Wyoming big sagebrush: efforts
towards development of target
plants for restoration
Anthony S. Davis
Center for Forest Nursery and Seedling Research, University of Idaho, Moscow, Idaho
Kayla R. Herriman
Center for Forest Nursery and Seedling Research, University of Idaho, Moscow, Idaho
R. Kasten Dumroese
USDA Forest Service, Rocky Mountain Research Station, Moscow, Idaho
The “target seedling concept”
• Targeting specific
physiological and
morphological
characteristics that can
be quantitatively linked
with outplanting success
“One Size Fits All”
Does not apply to all outplanting projects
With plant materials,
quality is “fitness for
purpose”
• Quality must be defined
at the outplanting site
•
Establishment
– Key to restoration success
– On some sites, direct seeding fails
• Limiting conditions for germination
– Wyoming big sagebrush has generally good survival
once established
– For other native plants, container seedlings tend to
have higher establishment success
• Largely unexplored for sagebrush
Seedlings
 Initial cost can be high
 Can produce seed 3 to 5 years following outplanting
 Container type can influence seedling performance
following outplanting
 Can allow for additional practices
Study Objectives
• Level of cold hardiness at end of growing season
and start of outplanting season
• Effect of container type on seedling morphology and
performance following outplanting
• Influence of field fertilization on performance
following outplanting
Plant Materials
• Grown in Moscow, Idaho
– Three container types (Styroblock™ )
• 112/105 ml, 415B (15.0 cm deep, 3.6 cm across)
• 60/250 ml, 515A (15.2 cm deep, 5.1 cm across)
• 45/340 ml, 615A (15.2 cm deep, 6.0 cm across)
– Outplanted March 14 and 15, 2008 in Southern
Idaho
Site Description
• Two field sites
– Orchard
– Mountain Home
• Tilled
• Untilled
Orchard
Mountain
Home
Experimental Design
• At each site
• Replicated 4 times
– 3 container types × 2 field fertilization factorial
• Container types (105, 250, and 340)
• Fertilizer rates (0 or 7.5 g plant-1)
– 10-12-12 Slow release fertilizer
• Planted at 1 m spacing
Environmental Data
• Nursery
– Chilling hours
• Outplanting
– Temperature
– Precipitation
– Soil moisture
Cold Hardiness (Electrolyte leakage)
• Conducted on 5 dates
• Expose tissue samples to range of temperatures
– -10°C, -20°C, -30°C, and -40°C, or a control 2°C
– After thawing, measure initial EL on sections of leaves
• Autoclave samples (125°C)
– Attains total cell death, facilitating electrolyte release
– Re-measure EL
• Calculate % damage
Initial EL
( Autoclave EL ) × 100 = % damage
– Multiple regression used to calculate LT50
Morphology
• All seedlings
– Height
– Root-collar
diameter
• Subsample
– Root and shoot
volume
– Root and shoot dry
mass
Nursery Results
• Low number of chilling hours
• Container type did not affect cold hardiness
• Container type influenced seedling size
– Larger container = larger seedling
Cold hardiness
• Chilling hours tracked beginning
September 1
• 26 October moved to hardening
Chilling Hours
Sample Date 5°C
10°C
5‐Nov
65
237
19‐Nov
125
499
5‐Dec
393
866
20‐Dec
677
1217
Cold hardiness
Influence of container size
20
3.5
A
Height
Root-collar diameter
a
b
Height (cm)
15
2.5
c
2.0
C
10
1.5
1.0
5
0.5
0
0.0
105
250
Container size (mL)
340
Root-collar diameter (mm)
3.0
B
Field results
• Results were different across sites
– Tilling influenced environmental conditions
• High mortality at Orchard (~15% survival)
– Browse damage
Soil Moisture
Tilled
Untilled
0.24
0.22
3
3-1
Volumetric soil water content (m m )
0.26
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0
50
100
150
Days after planting
200
250
Mountain Home – Untilled
 Survival: 59%
 Container type:
 (340) 60%
 (250) 61%
 (105) 57%
 Field fertilization*:
 Unfertilized 64%
 Fertilized 55%
Untilled
Height
Untilled
Root-collar Diameter
Untilled
Volume
Untilled
Height and Root-collar Diameter
A
Untilled
Volume
Summary
• Container type…
 Field fertilizer…
 Positively influenced:
– Positively influenced:
•Height
•Root-collar diameter
•Root volume
•Dry mass
– No influence:
•Survival
•Shoot volume
•Gas exchange
Root-collar diameter
 Shoot volume
 Shoot dry mass

 Negatively influenced:
 Survival
 Root volume
 No influence:
 Height
 Root dry mass
Mountain Home – Tilled
 Survival: 38%
 Container type*:
 (340) 44%
 (250) 43%
 (105) 28%
 Field fertilization*:
 Unfertilized 44%
 Fertilized 33%
Tilled
Height
Tilled
Root-collar Diameter
Tilled
Volume
Summary
• Container type…
 Field fertilizer…
 Negatively influenced:
– Positively influenced:
•Survival
•Height
•Root-collar diameter
•Root volume
•Dry mass
– No influence:
•Shoot volume
•Gas exchange

Survival
 No influence:
 Height
 Root-collar diameter
 Volume
 Dry mass
 Gas exchange
Outplanting…
• Survival was greater at the untilled site
– Container volume may not be a factor on
moister sites
• Field fertilization reduced survival
• Seedlings grown in larger containers were
larger at the end of the growing season
Target plants…
• Link seedling status to outplanting conditions
• Cold hardiness was high in November and
lower in March
– Stress resistance
• Container type is an important variable
– Can produce larger plants in larger containers
– Strong relationship between plant size and
field performance
Conclusion
• Field fertilization can improve growth, but did
not benefit establishment due to increased
mortality
– Formulation
– Rate
– Application
Future Directions
 Nursery Managers
 Cold-hardiness
 Effect of pruning in the nursery
 Container type
 Land Managers
 Need to compare direct seeding and planting
 Compare cost per established plant
 Improve ability to meet objectives
 Identifying suitable method of field fertilization
Acknowledgements
• Funding
– Great Basin Native Plant Selection and Increase
Project
– University of Idaho Center for Forest Nursery
and Seedling Research
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Annette Brusven
Debbie Dumroese
Heather Gang
Rob Keefe
Kiana Mhus
Sue Morrison
Jeremy Pinto
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Don Regan
Nathan Robertson
Amy Ross-Davis
Nancy Shaw
Karen Sjoquist
Eva Strand
Maggie Ward
www.nativeplantnetwork.org
Celebrating 100 Years of Nursery
Production at the University of Idaho
• 14 – 16 July 2009
– Intermountain
Container Seedling
Growers’ Association
– Intertribal Nursery
Council
– Western Forest and
Conservation Nursery
Association
• Presentations, tours,
and workshops