Assessing the Use of Shrub-Willows for Living Snow Fences in Minnesota

99 Pages·2015·9.23 MB·English

by  Diomy S Zamora

Assessing the Use of
Shrub-Willows for Living

Snow Fences in Minnesota
Diomy Zamora, Principal Investigator
University of Minnesota Extension

November 2015
Research Project
Final Report 2015-46
To request this document in an alternative format call 651-366-4718 or 1-800-657-3774 (Greater
Minnesota) or email your request to
Technical Report Documentation Page
1. Report No. 2. 3. Recipients Accession No.
MN/RC 2015-46
4. Title and Subtitle 5. Report Date
November 2015
Assessing the Use of Shrub-Willows for Living Snow Fences in
6.
Minnesota

7. Author(s) 8. Performing Organization Report No.
Diomy S Zamora, Eric Ogdahl, Gary Wyatt, David J. Smith,
Gregg Johnson, Dean Current, Dan Gullickson,
9. Performing Organization Name and Address 10. Project/Task/Work Unit No.
University of Minnesota Extension CTS # 2014007
Center for Agriculture, Food and Natural Resources | Extension 11. Contract (C) or Grant (G) No.
227 Coffey Hall, 1420 Eckles Ave
(c) 99008 (wo) 120
St. Paul, MN 55155-1899

12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered
Minnesota Department of Transportation Final Report
Research Services & Library 14. Sponsoring Agency Code
395 John Ireland Boulevard, MS 330
St. Paul, Minnesota 55155-1899
15. Supplementary Notes
http://www.lrrb.org/pdf/201546.pdf
16. Abstract (Limit: 250 words)
Blowing and drifting snow adversely affect winter driving conditions and road infrastructure in Minnesota, often
requiring removal methods costly to the state and environment. Living snow fences (LSFs)—rows of trees, shrubs,
grasses, or standing corn installed on fields upwind of roadways—are economically viable solutions for controlling
drifting snow in agricultural areas. Despite incentives and financial assistance by state and federal agencies, farmer
adoption of LSFs is low, in part due to concerns about removing cropland from production. Of recent interest in
Minnesota is the use of shrub-willows (Salix spp.) for LSFs, as they have been successfully implemented for LSFs
in other states and are researched increasingly as a marketable biomass product for bioenergy production. To
evaluate the potential of willow LSFs for multiple benefits in Minnesota, we established studies in Waseca,
Minnesota, 1) to test different designs of willow LSFs in their ability to trap snow, 2) to compare the growth of
willow varieties to willows native to Minnesota and other species traditionally used in LSFs, and 3) to assess the
costs of planting and establishing a willow snow fence and the viability of biomass harvest. We found all shrubs to
have generally high survival rates, with willows tending to have higher growth than traditional LSF shrubs.
Additionally, willow LSFs may have the potential to trap all blowing snow at the study site as soon as three to four
years after planting. This may provide earlier road protection than other shrub species traditionally used in LSFs.
Regarding economics, willows can provide affordable LSFs relative to traditional LSF species, although harvesting
for biomass may only be appropriate for very long transportation corridors.
17. Document Analysis/Descriptors 18. Availability Statement
Snow fences, Living things, Snowdrifts, Woody plants, No restrictions. Document available from:
Costs, Benefits National Technical Information Services,
Alexandria, Virginia 22312
19. Security Class (this report) 20. Security Class (this page) 21. No. of Pages 22. Price
Unclassified Unclassified 99
Assessing the Use of Shrub-Willows for Living Snow
Fences in Minnesota

Final Report

Prepared by:
Diomy S. Zamora
Eric Ogdahl
Gary Wyatt
University of Minnesota Extension

David J. Smith
Department of Applied Economics
University of Minnesota

Gregg Johnson
Southern Research and Outreach Center
University of Minnesota

Dean Current
Center for Integrated Natural Resources and Agricultural Management
University of Minnesota

Dan Gullickson
Minnesota Department of Transportation

November 2015

Published by:
Minnesota Department of Transportation
Research Services & Library
395 John Ireland Boulevard, MS 330
St. Paul, Minnesota 55155-1899

This report represents the results of research conducted by the authors and does not necessarily represent the views
or policies of the Minnesota Department of Transportation or the University of Minnesota. This report does not
contain a standard or specified technique.

The authors and the Minnesota Department of Transportation and the University of Minnesota do not endorse
products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered
essential to this report.
ACKNOWLEDGMENTS
We acknowledge the University of Minnesota’s Southern Research and Outreach Center (SROC)
for providing space for this research project and resources for maintaining the willow plantings.
Special thanks goes to Tom Hoverstad, Paul Adams, and Matt Bickell of SROC for providing
design, planting, and plot maintenance assistance during the establishment of this project.
Additionally, we are grateful for Don Baker’s (MnDOT District 7) assistance in establishing and
maintaining the project. We would also like to thank the local 4-H and Boy Scout groups for
providing assistance during the planting and maintenance of the willow study sites. Field work
assistance from Benjamin Katorosz and Alex Mehne is also greatly appreciated. We
acknowledge the University of Minnesota’s Statistical Consulting Service for providing helpful
suggestions during the design and analysis of this research. Thanks also goes to Justin Heavey
and Tim Volk of State University of New York, College of Environmental Science and Forestry,
and Martha Shulski of University of Nebraska, School of Natural Resources, for providing
helpful suggestions and information on living snow fence research protocols. We thank Anna
Dirkswager (MN DNR) and Kate MacFarland (USDA National Agroforestry Center) for
providing information on biomass markets in Minnesota. Lastly, we thank state botanist Welby
Smith, Minnesota Department of Natural Resources, for providing suggestions on appropriate
native willows for living snow fences.
TABLE OF CONTENTS
Chapter 1: Establishment and Potential Snow Storage Capacity of Willow (Salix Spp.) Living
Snow Fences in Waseca, Minnesota, USA ..................................................................................... 1
1.1 Abstract ................................................................................................................................. 1
1.2 Introduction ........................................................................................................................... 1
1.3 Materials and Methods .......................................................................................................... 3
1.3.1 Site description and experimental design ...................................................................... 3
1.3.2 Plant data collection ....................................................................................................... 4
1.3.3 Modeled snow storage capacity ..................................................................................... 6
1.3.4 Measured snow storage .................................................................................................. 7
1.3.5 Statistical analyses ......................................................................................................... 7
1.4 Results ................................................................................................................................... 8
1.4.1 Establishment and growth .............................................................................................. 8
1.4.2 Snow storage capacity.................................................................................................. 10
1.5 Discussion ........................................................................................................................... 13
1.6 Conclusion .......................................................................................................................... 16
Chapter 2: The Economics of Planting and Producing Biomass from Willow (Salix spp.) Living
Snow Fences ................................................................................................................................. 18
2.1 Abstract ............................................................................................................................... 18
2.2 Introduction ......................................................................................................................... 18
2.3 Methods............................................................................................................................... 19
2.3.1 Planting and Establishment .......................................................................................... 19
2.3.2 Labor ............................................................................................................................ 20
2.3.3 Chemicals ..................................................................................................................... 21
2.3.4 Machinery .................................................................................................................... 21
2.3.5 Planting Stock .............................................................................................................. 22
2.3.6 Erosion Control ............................................................................................................ 23
2.3.7 Harvest ......................................................................................................................... 23
2.3.8 Transport ...................................................................................................................... 23
2.4 Results and Discussion ....................................................................................................... 24
2.4.1 Planting and Establishment .......................................................................................... 24
2.4.2 Conservation Program Cost Sharing ............................................................................ 25
2.4.3 Comparison to Current Living Snow Fence Costs ...................................................... 26
2.4.4 Biomass Production ..................................................................................................... 26
2.4.5 Enterprise Budgets ....................................................................................................... 27
2.4.6 Cash Flow .................................................................................................................... 27
2.4.7 Costs of Production ...................................................................................................... 27
2.4.8 Biomass facilities in Minnesota ................................................................................... 29
2.5 Conclusions and Implications ............................................................................................. 29
Chapter 3: Establishment and Growth of Native And Hybrid Shrub-Willows, Gray Dogwood,
and American Cranberrybush for Use in Living Snow Fences .................................................... 32
3.1 Introduction ......................................................................................................................... 32
3.2 Methods............................................................................................................................... 32
3.2.1 Study site description ................................................................................................... 32
3.2.2 Experimental design and planting materials ................................................................ 33
3.2.3 Plant data collection ..................................................................................................... 35
3.2.4 Statistical analyses ....................................................................................................... 35
3.3 Results ................................................................................................................................. 35
3.3.1 Growth variables by species and year .......................................................................... 35
3.3.2 Effects of coppice timing on 2014 willow growth variables ....................................... 36
3.4 Discussion ........................................................................................................................... 37
3.5 Conclusion .......................................................................................................................... 39
Chapter 4: Conclusions ................................................................................................................. 40
4.1 Chapter 1 ............................................................................................................................. 40
4.2 Chapter 2 ............................................................................................................................. 40
4.3 Chapter 3 ............................................................................................................................. 41
References ..................................................................................................................................... 42
Snow Climatological Models for Waseca, Minnesota
Porosity Method for Adobe Photoshop CS Version 8.0
Biomass Facilities in Minnesota
Height And Porosity Assessment of a Living Snow Fence in Belle Plaine,
Minnesota
Financial Assistance for Living Snow Fences In Minnesota
Photo Timeline of the Establishment and Growth of the Willow Living Snow Fence
in Waseca, MN
LIST OF FIGURES
Figure 1.1: Example replicate of willow living snow fence experiment in Waseca, MN .............. 4
Figure 1.2: Using a large red backdrop to assess porosity in shrub-willow living snow fences .... 5
Figure 1.3: Mean heights for row positions in willow living snow fences with two- and four-row
planting arrangements. Error bars represent 95% confidence intervals ......................................... 9
Figure 1.4: Selected porosity images that closely resemble the average porosity (in parentheses)
for each willow variety and planting arrangement. Images presented do not necessarily imply
statistical differences. .................................................................................................................... 10
Figure 1.5: Mean measured snow storage in willow living snow fences with two- and four-row
planting arrangements. Different letters indicate significant difference under Tukey’s HSD test
at P<0.001. Error bars show 95% confidence intervals ............................................................... 13
Figure 2.1: Number of active biomass facilities in Minnesota counties ....................................... 30
Figure 3.1: Example replicate for the comparison of candidate shrub species for living snow
fences. All willows are represented by their common name provided in Table 3.2. "Native"
refers to Salix petiolaris. ............................................................................................................... 34
Figure 3.2: American cranberrybush with wilted leaves and stems in June, 2014, shortly after
herbicide application ..................................................................................................................... 38

LIST OF TABLES
Table 1.1: Selected soil characteristics for willow living snow fence establishment in Waseca,
MN .................................................................................................................................................. 3
Table 1.2: Number of days with snowfall, rainfall, and above-freezing temperatures and the
amount of snowfall during the 2014-2015 snow accumulation season at the Southern Research
and Outreach Center in Waseca, Minnesota ................................................................................... 7
Table 1.3: Height, porosity, potential snow storage capacity (Qc) and ratio of Qc to mean annual
snow transport (Q) for 6 willow living snow fence treatments after one growing season post-
coppice. Values in parentheses are the standard error of the mean .............................................. 11
Table 1.4: Predicted height, porosity, potential snow storage capacity (Qc) and ratio of Qc to
mean annual snow transport (Q) for two- and four-row willow snow fences at two, three, and
four years after planting based on willow living snow fence models ........................................... 11
Table 1.5: Mean snow storage measurements in willow snow fences by number of rows and
month during 2014-2015 winter ................................................................................................... 12
Table 2.1: Labor usage and costs for farm workers in Waseca, Minnesota during the willow
living snow fence establishment ................................................................................................... 20
Table 2.2: Chemical usage, rates, and prices for Willow living snow fence establishment in
Waseca, Minnesota ....................................................................................................................... 21
Table 2.3: Non-Harvest machinery, costs and hours for willow living snow fence establishment
in Waseca, Minnesota ................................................................................................................... 22
Table 2.4: Planting stocks, replacement, and costs by willow variety based on planting
arrangement designs...................................................................................................................... 23
Table 2.5: Harvest and transportation equipment cost of willow living snow fence in Waseca,
Minnesota ...................................................................................................................................... 23
Table 2.6: Summary of per meter and total establishment costs for willow living snow fences in
Minnesota, USA ............................................................................................................................ 25
Table 2.7: Reimbursement rates in US Dollars per hectare for two preparation methods and three
previous vegetation types .............................................................................................................. 26
Table 2.8: EQIP cost share for 2- and 4-row willow living snow fences ..................................... 26
Table 2.9: Summaries of the total, per hectare and per meter costs for biomass production from a
454-meter 2- and 4-row and corridor-length willow living snow fence in Waseca, Minnesota .. 27
Table 2.10: Enterprise budget cash flow for willow living snow fence in 2- and 4-row
arrangements. ................................................................................................................................ 28
Table 2.11: Summary of costs by net present value and annualized net present value for a 25-
year stand life using 2- and 4-row planting arrangements and corridor-length willow living snow
fences ............................................................................................................................................ 28
Table 2.12: Summary of annualized net present value of the 454-meter 2- and 4-row planting
arrangement and the corridor-length willow living snow fences.................................................. 29
Table 3.1: Selected soil characteristics for shrub establishment at the University of Minnesota’s
Agricultural Ecology Research Farm in Waseca, Minnesota ....................................................... 33
Table 3.2: Shrub species used in variety/species comparison study ............................................. 33
Table 3.3: Mean survival, heights, stem counts, and stem diameters for shrub-willows and
traditional living snow fence shrubs in 2013 and 2014. ............................................................... 36
Table 3.4: The effect of coppice time and species on 2014 mean willow height and number of
stems per plant. ............................................................................................................................. 37
EXECUTIVE SUMMARY
Blowing and drifting snow adversely affect winter driving conditions and road infrastructure in
Minnesota, often requiring removal methods costly to the state and environment. Living snow
fences (LSFs)—rows of trees, shrubs, grasses, or standing corn installed in fields upwind of
roadways—are economically viable solutions for controlling drifting snow in agricultural areas.
LSFs are an agroforestry practice and can provide a range of environmental benefits, including
wildlife habitat and carbon sequestration. However, they often require multiple years to become
effective and their adoption by landowners is relatively low, despite incentives and financial
assistance by state and federal agencies. In Minnesota, for example, approximately 1,200 miles
(1,930 km) of state roadways have severe blowing snow problems, but only 20 miles (30 km)
have been addressed through landowner adoption of LSFs. Landowners have cited multiple
barriers to LSF adoption, including removing cropland from production, hassle and time spent
installing LSFs, and risk of plant mortality. Therefore, to improve LSF adoption, it is necessary
to evaluate plants that are easily established and may provide landowners with a marketable
product.
Shrub-willows (Salix spp.) have been developed as a short-rotation woody crop (SRWC) and
proposed as a suitable LSF candidate. They are easily planted with dormant stem cuttings, have
fast growth rates, offer a marketable product as a biomass crop, are adaptable to an array of site
and climatic conditions, and offer numerous ecosystem services, such as pollinator habitat and
carbon sequestration. Additionally, shrub-willows have potential to achieve key growth
parameters for controlling blowing snow sooner than species traditionally used in LSFs.
Previous research has shown shrub-willows can provide effective LSFs as soon as three years
after planting, whereas other deciduous and coniferous species may require 5 to 20 years before
providing effective LSFs. Overall, however, little has been done to assess the use of shrub-
willows for LSFs, especially in Minnesota. To evaluate the potential of willow LSFs for
multiple benefits in Minnesota, this project sought to determine appropriate willow variety
selection and LSF planting designs in relation to trapping blowing snow, as well as evaluate the
economics of planting and producing biomass from willow LSFs.
In the first part of this research (Chapter 1), we evaluated appropriate willow LSF designs in a
demonstration LSF on a MnDOT right-of-way adjacent to US Highway 14 in Waseca,
Minnesota. The LSF was planted in spring 2013 with three willow varieties in planting
arrangements of two and four rows and replicated four times. We assessed willow establishment
and growth in relation to snow trapping ability, as well as measured snow drifts formed by the
LSF. We found that willows had generally high survival and growth rates after two growing
seasons, with the potential to trap all of the mean annual blowing snow at the site after three to
four growing seasons. Additionally, we found that willow LSFs with four rows tended to catch
more snow than two-row LSFs, likely due to denser vegetation in the four-row arrangements.
Four-row arrangements may therefore be more useful for providing snow capture earlier on
during LSF establishment than two-row arrangements. No differences were found among
willow varieties in terms of snow capture, suggesting that multiple willow varieties suited for
similar site conditions can be used in a LSF.
A few main challenges in this study included the control of weeds and the likelihood of soil
compaction on the LSF right-of-way. Controlling weeds in the first few growing seasons of LSF