The document summarizes a study on collecting seeds for a bottomland hardwood reforestation project on state land in Wisconsin. Seeds of swamp white oak and hackberry were collected locally at a lower cost than purchasing seeds. A total of $533 was spent on fuel and labor for seed collection. While seed collection has benefits like promoting genetic adaptability, purchasing seeds can be similarly priced and introduces more genetic variation. Better seed collection methods could increase efficiency and lower costs.

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Cost Effectiveness of Collecting Seeds for
Bottomland Hardwood Reforestation on State Land
By: Benjamin Sturm
ABSTRACT: The bottomland hardwood ecosystem is important to many wildlife and fisheries species
because of the many functions they provide. The abundance of this ecosystem has declined due to
conversion to agricultural land over the years. The Lower Wolf River Bottomlands Natural Resources
Area is an ongoing project by the Wisconsin Department of Natural Resources to protect this ecosystem
and the functions which they provide. Seeds of swamp white oak and hackberry trees were collected
for a reforestation project that will take place on this natural resources area and costs were evaluated as
well as pro's and con's of using seed collection as a reliable method for a reforestation project.
Collecting seeds from a local source will promote greater adaptability of the trees and could save the
State of Wisconsin a substantial amount of money that could thus go to other state funded projects.
Introduction:
Bottomland hardwoods are important buffers between a river and the landscape beyond the
lowlands. These ecosystems are important for fisheries and wildlife, maintenance of water quality,
regulation of flooding and stream recharge (Taylor et al. 1990). Some important tree species found in
the bottomland hardwood ecosystem in Wisconsin are silver maple, green ash, swamp white oak, red
maple, black willow, cottonwood, and hackberry (Steele 2011). The greatest loss of the bottomland
hardwood forest is due to conversion to agricultural land (Allen 1997) although not as much total area
has been lost as other forest ecosystems, due to the difficulty of farming this land (Steele 2011). This
report focuses on the Lower Wolf River Bottomlands Natural Resources Area, which is composed of
214,000 acres of wildlife, fishery and natural areas located on the Embarrass and Wolf Rivers in
northeastern Wisconsin. The protection of the Lower Wolf River Bottomlands Natural Resources Area

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contributes to the overall health and biodiversity of the Lower Wolf and Embarrass corridors (WDNR
Publication).
The seeds of swamp white oak (Quercus bicolor) and hackberry (Celtis occidentalis) were
collected for a future bottomland hardwood reforestation project that will be converting agricultural
land to habitat on a property recently acquired by the State of Wisconsin. Swamp white oak is a tree
species which is usually found in areas that are subject to flooding and is most commonly found in
bottomland hardwoods (WDNR 1996). Hackberry is another tree commonly found in bottomland
hardwoods and is especially important to the many birds and mammals that consume the fruits.
Genetically manipulated seeds do not necessarily meet the criteria for a reforestation project,
so seed collection by citizens is necessary to provide a more consistent supply from a larger variety of
genetic sources (Edge 2004). If all the seeds are harvested from one or two parents it is likely that the
genetic variation will be low, therefore seeds should be collected from several different stands to ensure
significant variation. A good rule of thumb is to not move seeds (oak especially) more than 150 miles
north or south of its origin; the more local the seed source, the more locally adapted the trees will be
(Edge 2004).
Plantation size is a crucial factor that must be accounted for in any type of restoration project.
When a person is directly seeding a plantation, seed predation can be one of the largest factors if
regeneration is slow, especially for smaller plantings that are surrounded by existing forest cover (Edge
2004). For plantings >10 acres it is recommended to do some with seed and the rest with seedlings
(Edge 2004), which could save valuable time and money. Considering this restoration is about 30 acres,
the best method would be to collect seeds two consecutive years. Prior to the restoration, collect seeds
that would be planted at a nursery for a year to a year and a half, then collect seeds the next season that
would be directly seeded at the restoration site soon after collection. Swamp white oak seeds exhibit no

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dormancy and should be planted directly after collection in fall for crucial winter growth and to avoid
the seeds from becoming unviable. The seedlings from the previous year could then be planted at the
same time as the direct seeding or the spring following the direct seeding.
Spacing is another factor that must be determined by a property manager because there are
advantages and disadvantages to both high and low-density plantings. Low-density plantings will allow
more space for each tree and cost less than high-density plantings, however, high density plantings will
ensure a fully stocked woodlot but may need to be thinned several years after the planting (Boozer).
The maximum number of trees/acre in a mixed species bottomland hardwood stand is 800, with a
spacing of 7-15 ft between each tree when the DBH is an average of < 6” (USDA NRCS 2003). This
number does not account for trees that will be lost due to herbivory and competition within the first
several years after the planting. If there is no fence to detract herbivores, in this case most importantly
deer, from entering the area and browsing on the seedlings, >800 seedlings/ acre will be needed to
ensure a fully stocked woodlot.
When directly seeding, it is recommended to base your seeding rate on estimated germination
rates and survival rates to reach approximately 3000 or more stems per acre (Edge 2004). When using
seedlings (to restore a forest), germination rates and nut predation are no longer a factor, but herbivory
and competition become larger factors of survival. As a stand of trees gets older, competition for light
and space will continue to increase and there will become fewer and fewer high-quality trees because
the better adapted trees will outgrow the others.
Methods:
The restoration will take place on an 80-acre parcel of land located in the town of Ellington,
Wisconsin in the SE 1/4, Section 6, T22N-R16E. The restoration will be converting agricultural land back
to natural wildlife habitat. In the spring of 2012, 22 acres of this property will be converted to native

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prairie. This leaves roughly 45 acres to be converted to forest. These 45 acres will be planted with silver
maple, swamp white oak, hackberry, red maple, white pine, black cherry, shagbark hickory, red oak,
white oak and bur oak. 15 acres will be planted with silver maple and winter rye in the spring of 2012,
leaving 30 acres to be converted to bottomland hardwood in the spring of 2013. The bottomland
hardwood restoration will connect the forest with an isolated woodlot and the Wolf River Bottoms
Wildlife Area- LaSage Unit.
Over several weeks, the seeds of hackberry and swamp white oak were collected for the
restoration project. The hackberry seeds were collected from a single parent tree which was less than 1
mile south of the restoration. The swamp white oak seeds were collected from several different stands
ranging from 7.4 to 15 miles north of the restoration site. The nearest site, the 156 boat landing, was
checked more regularly than the other swamp white oak site, and seemed to be a reliable indicator of
when the seeds were ready to fall. The method that was used for collection of both species of tree was
hand collecting seeds that had fallen on the ground. The hackberry seeds were collected by combing
through the grass under the tree at the beginning of October. Due to the size of the hackberry tree,
picking the berries was not an option because climbing in the tree would have been too dangerous
without proper equipment and the branches were too high to be reached with a ladder safely.
The seeds were stored in mesh bags in a cool, dry location and delivered to the nursery
promptly to avoid overheating and molding. The seeds were delivered to the WDNR nursery in
Wisconsin Rapids and floated in water to test the quality of the seeds. Sound seeds will sink, while
empty seeds will float. After the float test, the seeds were planted so they were in the ground before
winter. Planting the seeds at the nursery helps avoid nut predation and seedling herbivory that would
be much higher in the wild, and would likely destroy many before they could mature. The trees will be
grown for 2 years at the nursery and will be transplanted in the spring of 2013. The property will be

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planted at a rate of 800 seedlings/acre, and deer browse will not be a problem because the area has a
secure deer proof fence.
The major costs associated with the seed collection include the average cost to operate the
state 4x4's at $.62/mile. It also cost the state $8.00/hour for the time that was spent collecting the
seeds. These amounts will be used to calculate how much it actually cost the state of Wisconsin for the
collection of the seeds for this project.
Results:
The best dates for swamp white oak collection were September 28- September 30, 2011. On
September 29th
high winds knocked down the majority of the acorns, which made the following day the
most productive for acorn collecting. Had these high winds not come, the collection would likely have
been steadier for a longer period of time. The hackberry seed collection was time consuming and very
few seeds were actually collected due to the limited number of parent trees and the large size of the
tree.
Fuel costs should also be accounted for because the further a person travels to collect these
seeds the less cost efficient it becomes. Monitoring of the sites was necessary, which increased initial
fuel costs without much productivity. The hackberry tree that seeds were collected from had a low
output, and being ~24 miles away from the Navarino Wildlife Area field office, it is likely that fuel costs
to get to and from the location outweighed the costs of buying this number of seedlings from a nursery.
Swamp White Oak were harvested at two locations ranging from 7.4 miles (Highway 156 boat landing)
to 15 miles (Outagamie Wildlife Area) from the Navarino Wildlife Area field office. On the best days for
oak seed collection it was not unusual to hand collect a bushel in an 8 hour day, including the travelling
time between sites. The estimated total fuel costs of traveling while scouting the sites and collecting
the seeds was about $189.00 (Table 1).

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Site
Distance from Navarino field office
(miles/ round trip) Cost/mile ($) # of times visited Cost ($)
LaSage 48 0.62 2 59.52
Outagamie 30 0.62 4 74.4
156 Boat Landing 14.8 0.62 6 55.056
Total cost for fuel 188.976
Table 1: Total fuel costs for the seed collection project. Includes travel for scouting and collection at each of the sites.
Site Hours spent at site (including travel time) Cost/hr ($) Total hourly costs ($)
LaSage 8 8 64
Outagamie 17 8 136
156 Boat Landing 18 8 144
Total 43 8 344
Table 2: Total hourly costs at a pay rate of $8.00/hour. Includes time spent collecting at each site and estimated travel times to get to and from
each site.
Other than fuel the only real cost to the project was a wage of $8.00/hour. The amount of time
spent at each site for collecting was recorded and estimated travel times were used to get a total cost
for the hourly wage. This cost was roughly $344.00. The total fuel costs and hourly costs of the project
come out to be $533.00.
Discussion:
Seed collection can be a money saving technique for any person trying to restore a property to
natural habitat. One biological advantage to seed collection for any reforestation project is that a
person knows that the seeds are local and will have higher adaptability than trees that may have come
from farther away. To save even more time and money, one could use the technique of direct seeding
rather than purchasing/growing the seedlings, or growing half of the seedlings at a nursery and plant the
rest with direct seeding the following year.
The total costs for the state of Wisconsin was about $533.00 for the seed collection project.
Many more seeds will be needed for a restoration of this size and these will come from outside sources
who collect seeds and sell them to the WDNR nurseries. Swamp white oak seeds were purchased by the

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WDNR nurseries for $70.00/ bushel in 2010-2011. Hackberry prices were not available but are likely
more expensive per bushel due to the small size of the seeds. $70.00 per bushel is nearly the same as
an 8-hour day of collecting at the cost of $8.00/hour, along with several dollars for fuel. The seeds
which are purchased from these outside sources will likely be less locally adapted. This could make
these trees less competitive than the more local trees, or could even benefit the stand by introducing
greater genetic variation. It was not unusual to collect a bushel of acorns on the most productive days
for seed collection. This makes the cost for the seed collection nearly the same as the purchase of the
seeds from outside sources, but there are things that can be done to make this more cost efficient. It is
hard to put a price on genetic variation, but better genetics will increase stand productivity which will
likely increase the benefits to the State of Wisconsin in the long run.
A major downfall to collecting seed by hand is the amount of time it takes to actually collect the
seeds. The tarp collection method was successful in that it made the acorns easier to see when
collecting. This made for less crawling around and combing through the grasses looking for the acorns.
Due to high winds and uneven vegetation under the trees, most of the acorns pooled up in spots or
were found near the edge of the tarps. The tarps were also small and did not cover much area
underneath the crown of the trees, so combing the area was necessary even after the tarps were laid.
Several hours were spent gathering, laying, drying and folding the tarps that could have been spent
collecting the seeds. I would recommend laying tarps down over wet spots around the trees, because
these acorns are harder to find after they fall. For other, drier areas, where it is easy to crawl around
and search for the acorns, combing through the vegetation was the best method to use.
Better methods could be developed to catch more of the seeds before they fall to the ground,
this would allow for fewer of the seeds to be eaten by animals or getting buried under the mud. Swamp
white oak seeds need to be collected in a short amount of time to beat the deer and other animals that

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consume these nuts. Some type of netting system that catches the seeds higher than the deer can reach
is one technique that may have high initial costs, but would save valuable time and money in the long
run. The use of more fuel efficient vehicles could also lower the costs of the project substantially.
Hackberry seeds were more of a challenge to collect and this was due to only having one known
tree to collect from. Also, most hackberry seeds stay on the tree when they are mature so finding
smaller trees reachable by ladder would make this task much easier.
Conclusion:
For this project, not a lot of money was saved as opposed to purchasing the seeds from outside
sources. It is hard to put a price on genetic variation, but better genetics should increase stand
productivity which will increase the benefits to the State of Wisconsin in the long run. Overall, seed
collection can be a money saving technique that not only benefits the forest and wildlife through
biological aspects, but will benefit the people who use these forests for centuries to come.
Literature Cited:
Allen, J. A. 1997. Reforestation of bottomland hardwoods and the issue of woody species diversity.
Restoration Ecology 5(2): 125-134.
Boozer, G. Establishing and maintaining oak habitat. National Wild Turkey Federation Bulletin: 27.
<http://www.nwtf.org/conservation/bulletins/bulletin_27b.pdf>
Edge, G. 2004. Direct seeding of hardwoods in Wisconsin. Timberline: 3rd quarter.
Steele, Y. 2011. Wisconsin All Bird Conservation Plan: Bottomland Hardwood.
<http://www.wisconsinbirds.org/plan/habitats/BottomlandHardwood.htm>
Taylor, J.R., Cardamone, M.A., Mitsch, W.J. 1990. Bottomland hardwood forests: their functions and
values. Ecological Processes and Cumulative Impacts: Illustrated by Bottomland Hardwood
Wetland Ecosystems: 13-88.
United States Department of Agriculture Natural Resources Conservation Service. 2003.

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Tree spacing for riparian forest buffers. Wisconsin Forestry Note: 3.
<ftp://ftp-fc.sc.egov.usda.gov/WI/technotes/forestry-tn3.pdf>
Wisconsin Dept. of Natural Resources. Lower Wolf River Bottomlands Natural Resource
Area: A Users Guide to Public Wildlife Recreation along the Lower Wolf River.
Wisconsin Dept. of Natural Resources. 1996. Silviculture and Forest Aesthetics Handbook: Chapter 47,
Bottomland Hardwood Type.