Trees 101 - Parts of a Tree and Tree Identification

Biotic or Abiotic

Today, we learned about trees! We started off the day deciding whether trees were living (biotic) or non-living (abiotic) things. We did this by looking at seeds and considering their life cycle. After much careful consideration, we decided they are biotic. This is because they follow the 7 Characteristics of Life:

1. They are composed of cells
2. They have different levels of organization (they have things like tissues)
3. They use energy!
4. They respond to the environment
5. They grow (and die)
6. They reproduce (seeds!!!)
7. They adapt to their environment

Is a seed biotic or abiotic?

Our class discussion on whether plants are biotic or abiotic

Parts of a Tree

We decided to imitate the various parts of the tree by making a "Living Tree". Here, we broke down the various parts of the tree and acted each of the parts out:

Leaves: The leaves take in carbon dioxide, water and sunlight and make food for the tree...which is sugar!!!!

Bark: The bark is the armor that protects the tree from injury, insects and disease. The bark is the formed in the inner bark by the cambium and then is pushed out and dried out to make bark.

Roots: Located under the soil at the bottom of the tree. Roots are in charge of bringing water and nutrients from the soil all the way up through the trunk and into the branches and leaves.

Cambium: A thin layer of cells in the tree that forms the outer bark and branches or inner sapwood (also known as xylem).

Phloem: The system that brings sugar, hormones and enzymes from the leaves to the roots.

Xylem: The system that brings the water and nutrients from the roots to the leaves and branches.

Heartwood: The heartwood is the backbone of the tree. As new xylem is formed, the cambium pushes the older layers deep into the tree where they harden and form heartwood!

Tree Identification

We then hiked around the schoolyard to check out trees and see if we could identify them using ID guides.

Wahoo!!! Two Urban Naturalists
identified this as a Norway Maple!

Using her ID book, this Urban Naturalist
identified this oak tree!!!

We then talked about the tree and its root system. We discussed how a tree's roots sometimes extend 3x the length of the canopy! This brought up a good observation about the trees we plant along streets. Do trees like that have enough space to spread their roots out to take in healthy nutrients and water? The Urban Naturalists decided that this was probably not true. Street trees are usually confined to tiny plots of grass that doesn't give them much room to spread out. We decided it would be MUCH better to plant trees in schoolyards or in people's yards instead.

The tree in this photo would have roots that would extend all the way
to where the Urban Naturalist is standing in this photo!