Frequently Asked Questions

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Are you looking for information about Cover It Up research that is not answered below? Please email your question to coveritup@umn.edu.


 

2021 Activities, tools, and news

What do I do in 2021?

April or May: Check on site

June - August: Maintain site

August: Collect data

I went to cut non-test buckthorn and there was none to cut. Do I report my effort?

Yes. Use your paper "Log for cutting non-test buckthorn" (page 2 of this PDF) to report all efforts. Any time you check your site for non-test buckthorn with the intent to cut, record the date of your effort, even if there is nothing to remove.

Why do we cut non-test buckthorn?

Cutting non-test buckthorn maintains an area in which we compare how test buckthorn grow in the presence and absence of the native seed mix. This comparison depends on minimizing interference from residual buckthorn. “Residual” means buckthorn that re-sprout from stumps, or any buckthorn that survived your original removal efforts.

Do I need to water the site? It's so hot and dry!

No. Do not water your site. It's best to let it be. The Cover It Up Citizen Science experiment is designed to run in naturally occurring conditions in a variety of woodlands and forests. If interventions such as watering were to happen, it would prevent us from being able to compare observations among sites. Also, watering would interfere with the processes being studied.

I lost track of some project materials. What supplies do I need, and can I get replacements?

A list of supplies for summer activities at your site:

 

  • Your site map
  • Fisheye lens
  • Ruler
  • Clipboard
  • Twine (optional)
  • Pink and blue laminated cards
  • Scissors and/or pruning shears

If you're missing flags or other supplies, please contact Abbie (coveritup@umn.edu).

When will it be overcast, so I can take fisheye photos?

If possible, complete Activities 2b and 2c (part of Summer's End Activities) when it is overcast to avoid strong shadows. Here is a website for checking the cloud cover forecast: https://weatherstreet.com/states/minnesota-cloud-cover-forecast.htm

How do I know which buckthorn are from test seeds and which are not?

All buckthorn growing within 3 inches of a white flag can be considered “test buckthorn.” Do not disturb, cut or uproot them until asked to do so. (Yes, we will eventually uproot test buckthorn.)

If you see a buckthorn plant within 3 inches that you believe is not from a test seed, please send photos and a description to the research team. Together we can decide what to do.

I don't see native plants yet. Is this normal?

Don't be discouraged if you don't see much new growth in 2020, or even 2021. This is normal and does not mean the experiment is failing. The amount of light at your site strongly influences growth from the seed mix. In sunnier sites, plants emerge in greater density and at a faster pace compared to shady sites. Factors like soil moisture and nutrients also play a role.

Keep in mind, the Cover It Up experiment tests how well native plants shade out buckthorn seedlings, not older plants. When buckthorn emerges from seed, it is quite sensitive to light competition, so even modest establishment of native plants may effectively suppress buckthorn's growth and survival.

My site has invasive plants other than buckthorn. Should I remove those, too?

No, that is not necessary or expected. All you need to do to maintain your site is cut non-test buckthorn. (See coveritup.umn.edu/2021#cutting for details.)

If you need or have a strong preference to remove other invasive plants (e.g. garlic mustard) at the site, you may clip them. If you decide to do so, please follow these guidelines:

 

  • Be sure you can confidently identify plants before removing. As time progresses and native plants from the seed mix emerge, your identification skills become increasingly important.
  • Minimize disturbance to the site.
  • Carry out activities uniformly across all 6 squares or entire site. (That is, do not pay more attention to some squares than others.)
  • Use the "Cutting Activity Log" to write down:
    • which species you remove
    • what technique you use (i.e., cut plants taller than what height?)
    • the dates of your removal activities
    • and how much time you spent

At the end of the season, we will collect your records on these activities using an online survey.

These guidelines also apply to non-invasive plants you may prefer to remove from your site (e.g., a native plant such as prickly ash).

How do I distinguish between buckthorn and cherry?

For seedlings and young plants, pay attention to leaf shape and vein patterns. Examine this image (via MinnesotaWildflowers.info) which shows buckthorn leaves in the upper left and a cherry leaf in the lower right. The bullets below walk through what to look for:

 

  • Cherry leaf margins (edges) have small sharp teeth
  • Buckthorn leaf margins have small rounded teeth
  • Cherry leaf veins form fairly straight lines from the midrib to the margins
  • Buckthorn leaf veins are distinctly curved, forming arcs that originate along the midrib and point toward the leaf tip

For older plants, inspect additional traits such as bark and fruits.

These resources give detailed descriptions of common buckthorn's distinctive traits:

 


Project Commitments

What if property or land changes ownership? Or what if I can no longer participate?

If for any reason you need to stop participating in Cover It Up, please notify staff. This way, we keep our shared commitment to destroy test buckthorn plants at the end of the experiment. For most people, the experiment will end in late 2022. However, if land changes ownership or other circumstances arise, please communicate with staff so we can uphold ethical and legal commitments.

Was there a formal agreement volunteers made in order to participate?

Yes, a link to the agreement is here. All Citizen Scientists signed this form (digitally) before University staff sent them project materials.

Can I get a copy of the Noxious Weed Permit that was issued for my site?

Available by request, please email coveritup@umn.edu.


 

Study methods

Why do we plant test buckthorn seeds?

We understand that it seems counter-intuitive to plant buckthorn for a project aimed at removing buckthorn. However, to understand this plant, we're working closely with it—and yes, even planting it in a short-term, removable way—so that in the long term, we learn how to reduce it. In order to identify conditions that result in buckthorn failure, we need known numbers of buckthorn plants at known locations in every square, all starting off from seed at the same time. And although it may seem that buckthorn is ubiquitous, in truth, its occurrence (i.e., where it appears in the environment) is extremely variable. That is why this experiment uses a small number of "guinea pig" buckthorn, all of which will be (easily) removed at the end of the study before they produce any seeds.

People plant native species all the time. Hasn't this been done before?

There is considerable evidence that removing invasive plants and replacing them with native species reduces re-invasion of grasslands. However, there's actually little evidence on whether this is effective in woodlands or with woody invaders (Schuster et al 2018, link to PDF below). There haven't been any published tests of this idea with buckthorn. So this is a question we still need to answer.

Schuster_et_al-2018-Journal_of_Applied_Ecology.pdf

How else have you tried to find out if we can use native plants to control buckthorn?

We first tried to answer this question in 2016 using a retrospective approach (i.e., making observations of conditions as they are without running an experiment). We surveyed about 40 sites around Minneapolis/St Paul where buckthorn had been removed within the past few years. These sites had either been seeded with native plants or not. We measured buckthorn and native plant abundance, soil properties, tree canopy, and several other variables to try to isolate the effect of seeding. We saw that on average, re-seeded sites had about half as much buckthorn re-invasion as unseeded sites.

However, the results were not definitive because the data were highly variable, and because herbicides confounded the effect of seeding. The abundance of buckthorn and native plants vary from place to place depending on all kinds of factors such as history, soil, slope, deer abundance, tree canopy, and so on. This variability is so great that retrospective surveys have limited use for determining if native plants suppress buckthorn. The way around this is to conduct experiments that control some of the variability by a) having adjacent seeded and unseeded squares and b) having a consistent number of buckthorn seeds planted around flags to assess how seeding affects buckthorn growth.

Won't buckthorn pop up on their own in my experimental site, without my planting test seeds?

Maybe, but we can't count on it. Two factors make it so we can't count on new buckthorn plants emerging from seeds that are already present in the soil (i.e., seedbank). The first factor is the age of seeds and the second factor is their patchy distribution. As for seed age, most buckthorn seeds germinate within 1 year and a small portion will germinate after 2 years. (This is based on several large experiments that we have conducted over the past 3 years.) Therefore, at sites where buckthorn was removed more than one year prior to this experiment, the existing seedbank is only marginally viable.

Second, the seedbank is quite patchy because buckthorn fruit production varies from plant to plant. For example, a well-lit fruiting (female) buckthorn may grow next to a non-fruiting (male) buckthorn (or even a female plant that is too shaded to produce much fruit). After those plants are removed, one may see a dense carpet of buckthorn seedlings next to an area with few or no seedlings. Because of buckthorn's patchy seedbank, the seedbank in the squares at your site cannot provide a reliable "apples-to-apples" comparison between where you apply native seeds and where you do not.

The factors above are consistent with what we observed in an earlier phase of Cover It Up research: In 116 plots at 7 sites around the Twin Cities where buckthorn was recently removed, we monitored buckthorn seedlings in re-seeded and non-seeded areas. Buckthorn emerging from the natural seedbank were too variable to detect any effect of seeding, whereas buckthorn test seeds that we planted around flags showed reduced survival and growth with re-seeding at some sites. By having citizen scientists repeat the latter protocol across the state, we can find out more about site conditions that are conducive (or not) for using native plants to control buckthorn. Because naturally occurring seedbanks vary in age and patchiness, it is necessary to plant a known number of buckthorn test seeds at known locations.

Will the buckthorn planted as part of Cover It Up take over the property?

No. We've run similar experiments in approximately 800 research plots around the Twin Cities. Across all those plots, we've never seen a test buckthorn grow more than 2 feet tall  (most are shorter than 1 foot), or large enough to fruit, within 3 years (the duration of Cover It Up Citizen Science). Most importantly, participants are required to remove all buckthorn arising from seed at the end of the experiment. Given how small buckthorn are at that age, they are easy to uproot and will not resprout. So, if experimental areas are managed according to the project's protocol and the agreement that we enter into with participants, there is very little risk.

Which species in the native seed mix are most shade-tolerant?

Silky wild rye (Elymus villosus), red columbine (Aquilegia canadensis), pagoda dogwood (Cornus alternifolia), and basswood (Tilia americana) are among the more shade-tolerant species in the mix.


 

Native plants & restoration of forests & woodlands

Where can I obtain native plants, for projects other than this experiment?

This page compiles a list of nurseries and other vendors that sell native seed in the Midwest: https://www.mipn.org/cwma-resources/site-revegetation/native-plant-nurseries-of-the-midwest/.

What do we know about restoring forest or woodland vegetation after removing buckthorn?

In general, we know more about restoring grasslands and prairies than we know about restoring forests and woodlands.

We know from our experiments that densely planting shrubs (primarily red and common elderberry) or a mix of balsam fir and sugar maple can severely reduce buckthorn survival and growth. In areas where the canopy is more sparse, preliminary evidence suggests that a herbaceous seed mix (largely comprised of Elymus wild ryes) can suppress buckthorn. However, more supporting evidence is needed for this second approach and this is the goal of Cover It Up Citizen Science . By conducting experiments with herbaceous seed mixes across the state, we can not only find out if it is effective, but also where it is effective based on local conditions.

In general, these approaches suppress new growth (i.e., seedlings) rather than re-sprouting buckthorn plants. Additionally, a high density is necessary for these seeding or re-planting approaches to succeed. Finally, every site is unique and these replacement species may not thrive in all settings.

Where can I find out more on this topic?

Restoring your woodlands after a buckthorn invasion, YouTube video for the Minnesota Woodland Owner Workshop series. Presented by Jake Froyum, Minnesota Department of Natural Resources.

Woodland Gardening via Chicago Botanic Garden

Managing and Restoring Woodland and Forest Communities (Chapter 3 of Guidelines for Managing and Restoring Natural Plant Communities along Trails and Waterways by Minnesota DNR)

Landscape Alternatives for invasive trees, shrubs, and vines of the Great Lakes region by the Woody Invasives of the Great Lakes Collaborative

 


 

2020 Activities, tools, and news

In the news: Mystery seeds in the mail

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Mystery seeds in the mail? Do not plant them. Expand for more info.

In late July 2020, a news story hit about "mystery seeds" arriving by mail. Do not plant these seeds. Visit this page for information from the Minnesota Department of Agriculture.

Additionally, the Midwest Invasive Plant Network (MIPN) issued a special bulletin explaining DOs, DON'Ts, and what we know about this matter.

MIPN Special Bulletin: Mystery Seeds in the Mail (July 29, 2020)

My site is set up. Now what?

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What does the year 2020 look like at a glance, in terms of activities?

The at-a-glance calendar below provides an overview. For details on 2020 activities, see coveritup.umn.edu/2020.

2020 Timeline

Should I water my site? (No - expand to read more)

Please do not water your site. Because weather is part of what we are testing in this experiment, it is best to leave your site undisturbed.

Should I weed my site?

When it comes to removing plants from your site, there are only two expected activities:

  1. Remove buckthorn before set-up (i.e., spring 2020).
  2. Cut non-test buckthorn. Every 4 to 6 weeks between June and August every summer (2020-2022), carry out the steps on this how-to document.

No weeding is required beyond these two core activities. If you want to remove invasive or nuisance plants, we have two requests of you:

  1. When you remove plants (e.g., garlic mustard, burdock, etc.), carry out the removal uniformly across all 6 squares (or the entire site).
  2. Record your activities using your summer datasheet, taking note of which plant(s) you removed, when you did the "weeding," and what methods you used (e.g., cutting). If you need to reprint your summer datasheet, it is page 3 of this PDF.

How can I tell apart buckthorn and cherry plants?

For seedlings and young plants, pay attention to leaf shape and vein patterns. Examine this image (via MinnesotaWildflowers.info) which shows buckthorn leaves in the upper left and a cherry leaf in the lower right. The bullets below walk through what to look for:

  • Cherry leaf margins (edges) have small sharp teeth
  • Buckthorn leaf margins have small rounded teeth
  • Cherry leaf veins form fairly straight lines from the midrib to the margins
  • Buckthorn leaf veins are distinctly curved, forming arcs that originate along the midrib and point toward the leaf tip

For older plants, inspect additional traits such as bark and fruits.

These resources give detailed descriptions of common buckthorn's distinctive traits:

I don't see native plants growing. Is this normal?

Yes, this is normal. Don't be discouraged if you don't see much new growth this year. Unlike the garden-like results of cultivated seeds, vegetation from native seeds will start out spindly and is typically slow to establish. These signs do not mean the experiment isn't working.

Keep in mind, the Cover It Up experiment tests how well native plants shade out buckthorn seedlings, not older plants. When buckthorn emerges from seed, it is quite sensitive to light competition, so even modest establishment of native plants may effectively suppress its growth and survival.

The amount of light at your site will strongly influence what you see in terms of native plant growth from the seed mix. In sunnier sites, plants will emerge in greater density and at a faster pace compared to shady sites. Intermediate shade levels will have intermediate establishment rates. Other factors like soil moisture and nutrients also play a role.

Here are some guidelines on what you might see and how long it takes:

  • In sunnier sites:
    • 2020: spindly grasses
    • 2021: wildflowers show up but are sparse
    • 2022: vegetation thickens up and flowering is more dense
  • In shadiest sites:
    • 2022: spindly grasses might be all that appear

Below are images of experimental sites where native seeds were spread in February of 2017.

Murphy Hanrehan Regional Park Fall 2018 - very open canopy
Above: Very open canopy (much light reaching understory) at Murphy Hanrehan Regional Park. Located in an oak wilt gap within an oak canopy. By end of year 2 (fall 2018) modest grass and herb cover.

 

Murphy Hanrehan Regional Park Summer 2019 - very open canopy
Above: Very open canopy (much light reaching understory) at Murphy Hanrehan Regional Park. Located in an oak wilt gap within an oak canopy. By year 3 (summer 2019) there is diverse grass and herb cover.

 

St Croix Watershed Research Station - fall 2018 - mild shade
Above: Mild shade at St Croix Watershed Research Station. By end of year 2 (fall 2018), still only a sparse cover of grass.

 

Murphy Hanrehan Regional Park Fall 2018 - very shady
Above: Very shady (basswood-oak canopy) at Murphy Hanrehan Regional Park. By end of year 2 (fall 2018), seeded grasses (wild ryes) are still very sparse. This example is a case in which shade has limited establishment of native seeds.

 

What observations are expected in May 2020?

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What makes a useful site map?

Blank site map PDF

Your site map is an important tool for the three-year course of this study. It diagrams the configuration and features of your unique site. One important function of the site map is to show you where to stand when taking "time series" photographs of your squares. In order to compare photos across time, it helps to use the same vantage point again and again. Below is an example site map with a list of all the details that make it a useful tool:

Site map example
Example of a site map
  • Site name
  • Your name
  • Site perimeter
  • Anchor point ("AP")
  • 6 clearly numbered squares
  • An "X" in one corner of every square, showing where to find the metal tab
  • Along one edge of every square, the word "PHOTO" indicates where to stand so the metal tag is on your left
  • Sketched natural features such as logs, tree trunks, etc.

What are we looking for in the photographs of my squares?

In May 2020, the photographs of your squares capture your site's "baseline" condition. What did your site look like before the experiment started. Most importantly, we will be taking "time series" photos of each square. That way, you can examine how your site changes over time. You will be able to see the most interesting results if you use the same vantage point again and again. This is why it's helpful if you stand in the middle of one edge, with the metal tag to your left. Below is an example photograph and a list of what makes this photograph useful:

Example - photo of square
Example - photograph of Square 6
  • Photo marker indicates which square this is
  • Metal tag is in the lower left
  • Vantage point is a birds-eye view, standing at the center of one edge
  • All 4 corners are in the field of view
  • The square is framed snug within the field of view, without too much background or surrounding area

Anecdata

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What is geoprivacy and how does it work?

Anecdata's geoprivacy feature is enabled for the Cover It Up project. Geoprivacy obscures the publicly-displayed latitudes and longitudes of observations by up to 1/5th of a degree. When you add an observation, it has a pinpoint on a map (pictured below, left). When your observation is viewed by others, the location appears as a box around a general area (pictured below, right).

Anecdata - "Use this location" pinpoint on map
Anecdata - Observation veiw, general area

When I upload photos, what file type should I use?

Anecdata accepts a variety of file extensions including JPG, PNG, and BMP. However, it does not accept TIF or PDF files. If you encounter issues uploading photos, please contact coveritup@umn.edu.

I noticed something interesting at my site. Should I report my observation?

Yes, we'd love to hear about what you noticed. When you are at the Anecdata project page, click "Add observation." Choose the datasheet called "Non-standard observation." This is a datasheet for reporting data other than what is asked for in our standard protocols. If you took a photograph, please upload it. Also, please write a comment describing what you saw and why it is important.

Setting up my site

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I haven't received my supplies. When should I expect them?

Supplies are being shipped in batches in April and May 2020. Please contact Abbie at coveritup@umn.edu to ask about your shipping date and tracking number.

Should I remove leaf litter before applying the mix of native seeds?

No, for this experiment please distribute the native seeds directly onto the forest or woodland floor.

Why didn't my kit contain buckthorn test seeds?

The planting of buckthorn test seeds has been postponed. Please carry out the other steps of your set-up (mark squares with flags, draw a site map, take photos, and distribute native seed mixtures). Buckthorn test seeds and the round planting discs will be shipped to you in approximately early May.

What native plant species are in the seed mixes?

The project seed mix includes 29 native Minnesota plant species. These species were chosen because they:

  • may provide dense shade in situations ranging from fairly open woodlands through to closed forests
  • have approximately state-wide ranges
  • and are available locally through Minnesota seed suppliers.

Here is a link to the species list:  https://coveritup.umn.edu/seed-mix

My site has invasive plants other than buckthorn. Should I remove those, too?

If you have a need or strong preference to remove other invasive plants (e.g. garlic mustard) at the site, you may clip them. If you decide to do so, please follow these guidelines:

  • Be sure you can confidently identify plants before removing. As time progresses and native plants from the seed mix emerge, your identification skills become increasingly important.
  • Minimize disturbance to the site.
  • Do your activities uniformly across all 6 squares or entire site. (Do not pay more attention to some squares than others.)
  • Use the "Cutting Activity Log" to write down:
    • which species you remove
    • what technique you use (i.e., cut plants taller than what height?)
    • the dates of your removal activities
    • and how much time you spent

At the end of the season, we will collect your report on these activities using an online survey.

These guidelines also apply to non-invasive plants you may prefer to remove from your site (e.g., a native plant such as prickly ash).

There are many deer in my area. Should I protect my site with fencing?

The choice to fence off your site or not is left to you as the participant. Either choice is okay, so long as all six squares are treated uniformly.

Can I get a sign that explains Cover It Up research to curious passers by?

Yes. Some Cover It Up experimental sites are visible from public trails. Putting up signage accomplishes two things: First, we request that people stay on trails and not disturb the site. Second, we can give people information about Cover It Up research and our shared goal to restore native plants in Minnesota forests. Below is a link to a PDF you may print, protect by lamination or a plastic sleeve, and then display at your site.