This document discusses invasive species management. It defines invasive species and explains what traits allow plants to become invasive. It emphasizes the importance of identifying invasive plants, understanding their biology, prioritizing which species to manage, and using integrated management methods. Effective management requires developing a detailed plan, using a variety of control techniques such as pulling, mowing, herbicide application, and monitoring over multiple seasons. Early detection and prevention of new invasives is crucial to success.
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Managing Invasive Woodland Plants
1.
2. Today’s Outcomes
• Know why species are invasive
• Determine management goals
• Understand range of management methods
• Know integrated strategies
3. Early Vegetation
From John T. Curtis,
Vegetation of Wisconsin, 1959
4. Early Invasives?
“Our waters filled with fish, and the air with game
birds, and the rock ledges with rattlesnakes, and
the woods with large game…We have no Canada
thistles or mean men.”
Wm. H Canfield, 1842
Sauk County Surveyor
7. Definitions
“Invasive” definitions differ depending on the
goal.
“…causes economic harm to….”
“interferes with land management goals…”
“kills or displaces populations of native species…”
8. What makes a plant invasive?
• Tolerate wide range of soil, light, other
conditions
• Enjoy longer growing period
• Ability to alter soil chemistry
• Prolific seed production
• Have few or no natural controls
9. What do we do?
Learn to ID and know plants’ biology
Take inventory, map
Create a plan
Learn & use control methods
Monitor & adapt
21. Perennials: Bush
Honeysuckles
Habitat: upland, especially
under roost trees
Blooms: May to June; white,
yellow, orange or pink
Berries: orange or red
Early leaf-out, late leaf drop
24. Perennial vine: Oriental bittersweet
• Woody vine that climbs
other vegetation
• Thrives in a wide range
of conditions
• Grows to 60+’ in length
• Introduced as an
ornamental
31. Problem Ornamental Species
• Japanese knotweed
• Japanese barberry
• buckthorns
• Asian honeysuckles
• Amur maple
• Common tansy
• Oriental, or Round-
leaved bittersweet
32. Take inventory
Aerial photo or scaled lot layout
Estimate species present & density
Identify land use – past, present & future
Look beyond your property lines
34. Prioritize!
Importance of habitat?
Size of population?
Rate of spread?
Interfere with land use?
Resources available?
Other priorities?
35. General Management Strategies
• Monitor, especially
along trails, roads
• Look beyond property
lines
• Prioritize species; areas
• Timing is critical
• Attack outer edges first
38. Pull
• Good for young people,
small infestations, small
plants.
• *Flowers can still set
seed after pulling.
39. Mow/Cut
• Goal: weaken plant; prevent seed set.
• Timing is critical—best when in flower.
• Repeated mowing often needed
• Weakens, but may not kill plants.
• Can be combined with herbicide methods.
41. Grazing
Principles similar to
mowing
Goats can be “trained”
to some species
Repeated treatments
necessary
Contractors available
42. Girdle
• Goal: starve roots
• Good for clonal tree
species.
Photo courtesy of Tom Brock
• Labor intensive. Photo courtesy: Tom Brock
• Very effective if done
correctly.
• Timing: June-July best.
• 1 or 2 step method.
44. Cut-Stem Treatment
• Goal: kill plant
Photo courtesy of Tom Brock
• Good winter
option
• Very targeted use
of herbicides
Photo: Savanna Oaks Foundation, Inc
45. Cut-stem Control Method
Target:
• Shrubs/trees
• buckthorn, honeysuckle, autumn olive, prickly ash,
multi-flora rose, undesirable trees, etc.
Herbicides:
• Systemic
• Active ingredients glyphosate (Roundup/generic) or
triclopyr (Garlon 4/Element 4)
46. Cut-stem Control Method
Timing:
• Summer, Fall or Winter preferred
• Avoid early spring and deep snow periods
• Above-freezing temps with glyphosate
• Triclopyr (Garlon) at any temperature
• Apply glyphosate within minutes of cutting.
47. Cut-stem Control Method
Technique:
• Cut stems at no higher than 6”.
• Work in pairs, if possible, to
avoid “escapes”.
• Work in a pattern.
• Treat only outer edge of larger
stumps.
Photo courtesy: Tom Brock
48. Prescribed Fire
Requires training,
experience
Specialized equipment
Good public relations
Good neighbor relations
Photo courtesy of Tom Brock
Timing!
Effective when
integrated with other
methods
49. Foliar herbicide
• Safety first
• Better for larger infestations
• Selective vs. non-selective
herbicides
• Pre- vs. post-emergence
application
55. Develop a management plan
Garlic mustard control
1. Develop a map
2. Satellite plants--goal to eradicate.
3. Extensive patch along road--goal
to prevent further spread.
Road
56. Example Plan
• Satellite populations:
– Pull 2nd year plants before flowering
– Spray 1st year plants in fall or very early spring
57. Example Plan
• Large patch along road/trail:
– Mow, pull, spray along road before seed set.
– Work perimeter inward
• Spray rosettes fall/early spring
• Pull escapes in between
• Repeat, monitor, re-map subsequent years.
59. Other Resources
• County Extension office
– fyi.uwex.edu/weedsci
• County DNR foresters
– dnr.wi.gov/topic/ForestHealth/
• Oaksavannas.org
• www.ipaw.org
60. Summary
• Early detection & prevention are critical
• New species introduction & spread mostly
dependent on our behavior
• Set realistic goals
• Make a plan, then adapt, using…
• Integrated methods
Historically before settlement, we had a mosaic of plant communities in Wisconsin, each represented by myriad native species that evolved to be adapted to our climate, soils, topography, wetness and other site characteristics.
Hmmmm. Canada thistles and mean men the first invasives?
Early settlers unwittingly brought invasive plant seed, but also the means to expose soil to those invaders.
Point: some native species become/became invasive due to shifting influences of disturbances. For example, fire was often suppressed, which gave a competitive advantage to less or non-fire adapted species. i.e. prickly ash, which flourishes in old pastures, especially where fire is not allowed.
Habitat includes:ForestsField and forest marginsMeadows and prairieRight-of-waysFence rowsAlong waterwaysResidential landscapesOriental bittersweet is native to China, Japan, Korea, Mongolia, and the Russian Federation. It was introduced to the eastern US in the 1800s.Image of Oriental bittersweet climbing into the trees on the right and has pulled down the tree in front.
Both sexual (seed) and asexual (rhizome = root that sends up new shoots and stolon = root-like stem that sends up new shoots) reproduction. It can be difficult to identify individual plants due to clonal propagation.Oriental bittersweet is functionally diecious with separate male and female plants. Both male and female plants flower. Male flowers produce pollen that is received by female flowers. Pollinated by insects (bees) and wind.Birds aid the dissemination of seed by eating the fruit containing seed. The seed passes through the bird and can moved to uninfested areas. The seed germination rate is higher after the seed has passed through a bird.Seed viability in soil is not long (generally 1-3 years). A short-lived seedbank is helpful for long-term infestation control.Image of rhizome sending up new shootsImage of summer leaves and fruit.
People use the colorful fruiting vines for arrangements. Seed can be inadvertently dispersed when collecting, transporting, and disposing of the fruiting branches.
Although Oriental bittersweet is newly reported in MN, we can use assessments from the eastern and southern regions to prompt us into action before Oriental bittersweet is widespread. For example, Forest Service ranked Oriental bittersweet #5 of the top 10 invasive plant priorities for the Northeastern Area. Images: Oriental bittersweet vine girdling a tree (left) and a downed tree overwhelmed by bittersweet vines.
This mass of Oriental bittersweet vines climbed into the trees and is beginning to down trees.
When leafed out, Oriental bittersweet shades and smothers other vegetation. The images shows a Colorado blue spruce and fence engulfed by Oriental bittersweet.Infestation along Hwy 36 in the metro. Mn/DOT has controlled this infestation.
Identifying Oriental bittersweetTop left: Leaves are glossy green and leaf shape is highly variable Top right: Raised white bumps (lenticels) on the stemBottom left: Fruits are positioned at where the leaves attach to the stem (at the leaf axils). Green summer fruits are shown in this picture.Bottom right: Fall fruit with a bright yellow capsule.
Both American and Oriental bittersweet occur in the same habitat. Unfortunately, Oriental outcompetes American because it germinates better in the shade, has a longer period for photosynthesis because it leafs out early in the spring and holds its leaves late in the fall, and Oriental bittersweet can smother American bittersweet.Hybrids were created for a lab study demonstrating that the species can hybridize. Few viable progeny were produced from hybrids and hybrid pollen had a much lower viability compared to the species. Bittersweets with indeterminate characteristics (indicating hybrids) have been observed in the field.The nursery industry developed beautiful cultivars of American bittersweet that are a good choice for landscape use.
The easiest way to distinguish American and Oriental bittersweets is by the fruit capsule color (orange for American and yellow for Oriental) and fruit placement (at the terminal ends for American and at the leaf axils for Oriental).