Habitat Restoration

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In addition to all of the important uses for people that Baxter Woods plays, this park is also a great example of perhaps Maine’s most important and iconic wildlife habitat.  Mature forest like this one once covered well over 80% of Maine’s landscape.  For millennia, birds, bats, butterflies, and even fish have migrated from far away to what is now Maine because of the insects and breeding habitat our forests provided.  As trees were harvested for ship masts, building materials, pulp, and paper, and as whole forests were cleared to make way for neighborhoods and towns, our historic forests became more fragmented and less frequent.  However, the forestland that exists today remains just as important to global populations of birds and other wildlife.


Early during Portland’s settlement, effort was spent pushing back the seemingly encroaching forest.  As development of the city expanded West, development instead began to encroach upon and overrun the former forests.  Baxter Woods was conserved, the forest there permanently protected, and now serves as an island of forest in a sea of development, impermeable surfaces, and human activity.  Given its proximity and accessibility to so many people and communities, Baxter Woods now serves as an excellent opportunity to learn about forest habitat and management.


Baxter Woods is an excellent example of “a habitat patch.”  Ecologists define a patch as a small area of productive natural habitat that is very different from the areas surrounding it.  Although birds and other wildlife benefit more from large swaths of intact forest covering thousands of acres, it is still critically important to conserve and manage patches like this 60-acre parcel in the middle of town and wherever else we can.

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The artwork and content here are derived from Maine Audubon's Forestry for Maine Birds program, an approach to managing woodlands "with birds and other wildlife in mind."  For more information on this program, visit maineaudubon.org/ffmb.

A mature forest, even just a relatively small patch like Baxter Woods, is a complex environment with many valuable components, each of which supports different plants, animals, and ecosystem services.  Large trees and the shade they produce often define these habitats, but there are more dynamic forces and processes at work than often meet the untrained eye.  Plus, some of the most active and productive habitat can often be found on the edges, within sunny openings (or gaps), and in the layers of the canopy closer to the ground.  Managing for these features in addition to just protecting the largest trees helps keep the forest as productive and biodiverse as possible.


Below are illustrations and descriptions of some of the most important habitat features Baxter Woods contains and is being managed for today:

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Big, Old Trees

Older forests dominated by larger trees are more structurally diverse than younger forests. The vertical and horizontal diversity in older forests can house more species and more individuals of each species than younger forests–kind of like an apartment building compared to a single family home. Older forests also store more carbon.


Large blocks of forest at least 70 years old with >70% canopy closure and trees >10” diameter are preferred by birds like Northern Parula, Wood Thrush and Scarlet Tanager.


What Has Happened Over Time Here?

Baxter Woods has long been home to some of Portland's largest tree specimens.  White Ash, Eastern Hemlock, White Pine, and Red Maple are examples of species that live to full maturity and size here.


Do you see any wide-brimmed oaks in the canopy? That’s where you will most likely find the bright red Scarlet Tanager singing.


What We Are Doing To Manage For Birds Today

  • We work to retain numerous large, older trees across the property.

Click the images below to learn more about species you might find here:

  
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Canopy Gaps

Canopy gaps are small openings of 0.25 to 2 acres in a larger forest stand. In the natural landscape, gaps occur after a windstorm or disease knocks over several trees at once.


These gaps are essential feeding areas for species like Eastern Wood-pewees that catch insects in flight, and are used by American Woodcock for their aerial mating displays.


With a good understory of shrubs or small trees, gaps may be used as nesting habitat for species that prefer young forests or by young birds raised in nearby mature woods to feed and hide.


What Has Happened Here Over Time?

The City of Portland has kept a field mowed in Baxter Woods as long as it has owned it, mostly for recreation.  However, this gap in the surrounding forest canopy is also very important for many birds.  Recently, more effort has been placed on creating forest edge and succession plantings to make this gap even more productive habitat.


Note the shrubs and small trees growing in the open sunlight. In a few years young trees will fill in the gap, attracting species like Chestnut-sided Warblers.


What We Are Doing To Manage For Birds Today

  • We work to maintain this gap, which is strategically placed near the edges of larger forest blocks, with species selection and targeted cutting
  • Limiting the total area of gaps to no more than 20% of the forested area.
  • Managing any future loss of trees or canopy with new gaps and forest succession in mind.

Click the images below to learn more about species you might find here:

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Sources of Water in Forests

Streams, ponds, vernal pools and wetlands within forests attract and support many species of forest birds and other wildlife such as salamanders, frogs, and mink, as well as tree-nesting ducks, hawks, owls, flying squirrels, and bats.


Forests along streams are often used as travel corridors by animals moving between habitats. Up to 80% of all vertebrate wildlife in Maine use these areas sometime during the year to feed, nest, travel, and find water. These forests also protect water quality and shade streams.


What Has Happened Here Over Time?

There is an ephemeral pool formed by a small seep near the Forest Home site, and was probably enhanced at one point to be part of that landscaping.  Now, we have a functional vernal pool that should host salamanders and frogs, and an important stop for birds moving through the woods.


Notice the larger, older trees that form a dense canopy next to the water. This forest, which was only lightly thinned, will protect water quality by reducing runoff, provide shade to keep waters cool for aquatic life, and provide breeding habitat for birds and other wildlife.


How far from the water does this forest stand extend?


What We Are Doing To Manage For Birds Today

  • Restoration of herbaceous layer and shrubs around the pool to maintain water quality and places for critters to hide. 
  • Encourage a full canopy of tall, older trees with a healthy midstory and understory that extends out from the water source.
  • Use Best Management Practices to protect water quality by limiting soil compaction and erosion from trails and pet traffic.

Click the images below to learn more about species you might find here: 

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Snags: Decaying Standing Trees


Some forest birds, like woodpeckers, excavate nesting cavities in standing dead and decaying trees known as snags. Living trees may also have sections of dead or dying wood where animals create nesting cavities. These cavities may be used for years by other wildlife including bats, flying squirrels, wood ducks, and small mammals. Snags are often riddled with bark and wood-boring beetles, which are important sources of food for forest woodpeckers.


What Has Happened Here Over Time?

Baxter Woods has many dead standing trees, and we only remove trees that become unsafe for people.  Governor Baxter specified that dead wood would be left for birds he knew needed it.


Look around. How many other snags can you find?


Do you see any piles of wood chips at the base of the tree or holes in the trunk of the tree? If so, there’s probably a woodpecker nearby searching for food or building a nest.


What We Are Doing To Manage For Birds Today

  • We retain as many snags and live cavity trees across here as possible.
  • Bigger is better! Larger snags (≥ 12” diameter) can be used by larger birds like Pileated Woodpeckers and Barred Owls, and also by Raccoons and Fisher.
  • Where snags are felled for safety reasons, we leave them in place as downed wood.

Click the images below to learn more about species you might find here:

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Three Layers of Vegetation

Dense forest vegetation at three different heights provides many species and many individuals of each species with places to nest, food to eat, material for building nests, and cover from predators.


Ovenbirds use leaf litter to build a nest on the forest floor; Canada Warblers nest near water in the Understory (1) with shrubs < 6’ tall;  Wood Thrush nest on branches in the Midstory (2) between 6-30’ high; and Scarlet Tanagers prefer nesting in large old oak trees in a dense Overstory (3), well over 30’ tall with 80% canopy cover.


What Has Happened Here Over Time?

Some trees were selectively removed to let in more sunlight and encourage the remaining trees to grow big and tall with full Overstory canopies, younger trees to grow up and branch out in the Midstory, and shrubs and seedlings to take root and spread in the Understory.


What do you think this will look like 20 years from now?


What We Are Doing To Manage For Birds Today

  • We are using multi-aged management wherever possible to create a mix of the three vegetation layers over space and time to provide habitat for priority bird species (and other wildlife), and produce healthy forest growth.

Click the image below to learn more about species you might find here:


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Invasive Plants and Insects

Invasive exotic plants are a lot like weeds –they grow fast, in lots of different conditions, and displace the native species that provide food and shelter for forest birds and other wildlife. They also interfere with the ability of native trees such as red oak and white pine to reproduce.


Invasive insects can infest and kill hemlock, ash, and maple trees. Earthworms, which are not native to Maine, can denude soil and leaf litter, which is used by ovenbirds for nesting and by thrushes for finding food.


What Has Happened Here Over Time?

Baxter Woods has been intruded by several species of plants and insects, and the City has a management plan in place to monitor and control their spread.


How many nonnative plants or insects can you recognize?


Do you see any others in this forest?


What We Are Doing To Manage For Birds Today

•Learning to identify invasive nonnative plants from the Maine Natural Areas Program (see resources at www.maine.gov).

•Finding and removing or reducing invasive plants to the best of our ability.

•Reporting any sightings of invasive insects to the Maine Forest Service or other invasives to the Maine Invasive Species Network.

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Dead and Downed Wood

Dead wood – including both large logs and smaller branches in piles on the forest floor -- is sometimes called “downed wood.” It provides perching, hiding and nesting places for birds, and often harbors insects, salamanders, and mice that birds and other wildlife feast on. Dead wood also holds soil in place and replenishes soil nutrients as it decomposes. Species like the Ruffed Grouse use downed tree sites as drumming places to attract mates.


Did you know that dead wood was so important?


What Has Happened Here Over Time?

You will find many large trees and trunks in Baxter Woods, and the topography suggests that trees have grown old and died here for millenia. It is unique to find places in Southern Maine that haven't been cut over within the lifespan of the trees there.

Where would you hide if you were a mouse or salamander so a Barred Owl or fox couldn’t find you?


The dead tree trunks you see on the ground here probably blew over in a big windstorm or after disease killed them.


Where would you hide if you were a mouse or salamander so a Barred Owl or fisher couldn’t find you?


What We Are Doing To Manage For Birds Today

• Leaving some broken tree tops, limbs, and large fallen logs on the ground, including after timber harvests.

• If possible, we avoid crushing downed logs during forestry operations.

• Leave snags not only for current habitat value, but as a source of future downed wood.


Click the image below to learn more about species you might find here:


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