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Chinese Tallowtree
(Triadica sebifera (L.) Small)
Control and Seed Biology:
An Evaluation of Common Herbicides & Application Methods,
Seed fill, Germination & Seed Bank Longevity
Heather VanHeuveln
University of Florida
Masters in Agronomy
heatherv@ufl.edu
Biology
• Native to Southeast Asia
• Characteristics:
▫ Deciduous, monecious
▫ 6-15 meters
▫ Matures quickly
+100,000 seeds
Dispersed by
hydrochory
zoochory
 velocity~1-1.2 km/yr.
GREEN DEANE
CHUCK BARGERON
(Lin et. al, 1958)
(Wang et al. 2011, Renne et al. 2000)
JIM CONRAD
USA Distribution
• Introduced in mid 1700’s.
• Roadways, waterways, forest
edges and disturbed areas
• Cannot tolerate severe
winters/dry conditions
Plants.usda.gov
Eddmaps.org
Problematic
• Monotypic stands in 18-29
years
• Displaces native and
agronomic species
• Listed
▫ State Noxious Weed
(Wang et al. 2011 & Bruce et al. 1995)
 Florida, Louisiana,
Mississippi, Texas
▫ FLEPPC: Category 1
Objectives
1. Evaluate basal, hack & squirt and cut stump
application methods with common
broadleaf tree control herbicides
2. Determine seedling emergence patterns and
seed bank longevity to define post
treatment site monitoring recommendations
3. Evaluate seed germination and viability after
capsule split over time
Objective 1: Reasoning
▫ Common use herbicides
 Failed Treatments
 Multi Trunk Re-Growth
▫ Most Effective Herbicide
for Method
Trade
Name
Common Name
Mode Of
Action
Chopper®
Imazapyr
ALS/AHAS
inhibitor
Garlon 4®
Triclopyr
Auxin Growth
Regulator
Method®
Aminocyclopyrachlor Auxin Mimic
(DPX-MAT28)
Growth
Regulator
Roundup
Weather
Max®
Glyphosate
EPSPS Inhibitor
Velpar L®
Hexazinone
PSII Inhibitor
Treatment Sites
1. West Florida Research
and Education Center
(WFREC)- Jay, FL
2. Neal Land and Timber
(NLT)- Blountstown, FL
3. Paynes Prairie Preserve
Florida State Park (PPP)Gainesville, FL
Experimental Design
Study Design
• Completely Randomized
• Replicate=Single Tree
• 6 Reps/Herbicide /Site
 1 meter apart
• Visual Control Ratings
▫ 6 Months After Treatment
▫ 10 Months After Treatment
▫ 0-100% control
• 2 Trials
▫ Application Occurred
 Dec. 2013-Jan. 2014
 Dec. 2014-Feb. 2015
Analysis
• SAS 9.4
• Analysis of Means
• Fisher’s LSD
• Significance Level of α=0.05
Basal Bark Study
• Individual trees, DBH <4”
 Spray 8-12” band at base
including root crown
• Herbicide & Rates (in Carrier Oil)
 Method+Chopper-(5+2.5%)
 Chopper - 10%
 Garlon 4 - 20%
 Method - 5%
Hank Stelzer
Results: Basal Study
• 10 MAT*
▫ Significant
Treatment
Location
Interaction
Basal Bark
Source
DF 10 MAT
treatment
3
<0.0001
location
2
<0.0001
treatment x location 6
0.0039
*MAT: Months After Treatment
Results: Basal Study 10 MAT
Herbicide
Rate
% v/v
WFREC
Method
Method + Chopper
Chopper
Garlon 4
LSD0.05
5
2.5+5
10
20
100 a
99 a
98ab
89 b
9.5
NLT
Control %
93 a
87 a
43 b
84 a
18.7
PPP
86 a
85 a
57 b
83 a
24.9
Hack & Squirt Study
DBH 2-12”
Cuts determined by
circumference:
1: 6-9”
2: 10-22”
3: 23-34”
Hank
Stelzer
Hack & Squirt Study
Herbicide
Undiluted Chemical
(per hack)
Chopper
Chopper + Method
Garlon 4
Method
Roundup Weather Max
Velpar L
1 ml
0.5 ml + 0.5 ml
1 ml
0.5 ml
1 ml
1 ml
Hank
Stelzer
Results: Hack and Squirt Study
• 10 MAT*
▫ Significant
Treatment
Location
Interaction
Source
DF
10 MAT
treatment
5
<0.0001
location
2
0.0024
treatment x location
10
0.0248
*MAT: Months After Treatment
Results: Hack & Squirt Study 10 MAT
Herbicide
Method
Method + Chopper
Chopper
Garlon 4
Roundup
Velpar L
LSD0.05
WFREC
100a
100a
100a
74b
92a
86ab
14.6
NLT
Control %
100a
96a
87a
86ab
71bc
56c
15.5
PPP
100a
100a
88a
61bc
77ab
48c
24.8
Cut Stump Study
Trees DBH >4”
Cut 6” above ground
Herbicides applied in
band around the
cambium layer
 Undiluted, 2x around
 Within 5 minutes
Stump
Clean and Apply
Final Result
Cut Stump Study
Herbicide (Undiluted)
Chopper + Method
Chopper
Garlon 4
Method
Roundup Weather Max
Velpar L
Results: Cut Stump Study
• 10 MAT*
▫ Significant
Treatment
Source
DF 10 MAT
treatment
5 <0.0001
location
2 0.2849
treatment x location
10 0.9849
*MAT: Months After Treatment
Results: Cut Stump Study 10 MAT
Herbicide
Method
Method + Chopper
Chopper
Garlon 4
Roundup
Velpar L
LSD0.05
WFREC
100a
100a
100a
100a
71b
43c
16.6
NLT
PPP
100a
100a
100a
94a
68b
47c
15.6
100a
99a
88a
91a
61b
43b
20
Control %
Re-sprouting
100% Control
CHOPPER
METHOD
ROUNDUP
GARLON 4
VELPAR
METHOD+CHOPPER
Objective 1: Conclusions
Method provided over 90% control over all treatment methods
Basal Bark
 Garlon 4, Chopper-variable results
 Chopper-least effective
Hack & Squirt
 Velpar L ineffective;
 Chopper comparable to Method
 Roundup, Garlon 4; Good not complete control
Cut Stump
 Velpar L ineffective
 Roundup highly variable
 Garlon 4; Good/not complete
 Chopper comparable to Method
Objective 2: Determine seedling emergence patterns and
seed bank longevity to define post treatment site monitoring
recommendations
Reasoning
• Seeds are the main
mechanism of spread
• Lack of information on seed
bank life span
(Zang & Lin, 1994; edis.ifas.ufl pub. Ag148)
Oilseedcrops.org
Seedling Emergence and Seed Bank Longevity
Seed Exclusion Frames
• 2 Field Sites
▫ Gainesville, FL
▫ Jay, FL
• 1x1 meter frames
▫ Fine and wide mesh
screen
• Checked monthly
Timeline of Exclusion Frame Placements
2014
January
• Gainesville;
10 frames
2015
February
• Gainesville;
+10 frames
March
• Jay; 10 frames
Results: Emergence
Emergence
▫ Later for northern location
Mean Emergence
(Seedlings/m2)
• Occurs over 2-3 months
in spring
• Timing varies by location
50
First Year Mean Seedling Emergence
Gainesville & Jay Florida
40
30
20
10
0
Mar
Apr
May
Jun
Jul
Month
2014 Gainesville
2015 Gainesville
2015 Jay
Photos of Site Over time
• Seedlings emerge
while canopy still
open
• Canopy closure in
June-emergence
drops below 1
seedling/m2
Results: 1st Season of Seed Exclusion
2014 Seed Frame Mean Seedling
Emergence
Gainesville, FL
Mean Emergence
(Seedlings / m2)
• Emergence trends continued
• Indicator of dormancy
• 2nd year emergence decline
▫ 100%
March
▫ 82%
April
▫ 50%
May
30
25
20
15
10
5
0
Feb
Mar
Apr
May
Month
2014
2015
Jun
Objective 3: Seed Germination & Viability Over Time
Large amount of seed
produced but …
▫ Seed germination
▫ Seed viability
▫ Seed fill
Seedoilcrops.org
Objective 3: Seed Germination & Viability Over Time
Germination requirements
▫ Environmental Conditions
 Alternating Temperatures
 Moist soil
 Light not necessary
▫ Germination Improved
 Buried
 Defecated/Acid Treated
Overall highly variable results…
 Small sample sizes
 Varying collection dates
 Regional variation
(Cameron et al., 2000)
Objective 3:
Determine…in Central Florida.
1. after ripening affects on seed germination and viability
a) Time on tree
b) Storage
c) Aril
2. seed fill characteristics
Seed Collection
• After capsule split
▫ 75 capsules/tree
▫ 2 weeks  4 total harvests
• Sampled 10-15 trees
▫ Bulk sample
 100 seeds/tree
 100 seeds/treatment
Seedoilcrops.org
Germination Studies
Germination
 Growth Chamber
 Time-event analysis
Viability
 Non-germinated seed
 Tetrazolium Chloride (TZ) Test
 Pearson’s chi-square Test
Germination Studies
• Planting
▫ 200 cell tray
 2.29 cm. x 2.29 cm. x 4.5 cm.
▫ 1 cm. below surface
▫ Sub-surface watered
• Growth chamber
▫ 15°C dark (15 hrs.)
▫ 27°C light (9 hrs.)
Emerged
Germinated
Testing
Terminated
Viability
Testing
Germination: On Tree After Ripening
• Treatment=Time After
capsule Split
▫ 4 Treatments
▫ 2, 4, 6 and 8 weeks
▫ 2014 & 2015
• Results
▫ No significant differences
 Treatment
 Viability
Germination: Off Tree After Ripening
• Harvest Evaluated
• 2 Seed Treatments
▫ Time independent of
control
▫ Same Germination
Protocol
▫ 2014 seeds
Harvest
Bulk Sample
6 Month
Storage
CONTROL
Fresh
Treatment 1
5°C
Treatment 2
Ambient 25°C
Results: Off Tree After Ripening
• Germination
▫ H1-Removed (Sorting error)
▫ No Significant difference
 Harvest
(p=0.68)
 Treatment
(p=0.35)
 Interaction
(p=0.08)
Data pooled within seed
treatment
 Treatment Significant
(P=0.0083)
 No Significant Temperature
Effect*
Results: Off Tree After Ripening
6 months after harvest
• Viability
Seeds 74-76% less likely
▫ Viable Seed vs. Nonviable
to germinate than fresh
 Germinated + TZ viable
Germination
▫ No significant difference
9% (viable seed)
10 days Earlier than
 Harvest or Treatment
fresh (31 days)
 Overall 51% seed
Fresh seed
nonviable
Germination
29% (viable seed)
41 days
Germination: Presence of Aril
• Harvest Evaluated
• 2 Seed Treatments
▫ 10 days of harvest
▫ Same Germination
Protocol
▫ 2015 seeds
Harvest
Bulk Sample
48 hour Soak
CONTROL
No Soak/Aril Intact
Treatment 1
Aril Intact
Treatment 2
Aril Removed
Results: Presence of Aril
• Germination
▫ Significant…
 Harvest (P=0.008)
 Treatment (P=0.001)
▫ Aril Removal
Germination
Significantly
85%
39 days
2 days earlier than intact
• Viability
▫ Viable Seed vs. Nonviable
 Germinated + TZ viable
▫ No significant difference
 Harvest or Treatment
 ~37% seed nonviable
Results: Presence of Aril
Total Germinated Seed
Total Germination of Triadica sebifera Seeds
45
40
35
30
25
20
15
10
5
0
Control
Intact
Removed
H1
4
1
23
*
*
*
H2
7
1
27
H3
8
3
34
Harvest
Control
*
Intact
Removed
H4
6
4
40
Results: Presence of Aril
Total Germinated Seed
Germination of Triadica sebifera Seeds at Different
Harvests After Aril Removal
50
40
30
20
10
0
23
A
H1
27
A
34
B
A
H2
H3
Harvest After Capsule Split
40
B
H4
Progression of Black Mold
Pullularia spp. degrade aril
▫ Hyphae penetrate seed
▫ Embryo mortality
H1
H2
(Scheld et al., 1980; Burns and Miller, 2004)
(Bruce 1993)
H3
H4
Seed Fill
100% FILLED
0% EMPTY
• 2015 seed
• Harvest Evaluated
• Random 100 seed sample
• X ray imaging
• The Ohio State University
• Visually rate seed fill
• Independent, 2 sample
t-test
<100%
PREDATION
Seed fill: Results
• No significant difference of
Harvest
• 27% of sample <100% Fill
▫ Lack of embryo
development
▫ Predation
• 72% of non-viable seeds in
2015
2015 Seed Fill Characteristics of
Triadica sebifera
at Paynes Prairie Gainesville, FL
27%
73%
compromised
filled
Objective 3: Conclusions
• On tree after ripening
▫ Initially no difference in
harvest timing
• 6 Months After Harvest
▫ No temperature affect
▫ Decreases germination
timing
▫ Decreases total
germination
• Removal of Aril
▫ Increases Germination
▫ Decreases Germination Timing
▫ Increased germination with
harvest
• Non-viable seed frequency
consistent
▫ Possible indicator of dormancy
• Incomplete seed fill
▫ 27% of total seeds in 2015
▫ 72% of final non-viable seed
Acknowledgements
• Volunteers and Facilitators
▫ University of Florida






Agronomy Weed Shop Students & Staff
Justin McKeithen
Dr. Greg Macdonald
Dr. Kimberly Bohn
Dr. Hector Perez
Dr. Bill Haller
▫ The Ohio State University
 Dr. Susan Stieve
 Dr. Pablo Jourdan
▫ Neal Land and Timber
 Philip McMillan
▫ Florida Park Service
 Paynes Prairie Preserve
 Andrea Christman
 San Felasco Hammock Preserve
 Gary Kreitzer (AmeriCorps)
• Funding Sources
▫ University of Florida
▫ Florida Fish and Wildlife Conservation
Commission
▫ UF/IFAS Center for Aquatic and Invasive Plants
Questions?
Heather VanHeuveln
heatherv@ufl.edu