The root develops in much the same manner as the crown. Its depth and spread will vary with the species but will also depend somewhat upon the condition of the soil around it.
Roots Labeled on Tree
A deep or a dry soil will tend to develop a deep root, while a shallow or moist soil will produce a shallow root.
Roots Exposed by Tornado
The numerous fine hairs which cover the roots serve the purpose of taking up food and water from the soil, while the heavy roots help to support the tree.
Root Hairs (h) and Cap (c)
The root-hairs are extremely tender, are easily dried out when exposed to the sun and wind, and are apt to become overheated when permitted to remain tightly packed for any length of time.

These considerations are of practical importance in the planting of trees and in the application of fertilizers.
Roots Across a Path
It is these fine rootlets far away from the trunk of the tree that have to be fed, and all fertilizers must, therefore, be applied at points some distance from the trunk and not close to it, where merely the large, supporting roots are located.

In the cultivation of trees the same principle holds true.
Roots Sheltering Birds

Directions

Study the lesson for one week.

Over the week:

  • Read the lesson.
  • Review the synopsis.
  • Recite aloud the vocabulary words and their definitions.
  • Learn the concepts.
  • Complete the enrichment activities.
  • Study the review questions.

Synopsis

This lesson covers the structure and functions of tree roots. Soil conditions, such as moisture, affect the form of the root. Trees tend to grow deep roots in dry soils and shallow roots in moist soil. Roots are covered in fine hairs or rootlets to facilitate uptake of water and food from the soil. Roots also help keep the trees growing upright.

Vocabulary

Root: The part of a plant, generally underground, that anchors and supports the plant body, that absorbs and stores water and nutrients.
Rootlet: One of the smallest roots that expand the surface area of the root and absorb most of the water and nutrients needed by plants. Also called hair roots.
Nitrogen: A colorless, odorless gas and chemical element (symbol N) with 7 protons per atom.
Nitrogen Fixation: The conversion of atmospheric nitrogen into ammonia and organic derivatives, by natural means, especially such conversion, by microorganisms in the soil, into a form that can be assimilated by plants.

Concepts

ROOTS

There are five main functions of roots.

  1. Absorbing water and nutrients, such as nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur
  2. Supporting the plant and anchoring it into the ground
  3. Storing nutrients and food
  4. Reproduction
  5. Competing with other plants

Enrichment

Activity 1: Narrate the Lesson

  • After reading or listening to the lesson, narrate the lesson aloud using your own words.

Activity 2: Study the Lesson Pictures

  • Study the lesson pictures and describe how they relate to the lesson.

Activity 3: Take a Nature Walk

  • Bring a sketchbook and small collection bag and embark on a nature walk.
  • Search for a tree in which you can observe a portion of its root system.
  • Dig up and collect a small portion of a tree root, including the rootlets.
  • Create a sketch of the tree roots and rootlets and use the sketch to create the field book entry.

Activity 4: Complete a Field Book Entry   

After your nature walk, complete page 30 in 'Science Field Book for Fourth Grade.'

Review

Question 1

What is the different between roots and rootlets?
1 / 3

Answer 1

The rootlets are smaller and grow off the main root.
1 / 3

Question 2

Why do roots need rootlets?
2 / 3

Answer 2

The rootlets greatly expand the surface area for nutrient and water uptake.
2 / 3

Question 3

Why do trees need roots?
3 / 3

Answer 3

Roots absorb water and nutrients, anchor the plant, store food, and help with reproduction and competition.
3 / 3

  1. What is the different between roots and rootlets? The rootlets are smaller and grow off the main root.
  2. Why do roots need rootlets? The rootlets greatly expand the surface area for nutrient and water uptake.
  3. Why do trees need roots? Roots absorb water and nutrients, anchor the plant, store food, and help with reproduction and competition.

References

  1. 'Studies of Trees' by Jacob Joshua Levison. gutenberg.org/ebooks/16116. n.p.
  2. 'Root.' Wikipedia. Wikipedia.org. n.p.