Signs of the Seasons: A Maine Phenology Program

Maine Beaches Conference Slated July 12

Interview with Ivan Fernandez

UMaine researchers incorporate “chemical phenology” into their studies of the effects of climate change on forest ecosystems.

Phenology is the study of the timing of when things happen in nature, usually focusing on plant and animal life as it relates to seasons and a changing climate.  A parallel question is if climate change alters the chemical composition of leaves in a forest, particularly the timing of changes in nutrient concentrations?  Can we use measurements of the chemical composition of forest foliage to monitor climate change effects on nutrient cycling in forests?  Can this help us identify significant change in forests, and possibly prepare for damage to the forest ecosystem?

That is the questionthat UMaine professor Ivan J. Fernandez and graduate student Erin Redding tested in the Bear Brook Watershed in eastern Maine.  Much like Signs of the Seasons observers monitor the timing of seasonal biological events for a variety of plant and animal species (i.e.  phenology), Fernandez and Redding set out to study “chemical phenology”, which they define as the timing of changes in the chemical composition of leaves during the growing season.   Just like every gardener knows the early leaves are succulent and light green, but get darker and thicker as they age, so too does the concentrations of nutrients like nitrogen and phosphorus change over the life of the leaf.  The timing of those changes could be considered to represent “chemical phenology.”

Fernandez has spent nearly 30 years studying the response of ecosystems to perturbations, or abrupt changes that set a system out of equilibrium.  He has been involved with the Bear Brook Watershed project since the late 1980’s when experiments conducted there helped guide policy decisions related to the reauthorization of the Clean Air Act of 1990.   Since then, the West Bear watershed has been treated with bimonthly nutrient additions to mimic chronic acid rain deposition, while the East Bear serves as a reference.  Acid rain results when the gases sulfur dioxide (SO₂) and nitric oxides (NO_x) react with water and oxygen in the atmosphere to form dilute sulfuric and nitric acids that fall to ground with precipitation.  This acid deposition impacts lakes, streams, and groundwaters, and can harm the plants and animals that live in or rely on that water.  Though there are natural sources of SO₂ and NO_x, a significant contribution comes from the burning of fossil fuels.  Fernandez has used this experimental watershed to identify the effects of acid rain by looking for signals in the chemistry of the ecosystem before significant damage is done biologically.  When thinking about the effects of climate change, he wanted to take the same approach.  Phenology, the study of how annual biological events were influenced by changes in physical phenomena such as temperature, moisture, and photoperiod (the daily exposure to light), could be extended to look at biogeochemical changes in the ecosystem.  However in nature there are often effects that work in opposition to each other.  Carbon dioxide causes rising temperature, but it also stimulates the growth of forests.  Acid rain can damage forests, but the nitrogen in acid rain is also an important nutrient for forests.  As Fernandez puts it, climate change is a

“a really complex, modern perturbation of ecosystems [which] can have [both] positive and negative effects.  Sorting that out at the ecosystem level, and then at a the global scale, is an immense challenge.”

 Fernandez and Redding set out to ask three questions:

1)   Does the concentration of nitrogen or other nutrients in the leaves change over time, and what is the typical pattern of change (i.e. chemical phenology)?

2)   Do trees of the same species from the East and West Bear have different chemical compositions that would indicate the nutrient additions in the West  Bear had caused a change in “chemical phenology?

3)   Was there any evidence that the nutrient additions to the West Bear affected  phenological events, such as the timing of bud burst or leaf fall?

On a monthly basis from March to October 2010 they observed red and sugar maple trees in both the East and West Bear forests for the timing of budburst, flowering, leaf unfolding, fall color change and leaf fall.  Similarly, the red spruce trees were monitored for budburst, needle emergence and needle elongation.  Leaf samples were collected and analyzed for concentrations of various nutrients and metals.

They found no significant differences in the timing of phenophase events between the East and West Bear watersheds, indicating the nutrient treatments in the West Bear watershed did not have a detectable effect on things like the timing of bud break or leaf fall.

They were able to document distinct changes in nutrient concentrations within the leaves over time, as Fernandez summarizes,

 “Percent nitrogen and phosphorous showed a clear pattern of decline throughout the growing season.  Calcium and magnesium, which tend to be more structural materials in leaves, increased during the growing season, which is consistent with them building thicker cell walls and more structural material as the leaves age.”

 These patterns in nutrient concentrations were slightly different for each species.  While these patterns are not a surprise, they were not well documented at Bear Brook before this study, and there is limited data on patterns of foliar nutrient concentrations in forest species in the scientific literature.

Was there a difference in the pattern of nutrient concentrations between the West Bear and East Bear watershed trees of the same species, indicating a response to the nutrient additions? The answer was yes.  The decrease in nitrogen concentration in the spring for the maple trees in the West Bear was more dramatic than that in the East Bear.  The difference was slight, but it was still an indication of a change in chemical phenology.

Fernandez hopes to continue this study of how nutrient ratios (“stoichiometry”) may be altered with changing climate.  These initial observations provide a baseline for future studies, which are needed to capture phenophase changes that often happen quickly.  That would require a longer-term study incorporating a more frequent sampling schedule

Why pursue this research?  Who cares?  Since nitrogen is the limiting nutrient for Maine forests, it is important to know how plants are responding to changes in nutrient concentrations.  As Fernandez summarizes,

“There may be information in those differences [in chemical phenology] that allow us to determine how vulnerable plant and ecosystem health is to environmental change. That would be the practical implication of these findings.   There may be situations where the plant starts growing earlier and, depending on the character of the chemical phenology, we could determine how vulnerable to change plants are or will be in the future. “

Dr. Fernandez’s background information from interview:

I am Professor of Soil Science at the University of Maine, and the Forest Soils faculty member at the University and the Maine Agricultural and Forest Experiment Station.  My appointment is in the School of Forest Resources and the Climate Change Institute.  As Maine’s Land Grant institution in a heavily forested state, of course, it is logical to have this kind of faculty position.  I have been there for almost 30 years now.

My research over the years has included a wide variety of environmental issues having to do with air pollution impacts on forests (primarily acid deposition and climate change), biosolids and metals effects on forests, and biogeochemical cycling in forests.  We often look at biogeochemical cycling or nutrient cycling in a watershed context.  This allows us to study a closed system where we can measure inputs, outputs and everything that goes on “inside the box”.  Most of my work is about everything that goes on in that box; that is, the mechanisms of ecosystem function. I also teach soil science. I have taught a number of different classes in forest soils and related to climate change over the years.  I teach the basic soil science class that most students in natural science majors take at the University.  I have had over 2400 students in the basic soil science class so far, and I’m not done yet!

For the past two decades my outreach efforts have increasingly been focused on the extension of our ecosystem work to issues of climate change and adaptation.  We did the climate change assessment for the State of Maine, “Maine’s Climate Future”(http://climatechange.umaine.edu/research/publications/climate-future), in 2009. I was involved with the subsequent state adaptation efforts, although official state programs led by Maine DEP are no longer active.  However, I continue to work to see how the University can be a catalyst and resource for adaptation concerns relevant to climate across a range of natural resource based economic sectors for Maine.

Image Description: Picture of Prof. Ivan Fernandez collecting data in the woods

Tips for Making Spring Plant Observations

Lois Stack serves on the Signs of the Seasons Advisory Team.  You may recognize Lois from the WABI-TV Weekend Gardener program where she offered weekly gardening tips for many years.  She also had a regular horticulture column in the Kennebec Journal.  Currently, Lois is a professor of sustainable agriculture and also a Cooperative Extension specialist in ornamental horticulture.

Signs of the Seasons recently talked to Lois about her work and asked for advice about collecting plant phenology data this season.  

As we head into the second monitoring season, do you have any general advice for trained SOS volunteers?

People should make note of the second year and how it’s different from the first year.  Look for plant stages you may have missed in the first year. You can also anticipate things you’ve already seen. Also, now that you have plants staked out, you don’t need to spend as much time setting up your site and learning about the forms and the online data entry.  You can concentrate on closely observing the plants!  Phenology dates may change slightly from one year to the next, but I don’t think they’ll change dramatically.

Let’s talk about the 8 plants on the SOS Indicator Species List.  Are there any special features or peculiarities people should watch out for?  

Wild Strawberry

This plant is deciduous but retains greenness in the leaves throughout winter. People might not be sure if they see “initial growth” or last year’s leaves.  In early spring, when the snow is receding and before the grass turns green, nothing much is growing.  If you see strawberry leaves then, they’re probably last year’s.  Check back the next week to be sure.  As the grass starts to green up you’ll probably see strawberry greening up about the same time.  Look for new fresh growth from underneath the old leaves.  “Initial growth” (on the data sheet) will be leaves, flowers will happen sometime in May, and then fruits will appear in June.

If you have it staked out from last year that’s good because you might not see the leaves coming out among the blades of grass in the lawn.  It will produce a new rosette offoliage from the same roots in the same spot.  New foliage grows up over the old foliage.  The new rosette looks like tips of leaves with a flower bud in the middle.  Leaves will elongate and the flower will start to open—that first flower is often very close to ground.

Milkweed

This plant has a strong and extensive rhizome system.  Although it’s perennial, the shoots won’t necessarily come from the same place as last year’s shoots.  So, in this case, it would be a challenge to follow one plant from year to year. The first thing people will see is a fairly sturdy stalk with leaves folded up—like a stalk of asparagus.  It might be interesting to take a square meter plot and flag all milkweed stems at the end of one year and see where the new shoots come up the following year.

Rugosa Rose 

This plant will be easy to identify because it has one of the most thorny, stout rose stems around.   There will be an obvious stem from last year and look for apple-green leaf buds that are big and bright.  Note: Flowers and fruits will appear before colored and falling leaves.  The data sheets list flowers and fruits after colored and falling leaves—this might be confusing for people.

Forsythia

This shrub has stems with yellow lenticels (bumps). People generally aren’t aware that almost all plants, like forsythia, that flower in early spring (before mid-June) set their flower buds the previous year and the buds overwinter. The flower buds are separate from leaf buds. Flower buds are bigger than leaf buds.  On most forsythia, flowers open first, then as they’re fading leaf buds begin to open.  The data sheets reflect a different order so watch out for that.  People should check back frequently to confirm things: “Oh yes that was a flower bud not a leaf bud” etc.

Lilac

Like forsythia, this is planted in landscapes and also has separate leaf and flower buds.  The leaf buds are much smaller and more pointed than flower buds, which are big, round, chartreuse buds.

Red Maple and Sugar Maple

The trickiest part with the maples may be that leaves and flowers can be high up in the tree.  Take field glasses (binoculars) out with you so you can see the flowers, which are beautiful dark red, with yellow stamens (Red Maple). Pollen release is easy to tell—look at the ground for yellow powder.

Some people may not think of maple “samaras” as fruits but they are the fruits of maple trees. To a botanist anything that contains seeds is a fruit, but to homeowners those may be just “spinners.”  Remember, those are the fruits!

Tell us about your background and the work you do now.

My job is two-fold.  As a professor of sustainable agriculture I teach a plant science course.  I’m also a Cooperative Extension specialist in ornamental horticulture.  I’ve been here about 25 years and I’ve seen a lot of changes over that time.  When I first came, I spent a lot of time with nursery/greenhouse/garden centers on crop selection, crop production, and crop pest management.  Now a lot of that information has moved into the private sector.  That industry has matured to the point where nobody asks me for that information anymore because they can get all of that from whomever supplies the plants.

Now I find myself working more on issues.  For example, I still do pest management  but I spend a lot more of my time on issues like invasive species and how they impact people’s gardening habits and the “green industry.”  Native plants are a big issue now, too.  People are concerned about invasive species and the environment and they want to garden for butterflies and birds.  I’ve also seen a tremendous maturation in the knowledge level within the green industry and among their customers—people know a lot more about these things than they used to.  I see this in the Signs of the Seasons program as well.  People come to this program with a lot of background knowledge and interest.

Image Description: Picture of Lois Stack smiling

Image Description: Milkweed flowers

Image Description: Red Maple

Image Description: Sugar Maple

Stancioff, Bisson Present at Phenology Conference

Esperanza Stancioff, climate change educator for the University of Maine Cooperative Extension/Maine Sea Grant, and Beth Bisson, assistant director for outreach and education for Maine Sea Grant, recently presented at the 2012 International Phenology Conference at the University of Wisconsin, Milwaukee. The presentation, “Signs of the Seasons: A Maine Phenology Program — Linking Research, Climate Literacy and Action,” explained the collaborative network that works with scientific research professionals to train citizen scientists to record seasonal changes on common plants and animals throughout the state. Partners include UMaine Extension, Maine Sea Grant, Maine Audubon, U.S. Department of Fish and Wildlife, the Schoodic Education and Research Center at Acadia National Park, and the USA National Phenology Network.

Spring Paints the Piedmont Green

Spring Paints the Piedmont Green

Satellite observations can provide a time series of unique snapshots that capture seasonal changes in land vegetation.  This recent Nasa Earth Observatory article describes research integrating satellite imagery with ground observations (like those made by our Signs of the Seasons observers!) that indicate a trend toward earlier onset of spring greening over the past few decades.

Image Description:

A case of trickle-down climate effects

Dramatic Links Found Between Climate Change, Elk, Plants, and Birds

See this Science Daily report about a classic case of an “ecological cascade.” In this case, warming temperatures have made some habitat accessible to elk for more of the year, which appears to be having damaging consequences for other species.

Click here to read the article.

Image Description: Herd of elk in snowstorm

NASA: 131 years of global warming in 26 seconds

This 26-second video from NASA strikingly illustrates the increase of global temperatures since 1880.

The observations you record for Signs of the Seasons will help us understand how these changes in global temperature are affecting plants and animals in our own communities.

Image Description: Map of the world with colors indicating temperature variations around the planet

Notice of Signs of the Seasons Program Training

The Lewiston Sun Journal included a notice about training for the Signs of the Seasons program, a University of Maine Cooperative Extension and Maine Sea Grant initiative to study seasonal changes in plants and animals. Participants will gain practical experience for observing and recording plant and animal life cycles in their backyard, schoolyard or other community location, while contributing valuable data. In addition, participants will learn how to add their data to the national online database hosted by the USA-National Phenology Network.

What’s the Impact of Early Blooms?

Listen to this recent short interview on National Public Radio with Jake Weltzin, Executive Director of the USA-National Phenology Network.  Jake answers questions about our unseasonably warm winter and spring and the implications for plants and insects.

Image Description: Picture of Jake Weltzin smiling, Exec. Dir. of USA-NPN

Interview with Lois Stack–Plant Observing Tips!

Lois Stack serves on the Signs of the Seasons Advisory Team.  You may recognize Lois from the WABI-TV Weekend Gardener program where she offered weekly gardening tips for many years.  She also had a regular horticulture column in the Kennebec Journal.  Currently, Lois is a professor of sustainable agriculture and also a Cooperative Extension specialist in ornamental horticulture.

Signs of the Seasons recently talked to Lois about her work and asked for advice about collecting plant phenology data this season.  

As we head into the second monitoring season, do you have any general advice for trained SOS volunteers?

People should make note of the second year and how it’s different from the first year.  Look for plant stages you may have missed in the first year. You can also anticipate things you’ve already seen. Also, now that you have plants staked out, you don’t need to spend as much time setting up your site and learning about the forms and the online data entry.  You can concentrate on closely observing the plants!  Phenology dates may change slightly from one year to the next, but I don’t think they’ll change dramatically.

Let’s talk about the 8 plants on the SOS Indicator Species List.  Are there any special features or peculiarities people should watch out for?  

Wild Strawberry

This plant is deciduous but retains greenness in the leaves throughout winter. People might not be sure if they see “initial growth” or last year’s leaves.  In early spring, when the snow is receding and before the grass turns green, nothing much is growing.  If you see strawberry leaves then, they’re probably last year’s.  Check back the next week to be sure.  As the grass starts to green up you’ll probably see strawberry greening up about the same time.  Look for new fresh growth from underneath the old leaves.  “Initial growth” (on the data sheet) will be leaves, flowers will happen sometime in May, and then fruits will appear in June.

Dandelion

If you have it staked out from last year that’s good because you might not see the leaves coming out among the blades of grass in the lawn.  It will produce a new rosette of foliage from the same roots in the same spot.  New foliage grows up over the old foliage.  The new rosette looks like tips of leaves with a flower bud in the middle.  Leaves will elongate and the flower will start to open—that first flower is often very close to ground.

Milkweed

This plant has a strong and extensive rhizome system.  Although it’s perennial, the shoots won’t necessarily come from the same place as last year’s shoots.  So, in this case, it would be a challenge to follow one plant from year to year. The first thing people will see is a fairly sturdy stalk with leaves folded up—like a stalk of asparagus.  It might be interesting to take a square meter plot and flag all milkweed stems at the end of one year and see where the new shoots come up the following year.

Rugosa Rose 

This plant will be easy to identify because it has one of the most thorny, stout rose stems around.   There will be an obvious stem from last year and look for apple-green leaf buds that are big and bright.  Note: Flowers and fruits will appear before colored and falling leaves.  The data sheets list flowers and fruits after colored and falling leaves—this might be confusing for people.

Forsythia

This shrub has stems with yellow lenticels (bumps). People generally aren’t aware that almost all plants, like forsythia, that flower in early spring (before mid-June) set their flower buds the previous year and the buds overwinter. The flower buds are separate from leaf buds. Flower buds are bigger than leaf buds.  On most forsythia, flowers open first, then as they’re fading leaf buds begin to open.  The data sheets reflect a different order so watch out for that.  People should check back frequently to confirm things: “Oh yes that was a flower bud not a leaf bud” etc.

Lilac

Like forsythia, this is planted in landscapes and also has separate leaf and flower buds.  The leaf buds are much smaller and more pointed than flower buds, which are big, round, chartreuse buds.

Red Maple and Sugar Maple

The trickiest part with the maples may be that leaves and flowers can be high up in the tree.  Take field glasses (binoculars) out with you so you can see the flowers, which are beautiful dark red, with yellow stamens (Red Maple). Pollen release is easy to tell—look at the ground for yellow powder.   Some people may not think of maple “samaras” as fruits but they are the fruits of maple trees. To a botanist anything that contains seeds is a fruit, but to homeowners those may be just “spinners.”  Remember, those are the fruits!

A note about Maple ID—Observe Carefully!

It can be hard to tell them apart from just looking at new leaves. It’s easy to confuse Red and Sugar Maple; look at the leaf serration (Red is toothier).  Red Maple fruits mature earlier than Sugar Maple (maple fruits generally drop off by September). Red Maple flowers are redder than those of Sugar Maple.

Do you have any other general advice for volunteers as they begin their phenology monitoring this year?

First, I recommend people read the data sheets before they head out into the field so they’ll know how the phenophases are defined. Also, add your own comments explaining what you saw when you recorded something in “full flower,” for example.

Also, I only got a handful of questions last year and they were all good questions. I love the questions and people should ask more!

Tell us about your background and the work you do now.

My job is two-fold.  As a professor of sustainable agriculture I teach a plant science course.  I’m also a Cooperative Extension specialist in ornamental horticulture.  I’ve been here about 25 years and I’ve seen a lot of changes over that time.  When I first came, I spent a lot of time with nursery/greenhouse/garden centers on crop selection, crop production, and crop pest management.  Now a lot of that information has moved into the private sector.  That industry has matured to the point where nobody asks me for that information anymore because they can get all of that from whomever supplies the plants.

Now I find myself working more on issues.  For example, I still do pest management  but I spend a lot more of my time on issues like invasive species and how they impact people’s gardening habits and the “green industry.”  Native plants are a big issue now, too.  People are concerned about invasive species and the environment and they want to garden for butterflies and birds.  I’ve also seen a tremendous maturation in the knowledge level within the green industry and among their customers—people know a lot more about these things than they used to.  I see this in the Signs of the Seasons program as well.  People come to this program with a lot of background knowledge and interest.

Image Description: Picture of Lois Stack smiling

Image Description: Milkweed flowers

Image Description: Red Maple

Image Description: Sugar Maple