Plant Nature Study II by Jacob Joshua Levison Plant Nature Study II by Jacob Joshua Levison    

Lesson 18: Requirements of Trees: Heat, Season, and Frost


4. INFLUENCE OF HEAT

Trees require a certain amount of heat. They receive it partly from the sun and partly from the soil. Evaporation prevents the overheating of the crown.
Sun and Soil
The main stem of the tree is heated by water from the soil; therefore, trees in the open begin growth in the spring earlier than trees in the forest because the soil in the open is warmer.

Shrubs begin their growth earlier than trees because of the nearness of their crowns to their root systems.
Tall Trees, Short Shrubs
This also explains why a warm rain will start vegetation quickly. Too much heat will naturally cause excessive drying of the roots or excessive evaporation from the leaves and therefore, more water is needed by the tree in summer than in winter.
Dry Tree


5. INFLUENCE OF SEASON AND FROST

The life processes of a tree are checked when the temperature sinks below a certain point. The tree is thus, during the winter, in a period of rest and only a few chemical changes take place which lead up to the starting of vegetation.
Trees at Rest
In eastern United States, growth starts in April and ceases during the latter part of August or in early September.
Spring Leaves
The different parts of a tree may freeze solid during the winter without injury, provided the tree is a native one. Exotic trees may suffer greatly from extreme cold. This is one of the main reasons why it is always advisable to plant native trees rather than those that are imported and have not yet been acclimatized.
Winter Wonderland
Frosts during mid-winter are not quite as injurious as early and late frosts and, therefore, if one is going to protect plants from the winter’s cold, it is well to apply the covering early enough and to keep it on late enough to overcome this difficulty.
Trees and Frost
The mechanical injuries from frost are also important. Snow and sleet will weigh down branches but rarely break them, while frost will cause them to become brittle and to break easily. Those who climb and prune trees should be especially cautious on frosty days.
Icy Branches

    Plant Nature Study II by Jacob Joshua Levison Plant Nature Study II by Jacob Joshua Levison    

Lesson 18: Requirements of Trees: Heat, Season, and Frost

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 addresses heat, changing seasons, and frost as requirements of trees. Trees need heat, received from the sun, the ground, and from warm rain and groundwater. When the cold of winter comes, the tree goes dormant until the warmth of spring arrives. Trees native to colder climates survive icy winters well, however any exotics imported from warmer locales may perish.

Vocabulary

Heat: Energy transported from something hotter to something cooler.
Evaporation: The process of a liquid converting to the gaseous state.
Vegetation: Plants, taken collectively.
Native: Born or grown in the region in which it lives or is found; not foreign or imported.
Exotic: Non-native, imported, or foreign to the ecosystem.
Frost: A cover of minute ice crystals on objects that are exposed to the air.
Conduction: The conveying of heat or electricity through material.
Convection: The transmission of heat in a fluid (liquid or gas) by the circulation of currents.
Radiation: The transfer of energy via radiation (as opposed to convection or conduction).

Concepts

HEAT

  1. Heat is energy transferred from something hotter to something cooler.
  2. Heat can travel or be transferred in one of three ways:

Conduction (Solids)

  1. Solid objects touch one another and heat moves from the hotter object to the cooler object.
  2. For example, the metal bottom of a pan touches the coil of an electric stove.

Convection (Liquids/Gases)

  1. Liquids and gases circulate, moving hot liquids and gases to cooler areas of liquids or gas.
  2. For example, hot air blown by a furnace rising upward in a house.

Radiation

  1. Radiation, such as light, transfers the heat energy.
  2. Radiation does not require objects or molecules to come into contact with one another.
  3. For example, the sun transfers energy to the earth, although the sun does not touch the earth.

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 small sketchbook and embark on a nature walk.
  • Find a tree covered in snow or frost.
  • Observe and sketch the form, condition, and habitat of the snowy or frosty tree.
  • Use the gathered information to create the field book entry.

Activity 4: Complete a Field Book Entry   

After your nature walk, complete page 34 in 'Science Field Book for Fourth Grade.'

Review

Question 1

Is heat transferred to earth from the sun an example of conduction, convection, or radiation?
1 / 5

Answer 1

Sunlight transferring heat to earth is an example of radiation.
1 / 5

Question 2

You touch a hot stove coil and your finger is burned. Was your finger burned due to conduction, convection, or radiation?
2 / 5

Answer 2

Your finger and the stove coil are both solids so therefore conduction.
2 / 5

Question 3

You fill a half-filled pool with cold water, which swirls and mixes with the warm water. Is this an example of conduction, convection, or radiation?
3 / 5

Answer 3

The water is in liquid form, so convection.
3 / 5

Question 4

You hold an ice cube in your warm hand and the ice melts. Is this an example of conduction, convection, or radiation?
4 / 5

Answer 4

Both the ice and your hand are solids, so conduction.
4 / 5

Question 5

What is the risk of importing an exotic outdoor tree from a warm climate to a cold one?
5 / 5

Answer 5

Exotics imported from warmer locales may lack adaptations to the colder weather and perish during the winter.
5 / 5

  1. Is heat transferred to earth from the sun an example of conduction, convection, or radiation? Sunlight transferring heat to earth is an example of radiation.
  2. You touch a hot stove coil and your finger is burned. Was your finger burned due to conduction, convection, or radiation? Your finger and the stove coil are both solids so therefore conduction.
  3. You fill a half-filled pool with cold water, which swirls and mixes with the warm water. Is this an example of conduction, convection, or radiation? The water is in liquid form, so convection.
  4. You hold an ice cube in your warm hand and the ice melts. Is this an example of conduction, convection, or radiation? Both the ice and your hand are solids, so conduction.
  5. What is the risk of importing an exotic outdoor tree from a warm climate to a cold one? Exotics imported from warmer locales may lack adaptations to the colder weather and perish during the winter.

References

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