Treewalk Page 2

Quaking Aspen Populus tremuloides

Quaking Aspen is one of the tree species thay may be found in our local hills. In the fall a grove of aspen will change color at the same time. This is because the individual trees are clones of the founding tree. Notice how the leaves of the aspen 'tremble' in the breeze. They shimmer differently than leaves of other trees. Why do you think this is so? If you want to find out, compare the petiole (leaf stalk) structure of the aspen to that of other tree species.

Syringa, Idaho's State Flower Philadelphus lewisii

This is Idaho's State Flower. It is commonly referred to as Syringa or Mock-orange. It blooms in the spring and its flowers are generally white. The area of Idaho where you most likely will see it growing in the wild is in the central and northern regions.

Now that you have seen the Idaho State Flower you may be wondering what the Idaho State Tree is and where it is located on the walk. The Idaho State Tree is the Idaho White Pine (Western White Pine). Unfortunately no specimen of this species is located on the ISU campus. One reason for this is that the Idaho White Pine requires acidic soil to grow, but the soil in our area is highly alkaline. If you want to see the Idaho White Pine in its native habitat, you must venture to the northern part of our state.

Oriental Arbor-vitae Thuja orientalis

There are different varieties of Oriental Arbor-vitae. This one is not as tall or thin as another variety might be, but it does exhibit the vertically growing fanlike branches that can be found in any variety of Oriental Arbor-vitae.

Wisconsin Weeping Willow Salix blanda

The branches of this species droop and hang down;

thus the name "Weeping" Willow. Its leaves are generally greenish yellow. If today is windy, notice how the branches sway with the wind. The diameter of the trunks of these trees can get quite large. Can your arms fit around the trunk of this specimen?

Potentilla, Cinquefoil Potentilla fruticosa

Potentilla is a member of the rose family.

Its flowers are bright yellow and bloom throughout the summer. Do these specimens have thorns like the common rose? This species grows wild on the Fort Hall bottoms.

Japanese Barberry Berberis thunbergii

The Japanese Barberry has small needle-like spines.

How might these spines benefit the plant? Imagine how sharp they might be.

Colorado Blue Spruce Picea pungens

The cones of the

Colorado Blue Spruce are tan with papery, tapering scales. The length of these cones range from 4 to 6 inches (10 to 15 cm). This species generally has green or bluish green needles. What color are the needles of the specimen you are viewing? Stop and take a view around the quad area. How many colorado Blue Spruce do you see? This is the most common species of tree on the ISU campus. The states of Utah and Colorado have adopted this species as their state tree.

Horse-chestnut Aesculus hippocastanum

This species is the Horse-chestnut.

Its leaves are in a fan formation of usually 7 leaflets. If fruit is present, notice how prickly it is. The buds located at the end of the twigs are resinous and sticky. Reach out and touch the buds to feel ust how sticky they are.

Eastern Hackberry Celtis occidentalis

Rub your hand on the trunk of this tree.

Feel how rough it is and how warty it looks. If leaves are present, see if you notice any bumps on them. The bumps are caused by a small wasp that deposits its eggs in the leaf. This causes the leaf to grow a bump which provides protection and food for the developing wasp larvae. The wasps do not appear to harm the tree. The Hackberry resists drought and is an excellent shade tree.

American Elm Ulmus americana

The Zelkova is a member of the elm family and is purported to survive Dutch elm disease better than the American Elm, though it is not immune. As this specimen matures look for the small roundish fruit it produces. This fruit is much different in appearance than the papery, wing-like fruit produced by other members of the elm family.

Camperdown Elm Ulmus glabra var. camperdownii

Rub your fingers over the leaves

of the Camperdown Elm. Does the feel remind you of sandpaper? The top of this tree was grafted onto the trunk of a Siberian Elm. To see where the graft was make look for a big knob-like area where the branches come out from the trunk.

Siberian Elm Ulmus pumila

This species is the Siberian Elm.

This species is commonly planted in arid regions because of its ability to withstand drought and heat. Some people consider this species a weed tree. The fruits, which are produced in the spring, are flat and paper-like and float on the wind.