Credits

Created by Stephanie Bilodeau; additional voice by Alli Kenlan. Explore Natural Communities Intern Summer 2017, NatureServe.

Sound: Gravel Walking, recorded by tigersound (freesound.org). Shared under Creative Commons: Attribution-NonCommercial 3.0. Bird sounds recorded by ENC Interns 2017. Licensed under Creative Commons: Attribution 4.0.

Photo: Tree Canopy, by Stephanie Bilodeau, courtesy of NatureServe. Licensed under Creative Commons: Attribution 4.0.

Transcript

Podcast time: 4:32 minutes

[sound of birds singing and footsteps approaching]

[Voice 1] What a beautiful day to be out in the forest!

[Voice 2] And look at all these trees. They're so tall!

[Voice 1] Yeah. But didn't we read at the Visitor Center that this park used to have a lot of farmland? Where did this forest come from?

[Voice 2] Before there was farmland, this area was originally forest. When people moved in, they cleared the land. But after farming stopped and the cleared fields had been undisturbed for some time, animals and wind brought in seeds, which grew into new plants. These plants eventually grew into a forest. It's a process called succession—one set of plants follows another. You can actually tell this is a successional forest just by looking around. 

[Voice 1] Maybe you can tell. But how can I tell I'm in a successional forest?

[Voice 2] Well, see how the tree trunks here are mostly the same size around? That's one clue. It can mean these trees all grew back at the same time, so they're all about the same age. The first trees to settle in a cleared area like an old field are the ones that need lots of direct sunlight to sprout, like pine (Pinus spp.), eastern red cedar (Juniperus virginiana) and tuliptree . These are called pioneer species. They're often some of the tallest trees in a successional forest.

[Voice 1] Oh, I see. So what else do I look for?

[Voice 2] Look for trees with multiple trunks at knee or waist height. That's a sign that those trees may have been logged for wood in the past, but their roots were never removed, so they were able to sprout and regrow from the same stump. Multi-trunked trees like that are a great way to tell you're in a successional community that grew back after logging.

[Voice 1] How long does it take for a forest to come back?

[Voice 2] Well, that depends on the type of forest and why it disappeared in the first place! There are many different disturbances that can lead to succession. We talked about farming and logging, but the forest could also have been destroyed by natural events like fires or hurricanes. Disturbances that change the forest floor can slow recovery and also open the door for non-native invasive species to move in.

[Voice 1] Aren't invasive species, like, really bad?

[Voice 2] They can be. Many non-native invasives are like pioneer species in overdrive! They grow really fast and require lots of light, so they love the open, sunny conditions in early successional forests. Most native animals here don't eat these non-native plants, so they tend to take over! There are lots of invasive trees, shrubs, vines, and even grasses: Japanese honeysuckle  and (Japanese) stiltgrass , garlic mustard , princess-tree , tree of heaven –

[Voice 1] Wow! I'm surprised this whole forest isn't just made up of invasive species!

[Voice 2] Well, the National Parks work really hard to control invasive species in their forests, but people like us can also help out at home by removing invasive species from our yards. And in some successional forests, native species have one important advantage: If the topsoil is left intact after a disturbance, seeds that the native trees have dropped there over time are already in the soil ready to sprout and grow. We call this the seed bank. With these seed reserves, the forest can regrow much faster than if it has to wait for new seeds to be carried in. Successional communities can spring up pretty quickly, but it can take hundreds of years for a forest to mature. 

[Voice 1] Oh, I get it. So a successional forest is just a younger version of what was here before?

[Voice 2] Um... not exactly. Remember those pioneer species? See after they arrive, slower-growing trees that don't mind the shade start growing in their shadows. All this shade keeps new sun-loving pioneer species, whether native or not, from sprouting. As the pioneer trees grow old and die, they'll leave room for more shade-tolerant species in the forest. Eventually, these slow-growing trees will take over the canopy and transform the community. Older forests around here often have a mixture of shade-tolerant trees like maple (Acer spp.), oak (Quercus spp.), and beech  of many different ages, and they may also have a lot of fallen trees that have died out over time. This successional forest will likely look very different in a couple hundred years!

[Voice 1] Yeah, I think it's already grown some since we started talking!

[Voice 2] Okay, okay, let's keep going! [sound of footsteps departing]

back to top