Thinning Trees to Preserve and Restore Oak Woodland and Savanna Habitat

Have you ever wandered across a tree missing a ring of bark and wondered what was creating the ring and why? I too had these questions and they remained unanswered until I began performing the task as an Oakland Township Natural Areas Stewardship Technician. I learned that removing a complete ring of bark around a tree stem is called girdling, and it is used in Oakland Township’s natural areas to selectively phase out invasive trees by stripping off their nutrient pathways.

As deforestation awareness and efforts to plant trees continue to increase, girdling may register as counterintuitive. However, we girdle specific trees, and only in areas we are restoring to historic oak savanna or prairie communities. Lost Lake Nature Park, Paint Creek Heritage Area – Wet Prairie, and Bear Creek Nature Park contain these historic communities so we are focusing our girdling and restoration efforts this summer in these natural areas.

Although red maple and basswood are native to Michigan, they are quite damaging to the historic oak communities. These trees grow so abundantly that their dense stands take up the real estate, nutrients, and light that fire-dependent, light-loving understory plants require. In the dense shade under red maple it is very rare to find any young oak trees. At Lost Lake Nature Park red maples outnumbered the old growth oak trees 12:1!

In Oakland Township’s natural areas we use a low-cost, low-impact girdling tool composed of a metal handle and arched blade to strip the trees bark, phloem (sugar transport highway) and vascular cambium (cells that produce phloem and xylem) from the trunk. This tool is quite simple and easy to use, but you can also girdle with chainsaws and hatchets if you don’t have a special girdling tool.

As the girdled trees defoliate and phase out, the sun’s rays reach plants like poke milkweed, harebell and whorled loosestrife, providing the essential energy to thrive. Many other oak savanna and prairie specialist plants are either lying dormant in the soil as seeds, or holding out as small plants until the ideal light conditions are created. For example: hoary puccoon, a rare and high quality plant began to flower at Paint Creek Heritage Area – Wet Prairie when the canopy was thinned! Furthermore, there’s an abundance of small huckleberry and blueberry at Lost Lake Nature Park patiently waiting for an opened tree canopy to reach their full potential. I am very excited to revisit the areas we girdled in a couple years to see what new plants are claiming space in these beautiful communities.

Opening up the tree canopy and conducting occasional prescribed burns are important practices of Oakland Township’s restoration efforts, helping to reinvigorate our diverse and tightly knit natural communities. The landscape of southeast Michigan was maintained by the Anishinaabe people for thousands of years. This culturally related group of indigenous people inhabited much of the Great Lakes region and lived with the land through with a deep relationship and knowledge of its beautiful natural communities. Through cultural practices like prescribed burns and sustainable harvesting, the Anishinaabe maintained these unique oak communities. Now, after more than 200 years of degradation, we are doing our best to restore them and acknowledge the original stewards of the land.

Growing With the Seasons: Learning on Site

This post was written by Stewardship Technician Max Dunn

I am now more than halfway through my seasonal internship as a stewardship technician with Oakland Township Parks and Recreation. My work season is ending about 6 weeks earlier than the rest of the crew since I am heading back to college at the end of August. Although I haven’t been here long, I’ve learned and experienced more at this job than my past three combined. I am now able to confidently maneuver a truck and trailer, identify and treat multiple invasive species, input data into Geographic Information System’s (GIS), and most fun of all, experience beloved native plants in their natural habitats.   

Truck & Trailer Experience

In 2017 I purchased a 1997 Plymouth Breeze and have been driving it daily ever since. This small, easily maneuverable car stands 4.5 feet tall, a dwarf to the stewardship crews truck; a large-and-in-charge GMC 2500 standard 8 foot bed, often pulling a trailer. Driving a rig of this size and length may be common place for some of you, but it was very new to me. We first practiced in an open field to get comfortable then worked up to main roads. Before getting behind the wheel for the first time, thoughts of doubt and insecurity arose in my head. An occurrence that often accompanies me when learning new things. However, this time I realized my degrading thoughts and switched my outlook to one of confidence. This allowed me to be the controller instead of the controlled and made space for a present and enjoyable learning experience.

Backing up the trailer proved to be the hardest task for me since small trailers are very touch sensitive to your driving. It’s a great test of patience and focus and I have come to enjoy the sharp mental state it puts me in. Just remember, when you turn left, the trailer goes right. Unless it’s at too much of an angle, then it goes left. Also, this is an extension of your truck, so allow more space for clearance.

Although pulling a trailer can be a challenge, it is essential for our work. It’s equipped with a 130-gallon water tank, water pump, and heavy duty hose which supplies readily available water for prescribed burns and herbicide application. It requires a great amount of trust from Oakland Township to put this equipment into the hands of myself and the other stewardship technicians and I am grateful they have. I have gained numerous skills from this task alone which will stick with me well into the future.

Geographic Information System

GIS is an acronym for Geographic Information System, a mapping system that captures, stores, and displays data related to specific positions on Earth’s surface. The stewardship crew and I use an app on our phones called ESRI FieldMaps to document locations of invasive species and herbicide application out in the field. With each location, we input additional information such as plant density, herbicide concentration, and weather for that day.

This job introduced me to the hands-on aspect of GIS. I was familiarized with with these systems last spring in an agriculture class at Michigan State University and it was a great overview. But I have found that subjects like this are best learned from hands-on experience. Within the first three days on the job we were getting oriented and comfortable with the Field Maps app. It was early in the garlic mustard season, so documenting plant locations in the field was our orientation task (and what a great one to use since it is so prevalent!). It initially seemed like so much information needed to be included with the garlic mustard location. I was slightly concerned that I would miss out on something valuable and began to ask myself, “How do I properly estimate a plants density and how do I draw a polygon of the area we surveyed? More importantly, how do I remember the area I surveyed?” These all turned out to be useless concerns since the app is quite user-friendly.

Swallow-wort is an invasive plant that is related to milkweeds. It makes seeds attached to fluffy parachutes, so it can spread long distances to new areas.

I have really enjoyed scanning our parks for invasive plants like swallow-wort, and recording their locations and plant densities into the GIS. It is interesting to find a large, dense “mother” patch, then locate all the stragglers in an area. Once all the points are plotted, a rough dispersal outline is created which shows how far offspring of that colony spread. These dispersal outlines then provide valuable information for future stewardship crews because we can compare dispersal outlines throughout time and see how the plants respond to our treatments. If they are effective, the outlines will shrink in size.

Using this app consistently on the job site has taught me how to properly record data and take time to complete tasks that remove me from “actual field work.” My past three jobs were strictly manual labor so if I wasn’t working with my body, it was viewed as a waste of time. It took around a month at this job to break down that ideology and I have gotten much better at taking the time to input data.

Wildflowers at Gallagher Creek Park

One of the most enjoyable new experiences on the job has been finding mature, native plants in their natural habitats. It provides insight into how naturally occurring plants compare to landscaped ones in size, spread, and structure. Golden Alexanders (Zizia aurea), for example, seems to be pretty adaptable. I have seen them in wetland areas with dappled light, semi-dry areas with full sun, and in landscaped beds. Furthermore, they can be quite small and slender in the wild when competing with other plants, but can be very full and wide in landscaped areas; give them space and they will grow! These differences were witnessed in May at the native plant beds of Gallagher Creek Park. 

Golden Alexanders in the native plant landscaping beds at Gallagher Creek Park. Photo by Ben VanderWeide.

Gallagher Creek Park on Silverbell Road, just east of Adams Road is probably best known for the playground. However, it also houses some amazing plants such as Wild Lupine (Lupinus perennis) and Yellow Lady Slipper (Cypripedium parviflorum).

The day before we went to weed the native plant beds around the playground in May, our Stewardship Manager Ben VanderWeide let us know that Yellow Lady Slippers would most likely be flowering in the park. When we got to a garden bed near the suspected area, we took a quick intermission from weeding and began our search. Early on, I stumbled across a beautiful wild lupine, the first one I have ever seen uncultivated and growing naturally. Their loose flower clusters and unique foliage are quite striking!

As I was framing a picture of it, I noticed a helical blade of grass twisting its way into the frame and took it as a foreshadow of a Yellow Lady Slipper sighting. I thought this because the grass perfectly mimicked the helically-twisted sepals of a Yellow Lady Slipper. After admiring the lupine and golden grass blade, we continued our search, and as foretold, stumbled upon a colony of Yellow Lady Slippers! Partially bloomed flowers resembled Corinthian helmets, while the fully mature looked like sunbathing aliens. It was interesting to see how small they were in real life and appreciate their complexity up close. That was truly a day to remember.

Spending time on job sites is something I look forward to. I have realized that as I experience something new, I also learn more about myself. I now tackle new task with confidence and take breaks from manual labor in order to do activities like data entry that have delayed returns. It has been great to grow alongside the abundant wildlife each workday, and I am amazed at how much I have experienced on the job. I am curious to look back in 5 weeks and see what else I’ve learned!

Jack-in-the-Pulpit: What’s Under the Hood?

This week’s blog post was written by Stewardship Technician Max Dunn

Over the past few weeks, the stewardship crew has been hard at work pulling garlic mustard. As we grid the parks for these pesky weeds my eyes are also searching for Jack-in-the-Pulpit. Since we are walking every square inch of the parks to eradicate garlic mustard, I figured I should take some time to appreciate another plant. Life is all about balance right?

Jack-in-the-Pulpit flowering structures are composed of a modified leaf called a spathe and a pillar-like spadix which houses many small flowers and eventually striking red berries.

Jack-in-the-Pulpit (Arisaema triphyllum) is a widespread, eccentric perennial of woodlands that varies greatly in pigmentation, alters its sex overtime, and holds insects captive. This plant is easily recognized by its flowering structure, which is equipped with a hooded spathe and a pillar-like spadix. The spathe is a modified leaf that wraps around the spadix. This leaf initially caught my attention while gridding for garlic mustard because of their unique color patterns, ranging from a pure pastel green to a combination of dark green and waxy maroon. I am most interested in the underside of the spathe hoods since they create beautiful patterns, especially when the waxy maroon pigmentation contrasts pastel green veins.

The spadix also varies in pigmentation, but I found they tend to be green in Oakland Township. This pillar-like structure contains small, closely-arranged flowers that are either male or female depending on the plant. Nutrient reserves in the plant’s below ground corm (a modified stem for energy storage) helps determine the sex of the flowers. Plants with small corms and fewer stored nutrients are male, while plants with larger corms and more nutrient reserves are female. Larger corms allow plants to produce a second set of leaves and invest energy in female flowers that will produce striking, inedible red berries that are on display in the fall.

An interesting way to identify the sex of these plants is by looking at an insect trapping mechanism on the lower part of the spathe. Male spathes are equipped with a small little crook that allows pollen-covered insects like thrips and flies to easily exit and fly to a female flower. However, insects do not have an easy escape route in female plants since they lack this small crook in their spathe. With no easy escape these insects naturally spend more time near the flowers of the female spadix, frantically walking around and pollinating the flowers of the spadix more effectively.

These forest floor plants are an awesome sight if you take a second to look under the hood. The color variation of the spathes are beautiful and fascinating. If you catch a female at the right time you might just find a victim of successful pollination! Jack-in-the-Pulpit will be flowering for a couple more weeks so enjoy these unique plants before they finish flowering for the year. Comment below if you have a favorite Jack-in-the-Pulpit color variation!