Quantifying Effects of Quaking Aspen Silvicultural

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Undergraduate Theses and Professional Papers

2016

Quantifying Effects of Quaking Aspen Silvicultural Treatments on Quantifying Effects of Quaking Aspen Silvicultural Treatments on

Aspen Regeneration and Residual Growth Aspen Regeneration and Residual Growth

Philip W. Williams University of Montana, [email protected]

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Undergraduate Senior Thesis

QUANTIFYING EFFECTS OF QUAKING ASPEN SILVICULTURAL TREATMENTS ON

ASPEN REGENERATION AND RESIDUAL GROWTH

BY:

Philip W. Williams

Bachelor of Science in Forestry Candidate

The University of Montana

Davidson Honors College

College of Forestry and Conservation

Thesis Supervisor: Dr. Andrew J. Larson

Approved by:

Dr. Andrew J. Larson

College of Forestry and Conservation

THE UNIVERSITY OF MONTANA

MISSOULA, MONTANA

9TH

OF MAY 2016

2

ABSTRACT

Williams, Philip W., B.S., May 2016 Forestry

Quantifying Effects of Quaking Aspen Silvicultural Treatments on Aspen Regeneration and

Residual Growth

Faculty Mentor: Andrew J. Larson

Many quaking aspen (Populus tremuloides) populations are in decline across the western United

States, a trend likely driven by ongoing climate change and past management that has led to

increased competition with conifers. Restoration of aspen is a management goal potentially

achievable through active forest management, but treatment effects on regeneration and residual

growth have not been comprehensively studied. This project examined if removal of competing

conifers altered aspen regeneration density, ungulate browsing, and residual adult aspen diameter

growth using a control-impact study design. Sampling occurred at the Burnt Fork (ten

treatments, four controls) and Bandy (seven treatments, four controls) sites. Nested plot-centric

circles with a common center point were used for sampling. Regeneration was counted in 0.004-

hectare plots and examined for ungulate browsing. Adult trees were surveyed in 0.04-hectare

plots; diameters and increment cores were taken on the most vigorous tree to represent growth

before and after harvest. Ungulate browsing (percent of regeneration browsed) means were

higher in treated units (23% and 46% browsed at the Burnt Fork and Bandy, respectively) than in

control units (3% and 2% browsed at Burnt Fork and Bandy, respectively). Aspen regeneration

was higher in treated units than controls: regeneration at the Burnt Fork site averaged 10743

stems/ha in treated units and 7054 stems/ha in controls, while the Bandy site averaged 13438

stems/ha in the treated units and 6824 stems/ha in controls. Average adult aspen diameter growth

rates were stable or increased from pre- to post-treatment in treated units, while diameter growth

rates were stable or decreased from pre- to post-treatment in controls. This study demonstrates

that silvicultural treatments to remove competing conifer trees can increase aspen regeneration

density and maintain or increase adult aspen growth rates. Managers seeking to regenerate

declining aspen stands can use conifer removal treatments to promote aspen regeneration.

3

CONTENTS

LIST OF FIGURES & APPENDICES ............................................……………………………...4

Sections

1. ABSTRACT ..........................................................................................................................2

2. ACKNOWLEDGEMENTS ..................................................................................................5

3. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4. METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5. RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6. DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7. CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8. LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

9. APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4

FIGURES

1. Bandy Ranch understory results. ...........................................................................23

2. Bandy Ranch overstory results. .............................................................................24

3. Burnt Fork understory results. ...............................................................................25

4. Burnt Fork overstory results. .................................................................................26

5. Bandy control regeneration stems per acre by unit and control average ...............26

6. Bandy treatment regeneration stems per acre by unit and treatment average. .......27

7. Burnt Fork control regeneration stems per acre by unit and control average. .......27

8. Burnt Fork treatment regeneration stems per acre by unit and treatment average.28

APPENDICES

A. Prescription for the Bandy Ranch Jumpstart Project ....................................... 38-40

B. Map of the Bandy Ranch Jumpstart silvicultural operation and various silvicultural

treatments: summer 2009. ......................................................................................41

C. Research equipment and travel costs ............................................................... 42-43

D. Map of the Burnt Fork Ranch aspen study units....................................................44

E. Map of the Bandy Ranch aspen study units ...........................................................45

F. Burnt Fork Ranch raw data. ............................................................................. 46-49

G. Bandy Ranch raw data. .................................................................................... 50-51

5

ACKNOWLEDGEMENTS

I would like to express my gratitude to my undergraduate thesis supervisor, Dr. Andrew J.

Larson, for his insightful guidance in helping me develop scientific thinking skills and for

introducing me to the challenging but rewarding realm of independent study.

I wish to thank Dr. Elizabeth Dodson for introducing me to the University of Montana’s Bandy

Ranch Jumpstart Project and its relevance to quaking aspen management. I am also grateful to

Dr. Carl Seielstad and Mr. Kevin McManigal for their assistance with geospatial aspects of

natural resource data collection. In addition, Dr. John Goodburn offered excellent silvicultural

expertise that I am very thankful for.

Mr. and Mrs. Randy Creech of the Burnt Fork Ranch deserve a special thank-you for permitting

me to perform my study on their property. I also appreciate the logistical and research-design

advice from Mr. Mike Bradt and Mr. Mark Lewing. I am very thankful to Mr. Bill Bradt for

introducing me to the Burnt Fork Ranch aspen treatment and opening my eyes to the wonders of

quaking aspen ecology.

A very special thanks goes to my family for their unceasing support and encouragement as I

completed this project. I am also very grateful to my brother, Michael, for assisting me with data

collection on long summer afternoons.

6

INTRODUCTION

Quaking aspen (Populus tremuloides) spans the widest range of any tree species on the

North American continent (Worrall et al. 2013, Perala n.d.). Not surprisingly, humans have

found a wide array of uses for this diverse poplar from ice cream sticks to particleboard (Rook

2006). While it is used to make many wood products, quaking aspen also has significant value as

wildlife habitat. Many wildlife species (especially deer and beaver) utilize the watersheds filtered

by quaking aspen stands to satisfy essential life functions (Howard 1996). The moist, lush, and

camouflaging quaking aspen stands also attract ungulates that, in turn, browse available

understory graminoids (grasses) and shrubs (Perry et al. 1999). Quaking aspen clearly provides

many services to people and wildlife. However, contemporary research shows a general decline

in quaking aspen across the United States that seems related to climate change; this is largely due

to quaking aspen’s inability to tolerate hot temperatures that are becoming more widespread

during summer and late winter months (Worrall et al. 2013). Diminishing quaking aspen

translates to reduced wildlife habitat, fewer ecosystem services, and a decreased wood supply.

Restoring quaking aspen is a valid restorative and financial goal that may achievable through

timber harvests. But, the implications of timber harvests on residual tree growth (both aspens and

conifers) and on understory aspen regeneration have not been comprehensively studied. This

undergraduate-level research project was undertaken to examine each of the just-mentioned

variables and their relationships to a variety of timber harvests in western Montana.

Specific silvicultural treatments have been used throughout the western United States to

encourage aspen regeneration and learn how different treatments influence the regeneration

process. Thinning quaking aspen stands by removing vegetative competition is a silvicultural

method used to increase residual tree growth and productivity. This information is valuable to

7

managers and other scientists interested in how to use silvicultural prescriptions as a multi-

purpose tool to achieve management objectives while restoring critical quaking aspen habitat

through regeneration. One author describes clearcutting residual aspens as one of the most

efficient ways to regenerate an aspen stand in the northern Rocky Mountains (Doucet 1989).

While it seems much regeneration can be created from clearcutting aspen, clearcutting also

temporarily destroys wildlife habitat, shelter, and moist areas that are not re-gained until

regeneration matures to dominant overstory trees.

In addition, quaking aspen suffers from a wide-ranging disease – hypoxylon

canker (Anderson 1979). Most cankers form in dense, moisture-deficient stands (Bagga and

Smalley 1974). On the other hand, insects such as the large aspen tortrix are particularly

prevalent in thinned stands when residual trees have been damaged by a logging operation

(Stewardship 2011.). Understanding dynamics between silvicultural treatments and aspen

insects/diseases can give crucial information to forest managers responsible for restoring quaking

aspen and the multitude of services they provide.

According to several scientists (Bradt 2015, Lewing 2015, Howard 1996) deer

browse aspen regeneration heavily and rely on it for spring fawning and summer water sources.

Deer also browse bunchgrasses found in the understory; removing encroaching conifer from

aspen stands may lead to an increased abundance of graminoid species, and thus restore deer to

an aspen stand (Lewing 2015). Graminoids often respond only in the third year after a partial cut,

which may occur when encroaching conifer species are removed from an aspen stand (Perry et

al. 1999).

Quaking aspen is an extremely diverse tree that provides a wide range of habitats,

wildlife cover, and ecosystem services that many people take for granted. The pure water many

8

Americans enjoy largely comes from mountain watersheds filtered by quaking aspen stands.

While some studies have been dedicated solely to understanding the mechanisms that promote

aspen regeneration, few have investigated how aspen growth rates respond to thinning

treatments. Literature exists on wildlife uses of aspen, but fewer studies associate this with

silvicultural treatments. Because decades of research highlight the importance of quaking aspen

stands to wildlife, watersheds, and humans, knowing how the multiple features of aspen stands

respond to forest management practices becomes a necessity in an era of increased natural

resource use. Still, much of the existing information concerning quaking aspen regeneration

through silvicultural treatments is outdated and/or insufficient when considered separately. This

research will help fill knowledge gaps by providing a practical, methodical examination and

synthesis of various aspen silvicultural treatments performed in the Rocky Mountains of western

Montana. Relevant information produced by this research project will be particularly valuable to

wildlife and forest managers in the western United States. Quaking aspen is a significant mesic

species with potent impacts on other tree species, understory grasses, insects/diseases, and a wide

array of wildlife. Because the tree species is currently in decline across much of its native and

introduced ranges, knowing what silvicultural methods encourage overall stand restoration will

lead to informed and effective quaking aspen management that both sustains humans and the

natural realm.

This research project used a control-impact (CI) study to determine effects of silvicultural

treatments on quaking aspen stand responses. The research occurred on the privately-owned

Burnt Fork Ranch (Bitterroot Valley, MT) and on the University-of-Montana-owned Bandy

Ranch (Blackfoot River Valley, MT); both areas contain forestland that was subjected to various

silvicultural treatments two years before the study at the Burnt Fork Ranch and six years pre-

9

study at the Bandy Ranch. Study sites at both locations were used to introduce a variety of spatial

locations and timber harvest types. All timber harvests studied were performed to increase the

abundance and health of residual quaking aspen and of any existing/ensuing regeneration.

Browsing impacts were measured by intensity (percentage of aspen regeneration displaying

browsing on current year’s growth) in control and treatment units. It was not possible to

differentiate between livestock and cattle grazing because no wildlife or livestock-proof fences

were built for this study (Lewing 2015).

The overall objective of this research project was to examine how removing encroaching

conifers from quaking aspen stands altered residual aspen growth and aspen regeneration

(browsed vs. un-browsed). The primary metrics used to determine any change in the variables

was frequency, abundance, density, browsing intensity, and annual growth of the residual aspen

and conifers. The following specific research questions were addressed:

Does conifer removal in quaking aspen increase, decrease, or not affect aspen

regeneration?


regeneration browsing by ungulates?

Does conifer removal in quaking aspen increase, decrease or not affect residual growth?

What differences exist between variables at larger spatial scales (Bandy Ranch vs. Burnt

Fork)?

This author hypothesized that residual overstory aspens will have experienced an increase

in average annual radial growth since treatments. Also, aspen regeneration was expected to be

greater in treated than in untreated stands due to increased resource availability (Lewing 2015).

There may also be far more regeneration in treated stands where 1 or 2 stems were removed per

10

stand, as apical dominance of the residual tree has been suppressed (Sandberg and Schneider

1953).

All treatment measurements were compared to duplicated measurements made in no-

treatment control units. Comparing measurements allowed inferences to be made as to the

magnitude of effects (if any) implementations had on treated sites in a control-impact research

setting.

METHODS

Study Design

Burnt Fork Ranch Silvicultural Methods:

In the winter of 2013-14, the Burnt Fork Ranch released 23.82 acres of quaking aspen stands in

the Ambrose Creek area of the Sapphire Mountains. Conifers were marked for removal and

aspen stands were delineated based on the extent of the overstory aspen dripline. Ten aspen

stands of varying sizes (see Figure 1) were delineated, located on flat to north-facing slopes. A

dirt road, running east-west through the area, was used to split the aspen stands into northern and

southern units. Montana Fish, Wildlife, and Parks holds a conservation easement on the former

Bolin Ranch immediately east of the Burnt Fork Ranch property. There are two separate aspen

stands, both split by the same road that runs through the Burnt Fork units. Those areas feature

mostly flat to slightly north-facing topography. As no silvicultural treatment occurred on the

Bolin Ranch Conservation Easement, those four units (each of the two stands, like the treatment

areas, were divided into north and south units on account of their location to the road) were used

as control areas. Overall, there are 10 treatment units and 4 control units. All the treatment units

experienced the same treatment of complete conifer removal within the aspen stands by a

fellerbuncher and rubber-tired skidder whole-tree logging system. Slash was burnt on-site in

11

designated slash piles. Mature, overstory quaking aspen were only cut if they prevented the

fellerbuncher operator or skidder from removing conifers. As noted in the results section, some

conifers were left inside only one aspen clone (unit T3-N) at the discretion of the Burnt Fork

Ranch forester (Bradt 2015). All other stands had every conifer removed from within the clone.

Bandy Ranch Silvicultural Methods:

In the summer of 2009, the University of Montana launched its “Jumpstart” silvicultural

treatment at its Bandy Ranch in order to determine various effects of different forest treatments

on overstory and understory responses (Dodson 2015). Quaking aspen was a specific species of

interest and received three different treatments and a control to help measure those effects

(Dodson 2015). All harvest units were treated with a mechanical whole-tree logging system

using a fellerbuncher and rubber-tired skidders. Treatments were implemented by codes red,

blue, yellow and white; please see Appendix A for a complete description of all the treatments

and of the control. As far as quaking aspen was concerned, the red treatment did not remove any

conifers from within the aspen stands but did clear conifers within a 50-foot radius of the aspen

clone itself (Dodson 2015); the blue treatment also cleared 50 feet around the clones and

removed all conifer encroachment; and the yellow treatment cleared 50 feet around the clone,

removed all conifer encroachment, and cut 1-2 mature overstory aspen trees in each clone. The

white treatments were control areas and thus experienced no treatments. See Appendix B for a

map of treatment and control locations.

Burnt Fork Ranch Sample Design:

Dividing the quaking aspen stands into observable units was done based on the parameters

described in the introduction. Namely, this entailed using the main access road (which runs east

12

to west) as a break dividing aspen clones into northern and southern portions. The boundaries

and areas of each quaking aspen stand were delineated on the ground by walking the stand

borders. Borders were defined by the overstory canopy dripline. The boundaries of all control

and treatment units were delineated with a Samsung ® Galaxy S5 ® smartphone using the

Avenza Systems Inc. ® PDF Maps for Android application, version 1.4.9 Build(115). Yellow

ribbons were labeled for each unit and hung at the four vertices of each aspen clone. After each

aspen grove was defined geographically, they were named in the following way. Control units

were all given the prefix “C” for control, immediately followed by a number in increasing order

from east to west. “N” for north or “S” for south followed a hyphen to denote the location of the

unit in relation to the management road intersecting the stand. Treatment units were labeled in a

similar fashion, with the notable difference that “T” was used for treatment with the following

numbers in increasing order from west to east. The same road (although now on Burnt Fork

Ranch land) differentiated each stand into north and south units.

Because this study was a control impact observation of a past silvicultural manipulation,

the control and treatment units were measured in exactly the same fashion. Each treatment and

control unit would serve as a replication within the study, thus eliminating the need to perform

multiple samples within each unit. Measurements taken in the treatment areas would be

compared to duplicated measurements in the control areas. A diagonal line running from the

northeast to southwest corners of the stand was created in the Avenza ® environment and

measured in feet. The northeast-to-southwest trajectory was chosen based on the overall north-

south orientation of the aspen units. A diagonal line was chosen over a north-south or east-west

line because a diagonal may most likely incorporate varying differences in stand structure

resulting in north-facing topography (Bradt 2015). In other words, merely using a north-south

13

trajectory on north-facing topography would likely be biased toward sampling plants reacting to

that north aspect. This was undesirable as the control sites, and the majority of the treatment

sites, were flat to slightly north-facing.

Once the diagonal lines of each control and treatment unit were measured in feet, a

random number was generated by starting a countdown timer at 100 seconds and then randomly

stopping it. The resulting number was used as a percentage to multiply the total distance of the

diagonal line by, and that value was the distance of the sample point from the southwest corner

of the northern units and the northeast corner of the southern units. A nested sampling design of

plot-centric circles with a common center point was used to sample the overstory and understory

variables, inspired by a method used by Fowler (2014). An interior, 100th

-acre circular plot (11.7

ft. radius) was employed to sample quaking aspen regeneration, while an exterior, larger 10th

-

acre circular plot (37.2 ft. radius) was used to sample residual aspen growth and the number of

mature overstory quaking aspen and/or conifers. If a plot lacked all variables (both in the

overstory and understory), it was rejected and a new plot was subsequently established by

proceeding one chain (66 feet) down the diagonal sample line. If this led outside the clone, the

new sample area was located by pacing one chain in the opposite direction. Each treatment and

control unit only had one sample per unit, meaning that 14 total nested plots (4 controls and 10

treatments) were sampled at the Burnt Fork Ranch.

Bandy Ranch Sample Design: All observable quaking aspen stands were located first as they had

never been officially delineated at the Bandy Ranch before. Once all stands were located, all

were assigned numbers and two stands within each silvicultural treatment type were randomly

selected. Please note that Bandy aspen stands will be described by the color-coded silvicultural

14

system that they were treated with. For instance, “yellow clones” or “yellow groves” denote

aspen stands that were within the yellow, or 3rd

treatment, type (please refer to Appendix A).

This author only discovered three quaking aspen clones within the control units, so all three

control groves were selected for sampling. In addition, three blue groves were considered for the

study because each blue grove contained relatively little area. All aspen groves selected for the

study were delineated with the same Avenza ® PDF Maps application used at the Burnt Fork

Ranch. No flags were hung at the Bandy Ranch and, just as with the Burnt Fork sample design,

only one sample area per unit was done at the Bandy Ranch. Aspen clones were named based on

the pre-named Jumpstart unit in which they occurred. For instance, the control site occurring in

Jumpstart management area E(4) was named unit E(4). If more than one unit occurred in a

management area, an alphabetic suffix was added (for instance, E(4).a, E(4).b, etc.).

All aspen clones occurred on flat to nearly-flat terrain, so there was no special adjustment

needed for aspect biases. Sample location was determined by generating a random number

between one and four. The north side of a unit was represented by the numeral one, the east by

two, the south by three, and the west by four. It was necessary to sample a side of the unit, rather

than somewhere along a bisecting diagonal as at the Burnt Fork, because the Bandy aspen clones

were nearly all located around small seasonal wetlands and prairie-type potholes. In other words,

the aspen were usually formed in an outer ring around an interior, circular area with no

vegetation other than grasses. Once the randomly-selected side of a unit was selected, its length

was measured in the Avenza ® environment. Just as at the Burnt Fork Ranch, a random number

was generated by starting a countdown timer at 100 seconds and then randomly stopping it. The

resulting number was used as a percentage to multiply the total distance of the diagonal line by,

and that value was the distance of the sample point from one end of the unit. The end of the unit

15

to start measuring from was determined by assigning each end a number and randomly selecting

it.

Again, a nested sampling design of plot-centric circles with a common center point was

used to sample the overstory and understory variables. An interior, 100th

-acre circular plot (11.7

ft. radius) was employed to sample quaking aspen regeneration, while an exterior, larger 10th

-

acre circular plot (37.2 ft. radius) was used to sample residual aspen growth and the number of

mature overstory quaking aspen and/or conifers. If a plot lacked all variables (both in the

overstory and understory), it was rejected and a new plot was subsequently established by

proceeding one chain (66 feet) down the diagonal sample line in the original direction. If this led

outside the clone, the new sample area was located by pacing one chain in the opposite direction.

Each treatment and control unit only had one sample per unit, meaning that 10 total nested plots

(3 controls and 7 treatments) were sampled at the Bandy Ranch.

Measurements

The following measurements were taken within each sample plot for both the Burnt Fork and

Bandy Ranches. Measurements were identical in all control and treatment units.

100th

-acre Plots (Understory)

The plot center was established with a metal pin at the pre-determined location along the transect

line. A cloth tape measure was attached to the pin to delineate a radius of 1/100th

of an acre (11.

7 feet radius). Regeneration was counted by starting at a marked location on the plot

circumference and sweeping the cloth tape around the pivot point, keeping it tight at all times to

ensure distance accuracy. Any regeneration growing directly on the border of the plot was

included in the plot. As each individual aspen sprout was encountered, a graduated ruler using

16

tenths of centimeters was placed next to the stem of each individual aspen sprout just above

ground level. The stem was measured in centimeters and placed in the following categories: less

than 1 centimeter, 1-2 centimeters, 2-3 centimeters, and greater than 3 centimeters. All data was

recorded on a voice recorder and later transferred to an understory Excel spreadsheet (see

Appendices F and G). Regeneration tallies were further subdivided in each diameter class based

on whether the current year’s growth had been browsed or not by an ungulate. Current year’s

growth was determined based on leaf scars; any removal of current year’s growth, whether by

ungulate biting or tearing, placed that particular sprout into the browsed category in its respective

diameter class.

10th

-acre Plots (Overstory)

The 1/10th

-acre sampling plots were established with the same central pin, location, and cloth

tape used for the smaller 1/100th

-acre plots. These plots all had a 37.2-foot radius. Mature,

overstory trees were counted by starting at a marked location on the plot circumference and

sweeping the cloth tape around the pivot point, keeping it tight at all times to ensure distance

accuracy. If any trees touched the border of the sample plot, at least half the tree diameter at

breast height must be included in the plot for that tree to be sampled. The diameter at breast

height (DBH) was measured on every “in tree” with a standard logging diameter tape in tenths of

inches and recorded on a voice recorder. The data was later transferred to the overstory sample

sheet (see Appendix F). Next, an increment borer was used to retrieve cores from the most

vigorous and/or most dominant aspen and/or conifer tree in the canopy. Because the treatment

occurred two growing seasons ago at the Burnt Fork Ranch and six growing seasons ago at the

Bandy Ranch, increment corings were taken to display the last four years of growth at the Burnt

Fork and the last twelve years of growth at the Bandy Ranch. The total number of overstory

17

aspen and/or conifer trees were tallied and recorded in each sample plot. However, at the Bandy

Ranch, units G2 and P2.b contained nearly the same area as the 10th

-acre sample plots. In these

cases, a complete tallying census of the overstory was done. However, the most vigorous and/or

most dominant aspen and/or conifer tree in the canopy was still cored.

Analysis

Geospatial Analysis at Bandy and Burnt Fork Locations:

Geospatial track data was exported from the Avenza ® environment in .kml format. The “From

KML” Conversion tool found inside of ArcToolbox ® translated the .kml data into shapefiles

readable by ESRI’s ® ArcMap ® v. 10.2.2. A standard USA topographic basemap, courtesy of

National Geographic, was uploaded and projected into NAD 83 UTM Zone 12N. Avenza ®

described its datum as being in NAD 27; however, the tracks were in the wrong location when

the projection was changed to NAD 27. Eventually, it was discovered that Avenza ® had made

an error and its datum was actually NAD 83 (McManigal 2015). Unit labels, a scale bar, north

arrow, coordinate system description, and National Geographic credit was added to each map

(see Appendices D and E). The Avenza ® application determined areas of each unit’s track

polygon. These values were later transferred to an Excel spreadsheet.

Regeneration Analysis

After raw data was entered into Excel, the total number of sprout stems were multiplied by 100

to attain a per acre estimate of regeneration in the control and treatment sites at the Burnt Fork

and Bandy Ranches. This was done in the three census areas of the Bandy Ranch in order to

normalize the data and reduce ensuing bias. Per-acre calculations were performed for each aspen

sprout size class; the per-acre estimates of sprouts per size class were then summed in order to

18

understand the overall density of all sprouts across the unit. Utilization was measured for each

unit as the total number of browsed sprouts out of the grand total of sprouts in that unit; this was

expressed as a percentage and showed the amount of use by ungulate species (Holechek et al.

2003). The total acreages of the control and treatment units were summed, and control and

treatment sums were taken of number of regeneration in each size class. Averages were also

calculated for total stems per acre and utilization.

Overstory Analysis

Quaking aspen cores were allowed to dry for one month and then examined with a hand lens for

growth rings. However, the growth rings were extremely faint and nearly impossible to detect

with such a low level of magnification. Eventually, using a portable dissecting scope from the

College of Forestry and Conservation on low-to-medium power sufficiently revealed early and

late wood cells so growth could be determined. At the Bandy Ranch, the past twelve years of

radial growth were broken into two distinct segments and measured separately. The newest six

years showed growth since the treatment (post-treatment), and the older six years displayed

growth before the treatment (pre-treatment). An equal number of years were needed for pre-

treatment analysis in order to compare a consistent number of years before and after the

silvicultural manipulation of the quaking aspen stand. At the Burnt Fork Ranch, the past four

years of radial growth were broken into two segments and measured separately for the same

reasons. A standard dissecting probe was used to prick and mark the boundary delineating pre

and post-treatment growth and the termination of pre-treatment growth. The segments were

measured in centimeters with the same tenth-centimeter graduated ruler used to measure aspen

sprout diameters in the field. Results for the Bandy Ranch were divided by six years in order to

determine average annual growth in centimeters for post- and pre-treatment radial growth. The

19

number of trees within the 10th

acre plots was multiplied by 10 in order to arrive at per-acre

estimates. This was also done for the three Bandy units where a census was taken in order to

normalize data and reduce any ensuing bias. Averages of radial growth for post- and pre-

treatment were taken for the control and treatment sites of both the Bandy and Burnt Fork

ranches. Trees per acre were also averaged for the control and treatment locations at both

ranches.

In addition, the Bandy and Burnt Fork data was compared at the treatment and control

levels for average regeneration per acre (by size class and total), utilization, trees per acre (both

conifer and aspen), and average annual growth for post and pre-treatment time periods.

RESULTS

Burnt Fork Ranch

Regeneration

For the control location, C2-S contained the most regeneration per acre (7100 stems) while C1-N

contained the least (1200). Most regeneration occurred in the less-than-1 cm class and the least

occurred in the greater-than-3 cm class for the treatment area; the control area contained the most

regeneration in the greater-than-3 cm class and the least in the less-than-1 cm class. For the

treatment location, T1-S contained the most regeneration per acre (8700) while T3-S contained

the least (1900). Figures 7 and 8 illustrate this information graphically.

Utilization

The only ungulate utilization of quaking aspen regeneration in the control location occurred on

unit C2-N, which had 12.5% utilization of all aspen regeneration. Utilization was very poor in

the control overall with only 0.03% of the entire available regeneration being browsed, which

20

stood in sharp contrast to the 23.28% utilization of all available regeneration in the average

treatment unit. All but two treatment areas experienced utilization (T2-N and T5-S), with the

highest utilization occurring in T2-S (60.87%) and the lowest utilization in T5-N (4.55%).

Overstory

The greatest control growth pre-treatment occurred in C2-N (0.15 cm/year), while the

least control growth pre-treatment occurred in C1-S and C2-S (0.05 cm/year). The greatest

control growth post-treatment again occurred in C2-N (0.125 cm/year), while the least control

growth post-treatment occurred in C2-S (0.05 cm/year). The average control post-treatment

growth was 0.088 cm/year and the average control pre-treatment growth was 0.081 cm/year.

The greatest treatment growth pre-treatment occurred in T3-S and T4-S (0.25 cm/year),

while the least treatment growth pre-treatment occurred in T2-N, T5-N and T5-S (0.05 cm/year).

The greatest treatment growth post-treatment occurred in T1-S (0.275 cm/year), while the least

treatment growth post-treatment occurred in T2-N (0.05 cm/year). The only conifer measured

experienced 0.05 cm/year of growth after the treatment and 0.075 cm/year before it. It was

located in the treatment area in unit T3-N. The average treatment post-treatment growth was

0.153 cm/year and the average treatment pre-treatment growth was 0.119 cm/year. The average

mature trees per acre in the control location was 70 aspen with the most trees per acre existing in

C2-S (110 trees per acre); the least trees per acre occurred in C1-N (30 trees per acre). The

treatment location contained an average of 78 aspen per acre and 20 conifers per acre, with the

most aspen trees per acre existing in T1-S (130 trees per acre); the least trees least trees per acre

occurred in T5-N (30 trees per acre). These results are shown in tabular form in Figure 4.

21

Bandy Ranch

Regeneration

Control unit E4.a contained the most regeneration per acre (5050 stems) while E4.b contained

the least (1020 stems). Most regeneration occurred in the 1-2 cm class and the least occurred in

the greater-than-3 cm class for the treatment area; the control area contained the most

regeneration in the 2-3 cm class and the least in the less-than-1 cm class, as can be seen in

Figures 1 and 5. For the treatment location, P2.a contained the most regeneration per acre (9800)

while P2.b contained the least (1000). Please see Figure 6.

Utilization

As Figure 1 shows, the only ungulate utilization of quaking aspen regeneration in the control

location occurred on unit E4.a, of all aspen regeneration. Utilization was very poor in the control

overall with only 1.83% of the entire available regeneration being browsed, which stood in sharp

contrast to the 46.46% utilization of all available regeneration in the average treatment unit. All

treatment areas experienced utilization, with the highest utilization occurring in P2.a (71.43%)

and the lowest utilization in Q1.b (5%).

Overstory

The greatest control growth pre-treatment occurred in A4 (0.1 cm/year), while the least

control growth pre-treatment occurred in E4.b (0.05 cm/year). The greatest control growth post-

treatment again occurred in A4 (0.125 cm/year), while the least control growth post-treatment

again occurred in E4.b (0.05 cm/year). The average control post-treatment growth was 0.072

cm/year and the average control pre-treatment growth was 0.081 cm/year, as can be seen in

Figure 2.

22

The greatest treatment growth pre-treatment occurred in Q1.a (0.133 cm/year), while the

least treatment growth pre-treatment occurred in P2.a and H3 (0.075 cm/year). The greatest

treatment growth post-treatment occurred in P2.b (0.117 cm/year), while the least treatment

growth post-treatment occurred in D3 (0.075 cm/year). The only conifer measured experienced

0.05 cm/year of growth after the treatment and 0.075 cm/year before it. The conifer was located

in the treatment area in unit H3. The average treatment for both pre and post-treatment growth

was 0.086cm/year. The average mature trees per acre in the control location was 7 aspen with the

most trees per acre existing in A4 (14 trees per acre); the least trees per acre occurred in C1-N

(30 trees per acre). The treatment location contained an average of 49 aspen per acre and 30

conifers per acre, with the most aspen trees per acre existing in D3 (130 trees per acre); the least

trees least trees per acre occurred in T5-N (30 trees per acre).

Please see Figures 1-4 for a visual explanation of the above-mentioned results; figures 5-

8 give a graphical interpretation.

At the Burnt Fork Ranch, the average treatment unit contained 2672 more aspen

regeneration stems per acre than the average control unit. Similarly, the average treatment unit at

the Bandy Ranch contained 1490 more aspen than the average control unit. The average

treatment unit at the Bandy Ranch also experienced greater average annual radial growth both

post-and-pre-treatment, but only by 0.005 cm/year and 0.011 cm/year, respectively. In addition,

the average Burnt Fork overstory unit experienced greater average annual radial growth both

post-and-pre-treatment, by 0.065 cm/year and 0.037 cm/year, respectively.

23

Figure 1: Bandy Ranch understory results.

CONT

ROL

REGE

NERA

TION

(ste

ms p

er ac

re)

Unit

Area

(ac)

< 1 cm

coun

t1-

2 cm

coun

t2-

3 cm

coun

t> 3

cm co

unt

Tota

l Cou

ntut

iliza

tion

(%)

A40.

330

1300

600

300

2200

0

E4.a

0.2

025

035

0013

0050

505.

48

E4.b

0.24

100

220

400

300

1020

0

Cont

rol T

otal

s0.

77

Cont

rol A

vera

ges

33.3

359

0.00

1500

.00

633.

3327

56.6

71.

83

TREA

TMEN

TRE

GENE

RATI

ON (s

tem

s per

acre

)

Unit

Area

(ac)

< 1 cm

coun

t1-

2 cm

coun

t2-

3 cm

coun

t> 3

cm co

unt

Tota

l Cou

ntut

iliza

tion

(%)

Blue

P2.a

0.15

1700

4500

3300

300

9800

71.4

3

P2.b

0.1

500

500

00

1000

100

G20.

0935

0036

0060

010

078

008.

54

Red

Q1.a

0.34

400

1000

200

016

0031

.25

Q1.b

0.55

013

0010

060

020

005

Yello

w

H32.

7516

0031

0044

0030

094

0057

.45

D30.

9729

0017

0018

000

6400

51.5

6

Trea

tmen

t Tot

als

4.95

Trea

tmen

t Ave

rage

s15

14.2

922

42.8

614

85.7

118

5.71

5428

.57

46.4

6

24

Figure 2: Bandy Ranch overstory results.

cm/yr cm/yr OVERSTORY

Avg. ann. growth post-T: Avg. ann. growth pre-T: Species: # aspen/ac # conifers/ac

0.108 0.100 aspen 14

0.083 0.067 aspen 5

0.05 0.05 aspen 1

0.081 0.072 7



0.092 0.075 aspen 7

0.117 0.083 aspen 6

0.058 0.042 aspen 1

0.100 0.133 aspen 50

0.083 0.108 aspen 30

0.12 (con); .08 aspen 0.13 (con); 0.075 aspen con/aspen 120 30

0.075 0.083 aspen 130

.086 aspen 0.086 aspen 49 30

25

Figure 3: Burnt Fork understory results.

CO

NTR

OL

REG

ENER

ATI

ON

(st

em

s p

er

acre

)

Un

itA

rea

(ac)

< 1

cm c

ou

nt

1-2

cm c

ou

nt

2-3

cm c

ou

nt

> 3

cm c

ou

nt

Tota

l co

un

tu

tili

zati

on

(%

)

C1

- N

2.65

200

00

1000

1200

0

C1

- S

1.6

300

400

400

400

1500

0

C2

- N

2.36

800

600

020

016

0012

.50%

C2

- S

2.32

060

048

0017

0071

000

Co

ntr

ol T

ota

ls8.

93

Co

ntr

ol A

vera

ges

325.

0040

0.00

1300

.00

825.

0028

50.0

00.

03

TREA

TMEN

TR

EGEN

ERA

TIO

N

Un

itA

rea

(ac)

< 1

cm c

ou

nt

1-2

cm c

ou

nt

2-3

cm c

ou

nt

> 3

cm c

ou

nt

Tota

l co

un

tu

tili

zati

on

(%

)

T1 -

N1.

551

0012

0020

00

6500

13.8

5

T1 -

S2.

678

0080

010

00

8700

51.7

2

T2 -

N1.

0546

0030

00

200

5100

0

T2 -

S1.

4537

0080

010

00

4600

60.8

7

T3 -

N4.

810

019

0030

010

024

006.

06

T3 -

S1.

8490

020

060

020

019

0010

.53

T4 -

N1.

5138

0016

0010

050

060

0031

.67

T4 -

S6.

418

0030

010

060

028

0053

.57

T5 -

N0.

820

1600

400

200

2200

4.55

T5 -

S1.

8525

0050

010

010

032

000

Tre

atm

en

t To

tals

23.8

2

Tre

atm

en

t A

vera

ges

3030

920

200

190

4340

23.2

82

26

Figure 4: Burnt Fork overstory results.

Figure 5: Bandy control regeneration stems per acre by unit and control average.



0.075 0.075 aspen 30

0.1 0.05 aspen 50

0.125 0.15 aspen 90

0.05 0.05 aspen 110

0.088 0.081 70



0.175 0.15 aspen 90

0.275 0.175 aspen 130

0.075 0.05 aspen 70

0.125 0.1 aspen 100

0.05 (con); 0.125 (aspen) 0.075 (con); 0.1 (aspen) con, aspen 70 20

0.15 0.25 aspen 70

0.15 0.1 aspen 120

0.25 0.25 aspen 60

0.1 0.05 aspen 30

0.1 0.05 aspen 40

0.153 0.119 78 20

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

A4 E4.a E4.b Control Average

Ste

ms

pe

r ac

re

Bandy Control Regeneration

27

Figure 6: Bandy treatment regeneration stems per acre by unit and treatment average.

Figure 7: Burnt Fork control regeneration stems per acre by unit and control average.

0100020003000400050006000700080009000

10000

Ste

ms

pe

r ac

re

Bandy Treatment Regeneration

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

C1 - N C1 - S C2 - N C2 - S Control Avg.

Ste

ms

pe

r ac

re

Burnt Fork Control Regeneration

28

Figure 8: Burnt Fork treatment regeneration stems per acre by unit and treatment average.

DISCUSSION

Please note that the research questions are reiterated in italics. The fourth research question

(investigating differences between variables at the Bandy Ranch and Burnt Fork ranches) is

considered within each of the research question discussions below.

Does conifer removal in quaking aspen increase, decrease, or not affect aspen regeneration?

Aspen regeneration was greater on average than treatment at both the Bandy and Burnt

Fork Ranches. As hypothesized, this increase in regenerative growth was most likely due to the

removal of conifers that competed for water, sunlight, and nutrients. In addition to an increased

abundance of resources, quaking aspen regeneration was probably also influenced by the

disturbance of ground (stimulating shallow aspen root systems) (Doucet 1989, Howard 1996,

Sandberg and Schneider 1953, Perry et al. 1999), and from winter (Burnt Fork) and summer

(Bandy) logging activities that utilized tracked and chained-tire equipment. Doucet (1989) stated

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Ste

ms

pe

r ac

re

Burnt Fork Treatment Regeneration

29

that seasonality of timber harvests within quaking aspen stands do not have any significant effect

on clonal aspen regeneration productivity. The sprouts measured in this study were most likely

clonal sprouts, as fire is often one of the only naturally-occurring mechanisms that can trigger

viable quaking aspen seed production (Shinneman et al. 2013). No prescribed fire has occurred

within the Burnt Fork or Bandy Ranch aspen stands in the past twenty years at least. Therefore,

the timing of release treatments was probably not a significant factor in determining aspen

regeneration responses between the Burnt Fork and Bandy ranches.

Both locations offered specific evidence that removal of encroaching conifers increases

quaking aspen regeneration. Bandy Ranch units with 1-2 mature quaking aspen stems removed

per clone (units H3 and D3) experienced the second-highest regeneration densities per acre.

Several foresters mention how mature quaking aspen trees regularly secrete a hormonal chemical

to their root systems that keeps clonal reproduction relatively in check (Rook 2006, Bradt 2015).

Removing mature aspen stems, even if a partial removal, removes this stem-based inhibitory

chemical and should increase the probability of regeneration success. Although more factors

could be at play, the removal of 1-2 quaking aspen stems per clone seems a very probable cause

of the dramatic increase in quaking aspen regeneration in units H3 and D3 at the Bandy Ranch

(Williams, personal observation 2015).

The aspen release treatment at both locations seems to have resulted in an increase in

regeneration in the lower sprout-diameter classes, which likely means the roots are continuing to

produce regeneration until a threshold is reached. This would accord with existing aspen

silviculture literature, as aspen sprout age is usually correlated with diameter (Bradt 2015,

Lewing 2015, Howard 1996). The Burnt Fork Ranch was the best illustration of this relationship

as the most aspen regeneration occurred in the less-than-1 cm class at and the least occurred in

30

the greater-than-3 cm class. And, the Burnt Fork control area exhibited an opposite relationship

with the most regeneration in the greater-than-3 cm class and the least in the less-than-1 cm

class. The Bandy Ranch treatment units exhibited the densest regeneration in the 1-2 cm class

and the least in the greater-than-3 cm class, with the control area showing densest regeneration in

the 2-3 cm class and the least in the less-than-1 cm class. It seems that regeneration is older in

the control units at both the Bandy and Burnt Fork ranches when compared to the treatments

units, therefore implying that the silvicultural treatment of the stand directly influenced aspen

regeneration production because the regeneration was much younger than that in the control

units (Williams, personal observation 2015).

An interesting follow-up study might investigate the numbers of new regeneration

through time and determine when the released aspen clone stopped producing regeneration.

Answering that question, however, is beyond the scope of this current investigation and is best

left to future scientists.


regeneration browsing by ungulates?

Quaking aspen regeneration utilization by ungulates (measured as percent of regeneration

browsed) was extremely poor in all control sites at both the Bandy and Burnt Fork ranches. The

low percentage of total regeneration browsed (1.83%) at the Bandy control sites was most likely

due to the majority of regenerative stems (77%) occurring in the 2-greater-than-3 cm classes.

These thicker stems were observed to have far less browsing than stems in smaller diameter

classes, which contained most of the meager control utilization. This stark difference is most

likely due to younger stems containing more succulent and nutritious current year’s growth than

older stems in larger diameter classes (Williams, personal observation 2015). On average, the

31

Bandy Ranch regeneration occurring in treated areas experienced 46.46% more utilization than

the average control area. Again, this difference is most likely due to differences in size class

densities (69% of all regeneration occurred in the less-than-1 to 2 cm size classes). As noted in

section one of this discussion, conifer removal in quaking aspen stands seems to result in a pulse

of regeneration recruitment into the smaller size classes because increasing light availability

stimulates sprout growth (Sandberg and Schneider 1953).

Moreover, it is also likely that ungulates prefer tenderer current year’s growth which is

found in younger, and thus usually smaller, diameter classes (Bradt 2015, Howard 1996, Lewing

2015). Those factors would influence herbivores to selectively graze smaller diameter classes,

and this overall trend was observed at the Bandy and Burnt Fork ranches. Because conifer

removal (and especially the cutting of some overstory aspen) recruits more regeneration into

smaller diameter classes than a no-cut control unit, it makes sense that treatment units would

experience the greatest amount of utilization (Williams, personal observation 2015).

The Burnt Fork ranch utilization data showed a similar trend between control and

treatment sites. Only one control location experienced utilization (12.5%) to give an average of

.03% total control utilization. The treatment average utilization, however, showed a dramatic

increase to 23.28% of total regeneration. It is very likely that similar factors were at play at the

Burnt Fork and Bandy ranches, namely, that silvicultural manipulation of the aspen stands

resulted in more regeneration (Williams, personal observation 2015). Because 75% of Burnt

Fork control regeneration occurred in the 2-greater-than-3 cm classes and 25% in the less than 2

cm classes, the little regeneration that did occur was clustered in the less-than-1 diameter class.

The Burnt Fork treatment units, however, showed 91% of all regeneration grouped in the 2-

greater-than-3 cm classes and only 8% in the less than 2 cm classes. As palatable browsing

32

material was more abundant in treatment areas than in controls, selective browsing resulted in

higher ungulate utilization of treatment units (Williams, personal observation 2015).

Overall, then, the data trends and relationships suggest that removing encroaching

conifers from quaking aspen clones does seem to result in greater ungulate utilization of young

regeneration, mostly because there is simply denser, younger forage available in treated stands

due to an increased production of regeneration post-treatment (Williams, personal observation

2015).

Does conifer removal in quaking aspen increase, decrease or not affect residual growth?

Average annual growth of residual trees either increased or stayed the same post-harvest

for all but one location at the Bandy and Burnt Fork ranches, which showed a decrease in

residual growth. Both instances of decrease in average annual growth were found in treatment

units. The Bandy unit showing decreased radial growth (D3) contained the most overstory trees,

which could at least partially explain why growth decreased post-treatment. The Burnt Fork unit

with decreased radial growth (T3-S), however, did not contain the most trees per acre.

On the other hand, 45% of regeneration in unit D3 occurred in the less-than-1 cm

diameter class (which is the youngest diameter class), implying that its growth was stimulated by

the timber harvest. Unit T3-S at the Burnt Fork also showed a comparatively large (47%) portion

of its regeneration occurring in the youngest diameter class. Where conifer removal was

incomplete at the Bandy and Burnt Fork ranches, radial conifer growth declined from pre-

treatment to post-treatment. The overstory trees at both ranches may have experienced a decrease

in residual growth because resource consumption was switched post-treatment from radial

growth to clonal reproduction (Williams, personal observation 2015).

33

Any change, whether positive or negative, in average annual residual growth was very

small and only discernable with a dissecting microscope at both ranches. The average difference

between treatment and control at the Bandy Ranch was a positive growth but very small: only

0.005 cm/year post-treatment and only .011 cm/year pre-treatment. The Burnt Fork Ranch also

showed positive but nearly non-significant growth changes: 0.065 cm/year post-treatment and

only 0.073 cm/year pre-treatment. Still, the Burnt Fork Ranch showed a greater average annual

growth increase over a shorter time period (four years) than the 12-year time period at the Bandy

Ranch. This may indicate that the Burnt Fork overstory aspen trees are more responsive to

treatments than the Bandy Ranch aspen trees, most likely because the Burnt Fork trees are much

younger than those at the Bandy (Williams, personal observation 2015).

Overall, removing encroaching conifers from quaking aspen seems to increase the radial

growth of residual overstory aspen but only by a small amount. While there were instances

where overstory aspen radial growth decreased post-treatment, the overall trend suggests that

conifer removal has the ability to increase residual growth. In addition, time-scales make a

difference: if this study were repeated in ten years and regeneration production has slowed, then

the overstory stems may have more resources available to continue radial growth (Williams,

personal observation 2015).

34

CONCLUSION

This control-impact study quantified how releasing quaking aspen stands from conifer

encroachment affected aspen regeneration and residual radial growth. Releasing quaking aspen

stands at a large spatial scale shows similar results, giving implications for effective management

techniques across the wide ecological spectrum of western Montana. When quaking aspen stands

were released, regeneration increased abundantly in treatment units and was clustered in lower

diameter classes. Because of this regeneration concentration of smaller, more palatable stems,

ungulate utilization of current year’s growth was greater in all treatment units than in all control

units. Thus, while the goal of increasing aspen regeneration was met through silvicultural

manipulation of aspen clones, the ensuing regeneration was heavily grazed by ungulates at both

study locations. Average annual radial growth increased overall in both control and treatment

location, but only by very small amounts. There were two instances in treatment units where

annual radial growth actually decreased following a treatment, but this coincided with a large

percentage of regeneration occurring in small diameter classes. Overstory trees were most likely

devoting resources to the pulse of clonal reproduction following the treatment; this would help

explain the reason why overstory trees were only increasing (and sometimes decreasing) annual

radial growth following the conifer removal. The above-mentioned trends occurred at both the

Bandy and Burnt Fork ranches, implying similarity between silvicultural effects at a larger

spatial scale.

Results and relationships brought out in this study may be of help to managers who want

to restore quaking aspen stands without clearcutting. While clearcutting has been shown to

drastically increase regeneration (Doucet 1989), many landowners may wish to retain the myriad

of benefits (wildlife and bird cover, snag habitat, cooler soil temperatures and less water

35

evaporation, less erosion from spring runoff events) from leaving an aspen overstory (Bradt

2015, Howard 1996, Lewing 2015, Perry et al. 1999). This study has hopefully added to

previous, although scant, information on partially cutting quaking aspen stands to achieve

multiple objectives while retaining vertical structural diversity. Land managers should now have

more information, and therefore more options than clearcutting, about how to increase aspen

regeneration and ensure the future presence of aspen on a site.

This study would benefit from a future investigator determining the site-specific

relationships between Burnt Fork and Bandy aspen regeneration diameter and age. While

reviewed sources do state that smaller-diameter aspen regeneration usually implies younger

sprouts (Bradt 2015, Howard 1996), having site-specific correlations with regeneration and age

would help bolster assertions made in this study. In addition, an interesting follow-up study

might mark the browsed aspen stems now and then re-examine them a decade or so later to

determine if browsing had any detrimental effects on regeneration mortality. At the time this

study was carried out, no aspen regeneration had died from over-browsing. Monitoring overstory

aspen after a longer period (say a decade or two) would help researchers find if a longer time

period is necessary to notice a meaningful increase in residual overstory radial growth. As

mentioned earlier, the age of overstory trees is likely a significant factor in determining radial

growth responses.

Anyone interested in ensuring the future of quaking aspen and its many ecological, and in

turn monetary, benefits should be able to practice partial cuts in their quaking aspen stands,

remove encroaching conifers, and achieve abundant regeneration. Ungulates do browse the

ensuing regeneration, but browsed regeneration is still alive and thriving after four to six years

post-treatment. Overall, quaking aspen stands can be regenerated successfully by selective partial

36

cuts in order to meet stand objectives at the Burnt Fork and Bandy ranches. Managers may

hopefully apply principles explored and relationships found in this study to quaking aspen stands

throughout western Montana in order to ensure a future of a tree crucial to nature and society.

37

LITERATURE CITED

Anderson, R. L. 1979. Hypoxylon canker of aspen. Washington : Dept. of Agriculture, Forest

Service, Washington.

Bagga, D. K., and E. B. Smalley. 1974. The development of hypoxylon canker of populus

tremuloides: role of interacting environmental factors. American Phytopathological Society.

64.5:March 23 2015.-658-662.

Bradt, W. 2015. Personal Communication.

Dodson, E. 2015. Personal Communication.

Doucet, R. 1989. REGENERATION SILVICULTURE OF ASPEN. Forestry Chronicle;

For.Chron. 65:23-27.

Holechek, J., R. Pieper, and H. Carlton. 2003.

Howard, J. L. 1996. Populus tremuloides. Fire Effects Information System, [Online]. U.S.

Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences

Laboratory (Producer). March 18 2015.

Lewing, M. 2015. Personal Communication.

McManigal, K. 2015. Personal Communication.

Perala, D. A. n.d. Quaking aspen. U.S. Department of Agriculture, Forest Service. 2015.

Perry, R. W., R. E. Thill, D. G. Peitz, and P. A. Tappe. 1999. Effects of Different Silvicultural

Systems on Initial Soft Mast Production. Wildlife Society Bulletin 27:915-923.

Rook, E. 2006. Populus tremuloides: quaking aspen. Rook.org March 18 2015.

Sandberg, D., and A. E. Schneider. 1953. The regeneration of aspen by suckering. School of

Forestry, University of Minnesota. March 23 2015.

Shinneman, D., W. Baker, P. C. Rogers, and D. Kulakowski. 2013. Fire regimes of quaking

aspen in the Mountain West. Forest Ecology and Management; For.Ecol.Manage. 299:22-

34.

Stewardship, W. 2011. Forest Types: Aspen, University of Minnesota collaboration. March 18

2015.

Worrall, J., G. Rehfeldt, A. Hamann, E. Hogg, S. B. Marchetti, M. Michaelian, and L. Gray.

2013. Recent declines of Populus tremuloides in North America linked to climate. Forest

Ecology and Management; For.Ecol.Manage. 299:35-51.

38

APPENDICES

Appendix A: Bandy Ranch Jumpstart Prescription

The following four treatments will be implemented:

Treatment 1 - Red

This is a wildlife-focused treatment that leaves naturally-occurring clumps of trees and creates

clearings around these clumps. This treatment would break up fuels horizontally, minimizing

risk of continuous crown fire.

- Leave clumps should vary in size from a few trees to 1/4 acre in size.

- Leave clumps may be a mixture of species, sizes, and age classes.

- 50-80% open (no trees), with the remainder of the area in clumps.

- No thinning of clumps.

- Clumps will be arranged so as to minimize sight distance through the stand.

- When practical, lodgepole pine that has been hit by bark beetles or is of a susceptible size

(mature) should be favored for removal.

- Species preference for retention is: aspen, cottonwood, larch, ponderosa pine, spruce,

Douglas-fir, lodgepole pine.

Aspen: clear around aspen clones approximately 50 feet. No cutting within aspen.

Treatment 1 applies to Units B, J, L, and Q. Unit boundaries are marked with red flagging at

road intersections and along boundaries not formed by roads.

Treatment 2 - Blue

Same as 1 but with thinning of clumps to remove less-desired species and ladder fuels. This

treatment breaks up fuels both horizontally and vertically and also provides for increased browse

and some disruption of sight distance.

- Leave clumps should vary in size from a few trees to 1/4 acre in size.

- Leave clumps may be a mixture of species, sizes, and age classes.

- 50-80% open (no trees), with the remainder of the area in clumps.

- Clumps will be thinned to retain the most vigorous, best form trees (sanitation thinning). A

range of residual age and size classes is desired, when possible.

- Clumps will be arranged so as to minimize sight distance through the stand.

- When practical, lodgepole pine that has been hit by bark beetles or is of a susceptible

(mature) size should be favored for removal.



39

Aspen: Clear around aspen clones approximately 50 feet and remove conifer encroachment.

Unit G: This unit has a large volume of dead or dying lodgepole pine from an ongoing mountain

pine beetle outbreak. All dead, dying, and susceptible lodgepole pine will be removed from this

unit. This will create patch openings. In portions of the stand that are currently mixed conifer,

the above treatment will be applied.

Treatment 2 applies to Units F, G, O, and P. Unit boundaries are marked with blue flagging at

road intersections and along boundaries not formed by roads.

Treatment 3: Yellow

This treatment will thin by species preference, retaining the naturally-occurring clumpy stand

structure.

- Target species composition is 40-60% larch, 20-40% Douglas-fir, 20-40% ponderosa pine,

20% other.

- On average retain 50-70 sq. ft. basal area per acre (1/2 to 2/3 the pre-treatment basal area).

- Retain the most vigorous, best form trees in a variety of age and size classes.



Aspen: Clear around aspen clones approximately 50 feet. Remove conifer encroachment from

within each clone. Additionally, cut 1 to 2 mature aspen stems per clone to promote

regeneration.

Treatment 3 includes Units C, D, H, I, and K. Unit boundaries are marked with yellow flagging

at road intersections and along boundaries not formed by roads.

Treatment 4: White

Control (no treatment). No cutting is to occur within these units except where necessary for road

relocation.

Treatment 4 includes Units A, E, M, N. Unit boundaries are marked with white flagging at road

intersections and along boundaries not formed by roads.

40

Unit acreages:

Unit Acres Treatment Treated

A 20.1 4 no

B 11 1 yes

C 25.2 3 yes

D 22.1 3 yes

E 15.1 4 no

F 23.7 2 yes

G 26.6 2 yes

H 10.5 3 yes

I 14.7 3 yes

J 8.9 1 yes

K 11.1 3 yes

L 10.1 1 yes

M 13.8 4 no

N 26.8 4 no

O 18.5 2 yes

P 27.8 2 yes

Q 29.4 1 yes

Appendix A: Prescription for the Bandy Ranch Jumpstart Project (courtesy of Dr. Elizabeth

Dodson, University of Montana, Missoula).

41

Appendix B: Map of the Bandy Ranch Jumpstart silvicultural operation and various

silvicultural treatments: summer 2009 (courtesy of Dr. Elizabeth Dodson, University of

Montana, Missoula).

42

Equipment Cost

($)

Flagging Tape 5

50' Spencer Diameter Tape ft./10ths

(950DC)

57.98

Lufkin Fiberglass Tape - 3/4-inch X

100-foot

56.44

Haglöf 3-Thread Increment Borers 269.55

(16"L x 0.200 (5.15mm) Dia.)

Silva Ranger Orienteering Compass 50

Equipment Total Costs 438.97

Burnt Fork Ranch Travel

Date Miles Gal

used

Cost

($)

6/1/2015 31.8 2.54 6.56

6/4/2015 31.8 2.54 6.56

6/15/2015 31.8 2.54 6.56

6/17/2015 32.5 2.60 6.71

6/26/2015 29.2 2.34 6.03

7/16/2015 31.2 2.50 6.44

7/17/2015 31.2 2.50 6.44

7/21/2015 32.6 2.61 6.73

7/22/2015 23 1.84 4.75

7/23/2015 17 1.36 3.51

7/27/2015 30.1 1.00 2.59

7/31/2015 17 1.36 3.51

8/18/2015 26 2.08 5.37

9/12/2015 34 1.13 2.92

9/19/2015 29 0.97 2.49

Burnt Fork Ranch Total Costs ($) 77.17

43

Bandy Ranch Travel

Date Miles Gal

used

Cost ($)

6/22/2015 71 2.37 6.11

8/22/2015 160 7.27 18.04

9/11/2015 104.6 8.37 21.59

Bandy Ranch Total

Costs ($)

45.73

GRAND TOTAL

COSTS ($)

561.87

Notes

Price/Gal (Unlead) MPG

(truck)

MPG

(car)

MPG

(Diesel)

Price/Gal

(Diesel)

$2.58 12.5 30 22 $2.48

Appendix C: Research equipment and travel costs.

44

Appendix D: Map of the Burnt Fork Ranch aspen study units.

45

Appendix E: Map of the Bandy Ranch aspen study units.

46

Appendix F.1: Burnt Fork Ranch control raw data.

Un

it:

C1

- N

Un

it:

C2

- N

100t

h a

cre

100t

h a

cre

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

dB

row

sed

2

Un

bro

wse

d2

10U

nb

row

sed

66

2

10th

acr

eN

ote

s10

th a

cre

No

tes

Mo

st V

igo

rou

sM

ost

Vig

oro

us

DB

H:

13.2

Tota

l gro

wth

DB

H:

8.3

Avg

. gro

wth

po

st-T

:0.

075

0.15

Tota

l gro

wth

Avg

. gro

wth

pre

-T:

0.07

50.

15A

vg. g

row

th p

ost

-T:

0.12

50.

25

# o

vers

tory

tre

es:

3Sa

mp

leA

vg. g

row

th p

re-T

:0.

150.

3

# o

vers

tory

tre

es:

9Sa

mp

le

Un

it:

C1

- S

100t

h a

cre

Un

it:

C2

- S

Dia

me

ter

Cla

sse

s (c

m)

100t

h a

cre

< 1

1-2

2-3

> 3

Dia

me

ter

Cla

sse

s (c

m)

Bro

wse

d<

11-

22-

3>

3

Un

bro

wse

d3

44

4B

row

sed

Un

bro

wse

d6

4817

10th

acr

eN

ote

s

Mo

st V

igo

rou

s10

th a

cre

No

tes

DB

H:

9.9

Tota

l gro

wth

Mo

st V

igo

rou

s

Avg

. gro

wth

po

st-T

:0.

10.

2D

BH

:0.

8To

tal g

row

th

Avg

. gro

wth

pre

-T:

0.05

0.1

Avg

. gro

wth

po

st-T

:0.

050.

1

# o

vers

tory

tre

es:

5Sa

mp

leA

vg. g

row

th p

re-T

:0.

050.

1

# o

vers

tory

tre

es:

11Sa

mp

le9

de

ad

47

Appendix F.2: Burnt Fork Ranch treatment raw data, units 1 & 2.

Un

it:

T1 -

NU

nit

:T2

- N

100t

h a

cre

100t

h a

cre

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

d8

1B

row

sed

Un

bro

wse

d43

112

Un

bro

wse

d46

32

10th

acr

eN

ote

s10

th a

cre

No

tes

Mo

st V

igo

rou

sM

ost

Vig

oro

us

DB

H:

7.4

Tota

l Gro

wth

DB

H:

4.3

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

175

0.35

Avg

. gro

wth

po

st-T

:0.

075

0.15

Avg

. gro

wth

pre

-T:

0.15

0.3

Avg

. gro

wth

pre

-T:

0.05

0.1

# o

vers

tory

tre

es:

9Sa

mp

le#

ove

rsto

ry t

ree

s:7

Sam

ple

smal

l, a

bo

ut

30 f

ee

t.

Un

it:

T1 -

SU

nit

:T2

- S

100t

h a

cre

100t

h a

cre

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

d44

1B

row

sed

244

Un

bro

wse

d34

71

Un

bro

wse

d13

41

10th

acr

eN

ote

s10

th a

cre

No

tes

Mo

st V

igo

rou

sM

ost

Vig

oro

us

DB

H:

5.9

Tota

l Gro

wth

DB

H:

6.7

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

275

0.55

Avg

. gro

wth

po

st-T

:0.

125

0.25

Avg

. gro

wth

pre

-T:

0.17

50.

35A

vg. g

row

th p

re-T

:0.

10.

2

# o

vers

tory

tre

es:

13Sa

mp

le#

ove

rsto

ry t

ree

s:10

Sam

ple

2 ar

e d

ead

sn

ags

48

Appendix F.3: Burnt Fork treatment raw data, units 3 & 4.

Un

it:

T3 -

NU

nit

:T4

- N

100t

h a

cre

100t

h a

cre

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

d2

Bro

wse

d19

Un

bro

wse

d8

193

1U

nb

row

sed

1916

15

10th

acr

eN

ote

s10

th a

cre

No

tes

Mo

st V

igo

rou

s C

on

ifer

Mo

st V

igo

rou

s

DB

H: (

PP

)15

.5To

tal G

row

thD

BH

:5.

9To

tal G

row

th

Avg

. gro

wth

po

st-T

:0.

050.

1A

vg. g

row

th p

ost

-T:

0.15

0.3

Avg

. gro

wth

pre

-T:

0.07

50.

15A

vg. g

row

th p

re-T

:0.

10.

2

Mo

st V

igo

rou

s A

spen

# o

vers

tory

tre

es:

12Sa

mp

le

DB

H:

4.6

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

125

0.25

Avg

. gro

wth

pre

-T:

0.1

0.2

Un

it:

T4 -

S

# o

vers

tory

tre

es:

9Sa

mp

le7

asp

en

, 2 p

on

do

s.10

0th

acr

e

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

Un

it:

T3 -

SB

row

sed

122

1

100t

h a

cre

Un

bro

wse

d6

16

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

10th

acr

eN

ote

s

Bro

wse

d2

Mo

st V

igo

rou

s

Un

bro

wse

d7

26

2D

BH

:9.

6To

tal G

row

th

Avg

. gro

wth

po

st-T

:0.

250.

5

10th

acr

eN

ote

sA

vg. g

row

th p

re-T

:0.

250.

5

Mo

st V

igo

rou

s#

ove

rsto

ry t

ree

s:6

Sam

ple

DB

H:

5.8

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

150.

3

Avg

. gro

wth

pre

-T:

0.25

0.5

# o

vers

tory

tre

es:

7Sa

mp

leve

ry s

mal

l, 2

0-25

fe

et.

49

Appendix F.4: Burnt Fork Ranch treatment raw data, unit 5.

Unit: T5-N

100th acre

Diameter Classes (cm)

< 1 1-2 2-3 > 3

Browsed 1

Unbrowsed 16 3 2

10th acre Notes

Most Vigorous

DBH: 8.1 Total Growth

Avg. growth post-T: 0.1 0.2

Avg. growth pre-T: 0.05 0.1

# overstory trees: 3 Sample

Unit: T5 - S

100th acre


< 1 1-2 2-3 > 3

Browsed

Unbrowsed 25 5 1 1

10th acre Notes

Most Vigorous

DBH: 4.3 Total Growth




50

Appendix G.1: Bandy Ranch control raw data.

Unit: A4

100th acre


< 1 1-2 2-3 > 3

Browsed

Unbrowsed 0 13 6 3

10th acre Notes

Most Vigorous

DBH: 24.5

Avg. growth post-T: 0.108333333 0.65


# overstory trees: 14 Census

Unit: E4.a

100th acre


< 1 1-2 2-3 > 3

Browsed 2 2

Unbrowsed 23 33 13

10th acre Notes

Most Vigorous

DBH: 25


Avg. growth pre-T: 0.066666667 0.4

# overstory trees: 5 Census

Unit: E4.b

100th acre


< 1 1-2 2-3 > 3

Browsed 2 2

Unbrowsed 1 20 2 3

10th acre Notes

Most Vigorous

DBH: 13.2




51

Appendix G.2: Bandy Ranch treatment raw data.

Un

it:

P2.

aU

nit

:Q

1.a

Un

it:

H3

100t

h a

cre

100t

h a

cre

100t

h a

cre

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

d13

3024

3B

row

sed

23

Bro

wse

d11

1921

3

Un

bro

wse

d4

159

Un

bro

wse

d2

72

Un

bro

wse

d5

1223

10th

acr

eN

ote

s10

th a

cre

No

tes

10th

acr

eN

ote

s

Mo

st V

igo

rou

sM

ost

Vig

oro

us

Mo

st V

igo

rou

s C

on

ifer

DB

H:

12.8

Tota

l Gro

wth

DB

H:

17To

tal G

row

thD

BH

:22

D-f

Avg

. gro

wth

po

st-T

:0.

0916

670.

55A

vg. g

row

th p

ost

-T:

0.1

0.6

Avg

. gro

wth

po

st-T

:0.

1166

670.

7

Avg

. gro

wth

pre

-T:

0.07

50.

45A

vg. g

row

th p

re-T

:0.

1333

330.

8A

vg. g

row

th p

re-T

:0.

125

0.75

# o

vers

tory

tre

es:

7C

en

sus

# o

vers

tory

tre

es:

5Sa

mp

le1

snag

Mo

st V

igo

rou

s A

spen

DB

H:

21.7

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

0833

330.

5

Un

it:

P2.

bU

nit

:Q

1.b

Avg

. gro

wth

pre

-T:

0.07

50.

45

100t

h a

cre

100t

h a

cre

# o

vers

tory

tre

es:

15Sa

mp

le3

con

ife

rs: 2

D-f

, 1 W

L.

Dia

me

ter

Cla

sse

s (c

m)

Dia

me

ter

Cla

sse

s (c

m)

12 a

spe

n

< 1

1-2

2-3

> 3

< 1

1-2

2-3

> 3

Bro

wse

d5

5B

row

sed

1

Un

bro

wse

dU

nb

row

sed

121

6U

nit

:D

3

100t

h a

cre

10th

acr

eN

ote

s10

th a

cre

No

tes

Dia

me

ter

Cla

sse

s (c

m)

Mo

st V

igo

rou

sM

ost

Vig

oro

us

< 1

1-2

2-3

> 3

DB

H:

14.6

Tota

l Gro

wth

DB

H:

19.8

Tota

l Gro

wth

Bro

wse

d23

10

Avg

. gro

wth

po

st-T

:0.

1166

670.

7A

vg. g

row

th p

ost

-T:

0.08

3333

0.5

Un

bro

wse

d6

718

Avg

. gro

wth

pre

-T:

0.08

3333

0.5

Avg

. gro

wth

pre

-T:

0.10

8333

0.65

# o

vers

tory

tre

es:

6C

en

sus

# o

vers

tory

tre

es:

3Sa

mp

le10

th a

cre

No

tes

Mo

st V

igo

rou

s

DB

H:

11.6

Tota

l Gro

wth

Un

it:

G2

Avg

. gro

wth

po

st-T

:0.

075

0.45

100t

h a

cre

Avg

. gro

wth

pre

-T:

0.08

3333

0.5

Dia

me

ter

Cla

sse

s (c

m)

# o

vers

tory

tre

es:

13Sa

mp

le

< 1

1-2

2-3

> 3

Bro

wse

d3

4

Un

bro

wse

d32

366

1

10th

acr

eN

ote

s

Mo

st V

igo

rou

s

DB

H:

15.3

Tota

l Gro

wth

Avg

. gro

wth

po

st-T

:0.

0583

330.

35

Avg

. gro

wth

pre

-T:

0.04

1667

0.25

# o

vers

tory

tre

es:

1C

en

sus

Documents

Quantifying Effects of Quaking Aspen Silvicultural