The samaras are from an ash tree.

Several different species of ash trees grow in Arizona, all in the genus Fraxinus.

Ash trees are prized for their wood. In fact, ash wood is used for baseball bats.

Ash tree leaves are pinnate compound, which means they are made up of leaflets.

The leaves themselves are opposite each other, forming a V-shape with the main branch.

If you aren’t sure whether you have an ash tree, try this Ash Identification page.

The reason ash trees are in the news is because in certain regions they are being attacked by an insect. The emerald ash borer arrived in Michigan in 2002 and has been spreading and killing trees ever since.

(Photograph Pennsylvania Department of Conservation and Natural Resources – Forestry Archive, Bugwood.org found at Forestry Images)

Although the adult beetles are lovely, the larvae or grubs feeding on the trees under the bark is fatal to the tree. People are concerned that the ash trees will experience a similar devastation as occurred with the chestnut trees and elm trees in the past. In fact there is now a great effort being put into saving seeds of the remaining ash trees in the regions effected.

The emerald ash tree borer website has more information about the beetle and its spread. The main thing they are asking people to do is not to move ash tree firewood from place to place, as that moves the beetle larvae that live inside the wood.

We are going to plant some of the ash samaras we found. Sounds like ash trees could use all the help they can get.

What kind of ash trees grow where you live?

Designed with children in mind:

The Smithsonian National Zoo has “A Walk in the Forest” with six different animated walks. One allows you to take soil samples and measure soil pH. Another helps you learn how to identify trees using keys. Each is led by an animation of a real employee of the zoo. How cool is that!

University of Illinois Extension has a virtual walk in the woods and Secret life of trees. Both show photographs of actual forests. There’s a teacher’s guide with ideas, resources and many extras.

For children or adults:

Ever wanted to visit a redwood forest? Muir Woods has a virtual tour. There are 92 photographs, and you get to choose where you look next. The virtual tour always has good weather.

Florida Hikes has slide shows from various Florida parks.Check out the giant snails at Pine Land. Isn’t fun to see how different the landscape is at the different parks?

Finally, YouTube has a number of videos of walks. I like this one because the tour guide discusses, what else, science!

Hope you enjoy these virtual walks in the woods, and can talk your own walk soon.

Where’s your favorite place for a hike?

In fact they smell sweet and faintly reminiscent of chocolate.

These pods are from a carob tree, Ceratonia siliqua, which is grown as a landscape tree here in Phoenix.

The carob trees were originally from the eastern Mediterranean region. They grow well in areas with little rainfall.

Each leaf is made up of 6 to 8 rounded leaflets.

The tree retains its leaves and is green all year.

The pods start out green and then turn brown as they ripen. The hard seeds are inside.

To make carob powder, a chocolate substitute, separate the seeds from the pods. Roast and grind up the pods. Here in Phoenix, people harvest and mill both carob and mesquite pods. You can then use the carob powder to make brownies.

The carob seeds are used to make carob or locust bean gum, a thickener.

What an interesting plant!

Do you have a favorite carob recipe?

This is the eastern cottonwood, Populus deltoides.

The species name comes from the “deltoid” shape of the leaves.

Cottonwoods often grow near water.

They have deeply grooved, braided bark.

In the fall the leaves turn a gorgeous golden yellow.

This last photograph is from here in Arizona.

Do cottonwoods grow where you live?

]]> http://blog.growingwithscience.com/2010/07/seed-of-the-week-cottonwood-trees/feed/ 0 http://blog.growingwithscience.com/2010/07/more-tree-science-activities/ http://blog.growingwithscience.com/2010/07/more-tree-science-activities/#comments Sun, 11 Jul 2010 18:17:21 +0000 Roberta http://blog.growingwithscience.com/?p=1943 This week let’s continue tree science by investigating water movement through trees, and learning how to measure the height of a tree.

1. Tree Transpiration

Transpiration is a fancy word for the movement of water out of trees and other plants. Did you know that almost twice as much water enters the atmosphere through plants as through the surface of the oceans? (Another benefit of trees!)

Gather:

• a nearby tree (outside) with branches you can reach
• clear plastic baggy for each child
• chenille or twist tie to hold bag around branch (enough for each child)

You might want to gather enough of these materials to compare branches on different parts of the tree and/or branches on different types of trees. (You will see the best results on a hot, sunny day.)

Place the bag over the tip of a branch so that it contains at least one leaf. Use the chenille or twist tie to close the bag around the branch to hold it closed. Make a prediction about what will happen. Now wait for 15 or 20 minutes and check the bag. See anything? Try again after 1/2 hour.

The bag should fill with moisture and condensation. Each tree leaf has tiny holes called stomata. Moisture exits the holes not only to cool the tree (like our sweat does for us), but also to help plants move materials up from the roots.

Were there any differences between different parts of the tree or different kinds of trees? What do you think would happen if you did the same experiment at night?

You can also perform this experiment indoors if you place a cut tree branch in a water-filled vase. Be sure to place the tree branch in a sunny window or under a bright lamp to encourage water movement into the plastic bag.

Extension (for older students):

Make up and perform experiments to test the factors that influence transpiration:

• temperature
• sunlight intensity
• water supply
• tree growth rate

Where does the water come from?

Most plants and animals need a lot of water every day. Trees absorb the water they need through their roots and then move it up to the leaves through the xylem.

2. How far does the water have to travel from roots to top of the tree? Let’s learn how to measure the height of trees.

There are several different methods to measure the height of any tall object, including a tree.

Method 1 (requires math):

Gather:

• a stick
• a tree that is apart from other trees (so you can see its entire shadow at least one time of day)
• tape measure (longer the better)
• paper and pencil

For this activity, you will need a sunny day. Place the stick upright in the ground near the tree. Use the tape measure to measure the height of the stick from the ground, and the length of the resulting shadow from the base of stick. Also measure the longest length of the tree’s shadow from the base of the tree. Assuming the two ratios are the same, solve for the height of the tree by multiplying the length of the tree’s shadow x (the height of the stick/the length of the stick’s shadow). See the illustration:

I found this video that discusses two other methods. You will need a second person to help you and a measuring tape.

Now, how far does the water need to move? If you take into consideration that a tree’s root may be a large or larger than its crown, then a tree one hundred feet tall may have to move water two hundred feet or more. That one big straw!

Let me know if you have any questions or other methods for measuring trees.

I. What is a tree?

Most of us recognize a big tree when we see one, but sometimes it may be hard to tell whether a plant is a large shrub or a small tree. What do you think? Brainstorm and write down all the words you use to describe a tree.

One definition might be “a tree is a perennial, woody plant that grows to at least 20 feet tall and has an erect (straight up) main stem.” Talk about what that means and if all the trees you know will fit this definition. Can you think of something more? Let us know what you decide.

II. Why study trees?

Trees are so important. Can you think of a list of benefits of trees? Here’s just a few we thought of:

• shade (really important in Arizona!)
• food and shelter for wildlife
• rubber
• paper and paper products
• source of wood products such as furniture, houses, pencils, musical instruments
• food for us
• fuel for heating
• medicines such as aspirin and quinine
• produce oxygen
• conserve water
• reduce pollution

Can you add to this list? Do some research to find more benefits of trees.

III. External parts of a Tree

Vocabulary:

• bark
• trunk
• crown
• leaf/needle
• branches
• roots
• twigs
• nuts
• fruit
• flowers
• buds

Make index cards with each of these names (make sure you have at least one card for each child participating.) Punch holes in the cards with a hole punch.  Cut pieces of yarn of various lengths. Find a tree outside and have the children attach the cards to the correct parts with pieces of yarn – a fun way to decorate a tree. Take extra cards and draw any parts that are missing, such as flowers, nuts or fruit. Add those to the tree where they might be found. Older children can discuss the function of each of the parts, such as roots hold up the tree (support) and bring water into the tree. (Scissors speed up card removal when you are finished.)

Sketching trees is a good way to learn the shape of different kinds. Claire Walker Leslie has an excellent guide to sketching trees (click on the Guide to Tree Sketching resource to download a .pdf file). Sketch a tree and label the parts if you can’t go outside.

IV. How Trees Grow – The Internal Parts of a Tree

See if you can find a “tree cookie,” a cross-sectional piece of wood through a tree trunk. These are often available at craft stores. Those with the bark still on are the best.

Internal parts of a tree:

• cambium – layer of active cells that divide to form inner bark and sapwood
• sapwood
• xylem – water carrying elements (in sapwood)
• phloem-food carrying elements (inner bark)
• heartwood

Look at the tree cookie and see how new rings are added each year. Explain how the tree only grows from the cambium and cutting it (for example by carving initials on a living tree), damages its ability to grow and live. A fun demonstration of how a tree grows might be to add layers of clothes to a doll or person, to show how the tree expands by adding layers. See if you can tell how old the tree that made the tree cookie was when it was cut down by counting the rings. (More information on internal parts).

We’ll continue with more activities next week. Until then, here are two sources of more information about trees:

Illinois Department of Natural Resources has  lesson plans in .pdf format

Arbor Day Foundation has education links and online games.

Hope you enjoy our celebration of tees this month. If you have any suggestions for activities or websites, please let us know.

There are over 20 species of trees called walnuts in the genus Juglans, but one common one in the eastern US is the black walnut, Juglans nigra.

Walnuts are beautiful trees.

The wood is used for fine furniture and the nuts are edible.

The trees produce flowers in the spring.

The flowers produce fruit.

Did you know that the green husks can be used to produce a brown dye? In fact you can stain your hands and clothes if you play with the husks.

Walnuts and pears make a yummy salad.

Do you have a walnut tree nearby? What is your favorite walnut recipe?

]]> http://blog.growingwithscience.com/2010/06/seed-of-the-week-walnut/feed/ 10 http://blog.growingwithscience.com/2010/05/interesting-science-links-and-thoughts/ http://blog.growingwithscience.com/2010/05/interesting-science-links-and-thoughts/#comments Tue, 04 May 2010 15:12:13 +0000 Roberta http://blog.growingwithscience.com/?p=1629 There are a lot of things going on this month.

Look for Space Day celebrations May 7-8, 2010. In the left sidebar is a set of middle grade lesson plans to download for free. The “Other Resources” is a .pdf file of a chat with four former astronauts. There are also games and links.

The NSTA (National Science Teacher’s Association) blog has a number of interesting posts.

The first is a short list of websites with information about the recent oil spill.

I was particularly interested in the post:  Are children getting enough direct experience with natural materials? The middle and high school teachers were bemoaning that most of the children in their classes had little exposure to real organisms.  For example, most of their students had never seen a real grasshopper! The teachers in the blog post blame the elementary teachers, but I think that is unfair. I recently was going to visit a second grade class room with live insects, but my visit was canceled because the classes were too busy with standardized testing.

Elementary teachers have an enormous amount of pressure to get their students through a battery of standardized tests. Their jobs may be at stake. But obviously this emphasis on testing has unforeseen consequences for the students’ future success, at least in science.

What do you think?

For more information on oil spills for children:

First of all, I am sad because this year my parents decided to log the small woods that is on their property. They knew I wouldn’t be happy, so they didn’t let it slip until it was already done. And they were right. I felt loss for the walnuts and oaks who had been standing since as long as I can remember. I miss them.

Arbor day also reminds me of the story of Herbie the elm tree, which is a poignant one. Rambling Woods has a good summary of the Herbie story.

Maybe I miss the trees more because here in the desert trees are small and shrubby. A big tree is a rare and beautiful sight.

In any case, a book that came in the mail this week struck a chord with me.

I will say up front that this is an adult book, it is not written for children.

Keepers of the Trees:  A Guide to Re-Greening North America by Ann Linnea has the details right. It is printed on recycled wood-free paper.

Linnea writes about the stories of fourteen men and women who are dedicated to conserving trees, including herself. She includes people from a diversity of outlooks, races, genders, lifestyles and backgrounds, all brought together by their love of trees.

The author has a compelling writing style and sets just the right tone. The book isn’t preachy or heavy-handed at all. Basically, it is about the people and their work.

People like Corella Payne, who researches public health issues such as asthma for her job, and then volunteers as a Treekeeper for public parks during her off hours. Corella sees the link between being outside with nature, and overall health and well-being.

The story of Merve the logger stands out in my mind because of my recent experiences. Merve has been selectively and sustainably logging the same spot in Canada for years. Although he has removed the same amount of timber that he would have gotten if he had simply clear cut, the forest remains in place, still viable and diverse. He respects the soil, leaves natural drainage systems intact and tries to take trees that are mostly at the end of their natural life cycle. Inspiring!

The layout of Keepers of the Trees is visually appealing, with many color photographs and figures. In the back is a list of practical things that you can do if you are interested in “tree-keeping.” Suggestions include planting a tree, adopting a tree, and mentoring a child.

I think I will take up that suggestion to mentor a child by taking my son to see another cork oak I found out about recently. Seems like the right thing to do on Arbor Day.

And if you are interested in helping a child learn more about trees, check my review of the Leaf and Tree Guide at Wrapped in Foil.

Edit: Tricia has a fabulous list of children’s books about trees at The Miss Rumphius Effect.

What are you doing for Arbor Day?

Please read the disclosure page for information about my affiliation with Amazon. Book was provided by publisher.

That was because I found it in a park where tearing apart cones to find their seeds is frowned upon.

The seeds look something like this:

(Photo by Danny S. at Wikimedia)

It belongs to the coast redwood tree, Sequoia sempervirens.

It is amazing that such a small seed, only about the size of a tomato seed, can produce such a massive tree. Coast redwoods can grow up to 375 feet tall.

The trees also live a long time. You can tell how old a tree is by counting its rings.

Actually redwoods don’t often grow from seeds. More frequently they sprout from a parent tree, causing a ring of seedlings.

New redwoods can also sprout from burls, lumpy growths that form on the sides of the trunk. Now that is wild!

No matter how they grow, coast redwood trees are still impressive. So impressive that photographs can’t do them justice. You really need to see them in real life.

Coast redwoods are only found naturally along the west coast of California and Oregon, although they have been introduced a few other places.

This video trailer from National Geographic shows what it entails to photograph one of these redwoods.

Isn’t that amazing? With Earth Day and Arbor Day celebrations going on, it’s a great time to go out into the woods and learn more about big trees.

For more information, try:
A list of the tallest redwoods

Educational Resources from Save the Redwoods

Information about redwoods

One of our favorite books is the Newbery Classic Kildee House. FYI, for sensitive children, it does have guns and one of the animals is killed violently.

Note: I have no affiliation with National Geographic, but I do have an affiliation with Amazon. Please see the disclosure page for more information.