vegetation-monitoring plan to help RMNP 

managers assess the effectiveness of their management actions and determine when and where to 

alter actions to achieve the EVMP’s vegetation objectives. 

4 
Given the available funding, this monitoring plan focuses on the key vegetation types 

identified in the plan (upland herbaceous, montane willow, and aspen) on the low-elevation elk 

winter-range on the east side of the Park. An additional plan will need to be developed in order 

to monitor summer range (alpine and/or Kawunechee Valley). The methods described here 

would be appropriate for application to the Kawuneechee Valley and could be applied in similar 

fashion. During the first year of this project, we established several aspen sites in the 

Kawunechee Valley before the scope of this plan was limited, and data from those efforts are 

included here. 

Methods 

A previous monitoring plan outlined several important ecological concerns in RMNP and 

included chapters that presented basic information for monitoring aspen throughout the park and 

for monitoring montane, upland, and willow communities on the park winter-range (Stohlgren, 

2001). We based the design of our elk-vegetation management monitoring plan upon elements of 

this earlier plan. Stohlgren (2001) used data collected in prior studies of the target communities 

to develop suggested sample sizes, plot sizes, and timetables for measurement (for further detail, 

see “Design of Monitoring Methods). We took these plans a step further and fit them into a 

sample design that included the ability to analyze different elk management treatments (for 

example, fencing) and elk ranges (for example, “core” or “non-core” winter-range; see below) in 

the park. The EVMP defined the primary elk winter-range, as well as the area within the primary 

winter-range where elk concentrate during winter (Moraine Park/Beaver Meadows, Horseshoe 

Park). We refer to this area as the “core” elk winter-range. In this project, we refined the 

boundaries of the core winter-range based on further analysis of elk-distribution data (fig. 1). 

This core winter-range is determined to a great extent by available vegetation types and 

elevation. The area of the primary winter-range outside the core winter-range is referred to as 

“non-core” winter-range (fig. 1). The baseline data collected by this project define the difference 

in current conditions between core and non-core ranges. It is expected that most fencing will 

occur in core areas since this is where vegetation restoration needs are greatest. The management 

alternative that is being implemented relies to a large degree on improvement of aspen and 

willow conditions inside fences, while ensuring at a minimum that conditions do not decline 

outside fences. 

We used the Rocky Mountain National Park Vegetation Map (Salas and others, 2005) as 

our source for the locations of aspen and upland communities (fig. 2). Willow communities were 

identified based on the park vegetation map (Salas and others, 2005), willow habitat mapping in 

Moraine and Horseshoe parks done in 1999 (Peinetti and others, 2002), willow habitat mapping 

in Beaver Meadows conducted as part of this project, and maps of areas with the potential to 

support willow in Moraine and Horseshoe parks that were developed by hydrologists and 

wetland researchers (E. Gage and D. Cooper, Colorado State University, written communication, 

2006). For willow and upland types, the extent and abundance of these vegetation communities 

is greater in the core than the “non-core” winter-range (fig. 2). In the case of upland vegetation, it 

was difficult to find an adequate number of suitable non-core sample sites. Available willow 

habitat in the non-core winter-range was limited to three main areas where the majority of 

sampling sites had to be clustered. There was nearly 2.5 times the amount of aspen cover in the 

non-core winter-range compared to the core winter-range.

5 
EXPLANATION

Core elk winter range

Elk winter range

Rocky Mountain NP boundary

COLORADO

Study Area

 ́

036 1.5 KILOMETERS

024 1 MILES

Figure 1. Map of the primary elk winter-range and core elk winter-range in Rocky Mountain National 

Park, Colo. 

6 
7 

0 2 1.25 .5 5 KILOMETERS

EXPLANATION

RoadsPark elk winter rangeRocky Mountain National Park BoundaCore winter range boundaryUpland vegetation typeAspen vegetation typeWillow vegetation type

012 0.5 MILES  ́

Figure 2. Map of aspen, willow, and upland vegetation communities from which monitoring sites were selected on elk winte

Mountain National Park, Colo. The extent of vegetation types was derived from park vegetation maps (Salas and others, 

information (E. Gage, Colorado State University, written communication, 2006). The validity of vegetation types was dete
Selection of Monitoring Variables and Determination of Thresholds 

The selection of the variables to be measured by this monitoring program was determined 

to a great extent in the Elk and Vegetation Management Plan (U.S. Department of the Interior, 

2007) based on the desired future condition identified for each vegetation type (aspen, willow, 

and upland herbaceous) in the plan. The EVMP identifies specific indicators to be monitored as 

part of plan implementation and provides thresholds to be used in evaluating management 

actions and how well objectives are being met (U.S. Department of the Interior, 2007, p. 56–58). 

The indicators and thresholds presented in the EVMP were determined based on the best 

available information at the time the plan was written. We clarified and refined the indicators and 

thresholds in this monitoring plan (table 1) based on new information, as well as the evaluation 

of baseline conditions presented in this monitoring plan (see “Baseline Condition” section) in 

combination with research results from earlier studies used in developing the EVMP. The 

selected indicators are the measurable variables that will be monitored. These include variables 

that directly represent desired future conditions (aspen regeneration, willow cover and height), as 

well as variables linked to achieving those results (consumption of willow and upland 

herbaceous vegetation, referred to as offtake). Vegetation response toward desired conditions 

will be measured every five years to allow adequate response time, while consumption will be 

measured annually to provide the ability to distinguish offtake trend from interannual variation in 

this dynamic variable. 

The thresholds for aspen regeneration, willow cover, and willow height are the baseline 

conditions across the winter-range. Over the 20-yr life of the management plan, there should be a 

progressive increase in aspen regeneration, willow cover, and willow height to the desired future 

conditions (U.S. Department of the Interior, 2007), but increases will not necessarily be linear 

over time. Increases are expected to occur within fenced areas and may or may not occur in 

unfenced core areas or non-core winter-range. However, a net increase across the entire winterrange is expected to occur. Data gained from separate evaluations of conditions in fenced core, 

unfenced core, and non-core winter-range in comparison to individual baseline conditions (see 

“Baseline Condition” section) in each of those types will be important to understand changes, 

either increasing or decreasing, in each type. This understanding will also ensure that 

management actions can be altered as needed to achieve objectives across the winter-range. 

Thresholds for consumption of willow and upland herbaceous vegetation are the baseline offtake 

levels that, at a minimum, should not increase across the winter-range. Differences in offtake 

trends between non-core and unfenced core areas may indicate shifts in range use; however, no 

net increase in the weighted average across all grazed areas should be observed. Baseline data 

indicate there is diversity of grazing levels across the landscape, which will be maintained by 

limiting areas subject to very high grazing levels. 

The EVMP did not set management objectives for upland shrubs; however, a large 

proportion of the upland vegetation type is made up of shrublands. Herbaceous offtake in any of 

these areas is likely dependent upon the amount of shrub cover on the site. Changes in shrub 

cover may influence offtake rates rather than changes in elk use. Therefore, we included periodic 

measures of shrub cover along with our upland herbaceous measures. These measures will also 

be useful in helping park managers monitor changes in upland shrubs. However, any significant 

changes in upland shrub cover, heights, and species composition must be analyzed with caution 

because these shrublands are also used to a great extent by mule deer. Since reductions in elk 

populations or changes in their distribution could impact mule deer populations (positively or 

negatively), any observed declines in upland shrub cover could be attributed either to herbivory 

8 
9 

Table 1. Vegetation types and their desired future conditions, indicator variables, and thresholds to be used in implementing 

National Park elk-vegetation monitoring plan. [dbh, diameter at breast height; m, meter; cm, centimeter; yr, year] 

Vegetation category Desired future condition1 Indica tor Thresholds 

Aspen Riparian Montane Willow Upland Herbaceous 

At least 45% of aspen across the winter range 

regenerating. Distribution of stem dbh reflects many (~75%) small-diameter stems, some (~20%) medium-diameter stems, and few (~5%) large-diameter stems. 

At least 31% willow cover within suitable willow habitat across the winter range. Average willow height of at least 1.1 m. Reduction of the level of elk grazing on herbaceous vegetation and maintenance of a diversity of grazing levels across the landscape. 

Stem density by height and diameter class. 

Willow consumption Cover Structure Herbaceous consumption 

Progressive increase in aspen regeneration abovlevel of 13% (presence of stems < 2 cm dbh reatall). Progressive shift in the distribution of stem desired future condition. 

No net increase in annual willow offtake across above the baseline level of 35%. Progressive increase in willow cover across the above the baseline level of 21%. Progressive increase in willow height across thabove the baseline level of 0.9 m. No net increase in winter upland herbaceous ofwinter range above baseline levels of 47%, with 

with offtake > 70% and ≤ 10% of sites with off

1Desired future conditions for willow are specific to the 20-yr time frame of plan implementation. 
by elk or mule deer. These complicating factors were the reason the EVMP avoided setting 

management objectives for the upland shrub vegetation type. 

Design of Sampling Structure and Site Selection 

The management alternative that is being implemented relies on the improvement of 

aspen and willow conditions inside fences, while ensuring at a minimum that conditions do not 

decline outside fences. In order to monitor the effects of the full range of management actions 

being implemented, we selected a sampling design which stratifies vegetation communities into 

elk winter-range zones of fenced core winter-range, unfenced core winter-range, and non-core 

winter-range. This allows separate monitoring of vegetation responses to management actions for 

each type of range. Managers can determine whether management actions in one zone might 

have positive or negative impacts on another elk winter-range zone. For example, if removal of 

available elk forage due to the fencing of large areas of willow habitat leads to declines in willow 

cover and height and increases in browse pressure on non-core or unfenced core willow habitat, 

the sample sizes and stratification should be adequate to indicate and assess such changes. This 

will allow park managers to adapt their management strategies to address the impacts of 

management to any specific stratum. While there is the possibility that vegetation types may 

change over the time period of this plan (for example, an aspen stand might grow on an upland 

site), for the purposes of this monitoring plan, all original vegetation type designations will be 

maintained throughout the 20-yr monitoring period associated with the EVMP. 

At the outset of this study, very little pilot data were available for assessing appropriate 

sample sizes for aspen plots. Although several studies of aspen in the park have been conducted 

over the past several decades, (Olmsted, 1997; Baker and others, 1997; Kaye and others, 2003; 

Suzuki and others, 1999) either the measurement variables or sample selection (non-random 

methods) were not comparable or the raw data were not available. Stohlgren (2001) 

recommended a sample size of 10–15 plots per strata, but consultation with D. Binkley 

(Colorado State University, written comm., 2010) as to the objectives of the EVMP and the elkvegetation monitoring plan described here, led to agreement that 20 sites per strata should be 

adequate to assess the level of change indicated in the EVMP (table 2). 

The sample size for willow monitoring was based upon data from willow studies 

conducted in 1994–1998 on the core winter-range of elk in Rocky Mountain National Park 

(Singer and Zeigenfuss, 2002; Zeigenfuss and others, 2002) and from estimates derived with the 

assistance of biologists from the National Park Service Inventory and Monitoring (I&M) 

Program’s Rocky Mountain Network (W. Schweiger, National Park Service, written comm., 

2006). Estimates of necessary sample size from the I&M program were based not on data but 

rather on information from a monitoring perspective that assumes at the simplest level the use of 

design-based inference to generate measures of status that use proportions to express results (for 

example, in year y, x percent +/- a confidence interval of the park winter-range has willow above 

some established threshold of significance for a single sample interval). These initial analyses 

estimated a need for a minimum of 35 sites per vegetation type in each elk winter-range zone 

(table 2). We verified that this was an adequate number of sample sites based upon the data 

available from the studies of Zeigenfuss and others (2002) and Singer and Zeigenfuss (2002). 

Park managers requested that any analysis of sample size include options whereby 95 percent 

statistical power could be achieved, as well as a lower power (in this case 90 percent) to detect 

differences similar to those observed between fenced and unfenced areas in the earlier study. We 

used a two-sample power test which compared the means at the end of the 1994–1998 study 

10 
Table 2. Sample design of elk-vegetation management monitoring program at Rocky Mountain National 

Park, Colo. 

Vegetation 

type Variables sampled Elk winter-range zone # sites needed # sites established (2006–2009) 

Upland Winter herbaceous offtake Core winter-range 25 25 

Shrub cover 

Shrub species Non-core winter-range 25 23 

Aspen Size class density and Unfenced core winter-range 20 22 

distribution Fenced core winter-range 20 23 

Non-core winter-range 20 20 

Kawuneechee Valley 20 8 

Willow Shrub cover Unfenced core winter-range 35 35 

Shrub species Fenced core winter-range 20 22 

Willow height Non-core winter-range 35 34 

Annual offtake (only 

unfenced areas) 

Kawuneechee Valley 35 0 

between fenced and unfenced treatments for two variables, willow canopy area (we used this as 

an equivalent to willow cover) and willow average height. We performed these comparisons 

between the measured variables in the first and fourth years of the study in the fenced treatments 

as well. To estimate potential sample sizes for the variable of offtake rates, we used a one-sample 

power test since this could only be measured at unfenced sites. We investigated necessary 

sample sizes to get within plus or minus 7 percent of the observed mean (assumed to be the true 

mean) for 3 yr of offtake samples. 

The results of these tests gave a range of sample sizes depending upon the variable being 

tested and the type of comparisons being made (table 3). We found that a sample size of 35 sites 

would give a power of 95 percent in 75 percent of cases and a power of 90 percent in 87.5 

percent of cases for height and canopy area data. For offtake data, which can greatly vary each 

year, a sample size of at least 41 sites was necessary to get within 7 percent of the true mean with 

a power of 95 percent in the year which had the highest variability. However, when we averaged 

offtake over all years, we found a sample size of 33 was sufficient to determine offtake over all 

sites. Based on these results, we determined that a sample size of 35 would be more than 

adequate to measure the effectiveness of fences in reducing the effects of elk herbivory and 

increasing willow growth, as well as to measure variations in offtake levels equal to those 

observed during the earlier study. However, we had limited resources for establishing monitoring 

sites, and the park also has limited resources to monitor sites. We determined, in agreement with 

park resource managers that, since the fenced willow areas were going to be limited to 

approximately half the area of core winter-range willow habitat and since several monitoring 

sites were going to be located in each fenced area because of the large sizes of the fenced 

enclosures, we would limit the sample size in fenced core winter-range willow to 20 sites. 

We determined the sample size for upland monitoring (table 2) based upon analyses in 

the RMNP long-term monitoring plan (Stohlgren, 2001). This earlier analysis used data from two 

studies of offtake in upland habitats (Stevens, 1980; Singer and Zeigenfuss, 2002) to determine 

that a sample size of 25 was adequate to predict mean values of herbaceous offtake within 20 

percent of the true mean 90 percent of the time. 

We used a stratified, random sampling design to select potential monitoring sites. Using 

ArcGIS 9.2, we selected the vegetation communities of interest and clipped them using the 

winter-range boundary. We then further separated those vegetation polygons that fell within the 

11 
Table 3. Estimates of needed sample sizes to achieve powers of 0.9 and 0.95 to detect changes similar to

those observed in studies of willow growth in Rocky Mountain National Park 1994–1998 (Singer and 

Zeigenfuss, 2002; Zeigenfuss and others, 2

Treatments Variable measured compared 

Fence vs. unfenced Canopy area 

002). 

Sample size needed to 

achieve power of 0.9 

15 

Sample size needed to 

achieve power of 0.95 

18 

Average height 9 11 

Maximum height 14 17 

Fenced yr 1 vs. yr 4 Canopy area 18 21 

Average height 29 36 

Year 1 Offtake (w/in +/-7%) 27 33 

Year 2 Offtake (w/in +/-7%) 24 29 

Year 3 Offtake (w/in +/-7%) 33 41 

Average years 1–3 Offtake (w/in +/-7%) 27 33 

core winter-range from the entire winter-range to create maps of core and non-core winter-range 

vegetation communities. 

Finally, we used maps of potential fence locations to clip fenced vegetation polygons 

from the core winter-range map. The final results were three maps each for aspen and willow 

types (non-core winter-range, fenced core winter-range, and unfenced core winter-range) and 

two maps for upland vegetation types (core and non-core winter-range). We then used either the 

random-point generators included in ArcGIS 9.2 or Hawth’s Tools (H. Beyer, 

www.spatialecology.com) to generate random points in each vegetation type and elk winterrange zone. A minimum distance of 250 m (meters) between upland sites was imposed to allow 

movement of grazing cages over a large enough area to prevent site overlap while preventing 

resampling within the same site within a short time frame. Since willow and aspen monitoring 

plots were fixed in size, no minimum distance between plots was used, but plot boundaries could 

not overlap each other. Not all sites that appeared appropriate on the map were found to be 

suitable upon site visit, in which case the site was replaced with another randomly selected site. 

Design of Monitoring Methods 

The sample methods we used in this plan were based upon many sources. Plot sizes for 

aspen plots were based upon recommendations found in Stohlgren’s (2001) Rocky Mountain 

National Park long-term monitoring plan where a plot size of 5m × 5m was determined to be 

suitable for assessing size and age class structure of pure and mixed aspen stands (Stohlgren, 

2001). A 5- to 10-yr sampling interval was recommended as adequate to detect major changes in 

these variables. The draft sampling protocols we developed for aspen monitoring were reviewed 

by D. Binkley and W. Romme of Colorado State University, who have conducted extensive 

aspen research including research in RMNP. Their review comments were incorporated into the 

final protocol. The original protocol called for aging aspen trees using increment cores taken 

from stems in each site in order to determine age of small-diameter aspen trees; however, based 

on concern expressed that excessive coring might introduce additional sources for disease entry 

and thus imperil aspen stands that are already in decline, we eliminated coring and instead used 

size classes as an indicator of age and regeneration status. We designed sampling protocols for 

aspen that measure size classes of both aspen trees and saplings, number of alive and dead 

stems, and general degree of bark damage and signs of ungulate use at each monitoring site 

(Appendix 1). 

12 
Table 4. Cost estimates to identify willow cover on the primary winter-range using remotely-sensed 

imagery. Estimates assume acquisition of imagery for 210-km2 area encompassing primary winterrange. [km2, square

Task 

Acquisition of imagery 

 kilometers] 

Type of remote imagery 

Satellite imagery Aerial photography 

$13,500 $95,000 

Processing $16,500 $53,000

Comparative analysis to previous data $20,000 $20,000 

Total $50,000 $168,000

13 

Plot sizes for willow sites were based upon subplot sizes outlined in the draft protocols 

for wetland monitoring to be used by the National Park Service Rocky Mountain Vital Signs 

Monitoring Network (D. Cooper, Colorado State University, written comm.). We determined 

that a 4m × 4m plot size would be adequate to measure willow cover and height. Willow cover 

and average heights are determined by measuring all willows on the plot (Appendix 2). Since the 

primary methods to estimate shrub cover, height, and browsing are time intensive, we also 

incorporated an additional, faster, but less accurate method to measure shrub cover, species 

composition, and height using a line-intercept method (Canfield, 1941). This method measures 

only the parts of individual plant canopies that intercept a 5.7-m transect line and determines 

percent cover as the percent of the line intercepted by shrubs instead of basing measurements on 

plot and plant canopy areas. Our intention was to introduce some flexibility and options into the 

monitoring plan such that in years when funds might not be sufficient to conduct the full suite of 

sampling, monitoring could still be conducted albeit with some sacrifice in either (1) power to 

detect trends in measured variables, (2) accuracy of measures, or (3) both accuracy and power. 

Willow-monitoring methods were reviewed by D. Cooper and E. Gage of Colorado State 

University and D. Johnston of the Colorado Division of Wildlife. All reviewers had experience 

with willow measurements and are familiar with willow conditions in RMNP. 

The methods described above will enable the park to determine changes in willow cover 

within areas that are currently considered willow habitat (fig. 2). However, they may not be as 

accurate in detecting landscape-scale changes in willow habitat, particularly if large-scale 

changes in hydrology take place, as has happened in the western end of Moraine Park over the 

last several decades. Therefore, it would be prudent for the park to use aerial imagery (either 

aerial photography or high-resolution satellite imagery) to determine changes in landscape-scale 

willow cover over the next 20 yr, revisiting the imagery ideally at 5-yr intervals, minimally at 

10-yr intervals, to determine the extent of cover loss or expansion at this broader scale. 

Collecting data on the baseline condition using this method was beyond the scope of the 

current project. Acquiring satellite imagery is significantly less expensive than using 

conventional aerial photography and the processing costs are considerably lower as well (table 

4). However, as new sources of remotely-sensed imagery become available, it may be that much 

of the cost of this method may be absorbed or shared with other projects. 

Two methods of measuring ungulate browsing on willow were incorporated into the 

willow-monitoring protocols. The “stem-scaled diameter difference method” (also called the 

DD2 method in Bilyeu and others, 2007) calculates offtake as the difference between diameter at 
bud scar and at browse point scaled by the number of shoots browsed on the entire stem 

(equation 1). 

 b   D  p  D  DD2   t  (1)    b  u   Db  Dt 

In this equation, 

b, the number of browsed shoots on the stem; 

u, the number of unbrowsed shoots; 

Dp; shoot diameter at the point of browsing; 

Dt; the average diameter of unbrowsed shoot tips; and 

Db; the diameter at the base of the shoot. 

This method of estimating browse levels was used in previous studies in RMNP, (Singer 

and Zeigenfuss, 2002) and the thresholds identified in the EVMP were based upon these 

methods. We included this method in our monitoring design to provide a less time-consuming 

alternative if needed. 

In recent years, Bilyeu and others (2007) developed a novel method for scaling browse 

estimates to account for elk preference for larger, more productive shoots. The “productionweighted diameter difference method” (DD3) recommended by Bilyeu and others (2007) 

accounts for the fact that browsers often browse more productive shoots and it estimates the 

percentage of biomass removed based upon shoot size of browsed and unbrowsed shoots 

(equation 2). 

 b B   D    p Dt  DD3    (2)    b B  u U   Db  Dt 

In this equation, 

B, average pre-browse mass of browsed shoots; and 

U, the average mass of unbrowsed shoots. 

This method requires slightly more field time, but provides greater accuracy in results. 

Bilyeu and others (2007) also recommended the use of a method called the biomass 

comparison method in areas experiencing intense herbivory. This method accounts for the 

complete consumption of shoots by browsers. However, this method is very labor intensive—it 

requires site visits in both spring and fall, marking and then remeasuring the same stems each 

sample period, and a wider group of shoot samples for building regressions to estimate biomass 

removed and the development of several regression equations for each species. We conducted 

pilot studies that indicated that elk were browsing beyond the current year’s growth and we 

therefore tried to employ the biomass comparison method to measure offtake as part of this 

monitoring program. Unfortunately, our results from this method were very poor and 

inconsistent, likely attributable to observer error in the initial sampling. However, we believe that 

even with more detailed protocols and training describing the procedure, the costs outweigh the 

benefits of using this method due to the large amounts of time related to measuring shoots in the 

fall, locating marked stems again each spring, and calculating regressions. 

As part of the EVMP, park managers will be taking measures to ensure elk migration to 

summer ranges, so summer offtake is anticipated to be minimal. The DD2 and DD3 methods 

described above estimate total annual willow offtake but are being used as analogous to winter 

offtake only, because summer offtake should be minimal under this management plan. However, 

14 
weather conditions may cause summer offtake to be substantial in some years (for example, late 

snows might keep elk on the winter range into the calving season and then for a post-parturition 

period extending into the summer, or drought may cause elk to abandon summer range earlier 

because of low forage availability). Alternatively, portions of the elk herd may alter their 

behavior over time which could lead to decreased migration to the summer range, despite 

management actions intended to encourage seasonal migration. If this occurs, park managers 

may feel the need to begin to evaluate summer offtake. This could be done using the methods 

described above, but would require at least one sampling during the later part of each summer (in 

addition to the spring measures described above) in order to determine the amount of offtake 

which occurs during the summer season. 

While there are a variety of methods for estimating herbaceous offtake, we chose the 

method that has been used in the majority of prior studies and that has also been used as the basis 

for determining the threshold levels of offtake in the EVMP (Appendix 3). This method involves 

the use of movable grazing cages to protect plants from grazers during the grazing season (in this 

case, winter) and then clipping plots protected by the grazing cage and paired plots outside the 

cage to determine percentage of offtake (Bonham, 1989). The cages are moved to a new site at 

the beginning of each sampling period to protect a new plot from grazing. No individual plot is 

protected for more than a single sampling season because long-term grazing exclusion could 

potentially lead to litter accumulation, species composition changes, and productivity changes 

inside the ungrazed plots. Such changes from long-term grazing exclusion could result in 

incorrect estimates of annual offtake. Because the grazing cages will be moved over the site over 

many years, a plot with set boundaries was not used. Instead, each site was marked in one 

location and the measured area includes roughly all area of the upland vegetation within 125 m 

of that site marker. Cages are moved within this site for each offtake sampling. Winter offtake is 

determined by comparing biomass at the end of winter inside the cage to that remaining in the 

uncaged, grazed plot using Equation 3. 

B     i B

O 100 o  w  (3)

 Bi 

Here, 

Ow, the percent of standing crop remaining at the end of the growing season that is used 

overwinter; 

Bi, the amount of biomass in caged plot at the end of winter; and 

Bo, the amount of biomass in paired uncaged plot at the end of winter. 

Upland shrub cover and height will be measured by species using the line-intercept 

method (described above) for willow on a 30 m transect through the site (Appendix 3). 

Temporal Sampling Design 

The temporal sampling design for this monitoring protocol varies across metrics and 

community type. The nature of the offtake indicators requires annual monitoring, particularly as 

offtake measures are subject to a high degree of interannual variability based upon factors such 

as weather and ungulate population size. However, the sampling of all sites each year would be 

labor intensive and costly. Therefore, we selected a split-panel, serially alternating design with 

consecutive year revisits (Urquhart and Kincaid, 1999) to allow us to account for this interannual 

variability in the monitoring of offtake in both upland herbaceous and willow communities. We 

15 
Table 5. Example of split–panel, serially alternating design used for sampling offtake in this monitoring 

program. This example shows a vegetation type and strata (for example, upland core) with a total of 25 

monitoring sites, but in any given sampling year, only 10 sites will be visited. 

Panel # Metric # sites 

(n=25) 

Sampling year 

1 2 3 4 5 6 7 8 9 10 11 12 

 Site info 

 All sites  Shrub cover 

 Shrub height 25 X X X 

 Photos 

1 Offtake 5 X X X X X X 

2 Offtake 5 X X X X 

3 Offtake 5 X X X X 

4 Offtake 5 X X X X 

5 Offtake 5 X X X X 

16 

divided our 20-yr monitoring period (2009–2028) into five panels, such that each site would be 

visited for offtake measures twice within each 5-yr period. We then divided the total number of 

sites in each vegetation type and elk winter-range zone by 5 to determine how many sites would 

be assigned to any given panel (table 5). The repeat sampling at a site in this design allows 

estimation of annual changes from a direct comparison at a sample point, while allowing more 

precise estimates of long-term trends when points are remeasured after five yr. We also 

attempted to balance the temporal aspects of this design with the spatial distribution of sites. 

Therefore, within each vegetation type and elk winter-range zone, we visually grouped the 

randomly placed sites into spatial “neighborhoods” of five sites (one for each panel), then sites 

within the “neighborhood” were randomly assigned to one of the five panels (fig. 3). The 

“neighborhood” is defined as a group of sites that are spatially close together and linked by 

topography as much as possible. For example, one neighborhood in figure 3 falls within the 

Horseshoe Park/North Deer Mountain area, while another includes Upper Beaver Meadows. In 

this way, the sampling will be balanced to take into account spatial phenomena that may affect 

only one particular area in a given year. The social nature of an ungulate that moves and feeds in 

herds (like elk) can result in large spatial heterogeneity in offtake on the landscape (with some 

locations being more heavily grazed due to number of animals concentrated in a group) in 

addition to typically occurring heterogeneity in offtake resulting from the distribution of 

desirable forage species. 

Measures of willow cover and structure, upland shrub cover, and aspen stem density tend 

to change more slowly over the span of many years, so we selected a design where all sites were 

revisited on a 5-yr basis. From labor, cost, and planning perspectives, this should allow the park 

to plan for larger field crews every fifth year to sample all sites and to use the existing labor base 

to conduct annual sampling. 
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4

5

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2

 ́ 012 0.5 KILOMETERS

012 0.5 MILES

EXPLANATION

& Upland core winter range sites

Core elk winter range

Rocky Mountain NP boundary

Figure 3. An example of how random points were grouped into spatial “neighborhoods” for random 

assignment to temporal sampling panels. Each “neighborhood” has one point in each of the five panels. 

A panel consists of all the points measured within a year. 

Establishment of Monitoring Sites and Collection of Baseline Data 

Establishment of 210 monitoring sites began in 2006 (some aspen and upland sites) and 

extended through 2009 (willow and aspen sites, table 2). Baseline data were collected from all 

sites at their establishment. Of the 210 total sites, 73 sites were aspen sites including 20 sites in 

the non-core winter-range, 22 unfenced sites in the core winter-range, 23 fenced sites in the core 

winter-range, and 8 sites in the Kawuneechee Valley (fig. 4). The majority of these sites were 

established during 2006–2008; however, some designated fenced sites were not established until 

late summer 2009 when park managers had determined which sites might potentially be fenced 

over the life of the management plan. Nine aspen fences were constructed in late summer and 

fall 2009. All baseline data at fenced sites were collected prior to, or within a month of, 

completion of aspen fences. Some of the sites had baseline data collected in fall 2009 (after the 

first year of elk-culling actions had taken place) but prior to or coincident with the establishment 

of aspen fences. 

During the establishment of aspen sites, we measured general site characteristics, aspen 

suckering and regeneration (live and dead), aspen tree size and density (live and dead), degree of 

17 
bark scarring, and we also photographed each site. Suckering in aspen sites was defined as smalldiameter (less than 2 cm (centimeters) dbh) stems less than 1.5 m in height. Regeneration (those 

stems likely to grow into the tree canopy) was defined as small-diameter (less than 2 cm dbh) 

stems 1.5 m to 2.5 m in height. Stems greater than 2.5 m are generally beyond the height of elk 

browsing and were considered to have successfully recruited into the canopy. Bark scarring was 

categorized by the amount of the trunk surface less than 2.5 m in height that was scarred by 

ungulate browsing on the majority of trees in a site. 

A total of 91 willow sites were established in 2008 and 2009 (fig. 5). There was a dearth 

of suitable sites in the non-core for the willow vegetation type and this resulted in the 

establishment of one less willow non-core site than planned. Shrub cover and height, shrub 

species composition, winter offtake, and plot photos were collected during baseline-data 

collection in willow sites. Most willow sites were established in 2008 (77 sites) and had baseline 

cover and height data collected at time of establishment. Forty-seven of these sites had baseline 

offtake data collected at the end of winter 2008–2009, which was the first year of elk culling, and 

also after the establishment of 28 ha (70 acres) of fenced willow habitat in three locations on the 

core winter-range during fall 2008. The remaining 30 sites either fell within fenced areas and had 

little or no offtake during this winter, had no willow within the plot to measure offtake in the 

baseline year, or in a few cases, were not collected due to difficulties locating sites or meeting 

time and labor constraints (these sites were scheduled for measurement in 2009–2010). The 

minimal level of culling in winter 2008–2009 likely had little effect on elk-distribution patterns; 

however, it is possible that establishment of the elk fences may have increased willow offtake in 

non-fenced core winter-range. 

Sites selected for the “fenced” strata were based on initial projections of locations to be 

fenced in plan implementation. In 2009, after further identification of potential fence locations, 

an additional 14 monitoring sites were established (including two additional sites to provide for 

changes in projected fence locations). Some fence locations have not been confirmed, and it is 

uncertain when fencing will be completed, as it depends on funding availability and other 

factors. Therefore, the actual status of these sites will need to be accounted for during data 

analysis. At the time fences are established, park managers should resurvey baseline condition 

prior to fencing if more than 3 yr have passed since the establishment of these sites. These sites 

are included, however, in the count of sites needed to properly sample the fenced treatment. 

One non-core site was eliminated after it was established, due to a water table that was so 

high that the markers were underwater the majority of the year. Since the non-core willow sites 

are clustered in the four small areas on the non-core winter-range (Hidden Valley, Cow Creek, 

Glacier Creek, and Hallowell Park) and these areas are quite saturated with sites, we decided not 

to replace this site. 

A total of 48 upland sites were established, the majority of them in 2006 and 2007 (fig. 

6). There was also a dearth of suitable sites in the non-core for the upland vegetation type which 

resulted in the establishment of two less upland non-core sites than planned. One upland site was 

eliminated after it was established because of subsequent assessment of potential danger from 

rock slides. Many upland sites were inspected and rejected as unsuitable (reasons include 

improper vegetation type, proximity too near sites already selected for monitoring, and location 

within developed areas) in the non-core winter-range and we eventually selected only 22 noncore upland sites. Baseline data collected at the time of establishment included: site 

characteristics; shrub cover, height, and species composition; herbaceous offtake; and site 

photos.

18 
BEAVER BROOK

FALL RIVER

COW CREEK

BLACK CANYON CREEK

GLACIER CREEK

0 2 1.25 .5 5 KILOME

EXPLANATIONAspen monitoring sites

Core winter range, unfeCore winter range, fencNon-core winter range, StreamsRocky Mountain NP bouElk winter rangeCore elk winter range

Roads

Core winter range, pote

012 0.5 MILES 

Figure 4. Locations of aspen-monitoring sites on elk winter-range in Rocky Mountain National Park, Colo. Sites (yellow on 

as part of the “fenced” strata in locations identified to potentially be fenced based on the best available information as of 

19 
BEAVER BROOK

COW CREEK

FALL RIVER BLACK CANYON CREEK

GLACIER CREEK 0 2 1.25 .5 5 KILOMETERS

Rocky Mountain NP boundaryElk winter rangeCore elk winter rangeStreams

Roads

EXPLANATION

Willow Monitoring Sites

Willow core, unfencedWillow core, fencedWillow non-core, unfencedWillow core, potential fence

012 0.5 MILES 

Figure 5. Locations of willow-monitoring sites on elk winter-range in Rocky Mountain National Park, Colo. Sites (yellow on 

as part of the “fenced” strata in locations identified to potentially be fenced based on the best available information as of 

20 
BEAVER BROOK

COW CREEK

FALL RIVER BLACK CANYON CREEK

GLACIER CREEK

0 2 1.25 .5 5 KILOMETE

EXPLANATIONUpland monitoring sites

Upland core winter rangUpland non-core winter RoadsStreamsElk winter rangeCore elk winter rangeRocky Mountain NP bou

012 0.5 MILES

Figure 6. Locations of upland vegetation monitoring sites on elk winter-range in Rocky Mountain National Park, Colo. 

21 
Data were summarized before analysis. Aspen data were tallied by plot for each category 

(suckers/regeneration; small-, medium-, large-diameter stems) and then analyzed by core and 

non-core winter-range sites. Fenced sites were analyzed as part of the core winter-range because 

fence effects should not have been evident at the time of baseline-data collection, but we did 

look at these sites separately to see if they reflected baseline conditions similar to unfenced core 

sites. The percent of winter-range zones that showed aspen regeneration were determined by 

calculating the percent of measured plots in each winter-range zone that showed regeneration 

(stems less than 2 cm dbh, 1.5–2.5 m tall). Estimates of regeneration for non-core and core 

winter-range were weighted by the proportion of total aspen winter-range in each zone (non-core 

= 72.8 percent, core = 27.2 percent) and then averaged to determine regeneration rates for the 

entire winter-range. 

Willow shrub cover was calculated, using the line-intercept method, by totaling the entire 

length (in meters) of the transect line that was intercepted by willow for the site and then 

dividing by 5.7 m (the length of the transect line) and multiplying by 100 to get a percent cover 

value. Willow shrub cover was derived, using the macroplot method, by calculating the canopy 

area of each individual willow that intersected the macroplot (canopy diameter measures were 

converted to area measures using the elliptical area formula), then multiplying by the proportion 

of the willow plant that fell within the macroplot. Individual canopy areas were then totaled for 

the plot and divided by the macroplot area (16 m2

) and multiplied by 100 to derive percent 

willow cover estimate for the site. Average willow heights were determined for each site, using 

the macroplot method, by averaging all height measures of willows that fell within the plot and, 

using the line intercept method, by averaging height measures of all willows that intercepted the 

transect line. Willow offtake was calculated using equations 1 and 2 for each measured stem and 

was then averaged to determine offtake values for each site. Core and non-core site offtake, 

cover, and height values were then averaged to get offtake values for each elk winter-range zone. 

Fenced sites were analyzed as part of the core winter-range because fence effects should not 

have been evident at the time of baseline data collection, but we did look at these sites separately 

to see if they reflected similar baseline conditions as unfenced core sites. Estimates of offtake, 

cover, and height for non-core and core winter-range were weighted by the proportion of total 

willow winter-range area in each zone (non-core = 12.8 percent, core = 87.2 percent) and then 

averaged to determine offtake for the entire winter-range. 

Upland herbaceous offtake was derived by calculating offtake for each individual cage 

pair using equation 3. Then all three offtake measures collected at each site were averaged to 

derive the offtake for the site. Negative offtake values (greater standing crop outside the cage 

than inside) were only removed if the value was greater than -100 percent, to avoid inflating 

offtake data or creating a skewed data set by rounding these values to zero. Site-level upland 

herbaceous offtake, shrub cover, and height data were then averaged to get values for each elk 

winter-range zone. Estimates of offtake, cover, and height for non-core and core winter-range 

were weighted by the proportion of total upland winter-range in each zone (non-core = 42.2 

percent, core = 57.8 percent) and then averaged to determine offtake for the entire winter-range. 

Tests for differences between core and non-core winter-range were determined using 

non-parametric and general linear models as appropriate. All statistical analyses were performed 

using SAS v. 9.1 statistical analysis software (SAS Institute, 2003). 

22 
Table 6. Matrix of suckering and regeneration observed on aspen-monitoring sites on the elk winter-range 

of Rocky Mountain National Park, Colo. Designation of poor, moderate, and high levels is based on 

patterns observed in the data. Data gathered 2006–2009. Some sites had baseline data collected in fall 

2009, after the first year of elk-culling actions. 

Suckering (total stems < 1.5 m in 

height) 

Regeneration (stems 1.5 to 2.5 m in height) 

Poor (0 Moderate (< 324 High (≥ 324 

stems/acre) stems/acre) stems/acre) 

Core winter-range 

sites 

 

Non-core winterrange sites 

 

Kawuneechee 

Valley 

Poor (0–1,700 stems/acre) 

Moderate (1,700–4,500) 

High (> 4,500 stems/acre) 

Poor (0–1,700 stems/acre) 

Moderate (1,700–4,500) 

High (> 4,500 stems/acre) 

Poor (0–1,700 stems/acre) 

Moderate (1,700–4,500) 

High (> 4,500 stems/acre) 

15 

13 

14 

13 

3 

1 

4 

4 

0 

1 

1 

1 

0 

0 

2 

0 

0 

0 

0 

0 

0 

0 

0 

1 

0 

0 

0 

23 

Baseline Condition 

Aspen 

We found that only two aspen-monitoring sites in the core winter-range and one site in 

the non-core winter-range had no suckering (stems less than 1.5 m tall, approximate dbh 0–2 cm) 

within the monitoring plots. However, only approximately 7 percent of the core winter-range had 

any stems that would indicate successful regeneration (stems 1.5–2.5 m tall and less than 2 cm 

dbh), and none of the stems observed on the core winter-range exceeded 2.0 m in height. The 

non-core winter-range had slightly better regeneration with 15 percent of the winter range having 

stems less than 2 cm dbh and 1.5–2.5 m tall. Average aspen regeneration on the entire winterrange (weighted for the area of aspen stands in core and non-core winter-range) was 

approximately 12.8 percent plus or minus 3.6 percent. Based on the patterns observed in the data, 

we created a matrix to display the number of sites showing poor, moderate, and high suckering 

and regeneration (table 6, fig. 7). While several sites on the winter range showed moderate or 

high suckering, very few of these also showed moderate or high regeneration. No differences 

were found in height or stem counts between core winter-range areas that were planned to be 

fenced and those not fenced. 

In the Kawuneechee Valley, half of the established monitoring sites had poor suckering 

and half had moderate suckering. There was no evidence of successful stand regeneration 

occurring in the eight Kawuneechee Valley stands at the time of monitoring-site establishment in 

2007. 
Figure 7. Examples of differing levels of aspen suckering (all stems < 2.5 m in height) and regeneration (stems 1.5–2.5 m h

range of Rocky Mountain National Park, Colo. 

24 
25 

Distribution of stem size tends toward having the majority of stems in the larger size 

classes (greater than 15 cm dbh). However, the distribution is fairly even in these larger size 

classes (fig. 8) and is consistent with the findings of Binkley (2008) which indicated a lack of 

recruitment of young trees over the past 2–3 decades in low-elevation stands on the east side of 

the park but also indicated a trend of continuous recruitment of trees in the century preceding this 

time period. The density of small-diameter trees tended to be slightly greater in the non-core 

winter-range than in the core winter-range, but much lower in the Kawuneechee Valley (fig. 8). 

We defined small-diameter size class as less than 10 cm dbh, medium diameter size class as 10–

20 cm dbh, and large-diameter size class as greater than 20 cm dbh based on patterns observed in 

the data and consultation with an aspen expert who has experience working in the park (D. 

Binkley, Colorado State University, written comm.). The structure observed in all monitoring 

sites is far from the desired future condition of 75 percent small-diameter, 20 percent mediumdiameter, and 5 percent large-diameter stems (fig. 9). 

Bark scarring is used here as an additional index to the level of browsing that has 

occurred historically in these monitoring sites. Its usefulness will be limited in determining 

decreases in browsing over the short term, but reductions in the number of scarred stems may 

begin to occur over the long term if browsing declines and aspen regeneration occurs. Bark 

scarring was heavy in the core winter-range, with 88 percent of the core winter-range having 75–

100 percent bark scarring of the trunk surface and the remaining winter-range showing scarring 

on 50–75 percent of the trunk surface (fig. 10). Bark scarring was not as heavy in the non-core 

winter-range with 50 percent of the winter-range aspen being scarred on 75–100 percent of the 

trunk surface, 40 percent scarred on 50–75 percent of the trunk surface, and 10 percent of having 

less than 50 percent of the trunk surface scarred (fig. 10). In the Kawuneechee Valley, bark 

scarring was much more variable, with only 12 percent having heavy (75–100 percent of the 

trunk surface scarred) scarring, 50 percent having moderate (50–75 percent) scarring, and 38 

percent having low levels (less than 50 percent) of bark scarring. This may be due to the fact that 

fewer elk winter in the Kawuneechee Valley, when bark browsing may be more likely to occur 

due to limited forage availability. Signs of ungulates (scat, tracks, browse, and animal 

observations) were prevalent at all sites. 
0

1,000

2,000

3,000

0 3 6 9 12 15 18 21 24 27 30 33 36

STEMS PER ACRE

(a)

(b)

(c)

0

1,000

2,000

3,000

0 3 6 9 12 15 18 21 24 27 30 33 36

0

1,000

2,000

3,000

0 3 6 9 12 15 18 21 24 27 30 33 36

DIAMETER-AT-BREAST-HEIGHT CLASS

STEMS PER ACRE STEMS PER ACRE

Figure 8. Distribution of stems (> 2 cm dbh) per acre in various aspen dbh classes on (a) core winterrange, (b) non-core winter-range, and (c) Kawuneechee Valley monitoring sites in Rocky Mountain 

National Park, Colo. Each dbh class covers a range of 2 cm and numbers on x-axis denote midpoint. 

[dbh, diameter at breast height; cm, centimeter] 

26 
0%

25%

50%

75%

100%

AC10AC29AC11AC28

AC2

AC18

AC1

AC23AC31AC37AC40

AC5

AC15AC22

AC6

PERCENT OF STEMS

(a)

(b)

(c)

0%

25%

50%

75%

100%

ANC4

ANC23

ANC5

ANC15

ANC8

ANC10ANC16

ANC6

ANC19ANC21

Target

PERCENT OF STEMS

0%

25%

50%

75%

100%

AK8AK1AK5AK2AK7AK3AK4AK6

Target

PERCENT OF STEMS

% small-diameter trees (<10 cm dbh) % medium-diameter trees (10-20 cm dbh)

% large-diameter trees (>20 cm dbh)

Desired condition Desired condition

10 sites with no

trees in plots

4 sites with no 

trees in plots

Desired condition

Core winter range

Non-core winter range

Kawuneechee Valley

INDIVIDUAL MONITORING SITE

Figure 9. Distribution of stems among dbh classes from small (2–10 cm dbh), medium (10–20 cm dbh), 

and large stems (greater than 20 cm dbh) in (a) core winter-range, (b) non-core winter-range, and (c) 

Kawuneechee Valley aspen monitoring sites in Rocky Mountain National Park, Colo. Each bar 

represents one site, and the right-end bar represents the desired condition for aspen stands in the 

park. 

27 
Figure 10. Degree of bark scarring less than 2.5 m high on aspen trees on the elk winter-range of Rocky 

Mountain National Park was categorized as light (less than 50 percent of the trunk scarred by 

browsing, left photo), moderate (50–75 percent scarred, center photo), or heavy (greater than 75 

percent scarred, right photo). 

Willow 

Baseline browse measurements were collected from 47 sites in spring 2009. Of the 58 

core willow sites, willows at 23 sites were measured in 2009, an additional 5 sites had no willow 

within the sample microplots to be measured, willows at 16 sites were behind existing fences and 

therefore elk had little or no opportunity for browsing on these willows during that winter (some 

browsing may have occurred as the fences were being constructed in fall 2008), and the 

remaining 14 sites were installed in summer 2009 and therefore the willows at these sites could 

not be measured until spring 2010. Of the 33 non-core sites, only 25 were able to be sampled in 

2009, 3 more had no willow within the sample plot, 2 were underwater and we were unable to 

relocate the corner markers, and an additional 3 were not able to be sampled. The data were 

analyzed using both DD2 and DD3 methods (Singer and others, 2002; Bilyeu and others, 2007). 

Our data indicate that elk on the RMNP winter-range do preferentially browse more productive 

shoots (P < 0.0001, unbrowsed shoot basal diameter = 2.03 plus or minus 0.03 mm [mean plus or 

minus standard error], browsed shoot basal diameter = 2.86 plus or minus 0.05 mm). Since the 

DD3 method scales the offtake by the average size of browsed shoots, and elk in our monitoring 

area prefer larger shoots, this indicates that DD3 will provide a more accurate method for 

determining offtake compared to the DD2 method. Annual offtake was slightly higher using the 

DD3 method (table 7) compared to the DD2 method. Offtake was greater in the core winterrange than the non-core winter-range (P < 0.0004). 

Percent cover of willow was estimated using both line intercept and macroplot area data. 

The two measures yielded similar results in the core winter-range willow, but willow percent 

cover estimates were approximately 7.5 percent higher using the macroplot area compared to the 

28 
Table 8. Willow cover and height measurements on the elk winter-range of Rocky Mountain National Park, 

Colo., 2008–2009. Some baseline height and cover measures were collected in summer 2009 after the 

initiation of Elk and Vegetation Management Plan elk management actions (fencing and culling). [cm, 

centimeters] 

Line-intercept measures Macroplot measures 

(mean ± standard error) (mean ± standard error) # of 

Willow Willow cover sites Height (cm) Height (cm) cover (%) (%) 

Core winter-range 18.5 ± 2.7 94.5 ± 10.5 19.3 ± 3.3 79.5 ± 7.0 57 

Non-core winter- 29.2 ± 4.8 184.4 ± 20.8 36.6 ± 5.4 165.7 ± 19.0 34 

range 

Entire winter-range 19.3 ± 2.2 102.4 ± 9.2 20.7 ± 2.7 86.6 ± 6.8 91 (weighted by area) 

29 

Table 7. Baseline willow consumption measurements on the elk winter-range of Rocky Mountain National 

Park, Colo., 2008–2009. Note: Data were collected following winter 2008–2009. Baseline offtake data 

was collected at the end of winter 2008-2009, which was the first year of elk culling, and also after the 

establishment of 28 ha (70 acres) of fenced willow habitat. 

Production-weighted diameter- Stem-scaled diameter-difference method 

difference method (DD3) (DD2) 

Annual offtake Range n Annual offtake Range n 

(%) (%) (%) (%) 

Core winter-range 

Non-core winter-range 

Entire winter-range 

(weighted by area) 

36.9 ± 3.0 

21.9 ± 3.6 

34.9 ± 2.3 

14.6–62.5 

0–57.0 

23 

24 

47 

34.4 ± 2.9 

18.0 ± 3.2 

32.3 ± 2.2 

14.0–58.3 

0–49.7 

23 

24 

47 

line-intercept data in the non-core winter-range willow sites, though this difference was not 

significant when averaged over all the winter range (P > 0.31, table 8). Willow cover ranged 

from 0 percent to over 100 percent (due to overlapping canopies). Overall, willow cover was 

nearly twice as great on the non-core winter-range compared to core winter-range (P < 0.03). 

However, on the winter range as a whole, the weighted-average willow cover is far from the 

long-term desired future condition of 70 percent cover. Only 7 of the 91 monitoring sites had 

willow cover greater than or equal to 70 percent, and most of these sites (5 of 7 sites) were 

located in the non-core winter-range. 

Willow height was also measured using both line-intercept and macroplot measures. In 

all cases, the macroplot measures yielded average height measurements that were approximately 

10–20 percent shorter than the line-intercept method, but the differences in average heights were 

not significant (P > 0.2) between methods overall. Therefore, the line-intercept method may 

overestimate average willow heights. Data analysis using just line-intercept height data should be 

carefully interpreted. Willows were nearly a meter taller on average in the non-core winter-range 

than in the core winter-range using both measurement methods. No differences were found in 

height or cover between core winter-range areas that were planned to be fenced and those not 

fenced. 
Upland 

Winter offtake levels on upland herbaceous plants averaged 52.1 percent plus or minus 

5.9 percent on core winter-range and 40.3 percent plus or minus 1.0 percent on non-core winterrange (fig. 11). The average offtake for the entire winter-range, weighted for the area of upland 

vegetation in core and non-core winter-range, was 47.1 percent. The EVMP/EIS calls for moving 

elk off the winter range during the summer, so, in 2007, we also collected baseline information 

on summer herbaceous offtake at the monitoring sites. These data indicate little difference 

overall in summer offtake between the core and non-core upland winter-range. Average standing 

crop removed in August 2007 was 17.1 percent plus or minus 3.9 percent (n = 25) in the core 

winter-range and 15.0 percent plus or minus 3.2 percent (n = 14) in non-core winter-range, 

indicating that some amount of offtake is occurring during the summer season but that it is much 

lower than the offtake during the winter season. 

Upland shrub cover averaged 11.5 percent plus or minus 2.0 percent on core winter-range 

and 18.9 percent plus or minus 3.4 percent on non-core winter-range. Based on the observed 

vegetation types, our monitoring sites were similarly distributed between upland vegetation 

categories on the core and non-core winter-range (table 9). Mean upland shrub cover was 14.8 

percent plus or minus 1.9 percent across the primary winter-range (average weighted for 

proportion of upland area in core and non-core winter-range). Graminoid-dominated sites 

(upland herbaceous montane, Ponderosa Pine (Pinus ponderosa) graminoid, and Ponderosa Pine 

rocklands) made up approximately 27 percent of all the monitoring sites, while the remaining 73 

percent consisted of shrubby sites (Ponderosa Pine shrublands, big sagebrush shrublands, 

bitterbrush shrublands, and undifferentiated shrublands). 

Herbaceous offtake in upland areas was negatively related to total shrub cover (P = 

0.007) with the highest offtake levels found in the herbaceous upland montane (mean over all 

years = 67.5 percent plus or minus 9.5 percent), and lowest in areas with high shrub cover: 

sagebrush, bitterbrush, and undifferentiated shrublands (table 9). This may have been due to a 

variety of reasons, including higher availability of digestible forage in areas with low shrub 

cover and possibly the influence of shrubs on snow cover throughout the winter. However, when 

averaged over all years, the two upland vegetation categories with the highest offtake levels 

(greater than 55 percent) were upland herbaceous montane and Ponderosa Pine rockland. 

Retrospective Sample Size Tests 

We used the baseline data to further test our sample sizes to determine if they were 

indeed large enough to detect a small degree of change at a high level of power. We tested the 

ability to detect a 5 percent and 10 percent change from our measured baseline condition with 

power of 0.9 and 0.95 (table 10). Our results indicated that our samples sizes are indeed adequate 

to measure 5 percent changes in upland herbaceous offtake, willow offtake, and willow cover 

with a high power. However, the current sample size was only able to adequately measure a 10 

percent change in willow height at such a high power. However, these tests will provide 

managers the ability to adjust samples sizes to meet their needs, if necessary. 

30 
Table 9. Mean winter herbaceous offtake on various upland vegetation types on elk winter-range in Rocky 

Mountain National Park, Colo., 2007–2008. 

Total Number of 

Upland vegetation category number of core wintersites range sites 

Number of noncore winterrange sites 

Mean 

herbaceous 

offtake 2007–

2008 

Upland herbaceous montane 7 5 2 68.0 ± 3.4 

Ponderosa Pine graminoid 5 1 4 43.2 ± 8.6 

Ponderosa Pine rocklands 1 1 0 57.5 ± 7.9 

Ponderosa Pine shrublands 24 13 11 51.0 ± 3.9 

Big sagebrush shrublands 3 2 1 16.9 ±10.8 

Bitterbrush shrublands 2 0 2 41.0 ± 14.2 

Undifferentiated shrublands 5 3 2 37.3 ± 12.4 

31 

YEAR

2007 2008

PERCENT WINTER OFFTAKE

0

10

20

30

40

50

60

70

Core winter range sites 

Non-core winter range sites 

All sites (weighted average) 

Figure 11. Percentage of annual winter offtake (consumption) of herbaceous plants on upland sites on the 

elk winter-range of Rocky Mountain National Park, Colo., 2007–2008. 
Table 10. Sample-size tests using baseline data from upland and willow-monitoring sites in Rocky Mountain 

National Park, Colo. 

Change detect

Power = 0.95 

ion = 5 percent 

Power = 0.9 

Change detecti

Power = 0.95 

on = 10 percent 

Power = 0.9 

Sample size Sample size Sample size Sample size 

Upland Herbaceous Core 18 15 7 7 

n=20 Offtake Non-core 25 21 8 7 

Height Core 

Non-core 

43 

71 

35 

58 

13 

20 

11

16 

Willow 

n=35 Cover Core 

Non-core 

8 

15 

7 

18 

4 

13 

4

7 

Offtake Core 

Non-core 

8 

9 

7 

8 

4 

5 

4

4 

Implementation of Monitoring 

Monitoring of Existing Sites 

Detailed protocols have been included to guide field staff in collecting monitoring data 

for each vegetation type (Appendices 1–3). Information on site locations and special instructions 

regarding grazing-cage placement at upland sites near cultural resources (intended to minimize 

site disturbance) are available from the park biologist in charge of the monitoring program. Sites 

should be monitored on the schedule set out in these protocols, with annual measurement of total 

annual willow and winter upland herbaceous offtake on a subset of sites, and sampling of aspen, 

upland shrub, and willow cover and height measures on a 5-year basis. As discussed above, there 

are two areas that could be removed from the sampling regime to reduce labor and analysis costs 

(table 11). In both cases, the reduced sampling effort will result in less-accurate results. The first 

change would be to measure shrub height and cover in willow areas using only the line-intercept 

method instead of both macroplot and line intercept. The macroplot-cover method measures 

cover on an areal rather than linear basis and should yield more accurate estimates and is 

therefore the best method. However, it is more time intensive and it could be sacrificed in years 

of poor funding. In years with adequate funding, both macroplot and line intercept cover 

measures should be continued to maintain continuity between sampling periods. 

The second change that could be made to reduce effort would be an alteration to the 

method used to measure willow offtake. The DD3 method is preferable, as it is more accurate 

since the estimate is scaled based on productivity of browsed and unbrowsed shoots. This 

requires the additional collection of shoots late in the growing season each year and the 

development of annual species-specific regression equations. The DD2 method is less time 

intensive and could be used as the sole offtake measure if necessary based upon available 

funding. Both methods yield similar results in the baseline data analysis; however, the difference 

between methods appears to be greater at lower offtake levels with the DD2 method 

underestimating offtake. Further reductions of time and labor could be achieved by sampling 

only willow cover and height and no other shrub species in willow plots, but as noted previously, 

this would remove the ability to determine which type of community shifts were taking place in 

these willow areas. It should be kept in mind that the thresholds in table 1 were based upon 

baseline conditions calculated using the DD3 and macroplot cover and height methods. To 

interpret DD2 or line-intercept cover and height measures against thresholds, the thresholds 

should be recalculated from baseline DD2 and line-intercept data. 

32 
Table 11. Projected labor requirements for annual and 5-year sampling periods for the Rocky Mountain National Park elk-veg

program. “Reduced sampling option” refers to line intercept for shrub cover and DD2 method for willow offtake. 

Sample Vegetation Crew Full sampling option Task Season Period type size # plots Time Re

# 

Measure winter browsing 2 Spring 28 2 weeks Willow Collect and weigh willow shoots 2 Late August 2 weeks 

Annual 

(all years)

Upland 

Clip and weigh winter offtake from grazing cages 2 Spring 20 2.5 weeks 

Set grazing cages for next winter 2 Fall 20 1 week 

All types Data entry Data summarization and analysis 1 1 Fall-Winter Winter 5 weeks 2 weeks 

Aspen Stem demographics, sapling regeneration, photos 2 Summer 73 8 weeks 

Measure winter browsing 2 Spring 28 2 weeks 

5-year 

sample 

Years: 

Willow Collect and weigh willow shoots 

Macroplot, line intercept, plot photos 

2 

2 

Late August 

Late Springfall 

 2 weeks 

91 8.5 weeks 

2013201820232028

Upland 

Clip and weigh winter offtake from grazing cages Set grazing cages for next winter 

2 

2 

Spring 

Fall 

20 2.5 weeks 

20 1 week 

Shrub line intercept, photos 2 Spring-Fall 50 4 weeks 

All types Data entry 1 Fall-Winter 13 weeks 

Data summarization, analysis, reporting 1 Winter 8 weeks 

33 
34 

Data Summarization and Analysis

Within 3–6 months of data collection, data should be entered into the database, quality 

assurance performed, and summary analyses conducted. This increases the probability that data 

discrepancies can be discovered and corrected while field staff are still available and able to 

recall sampling visits. It also allows for timely management action in response to vegetation 

indicators that show objectives are not being met. Each year, data summaries should be 

conducted to calculate annual offtake estimates (Appendix 7). Offtake data should be averaged 

for each site first before estimating average offtake for winter-range zones in the manner 

described in the “Establishment of Monitoring Sites and Collection of Baseline Data” section. 

Estimates for the entire winter-range should be weighted by the proportion of area in each 

winter-range zone. Repeat sampling at some sites for two years in a row allows the estimation of 

annual changes from a direct comparison at a sample point, which provides insight into 

interannual variation in offtake that might otherwise be masked by simply averaging all offtake 

measures in an elk winter-range zone. Analyses conducted on an annual basis should include: 

• calculation of mean offtake (and standard error) for core and non-core upland 

herbaceous and willow; 

• graphs of mean offtake and previous years’ summary data for core and non-core 

upland and willow; 

• analysis of trend for two-year averages of offtake for sites with repeat measures 

and comparison to annual averages over all measured sites.

Statistical analyses should be conducted by a biologist with a sound statistical 

background or by a statistician. While the statistical methods laid out in this document should be 

adequate to detect trends in the data over time, periodic review by a biometrician or statistician 

(perhaps after the 10-year sample) may be useful so that, if applicable, newly developed 

statistical methods might be applied to the data. A summary of the main statistical analyses to be 

performed is listed in table 12. Prior to any statistical analysis, exploratory data analysis should 

be performed to check for normality and homogeneity of variances. Appropriate transformations 

should be applied, particularly to percentage data (offtake and cover data). Analyses should be 

aimed at answering three main questions at each 5-yr sample point. 

1. Analysis of trend: Has there been a change in the variables of interest from 

measurements at the time of site establishment (T1) and successive sample times 

(T2,T3) over the entire winter-range? 

2. Change among management types: Are there differences between mean parameter 

estimates of the variables of interest for each management sub-group (core winterrange, non-core winter-range, and fenced)?

3. Analysis of sub-groups: Do the trends differ between management sub-groups? Were 

these differences evident at the beginning of the monitoring program or have they 

developed as the EVMP has been implemented? 

Offtake, shrub cover, and shrub height data should be averaged for each site first before 

estimating average offtake for winter-range zones in the manner described in “Establishment of 

Monitoring Sites and Collection of Baseline Data” section. Estimates for the entire winter-range

should be weighted by the proportion of area in each winter-range zone. Analysis of trend can be 

examined using repeated measures analysis of variance (ANOVA) or general linear models with 

contrasts between years. This analysis will compare the trend (slopes) between sites adjusting for 
Table 12. Summary of statistical analyses to be conducted as part of the Rocky Mountain National Park elk-vegetation moni

[ha, hectare; m, meters; ht, height; dbh, diameter at breast height QA/QC, quality assurance/quality control] 

Objective Parameter Units or index QA/QC/details Scale of Analysis 

Preventing loss of aspen clones. 

Stem density by height stems/ha Stems < 2.5 m ht, < 2 cm dbh. Calculate percent sites suckering and regenerating. Entire winter-range Core vs. non-core winter-rang

Distribution of stem diameters reflects 

Distribution of stem 

Stems > 2 cm dbh only, small diameter stems = 2–10 cm dbh, medium diameter stems = 10–20 Fenced vs. unfenced core win

~75% small diameter, 20% medium diameter 

diameters % cm dbh, large diameter stems = > 20 cm dbh. range. 

and 5% large diameter trees. Increasing cover and height of riparian willow. 

Cover of willows Mean/SE Height of willows 

% m 

0–100; in cases with overlapping canopies can be greater than 100 Average of all willows intersected (line intercept method) or all willows in the site (macroplot method) 

Entire winter-range Core vs. non-core winter-rangFenced vs. unfenced core winrange 

No increase in mean offtake on the winterrange. 

Offtake, DD2 Offtake, DD3 

% % 

Based on equation 3 in Bilyeu and others (2007), range 0-100 Based on equation 5 in Bilyeu and others (2007), range 0-100 

Entire winter-range Core vs. non-core range 

Reduction of elk grazing on upland herbaceous. Maintenance of diversity of grazing levels. 

Herbaceous offtake Upland shrub cover 

% % 

Adjust for any values less than 0% Average of all shrubs intersected (line intercept) 

Entire winter-range Core vs. non-core winter-rang

35
individual site differences. A mixed-model approach may be appropriate if violations of the assumptions 

of compound symmetry and independent covariance are violated. Because a number of factors may 

influence the response variables (for example, wetland type—wetland, bog, wet meadow, or dry 

meadow—may affect the rate at which willow cover changes over time), analysis of covariance may be 

appropriate if patterns related to secondary variables are observed in the exploratory data analysis. 

These site-characteristic data are collected at the outset of the study and at 5-yr intervals to account for 

any changes that might result due to changes in underlying hydrology of the site (for example, a flood 

event or beaver damming changes the course of the creek and causes a previously wet area to become 

dry). 

Establishment of New Sites 

Establishment of additional sites may be considered as needed to replace sites that have to be 

removed from monitoring for various reasons, to expand monitoring inside fences, or if additional 

treatments (vegetative restoration treatments, elk harassment, etc.) need to be examined. Establishment 

of new sites should be conducted following the protocols found in Appendices 4–6. 

Cost and Labor Considerations 

There will be many costs associated with operation of this monitoring program throughout its 

lifetime. These costs can be divided into two main groups: Materials and Equipment Costs and Labor 

Costs. 

Material and Equipment Costs 

We attempted to use materials that were as durable as possible so that frequent replacement 

would not be a necessity. However, the requirements of working within the regulations for scientific 

research in the park and a desire on the part of all parties to make our monitoring as aesthetically 

unobtrusive as possible meant that we selected some materials that will need to be replaced throughout 

the life of the program. It became apparent in the fall of 2008 that the current grazing cage design may 

be problematic. We had based the design on previous work in the park, but for that study, most cages 

were placed in willow areas where soils were more solid for driving in rebar stakes, thus anchoring the 

cages more firmly. At that time, only approximately 40 cages were placed and concentrated in 4 upland 

locations and another 60 cages were spread among 12 willow sites. Over the previous, 4-yr study, there 

were approximately 4 cages destroyed by elk (most because the wire welds broke) and no known 

incidents of animals becoming entangled in the cages. Apparently, with nearly 150 cages scattered 

among 47 locations, there are more opportunities for curious bull elk to encounter the cages and the 

results have been destructive to the cages and distressing and potentially dangerous to the elk, as well as 

costing park staff time and effort capturing an animal with a cage snared on his antlers. After only 2 yr, 

we have had a large number of cages destroyed or in need of much repair. The original plan for the cage 

design was to find something inexpensive, unobtrusive, and easily replaceable. We suggested using 

metal fencing t-posts instead of rebar, but the considerable cost and larger size made them undesirable. 

However, in light of recent events and loss of cages, the park asked that we revisit the issue of cage 

construction. 

Three different designs could be considered (fig. 12), though all are more expensive to construct 

and more easily seen than the current design. These have all been used at other locations with success, 

including areas with bison and cattle (animals that are notoriously curious, larger than elk, and like to 

rub extensively). While these designs will be more costly than current designs, some of this cost could 

36
Figure 12. Three alternative grazing-cage designs that might be used in Rocky Mountain National Park monitoring 

program. One uses 3×2-in mesh stainless steel fence and heavy gauge steel fencing t-posts (left). Another 

uses welded angle iron with 6×6-in steel mesh cattle fencing attached to the sides (center). The third has a 

welded rod frame in a trapezoid design with 2×3-in steel mesh cattle fencing attached to the sides (right).

be absorbed by only placing cages at the sites to be monitored each year, in which case only 60 cages 

would be needed each year, instead of 150. However, there would be additional time and labor expense 

as 30 cages would need to be completely removed from 20 sites each spring and transported to new sites 

for use in the fall. The designs would also be more visually obtrusive and many of the upland sites are 

highly visible to the public since most of the upland areas in the core winter-range are near roads and 

draw park visitors who wish to observe the elk. 

The alternative to choosing a new grazing cage design would be to continue with the current 

design of using three rebar posts wrapped with cattle fencing with a chicken-wire top. These cages may 

need to be replaced a bit more frequently, but material costs are relatively cheap. The biggest tradeoff is 

whether the risk of animal entanglement is worth the cheap costs and less obtrusive design of the current 

cages. 

Additional materials and equipment to be considered include the replacement of marker caps 

and/or rebar posts that are removed by humans or kicked from the ground by animals. Because of the 6-

in (inch) length requirement set by the park for the marker posts, the corner markers in the willow sites 

are subject to frost heave and then to being knocked out of the ground by animals as they pass. Our first 

spring sampling found a few marker posts missing and a number out of the ground or nearly out. If the 

park management team reconsiders the requirements of marker length, replacement of the rebar markers 

with longer posts (12–18 in), in the willow sites at a minimum, would be a prudent action. 

Other than the replacement or upgrading of existing equipment (measuring tapes, calipers, GPS 

units, digital cameras, etc), we do not foresee any other regular costs. 

Labor Costs 

Labor will be an ever-increasing cost throughout the duration of this monitoring plan. The 

majority of the work (field sampling and data entry) in this monitoring program can be completed by 

minimally skilled technicians or interns with training and close supervision, or alternatively, more 

skilled technicians working independently. Data summarization should be performed by a skilled 

technician supervised by a biologist, or by a biologist. Data analysis should be performed by a biologist 

with some statistical background, by a biometrician, or by a statistician. Since future budgets are 

unknown and the program is quite labor-intensive (and therefore costly), particularly at the 5-yr 

sampling interval, we have included a reduced sampling option (table 11). This reduced option would 

37
scale back field time by two weeks for a two-person crew (four person-weeks total) plus an additional 

two weeks of data entry time for a total of six person-weeks of reduction for annual samples. At the 5-yr 

intervals, this reduced sampling option reduces field time by 5.5 weeks of field time (11 person-weeks), 

and three weeks of data-processing time for a total of 14 person-weeks reduction. The reduced sampling 

option would remove use of the production-weighted diameter difference method (DD3) to calculate 

willow offtake and would only use the line-intercept method without the macroplot method to estimate 

willow height and cover. The tradeoff for this reduced sampling option is less accurate willow offtake 

and cover data. An additional 3 weeks of field time (6 person-weeks) could be eliminated by removing 

the Kawuneechee Valley aspen sites and extra winter-range aspen sites from sampling. Further time 

reductions (a decrease of an additional 8–10 person weeks) could be achieved by eliminating the shrub 

cover measurements in upland areas and measuring only willow species cover in willow plots. This 

further reduction would come at the expense of knowing: (1) whether elk grazing was causing changes 

in upland sites from grass-dominated to shrub-dominated communities (or the reverse) and (2) 

determining if potential change in willow communities was to grass-dominated meadows, shrubby 

meadows, or birch-alder (Betula-Alnus) communities. 

Conclusion 

The success of any monitoring program is dependent upon the commitment of the managing 

entity to fully support and implement the program. The decision of when to make changes in elk or 

vegetation management because the objectives of the EVMP are not being met lies with the Park. Only 

those closely involved with managing Park resources have the ability to determine whether the data 

collected through this monitoring program indicate substantial and acceptable (or unacceptable) changes 

to vegetation conditions in these key communities. It is also the responsibility of those managing Park 

resources to respond appropriately with Park management. Park staff also have the knowledge of 

extenuating circumstances (localized weather events, prescribed or natural fire events, human 

disturbances, etc.) which could influence the data collected as part of this monitoring program and how 

to interpret those data in light of the specific circumstances occurring in the park. Periodic review and 

analysis of summary data collected in this monitoring program by an independent biologist (with strong 

statistical skills) or statistician could provide objectivity and new insight into interpretation of the 

monitoring data and could also take advantage of advances in statistics, remote sensing, GIS, and other 

technologies that may develop over the proposed 20-yr time frame of this monitoring program. 

Acknowledgments 

This project was funded by Rocky Mountain National Park. We appreciate the support and 

assistance of J. Visty, C. Yost, and R. Thomas of Rocky Mountain National Park. D. Binkley, W. 

Romme, D. Cooper, E. Gage, Colorado State University; D. Johnston, Colorado Division of Wildlife; 

and P. Geissler, U.S. Geological Survey–Fort Collins Science Center (USGS–FORT), provided valuable 

feedback during development of the monitoring protocols. I. Ashton, National Park Service Inventory 

and Monitoring Program; and P. Geissler, and C. Melcher, USGS–FORT, provided insightful reviews 

of the draft monitoring plan. G. Miller, Rocky Mountain National Park, improved the field protocols 

with many helpful comments. We were assisted in the field by Student Conservation Association interns 

K. Holland, S. Sink, A. Terway, B. Carroll, L. Holtrop, and T. Putt. R. Waltermire, USGS–FORT 

assisted with cost estimates for remote imagery. We also thank K. Schoenecker of USGS–FORT for 

advice, logistical and administrative support, and review of early proposals.

38
References Cited 

Baker, W.L., Munroe, J.A., and Hessl, A.E., 1997, The effects of elk on aspen in the winter range of 

Rocky Mountain National Park: Ecography, v. 20, p.155–165. 

Berry, J., Decker, D., Gordon, J., Heitschmidt, R., Huff, D., Knight, D., Romme, W., and Swift, D., 

1997, Science-based assessment of vegetation management goals of elk winter range—Rocky 

Mountain National Park: Fort Collins, Colo., Colorado State University Environment and Natural 

Resources Policy Institute, 16 p. 

Bilyeu, D.M., Cooper, D.J., and Hobbs, N.T., 2007, Assessing impacts of large herbivores on shrubs—

Tests of scaling factors for utilization rates from shoot-level measurements: Journal of Applied 

Ecology, v. 44, p.168–175. 

Binkley, D., 2008, Age distribution of aspen in Rocky Mountain National Park: Forest Ecology and 

Management, v. 255, p. 797–802. 

Bonham, C.D., 1989, Measurements for terrestrial vegetation: New York, John Wiley and Sons, 338 p. 

Canfield, R.H., 1941, Application of the line interception method in sampling range vegetation: Journal 

of Forestry, v. 39, p. 388–394. 

Kaye, M.W., Stohlgren, T.J., and Binkley, D., 2003, Aspen structure and variability in Rocky Mountain 

National Park, Colorado, USA: Landscape Ecology, v. 18, p. 465–486. 

Olmsted, C.E., 1997, Twenty years of change in Rocky Mountain National Park elk winter range aspen: 

Greeley, Colo., University of Northern Colorado, 45 p. 

Peinetti, H.R., 2000, Riparian willow dynamics and their interaction with environmental and biological 

factors in the elk winter range of Rocky Mountain National Park (Colorado) - a multiscale analysis. 

PhD. Dissertation, Colorado State University, Ft. Collins, Colo., 194 p. 

Peinetti, H.R., Kahlkan, M., and Coughenour, M.B., 2002, Long-term changes in willow spatial 

distribution in Rocky Mountain National Park: Landscape Ecology, v. 17, p. 341–354. 

Salas, D., Stevens, J., and Schulz, K., 2005, Rocky Mountain National Park, Colorado, 2001-2005 

Vegetation Classification and Mapping: U.S. Bureau of Reclamation Technical Memorandum 8560-

05-02, 146p. 

 SAS Institute, 2003, SAS Version 9.1 statistical analysis software: Cary, N.C., SAS Institute 

Incorporated. 

Singer, F.J. and Zeigenfuss, L.C., comps., 2002, Ecological evaluation of the abundance and effects 

of elk herbivory in Rocky Mountain National Park, Colorado, 1994-1999: U.S. Geological Survey 

Open-File Report 02–208, 268 p. 

39
Stevens, D.R., 1980, The deer and elk of Rocky Mountain National Park—A ten year study: National 

Park Service Report ROMO-N-13, 162 p. 

Stevens, J.E., J. Lemly, and R. Thomas, 2005, Dichotomous key to the plant associations of Rocky 

Mountain National Park: Fort Collins, Colo., Colorado State University, Colorado Natural Heritage 

Program, 49 p. 

Stohlgren, T.J., 2001, Rocky Mountain National Park long-term monitoring plan: Estes Park, Colo., 

Rocky Mountain National Park, 137 p. 

Suzuki, K., Suzuki, H., Binkley, D., and Stohlgren, T.J., 1999, Aspen regeneration in the Colorado 

Front Range—Differences at local and landscape scales: Landscape Ecology, v. 14, p. 231–237. 

Urquhart, N.S., and Kincaid, T. M.,1999, Designs for detecting trend from repeated surveys of 

ecological resources: Journal of Agricultural, Biological, and Environmental Statistics, v. 4, 

p. 404-414. 

U.S. Department of the Interior, 2007, Elk and vegetation management plan, Rocky Mountain National 

Park, Colorado: Washington D.C., National Park Service, unpaged, accessed December 17, 2010, at 

http://www.nps.gov/romo/parkmgmt/elkveg_mgmt_plan_feis.htm. 

U.S. Department of the Interior, 2008, Record of decision, Final environmental impact statement, Elk 

and vegetation management plan, Rocky Mountain National Park, Colorado: Washington D.C., 

National Park Service, 21 p., accessed online December 17, 2010, at 

www.nps.gov/romo/parkmgmt/upload/rod_evmp_signed_2-15-08.pdf. 

Zeigenfuss, L.C., Singer, F.J., and Bowden, D., 1999, Vegetation responses to natural regulation of elk 

in Rocky Mountain National Park: Biological Science Report USGS/BRD/BSR—1999-0003: Denver, 

Colo., U.S. Government Printing Office, 23 p. [Also in F.J. Singer, and Zeigenfuss, L.C., comps., 

2002, Ecological evaluation of the abundance and effects of elk in Rocky Mountain National Park, 

Colorado, 1994-1999: U.S. Geological Survey Open-File Report 02–208.] 

Zeigenfuss, L.C., Singer, F.J., Williams, S.A., and Johnson, T. L., 2002, Influences of herbivory and 

water on willow in elk winter range: Journal of Wildlife Management, v. 66, p.788–795. 

40
Appendix 1: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Aspen Monitoring Protocol 

The following steps outline the process of visiting and sampling the aspen-monitoring 

sites as part of the Rocky Mountain National Park elk-vegetation monitoring program. All site 

locations and special instructions are with the park biologist in charge of the monitoring program 

and should be acquired from this individual. Italic type indicates the name of datasheet to be 

filled out. Sample datasheets can be found at the end of this appendix. Sampling of all aspenmonitoring sites should be conducted once every 5 yr starting in 2013 (repeated in 2018, 2023, 

and 2028). Sampling should be conducted during summer, preferably when the majority of 

annual growth has already occurred and before elk begin browsing to any great extent in the fall. 

Photos should be taken any time an event of interest occurs at a site (for example, tree falls into 

site, ground torn up by animals/humans, etc.). Nothing should be removed from any site except 

for approved plant samples listed on your research permit. A general schematic of aspenmonitoring plot design can be found in figure 1.1. 

Figure 1.1. Diagram of aspen-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

monitoring program. 

1. Gather equipment and supplies 

FOR ALL FIELD WORK 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard, notebook 

• Hammer or mallet for pounding in loose site markers (a rubber mallet will help prevent 

damage to the marker labeling) 

41

5 m 

= landmark corner, permanent rebar marker w/ aluminum cap 

= corners marked with permanent rebar marker with aluminum cap 

5 m 

2.5 m 

 = subdivided plot lines (if necessary) 

3=S 2=E 

4=W 1=N 
• Metal detector (may be needed to find site corners) 

• 2 tape measures at least 25 m in length for plot layout (pre-measured lengths of chain or 

string can also be used to speed the process) 

• Chaining pins or other stakes for holding down tape measure/strings (10) 

• Compass (set current declination prior to each field season from info at 

http://www.ngdc.noaa.gov) 

• Handheld GPS unit and spare batteries 

• 2 pieces of 6-in (inch) rebar to replace wooden stakes if necessary (if approval is granted 

in the future (because of problems with frost heaving of site markers), these rebar pieces 

may be changed to 1 ft (foot) in length or longer) 

• 2 aluminum survey marker caps imprinted with “ELK-VEG MONITOR—NPS-DO NOT 

DISTURB—ROMO STUDY 06013” to replace wooden stakes if necessary 

• Diameter tape (tape that converts circumference to diameter) 

• 1-2 small metric tape measures (for measuring sucker height) 

• Digital camera with extra batteries 

• List of site locations (see park biologist in charge of monitoring program) 

FOR REFERENCE PHOTO POINT 

• Laminated placard (light, not white) with following information: 

• dry erase marker 

• wipes or cloth to clean placard 

2. Navigate to the site using GPS and UTM (Universal Transverse Mercator) coordinates on list 

provided by park biologist in charge of monitoring program. Be sure to have WAAS (Wide 

Area Augmentation System) enabled on the GPS to increase accuracy (although this will 

shorten battery life). Site corners are marked with rebar stakes with aluminum caps pounded 

flush with the ground and imprinted with “ELK-VEG MONITOR—NPS-DO NOT 

DISTURB—ROMO STUDY 06013”. Each cap has the site number (AC # or ANC#) and the 

cardinal direction of that corner. If corner stakes have heaved partially out of the ground, 

pound back into place. Direction of landmark corner (corner #1) in relation to rest of the plot 

is noted in table 1.1. In the earlier part of the study, we labeled corners 1–4 instead of the 

cardinal directions, so some of the corner stakes might still have this labeling: 1=N, 2=E, 

3=S, 4=W. If all four plot corners cannot be found easily, use chaining pins to temporarily 

hold the tape at located plot corners and lay out measuring tapes between these corners to 

determine rough location of missing corners. Use metal detector to locate missing corners in 

these areas. Each side of the plot should measure 5 m and the diagonal should measure 7.07 

m (fig. 1.1). Any corner that has come completely out of the ground should be replaced in the 

ground after using a compass and tape measure to determine correct corner location (90° 

angle, 5 m between replaced corner and adjacent corner markers). Due to changes in the 

protocols over the period of initial site establishment, it is possible that some plots that 

originated in 2006 have two rebar corners and two corners marked with wooden stakes. If 

this is the case, replace wooden corner stakes with rebar stakes capped with aluminum caps 

described above and stamped with the site and corner numbers. Once all four corners have 

42

ROMO EVMP 

SITE___________ 

DATE _________ 

CORNER_____ 
been located and the outline of the plot determined, dissect plot into four quarters by placing 

tape measures or cord across the mid-section of each line (fig. 1.1). This will make it easier 

to measure and account for all trees in the plot. When there are a limited number of suckers 

in the plot, it may not be necessary to subdivide the plot for an accurate count. 

3. Rocky Mountain National Park Elk-Vegetation Monitoring Project—Aspen Monitoring Data 

Sheet. Begin filling out the site information on the data sheet 

• Site name/number: letter and numeric combinations: A(aspen)+ NC(noncore) or C(core) 

+ individual number. For example, ANC4 would be aspen, noncore site 4. 

• Fenced?: identify whether the site is located inside an elk-proof fence (Y/N). 

• Date: full date including year (mm/dd/yyyy). 

• Observers: last name of those observing, measuring, and recording data. 

• Site coordinates: this should have the easting and northing coordinates in UTM NAD83 

zone 13N. Record the true bearing (corrected for declination) to each corner from the 

landmark stake. 

• GPS accuracy: record GPS error in meters. 

• General comments: record general site locations, directions, and additional information to 

help relocate the plot (distance and bearing from trail or other landmarks), events that 

have happened such as fires, excessive wind damage, etc. 

• Slope (percent): record the percent slope of the site. 

• Aspect: record the general site aspect (flat, N, NE, E, SE, S, SW, W, NW). 

• Elevation: record the elevation in meters as reported on the GPS. 

• Soil type/wetness: record general information on how wet or dry the site is—dry 

hillslope, wet meadow, wet streamside, etc. 

• Riparian or upland: record whether the aspen stand surrounding the plot is generally 

riparian or upland in nature. 

• Bark scarring: categorize the degree of bark scarring caused by elk on the aspen trees by 

circling the percentage of the trunk below 2.5 m height which is scarred: 0–25 percent, 

25–50 percent, 50–75 percent, or 75–100 percent. 

• Animal sign: record any signs (scat, browse, tracks, sightings, beaver dams, food caches, 

or cuttings) of elk, mule deer, moose, or beaver at the site. 

• Trees and sapling counts: using a diameter tape, determine aspen trunk diameter at 1.4 m 

height (this measure is known as dbh, or diameter at breast height) and using a 

telescoping measuring rod (if necessary), determine whether the height of the tree is 

greater than, less than, or equal to 2.5 m. 

• Tally the number of live and dead aspen trees greater than 2.5 m tall in 2 cm dbh classes 

ranging from 0–2 cm dbh to 32–34 cm dbh. Live and dead trees should be tallied 

separately. Any and all trees greater than 34 cm dbh should be pooled and a single tally 

each recorded for live and dead categories. Trees greater than 2.5 m tall with a dbh less 

than 2 cm should be uncommon, but a space has been provided if this condition is 

observed. 

• Tally the number of trees less than or equal to 2.5 m tall in each height class listed below. 

Tally separately for live and dead trees in each of the following categories: 

• 0–50 cm height 

• 51–100 cm height 

• 101–150 cm height 

• 151–200 cm height 

43
• 201–250 cm height. 

4. Four digital photos should be taken of the plot— one from each corner. Using a dry erase 

marker and the pre-printed placard of laminated colored paper, write the plot name/number, 

date, and the corner number (N, E, S, W) from which the photo is taken. The placard should 

be placed in the plot or held on the edge of the photo field to identify the photo. Using a dry 

erase marker to write the information on the placard and allows the placard to be wiped clean 

and reused for each photo. 

5. When all data collection is complete, remove measuring tapes and temporary markers. 

Double check to be sure that all rebar is pounded flush to the ground before leaving site at 

end of visit. 

6. Data entry and reduction. 

• Copy data sheets when they are complete (including weights). Put originals into binders 

by direction of the biologist in charge of elk management. Archive copies in a separate 

location in case of loss of originals. 

• Download digital photos from camera as soon as possible, print as 4×5-in, and store with 

original data sheets. Archive electronic images as directed by the biologist in charge of 

elk management and the monitoring program. 

• Data entry: Enter data into database as directed by biologist in charge of elk-management 

and vegetation-monitoring program. 

44
Table 1.1. Location information for aspen sites to be monitored every 5 years (2013, 2018, 2023, 2028) as part of the Rock

Park elk-vegetation monitoring program. [m, meters; km, kilometers] 

Unique Date Corner Comments General directions site established location 

AC1 8/8/2006 NE corner 3 was moved towards the middle of the plot Park at West Horseshoe Park. Walk a

because the true point is on a rock through the meadow about 150 m. 

AC2 9/1/2009 N Park before Alluvial Fan in lot with cAC3 8/30/2007 SE . 

AC4 8/9/2006 SW corner 2 was moved towards the middle of the plot Park at West Horseshoe Park. Walk a

due to landing on a rock, corner 3 was moved and into the meadow about 100 m. Thslightly out of the plot due to landing on a rock hill about 50 m. 

AC5 9/12/2009 N Park near Fan Lake Exclosure. West 

and up hillside 

AC6 8/9/2006 N corner 2 was moved slightly out of the plot due to Park at West Horseshoe Park. Walk a

a large boulder, corner 3 was moved towards the Walk away from the road about 150 m center due to rock, stake 1 has pin just to the hill about 200 m outside of the stake 

AC7 11/6/2006 N Park near turnoff to Moraine Park cam

is on north side of road ~ 25 m. 

AC8 11/13/2008 S . AC9 8/9/2006 N corner 3 was not hammered in all the way due to Park in West Horseshoe Park. Walk a

tree root and up the hill about 50 m. 

AC10 10/24/2006 SW ~25 m south of Fern Lake Rd. AC11 10/20/2006 SW Park in West Horseshoe Park. Point i

~250 m. 

AC12 8/10/2006 N Fern Lake Road ~100 m from main loAC13 11/6/2006 S Park at west Alluvial Fan lot. Point is 

Fall River ~450 m. 

AC14 8/9/2006 N Park in West Horseshoe Park. Walk a

and up the hill about 50 m and away about 100 m. 

AC15 9/12/2009 N Park near Fan Lake Exclosure. West 

and up hillside. 

AC16 10/20/2006 NE Drive behind Bighorn Ranger Station 

Entrance ~1/2 mile, ~ 20 m west of ro

AC17 11/7/2006 NW Park on Fern Lake Rd at bathroom lo

behind bathroom. 

AC18 11/6/2006 NE Park at end of Beaver Meadows Rd. F

45
Unique 

site 

Date 

established 

Corner 

location Comments General directions

Moraine Park for ~1 km. Site is ~60 m 

AC19 10/24/2006 

AC20 10/25/2006 SW AC21 7/23/2007 NW 

AC22 9/1/2009 N 

AC23 9/1/2009 . Large stand at southwest end of HorsAC24 9/1/2009 N Moraine Park near turn for campgrouAC25 9/1/2009 S Horseshoe Park AC26 9/1/2009 N Three cottonwood in plot, likely P. angustifolia, 

possibly P. balsamifera. One 0-50 cm tall, one 50-100 cm tall, one 2-4 cm dbh > 2.5m tall 

Fern Lake Road. 

AC27 9/1/2009 N Lots of cottonwood. Four 0-50cm tall, two 51-

100cm tall, two 101-150 cm tall, two 151-200cm tall, and three 201-250cm tall. 

Fern Lake Road. 

AC28 7/23/2007 NE AC29 9/1/2009 N Lots of P. balsamifera? 

151-200cm tall in plot. 

Three 101-150cm tall, two Fern Lake Road. 

AC30 7/20/2007 SE bones ~3 meters away from 1st landmark 

AC31 8/30/2007 NE AC32 8/30/2007 SE AC33 8/30/2007 N AC35 9/1/2009 N . Little Horseshoe Park AC36 9/1/2009 N Only N & S markers were placed. Real photo has 

circle around plot number and is listed as AC38. 

Horseshoe Park stand. 

AC37 8/20/2007 . 

AC38 9/1/2009 N Cottonwoods in the area. Only N & S corners are 

marked. 

AC39 9/1/2009 N Only N was marked. 

AC40 9/1/2009 N Only E & W markers were placed Just north of Fan Lake Exclosure. AC41 9/1/2009 N Only N & S corners were marked. No E marker 

due to big rock 

Park near Fall River Entrance. Up behind Ranger Station. 

dra

AC44 5/6/2008 NE 

AC45 5/6/2008 NE 

AC60 11/8/2009 N Beaver Meadows 

AC61 11/8/2009 N Moraine Park near museum, road goe

AC62 11/8/2009 . Hondius Park 

AK1 9/26/2007 N 

46
Unique 

site 

Date 

established 

Corner 

location Comments General directions

AK2 9/26/2007 S 

AK3 9/27/2007 SE 

AK4 9/27/2007 SSW AK5 10/4/2007 SE 

AK6 10/4/2007 N 

AK7 10/5/2007 S AK8 10/5/2007 NW ANC1 6/21/2007 SW ANC2 6/20/2007 N ANC3 11/13/2008 . 

ANC4 7/19/2007 SE Several 0–2cm dbh, but > 2.5 m tall. ANC5 11/13/2008 . game trail 

ANC6 11/14/2008 N 

ANC7 7/2/2007 . 

ANC8 7/2/2007 NE 

ANC9 11/14/2008 E 

ANC10 7/19/2007 NE 

ANC11 6/19/2007 SE 

ANC13 7/5/2007 N 

ANC15 8/8/2006 NW stake for corner 3 was moved 

to large rock 

towards center due 

ANC16 6/19/2007 SW 

ANC17 7/19/2007 W 

ANC18 6/20/2007 SW 

ANC19 7/2/2007 SE 

ANC21 6/21/2007 NE 

ANC22 11/14/2008 . coordinates pts 3 and 4 off likely due to loss of 

GPS signal reception 

ANC23 8/10/2006 . Site most easily reached 

Rockies. 

from stables 

47
 

Rocky Mountain National Park Elk-Vegetation Monitoring Program 

Aspen Monitoring Data Sheet 

Plot name/number:__________________ Date: ________________ 

Observers:_______________________________________ 

Plot Coordinates: UTM NAD83 Accuracy (m): ____________ 

Corner Easting Northing Location of Bearing from 

landmark corner landmark 

#1 (landmark) 

#2 

#3 

#4 

General Comments: 

Site Characteristics: 

Slope %:______________Aspect:______________GPS elevation(m):________________ 

Soil Type/Wetness:_______________________________ Site type: riparian / upland 

Bark scarring (circle one): 0–25% 25–50% 50–75% 75–100% 

 

Animal Species: (elk, deer, moose, beaver) Animal Sign: (scat, browse, tracks, sightings) 

 

 

Trees (Stems > 2.5 m tall dbh) Saplings (stems < 2.5 m tall) 

DBH (cm) alive dead Height (cm) alive dead 

0–2 0–50 

2–4 51–100 

4–6 101–150 

6–8 151–200 

8–10 201–250 

10–12 

12–14 additional comments: 

14–16 

 16–18 

18–20 

20–22 

22–24 

24–26 

26–28 

28–30 

30–32 

32–34 

>34 

48
Appendix 2: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Protocol 

The following protocol outlines the process for visiting and sampling willow-monitoring 

sites as part of the Rocky Mountain National Park elk-vegetation monitoring program. All site 

locations and special instructions are with the park biologist in charge of the monitoring program 

and should be acquired from this individual. Italic type indicates the name of datasheet to be 

filled out. Sample datasheets can be found at the end of this appendix. Description of general site 

characteristics, reference photos, and macroplot and line intercept measures of shrub cover 

should be performed at all sites at time of site establishment and once every 5 yr (during 

summer) according to the timetable set out in table 2.1. Willow sites scheduled for browse 

measures require individual site visits in spring of the sampling year to measure winter browse 

consumption following the timetable set out in table 2.1. Sites should be sampled in spring prior 

to leafout and onset of new growth, or if not possible, before new growth has advanced to any 

great extent. This pre-growth timeframe is typically from mid-April to mid-May in these sites. 

Additionally, willow shoot samples for building biomass regressions for calculating offtake 

should be collected in late August/early September each year in an attempt to capture the 

timeframe: (1) after the majority of annual growth has occurred and (2) prior to the onset of elk 

browsing in fall. Photos should be taken any time an event of interest occurs at a site (for 

example, tree falls into site, ground torn up by animals/humans, etc.). Nothing should be 

removed from any site except for approved plant samples listed on the research permit. A general 

schematic of willow-monitoring plot design can be found in figure 2.1. 

Figure 2.1. Diagram of willow-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

monitoring program. 

49

W

4 m

E

1 m x 1m 

4 m 

S

N

2.83 m 

0 m 

5.66 m 

= permanent rebar marker w/ aluminum cap 

= plot center, temporary marker only 
1. Gather equipment and supplies 

FOR ALL FIELD WORK 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard 

• Handheld GPS unit and spare batteries 

• Metal detector (may be needed to find site corners) 

• Hammer or mallet (for pounding in loose site markers), wood pad to protect engraved 

aluminum caps 

• Digital camera 

• Willow ID key 

• Voice recorder (if working alone) 

• List of site locations (see park biologist in charge of monitoring program) 

FOR MACROPLOT AND LINE INTERCEPT SAMPLING 

• 2 tape measures at least 25 m in length for macroplot and intercept line delineation 

• 5 m tape measure and/or meter stick for plant heights 

• 10 Chaining pins or other stakes for holding down tape measure 

• Height pole for measuring heights of tall plants 

• Compass set to proper declination (check current declination prior to each field season at 

http://www.ngdc.noaa.gov) 

FOR BROWSE SAMPLING 

• Survey flags for temporarily marking microplot corners, 

• Digital or dial calipers with metric units graduated to 0.5 mm (millimeters) 

• Small metric tape measure (2–5 m) or ruler 

FOR SHOOT COLLECTIONS 

• Small paper bags (lunch bag size) and small coin envelopes 

• Clippers 

FOR REFERENCE PHOTO POINT 

• Laminated placard (light, not white) with following information: 

ROMO EVMP 

SITE___________ 

DATE _________ 

CORNER_____ 

• dry erase marker 

• wipes or cloth to clean placard 

2. Navigate to the site using GPS and UTM coordinates on list provided by park biologist in 

charge of monitoring program. Be sure to have WAAS enabled on the GPS to increase 

accuracy (although this will shorten battery life). Site corners are marked with rebar stakes 

with aluminum caps pounded flush with the ground imprinted with “ELK-VEG 

MONITOR—NPS-DO NOT DISTURB—ROMO STUDY 06013”. Each cap has the site 

number (WC # or WNC#) and the cardinal direction of that corner (N, E, S, W). If corner 

stakes have heaved partially out of the ground, push back into place. 

3. If all four plot corners cannot be found easily, use chaining pins to temporarily hold the tape 

at located plot corners and lay out measuring tapes between these corners to determine the 

rough location of missing corners. Use metal detector to locate missing corners in these 

50
areas. Each side of the plot should measure 4 m and the diagonal should measure 5.66 m (fig. 

2.1). Any corner that has come completely out of the ground should be replaced in the 

ground after using a compass and tape measure to determine correct corner location (90° 

angle, 4 m between replaced corner and adjacent corner markers (see site establishment 

protocol)). The technique known as double-chaining is effective and efficient if two corners 

are found. Extend the tape measure 8 m between opposite corners, or 9.66 m (4 m + 5.66 m) 

between adjacent corners. Tighten the slack tape in the direction of the missing corner—the 4 

m mark will be at the correct angle and distance of the missing corner. 

4. Rocky Mountain National Park Elk-Vegetation Monitoring Program—Willow Monitoring 

Data—Site Characterization Data Sheet. The information on this sheet is gathered when a 

site is established and once every 5 yr according to the schedule found in table 2.1. 

Dimensional variables shall be in metric units. 

• Site number: letter and numeric combinations—W(willow)+ NC(noncore) or C(core) + 

individual number. For example, WNC4 would be willow, noncore site 4. 

• Fenced? (Y/N): specify if the site is inside an exclosure. 

• Location: general location of the site (for example, Horseshoe Park, Hidden Valley, etc). 

• Observers: last name of those observing, measuring, and recording data. 

• Date: full date including year (mm/dd/yyyy). 

• Dominant willow type: determine the dominant type of willow existing on the plot at the 

time of the survey ( for further detail see Peinetti, 2000). All sites should have some 

willow in the immediate area, if not in the actual plot, at the time of establishment, unless 

otherwise noted. 

51
• Ecosystem type: using the wetland key below, identify the site as: fen, riparian, marsh, or 

wet meadow. If the site does not appear to fit any of these wetland types because xeric 

conditions predominate (areas where hydrologic regime has changed over time) then 

choose dry meadow. 

1 1a. Soils organic1 Fen

 1b. Soils mineral Go to 2

 2 2a. Site adjacent to and hydrologically connected to stream or 

river by surface-water flows on timescales of years to decades Riparian

 2b. Site lacks surface water connection to stream or river2 Go to 3

 3 3a. Sites formed in depressions or basins and subject to 

inundation on relatively frequent basis; vegetation dominated 

by annual or perennial grasses and sedges; water tables 

highly variable on both a seasonal and inter-annual basis; 

hydrologic regimes may be influenced by precipitation and 

snow-melt, surface water inputs, or groundwater. Marsh

 3b. Sites found on both slopes and basins but rarely if ever 

inundated; vegetation dominated by perennial grasses, 

sedges, rushes, or shrubs such as willows (Salix spp.); water 

tables variable but rarely to surface; hydrologic regimes 

predominantly groundwater or, at high elevations, snow-melt Wet 

driven; surface water inputs relatively unimportant. meadow 1

Soils classified as Histosols, where at least 40 cm (16 in) of the upper 80 cm (32 in) is organic 

material with an organic carbon content (by weight) of 12 to 18 percent, or more, depending on the clay 

content of the soil. Organic soils may be primarily muck (sapric), mucky peat (hemic), or peat (fibric 

material). 

2

Sites may share a seasonal subsurface connection to streams; however, sites are topographically 

isolated from all but extreme magnitude flood events (for example, those with a recurrence interval greater 

than 100 yr). 

• Predominant herbaceous species: record the scientific name for the one or two most 

common herbaceous species observed at the site. 

• Beaver presence: identify any signs of recent beaver activity in the site, including dams, 

food caches, fresh cuttings, fresh tracks or droppings, sightings of beaver, or if no activity 

was observed. 

• UTM coordinates: UTM easting and northing coordinates of site center and each marked 

corner—be sure the GPS unit is set at UTM NAD83 . 

• GPS error (m): record the GPS error at the time of the recording of the UTM coordinates. 

• General comments: General information about events that have taken place at site (fires, 

floods, human disturbance, etc,) or additional directions to help find a difficult site to 

locate. 

5. Two digital photos should be taken of the plot. One from the north corner looking south, the 

other from the south corner looking toward the north. A placard of laminated colored paper 

(light, but not white), with the plot name/number, date, and the location of the photo (for 

example, north if photo is taken from the north corner) should be placed in the plot to 

identify the photo. 

52
6. Rocky Mountain National Park Elk-Vegetation Monitoring Program—Willow Monitoring 

Data— Macroplot Data Sheet. The information on this sheet is gathered once every 5 yr 

according to the schedule found in table 2.1. Record the site, location, observer, and date 

information. For each shrub whose canopy intersects the 4 m × 4 m macroplot, record the 

following information: 

• Species code: record species of plant being measured using a four-letter code based on 

first two letters of the genus and first two letters of species. Commonly used codes 

provided at bottom of datasheet. 

• Percent of plant in plot: estimate the percent of plant being recorded that falls within the 

macroplot (4 m × 4 m plot). 

• Canopy diameters: record the diameter across the widest axis of the plant’s live canopy 

and the diameter perpendicular to the widest axis to the nearest 5 cm. 

• Maximum height: record the maximum live height of the plant to the nearest 5 cm. 

• Height to tallest bud scar: record the height to the tallest bud scar (point at end of 

previous year’s growth and beginning of current year’s growth) to the nearest 5 cm. 

• Microplot ID: for willow only that intersects a 1-m x 1-m microplot, note the microplot id 

(N, E, S, W). 

• Stems in microplot: record the total number of willow stems intersecting the microplot. 

7. Rocky Mountain National Park Elk-Vegetation Monitoring Project—Willow Monitoring—

Line Intercept Data. The information on this sheet is gathered once every 5 yr according to 

the schedule found in table 2.1. A 5.66-m tape should be laid out between the west and east 

corners of the macroplot (fig. 2.1). Record the site, location, observer, and date information. 

Conduct a line intercept transect, from west to east, measuring all shrubs (willows plus any 

other shrub species) along the length of the 5.66 m. Gaps of less than 5 cm are considered 

continuous canopy cover (fig. 2.2). 

Figure 2.2. Diagram of layout of line intercept plot used in the Rocky Mountain National Park elkvegetation monitoring program. 

If a plant canopy intersects the line in more than one location, only one height is recorded for 

whole plant, not for individual sections of the plant. For each shrub encountered along the 

line, record: 

• Species code: record species of plant being measured using a four-letter code based on 

first two letters of the genus and first two letters of species. Commonly used codes are 

provided on the data sheet. 

53

0 m 5.66 m 0.8 m 0.2 m 1.2 m

= transect line/measuring tape

= shrub

W E 
• Intercept length: using another measuring tape, record the length to the nearest 0.1 m 

from the western edge where the shrub canopy first intersects the 5.66 m tape line to 

where the eastern edge of the shrub canopy intersects the line. 

• Height: record height to the nearest 5 cm of the shrub (not necessarily on the intercept 

line). 

• Browsing: record whether the plant has been browsed by ungulates (Y/N). 

8. Rocky Mountain National Park Elk-Vegetation Monitoring Project—Microplot Willow 

Browsing Data Sheet. Measure along macroplot sides for 1 m from each permanent corner 

and mark with a survey flag. Mark fourth corner of microplots at 1.42 m from the permanent 

macroplot corners along tapes that bisect the macroplot from north (1.42 m on tape 1) to 

south (4.24 m on tape 1) and west (1.42 m on tape 2) to east (4.24 m on tape 2). Record the 

site, location, fenced, observer, and date information. Using plants whose canopies intersect 

the microplots (1 m x 1 m), select 3–5 stems per plant, measuring 10–12 stems per willow 

species, if available. A stem is identified as the portion of an individual willow plant that 

emerges from the ground surface. If 10 stems per species cannot be located using plants in 

each of the four microplots, then more stems should be selected from plants in the macroplot 

that fall outside the microplots. Items Microplot ID through Shoot sampling ratio below 

(shaded in datasheet) need only be recorded once for each stem. For each marked stem 

record: 

• Microplot ID: record which of the 4 microplots is being measured. N=North, E=East, 

S=South, W=West. 

• Plant ID Number: this is a number assigned to each plant where stems will be measured 

for browsing. 

• Stem Count: total number of stems on plant. 

• Species Code: record species of plant being measured using a 4 letter code based on first 

2 letters of the genus and first 2 letters of species. 

• Stem ID: this is a letter (A,B,C, . . .) assigned to each individual stem measured. 

• Shoot sampling ratio: determine the shoot ratio that you will be sampling by estimating 

total shoot count on the stem. To ensure an unbiased sample of shoots, you should follow 

the method described in fig. 2.3. A shoot is defined as a single section of current year’s 

growth. When sampling in early spring, shoots are the previous season’s growth. As long 

as measures are made before the commencement of new shoot extension in spring, there 

should be no confusion on this matter. In fig. 2.3, the lightest gray areas are the shoots. 

The darker areas are growth from previous seasons. If a stem is large with a high number 

of shoots, the subsampling method should shift accordingly. Plants with less than 50 

shoots can use a sampling ratio of 3 (measure every third shoot), but stems with 51–100 

shoots should use a sampling ratio of 5 (measure every fifth shoot). For 101–250 shoots, 

use a sampling ratio of 10; for stems with greater than 250 shoots a sampling ratio of 20. 

54
Figure 2.3. Diagram illustrating shoot-sampling protocol for a stem (from Bilyeu and others 2007, used 

with permission of the author). Letters indicate the order of measurements; numbers indicate lengths in 

centimeters. To represent adequately the shoot size distribution in this example, choose a sampling ratio of 

3 (which means recording measurements on every third shoot encountered as you work apically from the 

base of the stem), accommodating side branches by sampling the lowest branches first. Here, seven 

measurements are made, with two shoots apical of the last shoot sampled. The count of shoots is then 

calculated as 7 × 3 + 2 = 23. If four of the seven measured shoots were browsed, along with the two apical 

of the last shoot sampled, then the count of browsed shoots is estimated as 4 × 3 + 2 = 14, and the count 

of unbrowsed shoots as 3 × 3 + 0 = 9. 

For each sampled shoot (based on the shoot-sampling methods above), record: 

• Additional shoot: check this box if this shoot is additional beyond those counted when 

using the shoot ratio. For example, if there are 28 shoots on the plant, you would measure 

every third shoot plus one more for a total of 10 shoots (9 measured shoots x 3 [shoot 

ratio] = 27 + 1 additional measured shoot). If the total number of shoots was 52, then 12 

shoots would be measured (10 measured shoots x 5 [shoot ratio]=50 + 2 additional 

measured shoots). 

• Browsed?: indicate whether the shoot is browsed (B) or unbrowsed (U). 

• Diameter at base of shoot: using a digital or dial caliper, measure the basal diameter to 

the nearest 0.05 millimeters of the shoot at the base of the current year’s growth. Be 

careful not to squeeze the calipers shut too tightly causing damage and an inaccurate 

measure. 

• Diameter at tip of shoot: for unbrowsed shoot, use a digital or dial caliper to measure the 

tip diameter (to the nearest 0.05 mm) below the swelling of the apical bud of the shoot. 

For a browsed shoot, use calipers to measure the shoot diameter (in millimeters) at point 

of browsing. 

• Shoot length: measure the length to the nearest 0.5 cm of the shoot from the base of 

current year’s growth to tip. 

55
When sampling is complete, be sure to fill in Page __ of __ information for all sheets from a 

site. 

9. Shoot Collections: Each year in late summer, select 50 unbrowsed shoots of each willow 

species found in the microplots from plants outside the monitoring sites for each of the six 

major sampling areas: Hallowell Park-Glacier Creek, Moraine Park, Beaver Meadows, 

Hidden Valley, Horseshoe Park-Endovalley, and Cow Creek. Table 2.2 indicates the 

distribution of willow species based upon baseline data collection. Shoots collected from 

each site/species should cover a range of sizes and canopy locations (upper, lower, inner 

canopy, outer canopy) from several different plants. If additional species appear in the 

monitoring plots over time, shoots should be sampled from these species as well so that 

offtake data is complete. Place each clipped shoot in an envelope marked with the following 

information: 

• Sample area 

• Date 

• Species 

• Diameter at base of shoot (mm) 

• Diameter at tip of shoot (mm) 

• Length of shoot (cm) 

10. Check to be sure all data sheets are complete. 

11. Gather tapes and remove temporary markers and survey flags. 

12. Drying and weighing willow shoot samples—Rocky Mountain National Park Elk-Vegetation 

Monitoring Project—Willow Shoot Data for Biomass Regressions. Drying of clipped 

vegetation samples should commence within a day of collection. Dry bagged samples in a 

drying oven set at 55°C for 48 hours. If oven space is not available right away and if the 

clipped material is already dry, store loosely in paper bags in a well-ventilated location. 

Record shoot weights with and without leaves along with species, diameter, and length 

information on data sheet. 

13. Data entry and reduction 

• Copy data sheets when they are complete (including weights). Put originals into binders 

by direction of biologist in charge of elk management. Archive copies in a separate 

location in case of loss of originals. 

• Download digital photos from camera as soon as possible, print as 4×5-in, store with 

original data sheets. Archive electronic images as directed by the biologist in charge of 

elk management and the monitoring program. 

• Data entry: Enter data into database as directed by biologist in charge of elk management 

and vegetation-monitoring program. 

56
57

Table 2.1. Schedule for site visits to willow-monitoring sites and location of site marker along transect line 

and declination corrected bearing of the transect line. * Denotes baseline sampling in 2009–10, not to be 

sampled with group 1 in following years. 

Site 

Fenced? 

(Y=Yes 

N=No 

P=Planned) 

Winter offtake sampling structure 

Macroplot/lineintercept sampling 

years: 

2013 

2018 

2023 

2028 

Group 1 

years 

sampled: 

2010 

2015 

2020 

2025 

Group 2 

years 

sampled: 

2011 

2016 

2021 

2026 

Group 3 

years 

sampled: 

2012 

2017 

2022 

2027 

Group 4 

years 

sampled: 

2013 

2018 

2023 

2028 

Group 5 

years 

sampled: 

2014 

2019 

2024 

2029 

WC1 Y X 

WC2 Y X 

WC3 Y X 

WC4 Y X 

WC5 N X X X 

WC6 Y X 

WC7 Y X 

WC8 Y X 

WC9 Y X 

WC10 Y X 

WC11 Y X 

WC12 N X X X 

WC13 N X X X 

WC14 N X X X 

WC15 N X X X 

WC16 Y X 

WC17 N X X X 

WC18 N X X X 

WC19 N X X X 

WC20 N X X X 

WC21 N X X X 

WC22 N X X X 

WC23 N X X X 

WC24 Y X 

WC25 Y X 

WC26 Y X 

WC27 Y X 

WC28 Y X 

WC29 P * X 

WC30 N X X X 

WC31 N X X X 

WC32 N X X X 

WC33 N X X X 

WC34 N X X X 

WC35 N X X X 

WC36 N X X X 

WC37 P * X 

WC38 N X X X 

WC39 N X X X 
58

Site 

Fenced? 

(Y=Yes 

N=No 

P=Planned) 

Winter offtake sampling structure 

Macroplot/lineintercept sampling 

years: 

2013 

2018 

2023 

2028 

Group 1 

years 

sampled: 

2010 

2015 

2020 

2025 

Group 2 

years 

sampled: 

2011 

2016 

2021 

2026 

Group 3 

years 

sampled: 

2012 

2017 

2022 

2027 

Group 4 

years 

sampled: 

2013 

2018 

2023 

2028 

Group 5 

years 

sampled: 

2014 

2019 

2024 

2029 

WC40 P * X 

WC41 P * X 

WC42 Y X 

WC43 N X X X 

WC44 N X X X 

WC45 N X X X 

WC46 N X X X 

WC47 N * X X X 

WC48 N * X X X 

WC49 N * X X X 

WC50 N X X X 

WC51 N * X X X 

WC52 N * X X X 

WC53 P * X 

WC54 N * X X X 

WC55 N X X X 

WC56 N * X X X 

WC57 N X X X 

WNC1 X X X 

WNC2 X X X 

WNC3 X X X 

WNC4 X X X 

WNC5 X X X 

WNC6 X X X 

WNC7 X X X 

WNC8 X X X 

WNC9 X X X 

WNC10 X X X 

WNC11 X X X 

WNC12 X X X 

WNC13 X X X 

WNC14 X X X 

WNC15 X X X 

WNC16 X X X 

WNC17 X X X 

WNC18 X X X 

WNC19 X X X 

WNC20 X X X 

WNC21 X X X 

WNC22 X X X 

WNC23 X X X 

WNC24 X X X 

WNC25 X X X 

WNC26 X X X 
59

Site 

Fenced? 

(Y=Yes 

N=No 

P=Planned) 

Winter offtake sampling structure 

Macroplot/lineintercept sampling 

years: 

2013 

2018 

2023 

2028 

Group 1 

years 

sampled: 

2010 

2015 

2020 

2025 

Group 2 

years 

sampled: 

2011 

2016 

2021 

2026 

Group 3 

years 

sampled: 

2012 

2017 

2022 

2027 

Group 4 

years 

sampled: 

2013 

2018 

2023 

2028 

Group 5 

years 

sampled: 

2014 

2019 

2024 

2029 

WNC27 X X X 

WNC28 X X X 

WNC29 X X X 

WNC30 X X X 

WNC31 X X X 

WNC32 X X X 

WNC33 X X X 

WNC35 X X X 
Table 2.2. Summary of locations, willow species, and sample sizes of shoots that should be collected late 

each summer as part of the Rocky Mountain National Park elk-vegetation monitoring program. [SAGE, 

Salix geyeriana; SAMO, Salix monticola; SAPL, Salix planifolia; SABE, Salix bebbiana; SALA, Salix 

lasiandra; SAPE, Salix petiolaris; SADR, Salix drummondiana] 

Sample Area Species to be sampled 

# shoots sampled 

of 

each/species 

Total # of shoots 

to collect 

Endovalley-Horseshoe Park SAGE, SAMO, SAPL 50 150 

Beaver Meadows SAGE, SAMO, SAPL 50 150 

Moraine Park SABE, SAGE, SAMO, 50 200 

SAPL 

Cow Creek SADR, SAGE, SALA, 50 300 

SAMO, SAPE, SAPL 

Hallowell Park-Glacier Creek SAGE, SAMO, SAPL 50 150 

Hidden Valley SAGE, SAMO, SAPL 50 150 

TOTAL 1100

60
 

 

Rocky Mountain National Park Elk-Vegetation Monitoring Project 

Willow Monitoring Data—Site Characterization 

Site #:____________Fenced (Y/N)? __________ 

Location:______________________________________ 

Observer(s):_____________________________________Date (mm/dd/yyyy):______________ 

Dominant Willow Type (circle one): no willow (meadow /no willow evident) tall (> 2.5 m ht 

(height)) 

intermediate (1.5–2.5 m ht) short-young (< 1.5 m ht, no dead stems, many colored stems) 

short-old (< 1.5 m ht, larger crown w/ some dead stems, few young, colored stems) 

sapling (< 50 cm ht, largest stem < 5 mm diameter at base, small crown, no lignification) 

Ecosystem Type (circle one): fen riparian marsh wet meadow dry meadow 

Predominant Herbaceous Species: 

______________________________________________________________________________ 

Current or Recent Beaver Presence (circle all that apply): 

dam food cache cuttings tracks/droppings animal sighting none 

Site corner UTM locations (NAD83): Site center_____________________ 

GPS error (m)___________ 

N _________________________________E___________________________________ 

S _________________________________W___________________________________ 

Comments____________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________ 

61
62

Rocky Mountain National Park Elk-Vegetation Monitoring Project

Willow Monitoring Data—Macroplot Data 

Site #:_____________Location:______________________Observer(s):_____________________Date (mm/dd/yyyy):__________ 

Species

code 

% of 

plant 

in plot 

Canopy

diameters 

(cm)

Height

(cm)

Height to

tallest

bud scar 

Micro

-plot 

ID

# stems 

in

microplot

Species

code 

% of 

plant 

in plot 

Canopy 

diameters

(cm)

Height 

(cm)

Height to

tallest

bud scar 

(cm)

Micro

-plot 

ID

# stems

in 

microplot

Species Codes

Geyer’s willow Salix geyeriana=SAGE River birch or water birch Betula occidentalis=BEOC 

Plane-leaf willow Salix planifolia=SAPL Bog birch or resin birch Betula glandulosa=BEGL 

Mountain or Park willow Salix monticola=SAMO Thin-leaf alder Alnus incana=ALIN

Blue-stem or Drummond’s willow Salix drummondiana=SADR Twinberry honeysuckle Lonicera involcrata=LOIN

Bebb willow Salix bebbiana=SABE Shrubby cinquefoil Dasiphora fruticosa=DAFR 

Whiplash willow Salix lasiandra=SALA Whitestem gooseberry Ribes inerme=RIIN

Meadow willow Salix petiolaris=SAPE Wax currant Ribes cereum=RICE

Delicious raspberry Rubus deliciosus=RUDE Grayleaf red raspberry Rubus idaeus=RUID
Rocky Mountain National Park Elk-Vegetation Monitoring Project 

Willow Monitoring Data—Line-Intercept Data 

Site #:___________________________________Location:__________________________________ 

Observer(s):_____________________________________________Date (mm/dd/yyyy):__________ 

Line Intercept Data (5.66-m line): 

Species Intercept Max Browse Species Intercept Max Browse

Code length (m) Height (cm) (Y/N) Code length (m) Height (cm) (Y/N) 

 

Species Codes: 

Geyer’s willow Salix geyeriana=SAGE 

Plane-leaf willow Salix planifolia=SAPL 

Mountain or Park willow Salix monticola=SAMO 

Blue-stem or Drummond’s willow Salix drummondiana=SADR 

Bebb willow Salix bebbiana=SABE 

Whiplash willow Salix lasiandra=SALA 

Meadow willow Salix petiolaris=SAPE 

River birch or water birch Betula occidentalis=BEOC 

Bog birch or resin birch Betula glandulosa=BEGL 

Thin-leaf alder Alnus incana=ALIN 

Twinberry honeysuckle Lonicera involcrata=LOIN 

Shrubby cinquefoil Dasiphora fruticosa=DAFR 

Whitestem gooseberry Ribes inerme=RIIN 

 Wax currant Ribes cereum=RICE 

 Delicious raspberry Rubus deliciosus=RUDE 

 Grayleaf red raspberry Rubus idaeus=RUID 

63
Rocky Mountain National Park Elk-Vegetation Monitoring Project 

Microplot Willow Browsing Data 

Site #:___________________________Location:__________________________________________ 

Fenced?_________Observer(s):_______________________________________ 

Date (mm/dd/yyyy):_______________ Page____ of ______ 

Microplot Data: Items in gray need only be filled out once for each marked stem. 

 

Microplot 

(N, E, 

S, W) 

Plant 

ID # 

Species 

code 

Total 

stem 

count 

Stem 

ID 

letter 

Shoot 

ratio 

Additional

shoot? 

(check if 

Yes) 

Browsed? 

B/U 

Diameter 

at base 

of 

shoot 

(mm) 

Diameter

at tip of 

shoot 

(mm) 

Shoot 

length 

(cm) 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

64
Rocky Mountain National Park Elk-Vegetation Monitoring Project 

Willow Shoot Data for Biomass Regressions 

Sample Species Diameter at Diameter at Shoot Shoot 

area code base of tip of shoot length (cm) weight 

shoot (mm) (mm) without 

leaves (g) 

 

 

65
Appendix 3: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Upland-Herbaceous Site Monitoring Protocol 

The following steps outline the process of visiting and sampling the upland-herbaceousmonitoring sites that are part of the Rocky Mountain National Park elk-vegetation monitoring 

program. All site locations and special instructions are with the park biologist in charge of the 

monitoring program and should be acquired from this individual. Italic type indicates the name 

of datasheet to be filled out. Sample datasheets can be found at the end of this appendix. The 

sampling of general site characteristics, reference photos, and line-intercept measures of shrub 

cover should be performed at all sites once every 5 yr during summer according to the timetable 

set out in table 3.1. Only those sites scheduled for sampling in a given year should be measured 

for winter offtake (consumption) in spring each year following the timetable set out in table 3.1. 

Winter offtake measures should be collected prior to green-up of new growth each year, and if 

not possible, before such green-up has advanced to any great extent. Green-up typically occurs 

between late March and late April in these sites. Placement of grazing cages for monitoring of 

winter consumption should be conducted in late August-early September—ideally after the peak 

growing season, but before elk herds arrive on the winter range and begin to graze to any great 

extent. Photos should be taken any time an event of interest occurs at a site (for example, tree 

falls into site, ground torn up by animals/humans, etc.). Nothing should be removed from any 

site except for approved plant samples listed on the research permit. A general schematic of 

upland-monitoring plot design can be found in figure 3.1. 

= plot center marker w/ aluminum cap = paired ungrazed plot 

=30 m transect line = randomly placed grazing cage 

Figure 3.1. Schematic of upland-vegetation-monitoring plot design.

66
1. Gather equipment and supplies 

FOR ALL FIELD WORK 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard, notebook 

• Handheld GPS unit and spare batteries 

• Compass set to proper declination (check current declination prior to each field season at 

http://www.ngdc.noaa.gov ) 

• Metal detector (may be needed to find site center) 

• Hammer or mallet (for setting cages in August through September) 

• Digital camera with extra batteries 

• Maps 

• Pliers, bailing wire (for cage repair) 

• List of site locations (to be supplied by park biologist in charge of monitoring program) 

FOR LINE INTERCEPT 

• Tape measure (longer than 30 m) 

• 4 chaining pins or stake to hold ends of tape 

• Clinometer 

• Five-meter tape measure and meter stick for plant heights 

• Vegetation ID key: Stevens, J.E., J. Lemly, and R. Thomas, 2005, Dichotomous key to 

the plant associations of Rocky Mountain National Park: Fort Collins, Colo., Colorado 

State University, Colorado Natural Heritage Program, 49 p. 

FOR REFERENCE PHOTO POINT 

• Laminated placard (light, not white) with following information: 

• dry erase marker 

• wipes or cloth to clean placard 

FOR PLOT CLIPPIPNG & COLLECTION 

• 0.25-m2

 (square meters) steel circular clipping rings (usually kept in the wildlife cache—

look like a steel ring divided into quarters) 

• Scissors, shears, or other clippers appropriate for clipping grasses (2 per crew member) 

• Small paper bags (lunch-bag size) and small coin envelopes (42 per site) , stapler or 

rubber bands, Sterilite container for storage 

• Nitrile gloves (for clearing scat from plot) 

• Sharpie® marker for labeling bags 

2. Navigate to the site center using GPS and UTM coordinates on list provided by park 

biologist in charge of monitoring program. Be sure to have WAAS enabled on the GPS to 

increase accuracy (although this will shorten battery life). Site center is a rebar stake with 

aluminum cap pounded flush with the ground imprinted with “ELK-VEG MONITOR—NPSDO NOT DISTURB—ROMO STUDY 06013” and the plot number. The presence of grazing 

cages at a site should indicate that you are in the correct overall location. The metal detector 

may be useful for locating plot center. 

67

ROMO EVMP 

SITE___________ 

DATE _________ 

DIRECTION_____ 
3. Rocky Mountain National Park Elk-Vegetation Monitoring Program—Upland Site 

Characterization Data Sheet. The information on this sheet is gathered once every 5 yr 

according to the schedule found in table 3.1. Dimensional variables shall be in metric units. 

• Site name/number: letter and numeric combinations—U(upland)+ NC(noncore) or 

C(core)+ individual number. For example, UNC4 would be upland, noncore site 4. 

• Location: general description of the location (for example, Moraine Park, Beaver 

Meadows, etc.). 

• Date: full date including year (mm/dd/yyyy). 

• Start time: time starting plot. 

• E.T.: end time—time work was finished. 

• # persons: size of field crew making measurements. 

• Observers: last name of those observing, measuring and recording data. 

• Site coordinates: UTM easting and northing coordinates of site center if different from 

table 3.1—be sure the GPS unit is set at UTM NAD83 zone 13, WAAS-enabled. 

• GPS error: record error on GPS in meters. 

• General comments: additional information (for example, distance and bearing from 

landmarks) to help in future relocations, information about events at site (slides, fires, 

etc.). 

• From site center record: 

• Slope (percent) using clinometer. 

• Aspect (flat, N, NE, E, SE, S, SW, W, NW) for later comparison with data derived 

from Digital Elevation Models (DEMs). 

• Elevation: record reading from GPS in meters (if GPS is set for statute to help in 

navigation with vehicle, use conversion of 3.281 ft=1 m). 

• Site characteristics: as described on data sheet. Animal signs (scat, tracks, presence, 

excavations) should be limited to ungulates that may graze in the area and burrowing 

animals that might affect herbaceous plants or bury site markers. Be sure to identify 

species of ungulate. 

• Dominant vegetation type: record which one of these general vegetation types you 

observe at the site based on the Dichotomous Key to the Plant Associations for Rocky 

Mountain National Park (Stevens and others, 2005). Choices are: Herbaceous Upland 

Montane (MU4), Shrub-Upland-Lower Montane-Bitterbrush (MU142), Shrub-UplandLower Montane-Undifferentiated (MU14), Shrub-Upland-Big Sagebrush (MU141), 

Ponderosa Pine-Graminoid (MU34), Ponderosa Pine-Rockland (MU35), and Ponderosa 

Pine-Shrubland (MU36). 

• Shrub cover (line intercept): using the capped rebar site marker as an anchor point, 

stretch a 30-m tape along the true compass bearing listed in table 3.1 for the site (see 

figure 3.2). True bearing is magnetic bearing plus or minus declination. It is best to use a 

compass with the declination preset. The Marker Point Location column in table 3.1 

specifies the position of the site center marker on this 30 m transect: 

• middle: Place the 15-m mark on the tape on the site center marker, extend the tape 15 

m in the true bearing given in table 3.1, and 15 m along the back bearing (bearing 

minus 180 degrees) using compass set to the correct declination. 

• west or east: place the west or east end of the 30-m tape on the site center marker and 

extend the tape 30 m along the true bearing given in table 3.1. 

68
0 m 4.6 m 1.8 m 30 m 9.2 m

= transect line/measuring tape

= shrub

Figure 3.2. Schematic diagram of line-intercept method to measure upland shrub cover. 

• Along the 30-m line, conduct a line-intercept plot, measuring all live shrubs along the 

length of the line. For each shrub encountered along the line, record: 

• Species: four letter identification codes should be used for each shrub species, based 

on the first two letters of the genus and the first two letters of the species (for 

example, Artemisia tridentata=ARTR, Purshia tridentata=PUTR, Chrysothamnus 

nauseosus=CHNA, etc). 

• Intercept length: distance along the tape to nearest 0.1 m where the outer edges of the 

shrub canopy intersect the line (see figure above). 

• Height: maximum height of the shrub (not necessarily on the intercept line) to nearest 

0.05m. 

4. Take 2 digital photos from the site center and looking in opposite directions along the 

transect line. Place the laminated placard with the site name/number, date, and the direction 

of the photo (for example, N if photo is taken looking north from site location point) within 

the photo field. 

5. Rocky Mountain National Park Elk-Vegetation Monitoring Program—Upland Herbaceous 

Offtake Data Sheet. These measures shall be gathered annually according the schedule 

outlined in table 3.1. Each site has three grazing-exclusion cages. The objective here is to 

collect comparable data from the 0.25-m2

 (clipping ring) plots outside (available for 

fall/winter grazing) and inside the exclusion cages. 

Uncaged plot: (Do first to minimize your influence) The uncaged plot should be 3–5 m from 

the caged plot to reduce the influence of the cage on the uncaged plot (trailing/trampling that 

may occur along the edge of the cage, snow deposition on one side of the cage, etc). Select a 

general location south of the caged plot with similar slope/aspect, overstory/exposure, 

species composition, and soil characteristics. If the area to the south of the caged plot is 

unusable, select the first suitable location found (in priority order) to the west, north, or east. 

All attempts should be made to not trample either study plot. Be sure that each pair of plots 

has the same quadrat/cage number and that no other pair in that site has the same numbers. 

Caged plot: Place 0.25-m2

 steel circular quadrat in the center of the area protected by a 

grazing cage. 

Record the following information on the data sheet: 

69
• Site name/number: letter and numeric combinations—U(upland) + NC(noncore) or 

C(core) + individual number. For example, UNC4 would be upland, noncore site 4. 

• Clipped by: last names of observers doing the clipping. 

• Date: full date including year (mm/dd/yyyy) plot was clipped. 

• Weighed by: last name of observers conducting the weighing. 

• Date: full date including year (mm/dd/yyyy) samples were weighed. 

• Cover class: for each 0.25-m2

 plot, inside and outside the grazing exclusion cage, first 

(before clipping) visually assess and record percent coverage of the previous growing 

season’s vegetation and other categories listed on the data sheet. Be sure to record zeroes. 

The clipping ring is divided into 4 quadrants (each 25 percent) to aid this assessment 

(observer mentally “compresses” categories into one or more quadrants and can generally 

assess as 1⁄2 (12.5 percent), 1⁄4 (6.25 percent), 1/8 (3.125 percent) of a quadrant. For 

categories that are present but less than roughly 2 percent, enter “T” (for trace). The 

values should total 100 percent, although the presence of overhanging shrubs could 

potentially increase this number to greater than 100 percent. 

• Clipping and collecting: At each 0.25-m2

 plot, clip biomass at ground level and sort by 

category (sub-shrub, forbs, graminoids, other not-litter). Litter is considered to be nonrooted dead and down plant material in the plot and is not collected. Rooted plants which 

appear to be gray, in contact with the soil, and more than one season old are also 

considered to be litter. Litter should not be confused with plant material produced the 

previous season which is now standing dead and should be collected as graminoids or 

forbs—these plants will appear yellow, brown, or tan in color. 

When clipping vegetation, if a category is not present and not collected, be sure to enter a 

zero for that category in the weighing section of the data form. This prevents confusion as 

to whether the sample was misplaced or non-existent. When clipping in the spring, be 

sure to remove from the sample any new green growth that is from the current year’s 

production. The spring sample is only designed to measure winter plant consumption by 

ungulates and therefore no new growth should be included. 

Definitions of plant categories and which types to collect (clip) are as follows: 

• Graminoids: includes grasses and grass-like plants such as rushes (Juncus spp.) and 

sedges (Carex spp.). Collect only previous season’s growth and remove current 

season’s green growth from clippings. 

• Forbs: collect only previous season’s growth and remove current season’s green 

growth from clippings. 

• Sub-shrubs: predominantly low-growing (less than 20 cm) herbaceous plants with 

woody stems and basal branches—includes such plants as fringed sage (Artemisia 

frigida), Oregon grape (Mahonia repens), and Kinnikinnik (Arctostaphylos uva-ursi). 

Clip all parts of subshrubs, woody as well as the previous year’s herbaceous growth. 

Place sorted clipped plant material in paper bags, labeled with: 

• ROMO EVM (stands for Rocky Mountain NP Elk Vegetation Monitoring) 

• full date (MM/DD/YYYY) 

• site name/number (for example, UC20 or UNC1, etc.) 

• quadrat/cage number (1–3), whether IN or OUT (use different colored labeling for 

IN vs. OUT bags) 

70
• bag contents (category as listed on data sheet) 

• Storage of cages: when clipping is complete, store cages on sites—securely staked in a 

group on the edge of a clearing or away from center of site until fall when the cages will 

be relocated. 

6. Drying and weighing: the drying of clipped vegetation samples should commence within a 

day of collection. Dry bagged samples in a drying oven set at 55°C for 48 hr—longer if 

samples are exceptionally wet when collected. If oven space is not available right away and if 

the clipped material is already dry, store loosely in paper bags in well-ventilated location. 

After plant samples are dried, weigh contents of each bag by placing in a tared pan on a scale 

(balance). Measure dry weight of sample in the bag to the nearest 0.01 g and record this 

weight on the bag and on the associated data sheet. Return data sheets to the biologist in 

charge of this monitoring program after weights are recorded. 

7. Relocating cages in fall: Relocate the cages at the appropriate sites following the timetable in 

table 3.1 each fall (late August/early September before elk presence on the winter range 

increases to winter concentration levels). Remember that the dates in table 3.1 are for the 

year the sites will be sampled, therefore in fall 2009, the Group 2 sites to be sampled in 

spring 2010 should have cages set. Using a random number table (table 3.2), select a random 

compass bearing to determine direction from the site-center point and a random number of 

full paces (between 1 and 100) to travel in that direction. If the distance or direction to locate 

a cage places the cage out of the upland vegetation type, first halve the original distance. If 

the cage location is still outside the vegetation type, pick a new random direction and 

distance. If site is UC14, UC18, or UC20, be sure to follow the special instructions to protect 

cultural resources—acquire photos for cage placement at these sites from park biologist in 

charge of monitoring program. Cages should be located no more than 125 m from the site 

center to prevent the possibility of overlap with other upland monitoring sites. If cages are 

not easily visible from the site center due to topography or trees, note location of cages on the 

data sheet (bearing and distance from center). Grazing cages should be staked to the ground 

using three 4-ft lengths of rebar placed approximately equidistant along the cage perimeter, 

woven through the fencing mesh, and hammered at least 1ft into the ground. In this manner, 

the rebar will not protrude above the height of the cage. A 4-ft square of chicken wire should 

be placed over the top of each cage to prevent elk grazing over the top of the cage. The 

chicken wire should be crimped around the edge of the top of the cage and fixed in place 

with 2–3 shoat or pig rings. Use bailing wire to connect the cage to each length of rebar in 

one or two places. Two or three 6-in u-shaped landscaping staples may be used to 

additionally hold the bottom strand of fence wire to the ground to prevent elk from nosing 

under the cage, though their usefulness is limited in loose, gravel soils. 

8. Data entry and reduction 

• Copy data sheets when they are complete (including weights). Put originals into binders 

by direction of the biologist in charge of elk management. Archive copies in a separate 

location in case of loss of originals. 

• Download digital photos from camera as soon as possible, print as 4×5-in, store with 

original data sheets. Archive electronic images as directed by the biologist in charge of 

elk management and the monitoring program. 

• Data entry: Enter data into database as directed by the biologist in charge of elk 

management and vegetation monitoring program. 

71
Table 3.1. Schedule for site visits to upland-monitoring sites and location of site marker along transect line and declination

the transect line. 

Winter offtake sampling structure Line- (herbaceous clipping in April of sampling year) intercept 

Group 1 Group 2 Group 3 Group 4 Group 5 sampling Bearing Marker years: Site years years years years years of line point Gene

sampled: sampled: sampled: sampled: sampled: 2013 from true location 

2009 2010 2011 2012 2013 2018 north 

2014 2015 2016 2017 2018 2023 

2019 2020 2021 2022 2023 2028 

2024 2025 2026 2027 2028 

UC1 X X mid X dl 2e .41 

UC2 X X X dl 1e .64 mid

UC3 X X mid X dl 1e .04 UC5 X X X middl 2e .64 

UC8 X X mid X dl 2e .62 

UC9 X X X dl 1e .60 mid

UC11 X X X dl 1e .24 mid

UC12 X X X middle 268 ~5 m off h

UC13 X X X middl 2e .60 

UC14 X X mid X dl 2e .08 

UC16 X X mid X dl 2e .54 UC17 X X X dl 2e ~1 m mid 06 off 

0 

UC18 X X X e 3st ~3 m of w 08 t

 f 

UC19 X X X dl 2e ~3 m fr mid 68 om 

 

UC20 X X X middl 1e .84 

UC21 X X X dl 3e .10 mid

UC24 X X X dl 2e .68 mid

UC25 X X X 

UC26 X X X middl 1e .42 

UC28 X X mid X dl 2 e .10 

UC29 X X X UC31 X X mid X dl 1e .82 UC34 X X mid X dl 2e .72 UC35 X X X middl 2e .54 

UC36 X X mid X dl 9e .4 UNC2 X X mid X dl 7e 8 

72
73

Site 

Winter offtake sampling structure 

(herbaceous clipping in April of sampling year) Line- intercept 

sampling 

years: 

2013 2018 2023 2028 

Marker 

point 

location 

Bearing 

of line 

from true 

north 

Gene

Group 1 

years 

sampled: 

2009 2014 2019 2024 

Group 2 

years 

sampled: 

2010 2015 2020 2025 

Group 3

years 

sampled: 

2011 2016 2021 2026 

Group 4

years 

sampled: 

2012 2017 2022 2027 

Group 5

years 

sampled: 

2013 2018 2023 2028 

UNC4 X X X middle 254 . 

UNC5 X X X middle 244 . 

UNC6 X X X middle 271 . 

UNC8 X X X . . . 

UNC9 X X X middle 12 . UNC10 X X X NW end 152 . UNC14 X X X middle 260 . 

UNC16 X X X middle 358 . UNC21 X X X N end 180 . 

UNC22 X X X 

UNC24 X X X 9.5 m 12 Extends 2

9.5 m at 1

UNC27 X X X middle 186 . 

UNC30 X X X UNC32 X X X middle 66 . 

UNC34 X X X middle 202 . 

UNC38 X X X middle 264 . 

UNC40 X X X middle 12 

UNC41 X X X 

UNC42 X X X middle 198 

UNC49 X X X middle 82 

UNC50 X X X . 

UNC60 X X X middle 78 . 
Table 3.2. Random-number table. With eyes closed, drop a pencil anywhere on the page to indicate a 

starting place in the table. If single-digit random numbers are needed, use the last digit of the number 

you started on as your first random number and proceed down the column to the bottom of the page 

and then to the top of the next column, and so on. Ignore duplicates and record zero (0) as ten (10). If 

two-digit random numbers are needed, use last 2 digits of starting number and proceed as above. If 

looking for bearing, use last 3 digits and only choose numbers less than or equal to 360. 

 13962 70992 65172 28053 02190 83634 66012 70305 66761 88344 

 43905 46941 72300 11641 43548 30455 07686 31840 03261 89139 

 00504 48658 38051 59408 16508 82979 92002 63606 41078 86326 

 61274 57238 47267 35303 29066 02140 60867 39847 50968 96719 

 43753 21159 16239 50595 62509 61207 86816 29902 23395 72640 

 83503 51662 21636 68192 84294 38754 84755 34053 94582 29215 

 36807 71420 35804 44862 23577 79551 42003 58684 09271 68396 

 19110 55680 18792 41487 16614 83053 00812 16749 45347 88199 

 82615 86984 93290 87971 60022 35415 20852 02909 99476 45568 

 05621 26584 36493 63013 68181 57702 49510 75304 38724 15712 

 06936 37293 55875 71213 83025 46063 74665 12178 10741 58362 

 84981 60458 16194 92403 80951 80068 47076 23310 74899 87929 

 66354 88441 96191 04794 14714 64749 43097 83976 83281 72038 

 49602 94109 36460 62353 00721 66980 82554 90270 12312 56299 

 78430 72391 96973 70437 97803 78683 04670 70667 58912 21883 

 33331 51803 15934 75807 46561 80188 78984 29317 27971 16440 

 62843 84445 56652 91797 45284 25842 96246 73504 21631 81223 

 19528 15445 77764 33446 41204 70067 33354 70680 66664 75486 

 16737 01887 50934 43306 75190 86997 56561 79018 34273 25196 

 99389 06685 45945 62000 76228 60645 87750 46329 46544 95665 

 36160 38196 77705 28891 12106 56281 86222 66116 39626 06080 

 05505 45420 44016 79662 92069 27628 50002 32540 19848 27319 

 85962 19758 92795 00458 71289 05884 37963 23322 73243 98185 

 28763 04900 54460 22083 89279 43492 00066 40857 86568 49336 

 42222 40446 82240 79159 44168 38213 46839 26598 29983 67645 

 43626 40039 51492 36488 70280 24218 14596 04744 89336 35630 

 97761 43444 95895 24102 07006 71923 04800 32062 41425 66862 

 49275 44270 52512 03951 21651 53867 73531 70073 45542 22831 

 15797 75134 39856 73527 78417 36208 59510 76913 22499 68467 

 04497 24853 43879 07613 26400 17180 18880 66083 02196 10638 

 95468 87411 30647 88711 01765 57688 60665 57636 36070 37285 

 01420 74218 71047 14401 74537 14820 45248 78007 65911 38583 

 74633 40171 97092 79137 30698 97915 36305 42613 87251 75608 

 46662 99688 59576 04887 02310 35508 69481 30300 94047 57096 

 10853 10393 03013 90372 89639 65800 88532 71789 59964 50681 

 68583 01032 67938 29733 71176 35699 10551 15091 52947 20134 

74
Rocky Mountain National Park Elk-Vegetation Monitoring Program 

Upland Site Characterization Data Sheet 

Site name/number: __________________ Location:___________________________ 

Date (mo/da/yyyy): ____________ Start: ______ E.T. _______ # Persons ___________ 

Observers: _______________________________________ 

 

Site Coordinates: UTM NAD83 GPS make/model: ___________ 

Easting___________________Northing____________________Error (m)_________ 

General Comments: 

Slope %:______________Aspect______________GPS elevation (m)___________________ 

Site Characteristics: 

Soil Type/Wetness (wet/dry; rocky, sandy, clay, loam, 

etc):_______________________________ 

Animal Signs: Spp. Evidence

Vegetation type:___________________________________ 

Shrub cover: line-intercept method Marker Point Location (if different from table 3.1):______ 

 Bearing (if different from table 3.1):_______ 

Species Intercept length Height (m Species Intercept length Height 

(m) (m) 

 

75
Rocky Mountain National Park Elk-Vegetation Monitoring Program 

Upland Herbaceous Offtake Data Sheet 

Site name/number _______________ Clipped by___________________________ 

Date____________/20____ 

Weighed by_____________________________Date__________________ 

Quadrat OUTSIDE Cage Quadrat INSIDE Cage Life Forms Weight (g) Weight (g) (standing dead) 1 2 3 1 2 3 

Graminoids Graminoids 

Forbs Forbs 

Sub-Shrubs Sub-Shrubs 

Other Other

Quadrat OUTSIDE Cage Quadrat INSIDE Cage 

Cover Class % cover Cover Class % cover 

1 2 3 1 2 3 

Bare Ground Bare Ground 

Litter Litter 

Grams Grams 

Forbs Forbs 

Cactus Cactus 

Shrub Shrub 

Sub-shrub Sub-shrub 

Rock Rock 

Scat Scat 

Moss Moss 

Hole Hole 

Other Other

UTM (NAD83) location of stored cages: Easting______________Northing______________ 

Comments:____________________________________________________________________

______________________________________________________________________________ 

NOTE: IF NO COLLECTION MADE OF A CATEGORY, ENTER A “0” IN THE 

WEIGHT COLUMN 

76
Appendix 4: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Aspen Monitoring Site-Establishment Protocol 

The following steps outline the process of establishing aspen-monitoring sites as part of 

the RMNP elk-vegetation monitoring program. Boldface type indicates the name of an 

associated monitoring protocol. Italic type indicates the name of datasheet to be filled out. Plot 

establishment should be conducted during summer, preferably when the majority of annual 

growth has already occurred and before elk begin browsing to any great extent in the fall. 

Nothing should be removed from any site except for approved plant samples listed on the 

research permit. 

1. Using a GIS (geographic information system) program, randomly select potential sites from 

available aspen areas. If new sites are desired within aspen fences, use GIS software and 

current fence and vegetation maps to identify the fenced areas that need to be monitored, and 

use a random-point generator to select points within the fences. You should buffer the 

fenceline so that the points fall at least 5 m from the fence. If the sites need to be selected 

from aspen area outside the fence, use a map of projected aspen vegetation to determine area 

to select from. Be sure to buffer the fence by 10 m so that plots won’t fall in areas where elk 

may trail along the fenceline and cause excessive trampling or herbivory and so that plots 

won’t fall in areas where there may be disturbance caused by fence building. All intended 

sample locations should be checked with NPS cultural-resources staff to ensure culturalresources compliance. 

2. Gather equipment 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard 

• Hammer or mallet for pounding in site markers 

• 2 tape measures at least 25 m in length for plot layout 

• 4 pieces of 6-in length rebar (if approval occurs in the future because of problems with 

frost heaving of site markers, these rebar pieces may be changed to 1 ft in length or 

longer) 

• 4 aluminum survey marker caps imprinted with “ELK-VEG MONITOR—NPS-DO NOT 

DISTURB—ROMO STUDY 06013” 

• Metal die kit 

• 10 chaining pins or other stakes for holding down tape measure 

• Compass (declination should be set to appropriate number) 

• Handheld GPS unit and spare batteries 

• Diameter tape (tape that converts circumference to diameter) 

• Digital camera 

77
• Laminated placard (light, not white) with following information: 

• dry erase marker 

• wipes or cloth to clean placard 

3. Locate the plot using GPS. Be sure to have WAAS enabled on the GPS to increase accuracy 

(although this will shorten battery life). The site should be surveyed to be sure it is the correct 

vegetation type—predominantly aspen—and to be sure that placing the plot using that point 

will not lead to the majority of the plot lying in a vegetation type other than aspen. The plot 

should be located within the stand of aspen so as not to include edge or mixed conifer/aspen 

areas. Conifer in the understory of a stand with an aspen overstory is acceptable. Assess 

whether there are any other conflicts (roads, trails, picnic areas, campgrounds, or other 

human impacts) which may make the site unacceptable for use in the monitoring study. If the 

plot center needs to be moved, move the plot 10 m in the cardinal direction that will put it in 

the aspen vegetation type. If a 10 m move does not result in successfully locating a plot 

center in the target vegetation type, moving an additional 10 m toward the vegetation type 

may be attempted. If this second attempt at relocation does not succeed in achieving an 

appropriate plot location, abandon this point and move to another. If cultural artifacts or 

indications of cultural resource issues are identified, discontinue work and contact park 

cultural resources staff before proceeding. Do not remove any artifacts, or animal, plant, or 

geologic material unless approved on the research permit for this project. 

4. A 5-m × 5-m square plot should be located as close to the random point as possible. Assign 

an unused site number. Do not reuse numbers if a previous site has been discontinued. The 

plot should be marked with rebar stakes in each corner. All corners should have UTM 

coordinates marked with a GPS set to NAD83 projection. The starting point for the plot 

should be determined as the landmark corner and its coordinates and general 

direction/location (that is, southeast corner or south corner) in relation to the rest of the plot 

should be noted on the data sheet. 

5. From the landmark corner (#1), stretch a 25-m tape 5 m along a line that will ensure the plot 

falls within the stand. Place a rebar marker stake at the 5-m point. This is corner #2. Run 

another tape at a 90° bearing for 5 m from the first tape to make the second side and also 

mark corner (#4) with a stake. To mark the last corner (#3), take bearings 90° from corners 

#2 and #4 and run a tape 5 m from each of these corners. If the meeting point does not appear 

square, either by bearing line or by 5-m distance along the line, remeasure corners #2 and #4 

to ensure the last corner is placed as accurately as possible. Trueing of the corners can also be 

achieved by running a tape 7.07 m across the diagonal from corner #1 to corner #3 and from 

corner #2 to corner #4. Put in a rebar stake at the final corner. Leave tape measures in place 

until finished measuring the plot (fig. 4.1). 

6. Dissect plot into four quarters by placing tape measures or cord across the mid-section of 

each line (fig. 4.1). This will make it easier to measure and account for all trees in the plot. 

78

ROMO EVMP 

SITE___________ 

DATE _________ 

CORNER_____ 
Figure 4.1. Diagram of aspen monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

monitoring program. 

7. Once the plot has been laid out, Proceed to Rocky Mountain National Park ElkVegetation Monitoring Program—Aspen Site Monitoring Protocol (Appendix 2), step 3, 

data sheet titled Rocky Mountain National Park Elk-Vegetation Monitoring Project—Aspen 

Monitoring Data Sheet . 

8. Aluminum caps should be placed on top of each piece of rebar that mark the corners. These 

caps should have the following information imprinted on them: “ELK-VEG MONITOR— 

NPS-DO NOT DISTURB—ROMO STUDY 06013”. The plot name/number and the corner 

number will need to be added at the time of plot establishment using a die-stamping kit. 

Rebar should be hammered in such that the cap is flush with the ground. 

9. When all data collection is complete, remove measuring tapes and temporary markers. 

Double check to be sure that all rebar is pounded flush to the ground before leaving the site at 

the end of the visit. 

79

5 m 

5 m 

2.5 m 

 = subdivided plot lines 

= landmark corner, permanent rebar marker with aluminum cap 

= corners marked with permanent rebar marker with aluminum cap 

1 2 

4 3 
80

Appendix 5: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Site-Establishment Protocol 

This protocol outlines the procedures for selecting and establishing willow-monitoring 

sites as part of the RMNP elk-vegetation monitoring program. Boldface type indicates the name 

of an associated monitoring protocol. Italic type indicates the name of datasheet to be filled out. 

Plot establishment should be conducted during summer, preferably when the majority of annual 

growth has already occurred and before elk begin browsing to any great extent in the fall. 

Nothing should be removed from any site except for approved plant samples listed on the 

research permit. 

1. Using a GIS program, randomly select potential sites from available willow areas. If new 

sites are desired within willow fences, use GIS software and current fence and vegetation 

maps to identify the fenced areas that need to be monitored and use a random-point feature to 

select points within the fences. You should buffer the fenceline so that the points fall at least 

5 m from the fence. If the sites need to be selected from willow area outside the fence, use a 

map of projected willow vegetation to determine area to select from. Again, be sure to buffer 

the fence to a distance of 10 m so that plots won’t fall in areas where elk may trail along the 

fenceline and cause excessive trampling or herbivory and so that plots won’t fall in areas 

where there may be disturbance caused by fence building. All intended sample locations 

should be checked with NPS cultural-resources staff to ensure cultural-resources compliance. 

2. Gather equipment needed to establish plot 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard 

• Hammer or mallet for pounding in site markers 

• 2 tape measures at least 25 m in length for plot layout 

• 4 pieces of 6-in length rebar (if approval occurs in the future because of problems with 

frost heaving of site markers, these rebar pieces may be changed to 12–18-in length or 

longer) 

• 4 aluminum survey marker caps imprinted with “ ELK-VEG MONITOR—NPS-DO 

NOT DISTURB—ROMO STUDY 06013” 

• Metal die kit 

• 10 chaining pins or other stakes for holding down tape measure 

• Compass (check current declination prior to each field season at 

http://www.ngdc.noaa.gov ) 

• 12 survey flags for marking microplot corners 

• Handheld GPS unit and spare batteries 

• Digital camera 

• Laminated placard (light, not white) with following information: 

ROMO EVMP 

SITE___________ 

DATE _________ 

CORNER_____ 
• dry erase marker 

• wipes or cloth to clean placard 

3. Navigate to desired plot center using GPS unit and coordinates of randomly selected points. 

Be sure to have WAAS enabled on the GPS to increase accuracy (although this will shorten 

battery life). Survey site to be sure it is the correct vegetation type (willow) and to be sure 

that placing the plot using that center point will not lead to the majority of the plot lying in a 

vegetation type other than either willow, other riparian shrub interspersed with willow, or 

meadow interspersed with willow. If the plot center needs to be moved, move the plot 10 m 

in the cardinal direction that will put it in the willow vegetation type. If a 10-m move does 

not result in successfully locating a plot center in the target vegetation type, moving an 

additional 10 m toward the vegetation type may be attempted. If this second attempt at 

relocation does not succeed in achieving an appropriate plot location, abandon this point and 

move to another. If the general area does not appear to have the potential to support willow 

(for example, the area is too dry, dead willow exist but indications that the water regime has 

changed and no longer will support willow, or no sign of willow in the general area (not just 

the plot area)) then proceed to another random point. If cultural artifacts or indications of 

cultural resource issues are identified, discontinue work and contact park cultural resources 

staff before proceeding. Do not remove any artifacts, or animal, plant, or geologic material 

unless approved on the research permit for this project. 

4. Set a stake to temporarily mark the plot center. Assign an unused site number. Do not reuse 

numbers if a previous site has been discontinued. Site corners will be marked with rebar 

stakes with aluminum caps pounded flush with the ground imprinted with “ELK-VEG 

MONITOR—NPS-DO NOT DISTURB—ROMO STUDY 06013”. Use metal die kit to 

additionally stamp four caps of these caps with the site number (WC # or WNC#) and the 

cardinal direction of each corner (N,E,S,W). This can be done ahead of time, if desired. 

5. Using a compass with declination appropriately set, draw out the measuring tape end on a 

bearing due north for 2.83 m. Pin the end of the tape with chaining pin. Place permanent 

rebar marker at same point as chaining pin. This is the N corner of the plot. 

6. From this north corner marker, proceed 5.66 m due south through the center with the tape 

spool. Mark end with chaining pin and permanent rebar marker. This is the S corner of the 

plot. 

7. Return to plot center (2.83 m along the tape). Pull the tape end of the second tape 2.83 m due 

west and mark the W corner of the plot with a chaining pin to hold tape and a permanent 

rebar marker. 

8. Proceed 5.66 m due east through the plot center with the tape spool, mark the E corner of the 

plot with a chaining pin and a permanent rebar marker. 

9. Use additional tapes or cord to connect the 4 corners of the macroplot (4-m × 4-m plot), 

keeping tapes as straight as possible. Each side should measure 4 m between adjacent 

corners. If not, redo steps 3–6 as needed to “square” the plot. 

10. Measure along macroplot sides for 1 m from each permanent corner and mark with a survey 

flag. Mark the fourth corner of microplots at 1.42 m from the permanent macroplot corners 

along tapes that bisect the macroplot from north (1.42 m on tape 1) to south (4.24 m on tape 

1) and from west (1.42 m on tape 2) to east (4.24 m on tape 2). The distance between each 

adjacent survey flag should be 1 m. If it is not, redo until microplot is square. 

81
82

11. The plot should now be laid out with one 4-m × 4-m macroplot with four permanent rebar 

corner markers and one temporary center marker, one 5.66 m transect line running from the 

west to the east corner, and four 1-m × 1-m microplots located in each corner of the 

macroplot. The plot should also have one permanent corner marker and three survey flag 

corner markers each (see fig. 5.1). 

12. Place appropriate stamped aluminum caps on each rebar corner. 

13. Proceed to Rocky Mountain National Park Elk-Vegetation Monitoring Program Willow 

Monitoring Protocol (Appendix 3), Step 4, and complete information on all four data sheets 

(Site Characteristics, Macroplot Data, Line Intercept, and Browse Data). 

14. When all data collection is complete, remove measuring tapes, temporary center marker, and 

temporary survey flags. Double check to be sure that all rebar is pounded flush to the ground 

before leaving site at end of visit. 

Figure 5.1. Diagram of willow-monitoring plot layout for the Rocky Mountain National Park elk-vegetation 

monitoring program. 

E

1 m x 1m 

4 m 4 m 

S

N

2.83 m 

0 m 

5.66 m 

= plot center, temporary marker only 

= permanent rebar marker w/ aluminum cap 

= temporary survey flag 

W 
Appendix 6: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Upland Herbaceous Site-Establishment Protocol 

The following steps outline the process of establishing upland herbaceous monitoring 

sites that are part of the RMNP elk-vegetation monitoring program. Boldface type indicates the 

name of an associated monitoring protocol. Italic type indicates the name of datasheet to be filled 

out. Plot establishment should be conducted during summer, preferably when the majority of 

annual growth has already occurred and before elk begin browsing to any great extent in the fall. 

Nothing should be removed from any site except for approved plant samples listed on the 

research permit. 

 

1. Using a GIS program, randomly select potential sites from available upland areas. Site 

locations should be in NAD83 projection. Areas delineated as Herbaceous Upland Montane 

(MU4), Shrub-Upland-Lower Montane-Bitterbrush (MU142), Shrub-Upland-Lower 

Montane-Undifferentiated (MU14), Shrub-Upland-Big Sagebrush (MU141), Ponderosa PineGraminoid (MU34), Ponderosa Pine-Rockland (MU35), and Ponderosa Pine-Shrubland 

(MU36) on the Rocky Mountain National Park Vegetation Map are eligible for consideration 

as upland-monitoring sites. All intended sample locations should be checked with NPS 

cultural-resources staff to ensure cultural-resources compliance. A suitable site must be a 

minimum of 250 m from any other established site to allow ample room for movement of 

grazing cages without site overlap. 

2. Gather equipment and supplies 

• Research permit 

• Radio pack set 

• Protocol, data sheets, pens, clipboard 

• Handheld GPS unit and spare batteries 

• Hammer or mallet (for setting cages in August through September) 

• 1⁄2-in diameter rebar marker post, 6-in length (if permitted in future, 12–18-in posts 

should be used), one per site 

• Compass (check current declination prior to each field season at 

http://www.ngdc.noaa.gov ) 

• 5 chaining pins or other stakes for holding down tape measure 

• Aluminum survey marker caps imprinted with “ ELK-VEG MONITOR—NPS-DO NOT 

DISTURB—ROMO STUDY 06013” (one per site) 

• Metal die stamping kit 

• Digital camera 

• Laminated placard (light, not white) with following information: 

• dry erase marker 

• wipes or cloth to clean placard 

• 3 grazing cages—these can be any design that is unobtrusive and at least 1 m tall with at 

least a 1-m area under the cage. Current design uses 39-in ht cattle fencing, three 1⁄2-in or 

83

ROMO EVMP 

SITE___________ 

DATE _________ 

DIRECTION_____ 
greater diameter rebar posts, and a chicken-wire top. The cattle fencing is cut to enclose a 

1-m diameter circle (roughly 3.5 m length of fencing) and then bent into a circle and the 

fencing ends attached to the rebar posts with shoat rings. Three 1.5 m rebar posts are 

woven thru the wire and then driven into the ground until the top of the post is flush or 

below the top profile of the cage. Rebar can be attached to fencing with baling wire, if 

desired. A piece of chicken wire is then attached to the top with shoat rings, or wire 

crisscrossed over the top to prevent elk from leaning over the top to graze taller grasses. 

To prevent elk from nosing up under them, cages may be further staked to the ground 

using landscape staples or rebar bent into hooks or “u” shape. See figure 6.1 for 

examples. 

Figure 6.1. Photo of grazing cage design currently being used in elk-vegetation monitoring program. 

3. Navigate to the site center using GPS and UTM coordinates (NAD83 projection). Be sure to 

have WAAS enabled on the GPS to increase accuracy (although this will shorten battery 

life). Evaluate site to determine if it is one of the upland vegetation types listed above and 

described in the Dichotomous Key to the Plant Associations for Rocky Mountain National 

Park (Stevens and others, 2005). If the plot center needs to be moved, move the plot 10 m in 

the cardinal direction that will put it in the upland vegetation type. If a 10 m move does not 

result in successfully locating a plot center in the target vegetation type, moving an additional 

10 m toward the vegetation type may be attempted. If this second attempt at relocation does 

not succeed in achieving an appropriate plot location, abandon this point and move to 

another. If the general area does not appear be an upland site (for example, lands in the 

middle of a lodgepole pine forest or wet meadow) then proceed to another random point and 

report discrepancies with the park vegetation map to park GIS coordinator. If cultural 

artifacts or indications of cultural resource issues are identified, discontinue work and contact 

84
85 

park cultural resources staff before proceeding. Do not remove any artifacts or animal, plant, 

or geologic material unless approved on the research permit for this project. 

4. Assign an unused site number to the site based on the following naming convention: 

UC=Upland Core, UNC=Upland Non-Core + unique id number. Do not re-use numbers of 

discontinued sites. Stamp the assigned number onto an aluminum marker cap and place cap 

on rebar marker stake and drive marker stake into the ground until it is flush with the ground 

surface.

5. Proceed to Rocky Mountain National Park Elk-Vegetation Monitoring Program—

Upland Site Monitoring Protocol—step 3, Rocky Mountain National Park Elk-Vegetation 

Monitoring Program—Upland Site Characterization Data Sheet (Appendix 1). 

6. When all measurements are completed and grazing cages are placed, gather and remove all 

tape measures and temporary markers before leaving the site. Double check to be sure you 

have used the GPS to record the location of the site center marker, in case you changed the 

position from the original site.
86 

Appendix 7: Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Offtake Calculation Protocol

This protocol outlines the procedures for calculating landscape-scale willow browse 

offtake estimates from raw data collected from individual stems at willow-monitoring sites as 

part of the Rocky Mountain National Park (RMNP) elk-vegetation monitoring program. The 

term “offtake” in this document refers to the percentage of the current year’s shoot growth that is 

removed by browsing ungulates (primarily elk in RMNP). 

Two methods of measuring ungulate browsing on willow were incorporated into the 

willow-monitoring protocols. The “stem-scaled diameter difference method” (also called the 

DD2 method in Bilyeu and others, 2007) calculates offtake as the difference between diameter at 

base of current year’s growth and at browse point scaled by the number of shoots browsed on the 

entire stem (equation 7-1).

















−

− ×



 





+ =

tb

tp

DD

DD

ub

b DD2 (7-1) 

where 

b, the number of browsed shoots on the stem; 

u, the number of unbrowsed shoots; 

Dp, shoot diameter at the point of browsing; 

Dt, the average diameter of unbrowsed shoot tips; and 

Db, the diameter at the base of the shoot. 

This method of estimating browse levels was used in previous studies in Rocky Mountain 

National Park, (Singer and Zeigenfuss, 2002) and the thresholds identified in the Elk Vegetation 

Management Plan (U.S. Department of the Interior, 2007) were based upon these methods. 

In recent years, Bilyeu and others (2007) developed a novel method for scaling browse 

estimates to account for elk preference for larger, more productive shoots. The “productionweighted diameter difference method” (DD3) recommended by Bilyeu and others (2007) 

accounts for the fact that elk often browse more productive shoots, and the method estimates the 

percentage of biomass removed based upon shoot size of browsed and unbrowsed shoots 

(equation 7-2).

















−

− ×



 





×+×

× =

tb

tp

DD

DD

UuBb

Bb DD3 (7-2) 

where 

B, average pre-browse mass of browsed shoots; and 

U, the average mass of unbrowsed shoots. 

Variables B and U are estimated using regression equations which predict mass from diameter at 

base of shoot and shoot length measures from species-specific samples of unbrowsed shoots 

collected the previous fall.

Currently, the RMNP Elk-Vegetation Monitoring Plan calls for only measuring browse 

offtake in spring because the majority of browsing presently occurs over winter, but also 

recognizes that measurements of summer offtake may be necessary in the future if increasing 

numbers of elk begin to summer on the current elk winter range on the east side of the park. The 

steps outlined in this protocol are appropriate for estimating browse offtake in both seasons as 
87 

long as field measurements are taken at the end of the summer growing season to assess summer 

browsing. 

Before using this protocol, first collect and process willow measurement data as 

described in steps 8–13 of the Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Protocol (Appendix 2). The following steps should be performed 

after data has been entered into an appropriate digital spreadsheet or database and quality 

assurance has been performed to assure the accuracy of data entry. Table 7.1 provides a sample 

datasheet with example data for the purpose of illustrating the calculation steps described in this 

protocol. 
88 

Table 7.1. Example data for estimating stem-level browse offtake. (N, north; S, south; E, east; W, west; M, middle; mm, millimeters; cm, 

centimeters; g, grams) 

Site ID

Microplot 

Location 

(N, S, E, W, 

M)

Plant 

ID#

Species 

Code

Total 

Stem 

Count

Stem 

ID 

Letter

Shoot 

Ratio

Addtional 

shoot 

(check if 

yes)

Measured shoot 

browsed (B) or 

unbrowsed (U)?

Diameter at 

base of 

shoot (mm)

Diameter 

at tip of 

shoot 

(mm)

Shoot 

length 

(cm)

Estimated 

shoot 

weight (g)

WC13 E 1 SAMO 26 A 3 . U 1.3 0.8 3.5 0.036159

WC13 E 1 SAMO 26 A 3 . U 2.0 .9 7 0.191284

WC13 E 1 SAMO 26 A 3 . B 1.1 .5 2.5 0.014286

WC13 E 1 SAMO 26 A 3 . U 1.0 .5 6 0.019771

WC13 E 1 SAMO 26 A 3 . U 1.5 .5 7.5 0.091861

WC13 E 1 SAMO 26 A 3 . U 1.0 .5 4.5 0.014271

WC13 E 1 SAMO 26 A 3 . U 1.3 1.0 6 0.050807

WC13 E 1 SAMO 26 A 3 . U 1.2 .8 5.5 0.036134

WC13 E 1 SAMO 26 A 3 . U 1.0 .8 3.5 0.011101

WC13 E 1 SAMO 26 A 3 . U 2.1 1.2 10.0 0.257988

WC13 E 1 SAMO 26 A 3 . B 2.0 1.5 13.5 0.279852

WC13 E 1 SAMO 26 B 3 . U 2.2 .7 17.5 0.412087

WC13 E 1 SAMO 26 B 3 . U 2.3 1.0 17.0 0.439775

WC13 E 1 SAMO 26 B 3 . U 1.8 1.1 13.0 0.216625

WC13 E 1 SAMO 26 B 3 . B 1.9 1.2 6.5 0.161640 

WC13 E 1 SAMO 26 B 3 X U 2.8 1.0 29.0 0.948053

WC13 E 1 SAMO 26 C 3 . U 1.8 1.1 7.5 0.150451

WC13 E 1 SAMO 26 C 3 . U 3.5 .7 35.5 1.595636

WC13 E 1 SAMO 26 C 3 X B 3.8 3.0 17.0 1.181852

WC13 E 1 SAMO 26 D 3 . B 2.8 2.8 0 0.318976

WC13 E 1 SAMO 26 D 3 . U 2.0 1.8 11.5 0.250811

WC13 E 1 SAMO 26 D 3 . U 1.4 0.7 5.5 0.060821

WC13 E 1 SAMO 26 D 3 . B 2.0 1.3 8.5 0.210231

WC13 E 1 SAMO 26 D 3 X U 2.4 .8 18.0 0.497758
89 

1. The finest level of data acquired is from shoot-level measurements. These are the measures 

described in step 8 of the Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Protocol (Appendix 2). Total browsed and unbrowsed shoot 

counts are calculated for each stem by multiplying the shoot ratio for the stem by the sum 

count of all the measured browsed and unbrowsed shoots respectively on an individual stem 

of a plant with the exception of those marked as additional shoots. An individual stem is 

identified in table 7.1 by the columns headed site #, microplot location, plant ID #, and stem 

ID letter (for example, WC13-E-1-A is an individual stem). The group [browsed (B) or 

unbrowsed (U)] that the individual shoot belongs to is identified in the data sheet in the 

column, Measured shoot browsed (B) or unbrowsed(U)?(table 7.1). After tallying those 

shoots any additional shoots which were measured for each browse category (browsed and 

unbrowsed) are added as single count shoots. After calculating the stem-level browsed and 

unbrowsed total shoot counts, these two totals can be summed to calculate a total stem shoot 

count. 

Using the example data in table 7.1, plant #1 at site WC13-E had 4 sampled stems (A, B, C, 

and D). Stem A was sampled using a shoot ratio of three (every third shoot on the stem was 

measured). Eleven shoot diameter and length measurements were collected. Nine of these 

measurements were from unbrowsed shoots and none of these were marked as additional 

shoots. Therefore we applied the shoot ratio of three to the nine sampled shoots to determine 

the total number of unbrowsed shoots on the stem (9×3=27). Measurements were collected 

from two browsed shoots and none of these were marked as additional shoots, so the shoot 

ratio of three is applied to these two browsed samples to determine total number of browsed 

shoots (2×3=6). Total shoot count for this stem is the sum of unbrowsed plus browsed shoots 

(27+6) for a total of 33 shoots per stem. 

Stem B had three unbrowsed shoots sampled using a shoot ratio of 3 (3×3=9), plus one 

unbrowsed shoot that was marked an additional shoot (meaning there was not a total number 

of shoots on the stem that was divisible by the shoot ratio of three and that an additional 

shoot had to be sampled). This additional shoot is added to the unbrowsed shoot count of 

nine unbrowsed shoots for a total of ten unbrowsed shoots (9+1=10). There was one 

measured browsed shoot with a shoot ratio of three for a total of three browsed shoots 

(1×3=3). The total shoot count is 10+3=13. 

For stem C, there were two unbrowsed shoot measurements with a shoot ratio of three

(2×3=6) with no additional unbrowsed shoots. There was one additional shoot measurement 

(which was a browsed shoot) for a total browsed shoot count of one. Total shoot count is 

6+1=7. 

For stem D, two unbrowsed shoots were sampled using a shoot ratio of three (2×3=6) plus 

one additional unbrowsed shoot for a total of seven unbrowsed shoots (6+1=7). There were

two browsed shoots sampled with a shoot ratio of three for total of six browsed shoots 

(2x3=6). Total number of shoots is 6+7=13. 
90 

2. Calculate percent of shoots browsed (also called percent leader use).

a. Calculate percent of shoots browsed per stem. This is simply the number of browsed 

shoots (b) divided by the total shoot count (b+u) and then converted to a percentage 

(equation 7-3). 

__% × ( ) 100 

 





+ = ub

b browsed shoots (7-3) 

Using example data from table 7.1, the percent browsed shoots 

for stem A is (6/33)×100=18.2%; 

for stem B is (3/13) ×100=23.1%; 

for stem C is (1/7) ×100=14.3%; and

for stem D is (6/13)×100=46.2%. 

b. Calculate percent of shoots browsed per site. This is the average percent browsed 

shoots for all stems measured at a site. 

Using the example data: (18.2%+23.1%+14.3%+46.2%)/4=25.4 %. 

Species-specific percent browsed shoots can also be calculated at this point, if 

desired, by averaging across all measured stems of each species at a site. This might 

be of interest if needed to verify whether observed declines of one species of willow 

might be linked to browsing preference for that willow species. 

3. Calculate the average proportion of shoot consumed per stem. Knowing the average diameter

of unbrowsed shoot tips is necessary to determine the proportion of an individual shoot 

consumed. This average tip diameter is then used to determine the proportion of a shoot 

consumed (DD1) for all browse shoot measurements on a stem using equation 7-4, 

















−

− =

tb

tp

DD

DD

DD1stem (7-4) 

where 

Dp, shoot diameter at the point of browsing; 

Dt, the average diameter of unbrowsed shoot tips; and 

Db, the diameter at the base of the shoot. 

There are some cases where no unbrowsed shoots were measured on an individual stem and 

thus an average unbrowsed tip diameter (Dt) for the stem cannot be calculated. In this case, 

an average unbrowsed tip diameter for all the stems of a particular species within a site is 

calculated (Dtsite) and then substituted for Dt. If there were no unbrowsed shoots of a species 

found within an individual site, then an average unbrowsed shoot tip can be calculated from 

all shoot measurements of that species (Dtsp) that were collected from other willowmonitoring sites measured within the same year and this average is substituted for Dt. In 

these cases the calculation for DD1stem becomes:
91 

















−

− =

b tsite

p tsite

DD

DD

DD1stem

and

















−

− =

b tsp

p tsp

DD

DD

DD1stem

respectively.

where 

Dp; shoot diameter at the point of browsing; 

Dtsite; the average diameter of unbrowsed shoot tips for a particular species within a site; 

Dtsp; the average diameter of all unbrowsed shoot tips for a particular species; and 

Db; the diameter at the base of the shoot. 

In some cases, the measured diameter at point of browsing (Dp) is smaller than the average 

diameter of unbrowsed shoot tips (Dt)—this results in a negative proportion of shoot 

consumed and thus underestimates offtake. If Dtsite or Dtsp are smaller than Dp, these 

estimates should be used to replace Dt. In a similar manner, proportions greater than 1 (cases 

where the diameter at point of browsing is larger than the shoot basal diameter) are converted 

to 1 since the current year’s growth can be no more than 100 percent browsed (proportion of 

1).

For the example data, 

Stem A: Dt=0.78 

Stem B: Dt =0.95 

Stem C: Dt =0.9 

Stem D: Dt =1.1 

Dtsite=(0.78+0.95+0.9+1.1)/4=0.93 

 Dtsp=1.0 (calculated using data not found in example) 

Stem A has 2 browsed shoots and DD1shoot=(0.5-0.78/2-0.78) and (1.5-0.78/2.0-0.78)=(-0.23 

and 0.59). Substitution with Dtsite and Dtsp still results in a negative proportion removed, so 

the first DD1shoot estimate for this stem is deleted from the data set and the remaining shoot 

measure is used, thus DD1stemA=0.59. 

Stem B has 1 browsed shoot and DD1stemB=(1.2-0.95/1.9-0.95)=0.26 

Stem C has 1 browsed shoot and DD1stemC=(3.0-0.9/3.8-0.9)=0.72 

Stem D has 2 browsed shoots and DD1stemD=(2.8-1.1/2.8-1.1) and (1.3-1.1/2.0-1.1) or (1.0 

+0.22)/2=0.61 

4. Calculate DD2 offtake for each stem. The DD2 offtake method (Bilyeu and others, 2007) 

calculates offtake at the stem level by multiplying percent of shoots browsed per stem by 

average proportion of shoot removed (equation 7-5). 

DD stem

ub

b DD stem 1002  × 1 

 





+

×= (7-5) 
92 

For the example data: 

DD2stemA=18.2%×0.59=10.7% 

DD2stemB=23.1%×0.26=6.0% 

DD2stemC=14.3%×0.72=10.3% 

DD2stemD=46.2%×0.61=28.2% 

5. Calculate DD2site by averaging all DD2stem measures. Using the example data yields:

 (10.7+6.0+10.3+28.2)/4=13.8%. 

6. Determine shoot mass regressions as first step to estimating DD3 offtake. Products of some 

steps of the DD2 calculation are used in calculation of DD3 offtake estimate. The DD3 

offtake estimate accounts for the preferential browsing of larger shoots by elk and scales the 

offtake estimate accordingly. This preference was demonstrated by Bilyeu and others (2007) 

and was also found using the Rocky Mountain National Park Elk Vegetation Monitoring 

Program baseline data (see “Baseline Condition—Willow,” p. 28). Unbrowsed shoots of a 

variety of sizes from each species must be collected each year in the late summer/fall (when 

more unbrowsed shoots are readily available) in order to build regressions for determining 

shoot mass based upon shoot basal diameter and length. The shoot size and weight 

information collected in Rocky Mountain National Park Elk-Vegetation Monitoring 

Program Willow Monitoring Protocol (Appendix 2, step 12) is necessary to continue with 

the DD3 calculation. Shoot weights without leaves should be used in creating regression 

equations. Shoots collected for developing the regressions apply to offtake measures taken in 

spring of the following year (for example, shoots collected in fall 2009 are used to calculate 

DD3 for spring 2010). If summer offtake will be calculated, shoots collected in fall of the 

year are applied to shoot measurements taken at the end of summer of the same year (for 

example, shoots collected in fall 2009 are used to calculate summer DD3 for summer 2009). 

Several regression models used to estimate shoot weight from shoot basal diameter and 

length for each willow species were assessed using the baseline data and data collected in 

2010. Comparisons between regression lines showed interannual differences, so data should 

be collected on a year-by-year basis whenever possible. 

Shoot mass regressions relating the square root of mass to shoot basal diameter and shoot 

length were found to provide the best relationship (equation 7.6; r2 (the coefficient of 

determination) range from 0.83–0.98 with the majority greater than 0.95). R2 improved when 

regressions were individually fit to the seven main locations (Beaver Meadows, Cow Creek, 

Horseshoe Park [including Endovalley], Hidden Valley, Hallowell Park, Moraine Park, and

Kawuneechee Valley) where monitoring sites were located. However, this resulted in 

minimal change in the final values for DD3 for the entire winter range and for core and noncore winter ranges individually. Therefore, while it is recommended to gather shoot samples 

for building regressions across all locations, samples can be pooled across locations for each 

species regression. This pooled regression takes the form: 

√shoot mass = β0 + (β1 × basal shoot diameter) + (β2 × shoot length) (7-6) 
93 

7. Using the appropriate regression equation with species-specific y-intercept (β0) and 

coefficients (β1 and β2), estimate the pre-browse shoot weight for each measured shoot. Then 

average the pre-browse shoot weights to get a mean pre-browse shoot weight for both 

browsed (Bstem) and unbrowsed (Ustem) shoots for each stem. 

Using the data from Salix monticola (SAMO) shoots collected in the area near site WC13, 

the following equation was developed with β0, β1, β2 terms. 

√shoot mass = −0.22664 + (0.28265 × basal shoot diameter) + (0.01410 × shoot length)

When applied to the data in table 7.1 this regression equation yields the estimated shoot 

weights listed in the final column of the table 7.1. If these shoot weights are averaged, we get 

the following mean browsed and unbrowsed shoot weights for each stem.

BstemA=0.147 g UstemA=0.079 g 

BstemB=0.162 g UstemB=0.504 g 

BstemC=1.182 g UstemC=0.873 g 

BstemD=0.265 g UstemD=0.270 g 

8. Calculate DD3stem. Total shoot counts estimated in step 2 of this protocol and the DD1stem

estimates from step 5 of this protocol are used to calculate DD3stem following equation 7-7. 

stem

stem stem stem stem

stem stem

stem DD

UuBb

Bb DD 1003 × 1 































×+×

×

×= (7-7) 

Using the example data this yields:

%3.1759.0

)079.027()147.06(

147.06 1003 =×































×+×

×

DD stemA ×=

%3.226.0

)504.010()162.03(

162.03 3 100 =×































×+×

×

DD stemB ×=

%3.1372.0

)873.06()182.11(

182.11 3 100 =×































×+×

×

DD stemC ×=

%9.2761.0

)270.07()265.06(

265.06 3 100 =×































×+×

×

DD stemD ×=

9. Calculate DD3site by averaging all stems in a site:

DD3site=(17.3% + 2.3% + 13.3% + 27.9%)/4=15.2% 
94 

10. Calculate DD2site and DD3site for all sites in the core and all sites in the non-core winter range 

to get DD2core, DD2non-core, DD3core, and DD3non-core estimates. These estimates can be 

compared to determine whether significant differences between core and non-core willow 

winter range willow offtake exists.

11. Calculate DD2winter_range and DD3winter_range. A weighted average for the entire winter range is 

calculated for each offtake method. At the outset of the study, weighting was based on the 

percentage of willow area falling within core and non-core winter range. At the outset of the 

monitoring, the 87.2 percent of the entire elk winter range willow area was located on the 

core winter range and the non-core winter range contained the remaining 12.8 percent of all 

winter range willow. 

Publishing support provided by: 

Denver Publishing Service Center

For more information concerning this publication, contact:

Center Director, USGS Fort Collins Science Center

2150 Centre Ave., Bldg. C

Fort Collins, CO 80526-8118

(970) 226-9398

Or visit the Fort Collins Science Center Web site at:

http://www.fort.usgs.gov/