Lesson 1: How to Identify Trees

Week: 1

Characters are distinguishing features, characteristics, or traits. The first chapter overviews some defining characters of trees, including the general form of the tree, its color, its mode of branching, bark, bud or fruit or the number and position of the needles or leaves.

Lesson 2: Deciduous - The Elm

Week: 2

Lesson 2 overviews the elm tree, which grow to create a beautiful arching tunnel when planted on both sides of the street. Note: In modern times, Dutch elm disease has devastated the elm tree. Dutch elm disease is a fungal disease spread by elm bark beetles.

Lesson 3: Deciduous - The Poplar

Week: 3

This lesson covers the hardy Lombardy poplar tree, which grows into a narrow, identifying spire and has branches low on its trunk. The Lombardy poplar tree is often called black poplar. The scientific (Latinized) name of the Lombardy is Populus nigra.

Lesson 4: Deciduous - The Birch

Week: 4

This lesson overviews the gray birch. The gray birch grows in clumps and has white bark marred by horizontal lines called lenticels, which serve as the breathing pores of the tree. The gray birch is also called white birch. The scientific (Latinized) name of the gray birch is Betula populifolia.

Lesson 5: Deciduous - The Ash

Week: 5

This lesson introduces the white ash tree, a rapidly growing tree with a straight trunk and compound leaves. The scientific (Latinized) name of the white ash tree is Fraxinus americana.

Lesson 6: Deciduous - The Maple

Week: 6

This lesson covers the sugar maple, the silver maple, and the red maple trees. The silver maple has a silvery underside to its leaves. The red maple has red terminal twigs and buds. The scientific (Latinized) name of the sugar maple is Acer saccharum, the silver maple is Acer saccharinum, and the red maple is Acer rubrum. Note that the three trees are in the same genus (Acer) but are different species (Acer saccharum, Acer saccharinum, and Acer rubrum). The sugary sap of the sugar maple and the red maple can be made into delicious maple syrup for pancakes and other sweet culinary delights.

Lesson 7: Deciduous - The Hickory

Week: 7

This lesson introduces the hickories, walnut, and butternut trees and focuses on the shagbark hickory. The shagbark hickory earned its name because it 'shags' or sheds off its bark in long strips. The shagbark hickory has compound leaves and buds covered by two dark scales. It produces the hickory nut, a segmented and sweet tasting nut. The scientific (Latinized) name of the shagbark hickory is Carya ovata (historically Hicoria ovata).

Lesson 8: Deciduous - The Walnut

Week: 8

This lesson involves the black walnut tree, which has compound leaves and grows the edible and familiar round walnut. Black walnut stems are distinctive for their chambered pith. The scientific (Latinized) name of the black walnut is Juglans nigra.

Lesson 9: Deciduous - The Butternut

Week: 9

This lesson covers the Butternut tree, which belongs to the same genus as the walnut tree and also has its pith divided into chambers. The butternut tree produces nuts, but they are elongated compared to the walnut. Its leaves are lighter and have fewer leaflets than the walnut tree. The scientific (Latinized) name of the butternut tree is Juglans cinerea.

Lesson 10: The Structure of Trees: Leaves

Week: 10

Leaf colors, such as reds, browns, and yellows, comes from many pigments, including shades of green from chlorophyll. In the autumn, the pigments of the reds, browns, yellows, and oranges become more conspicuous than the green of chlorophyll, causing the leaves of many deciduous trees to change color. The pigment chlorophyll plays an important role in generating energy for the trees and enabling them to grow.

Lesson 11: Deciduous - The Oak

Week: 11

This lesson overviews the mighty oak tree, which is identified by its many lobed leaves and acorns. Black oaks have both young and mature acorns as they take two years to mature, while the acorns of the white oak mature in one year and are all of similar maturity. The scientific (Latinized) names of the three covered species of oak tree are Quercus alba (white oak), Quercus velutina (black oak), and Quercus rubra (red oak).

Lesson 12: Deciduous - The Chestnut

Week: 12

This lesson covers the chestnut tree, whose nut is featured in a popular Christmas song subtitled, 'Chestnuts Roasting on an Open Fire.' Prickly burrs surround the edible nuts. One interesting fact about chestnut trees is when they are cut, leaving a stump, multiple trees may sprout from the stump. The scientific (Latinized) name of the Lombardy is Castanea dentata.

Lesson 13: The Structure of Trees: Stem and Crown

Week: 13

This lesson looks at the stem (trunk) and the crown (leaves and branches) of the tree. A cross-section of the stem reveals the pith, heartwood, sapwood, cambium, and bark.

Lesson 14: The Structure of Trees: Roots

Week: 14

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.

Lesson 15: Requirements of Trees: Moisture

Week: 15

This lesson overviews moisture from the soil and in the atmosphere as a requirement of trees. Trees that grow in moist places are called hydrophytes, trees that grow in medium soils are called mesophytes, and trees that grow in dry places are called xerophytes. Either too little water or too much water can harm trees. For example, too much moisture is a contributing factor to the development of disease in trees.

Lesson 16: Requirements of Trees: Soil

Week: 16

This lesson covers soil as a requirement of trees. Soil consists mainly of sand, rock, clay, and humus. Humus is made of decayed organic matter such as dead leaves and animals. Too much of any soil component renders it unsuitable for plant growth. Unfavorable soil can be rendered suitable for growth by tilling and cultivation. Worms, the smallest farmers of all, help plow the soil and keep it aerated.

Lesson 17: Requirements of Trees: Light

Week: 17

This lesson addresses light as a requirement of trees. Light enables assimilation, or plants taking in nutrients from their surroundings and turning them into plant tissue. Plants in general cannot grow without light. Without light they cannot make chlorophyll, they will lose their green color, and they will eventually die. Some plants grow well in shady locations and others require sunny locations. Trees growing in the open grow broad branches, while trees in the forest grow tall and lanky. In thick forests, where light cannot reach the bottom branches of trees, those bottom branches fall off in a process called natural pruning.

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

Week: 18

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.

Lesson 19: Requirements of Trees: Air

Week: 19

This lesson overviews air as a requirement of trees. Trees take carbon dioxide gas in from the air and expel oxygen gas out through stomata and lenticels. Stomata are small pores on the underside of leaves, and lenticels are openings in the bark of certain trees. Trees may be injured if their ability to exchange gases with the air is hindered by pollution or flooding.

Lesson 20: Planting Trees

Week: 20

This lesson covers buying, planting, and caring for trees. Note: Later in the spring, in lesson 30, we will be planting the acorns collected last fall to grow our own oak tree saplings.

Lesson 21: Pests

Week: 21

This lesson overviews the life history of insects as well as several pest insects that plague popular trees. Insect stages include: 1) Egg, 2) Caterpillar/Grub/Larva, 3) Pupa/Cocoon/Chrysalis, and 4) Adult.

Lesson 22: Tree Diseases

Week: 22

This lesson looks at signs of ailing trees as well as several diseases that have devastated tree populations. In the lush times of late spring and summer, ailing trees may be detected by withered, spotted, or discolored leaves, including when the top leaves are dead. Throughout the year, mushroom-like growths or brackets protruding from the bark are sure signs of disease.

Lesson 23: Pruning and Repair

Week: 23

This lesson addresses proper tree pruning practices, pruning tools, and tree repair. Wounded trees must be protected from infection and diseases similar to humans. Trees can be best pruned in the autumn, although dead branches should be removed immediately. Overpruning may damage trees and should be avoided. Tools such as saws, pole-shears, ladders, pruning knives, chisels, and gouges prove useful for tree maintenance. The outer bark of the tree protects the living cambium layer, which transmits the sap from root to crown. If wounded, the cambium layer should be cleaned and covered to prevent the spread of insects and infection.

Lesson 24: Coniferous - The Hemlock

Week: 24

This lesson involves the coniferous eastern or Canadian hemlock tree, which has leaves arranged on little stalks and marked by two white lines on the underside. The hemlock retains its lowest branches and withstands shearing, making it suitable for hedges. The bark of the Hemlock produces tannins for commercial purposes. The scientific (Latinized) name of the hemlock is Tsuga canadensis.

Lesson 25: Coniferous - The Red Cedar

Week: 25

This lesson looks at the red cedar or juniper tree, which is smaller than the other coniferous trees studied this year. The tree produces purple-blue berries coated in a whitish wax covering. The scientific (Latinized) name of the juniper is Juniperus virginiana.

Lesson 26: Coniferous - The Cypress

Week: 26

This lesson overviews the bald cypress tree, which has adaptations enabling it to grow in wet and swampy areas. They bald cypress has feather-like twigs and bears cones. Bald cypress trees grow "knees" above the water which has been hypothesized to provide air to the roots and/or structural support for the tree. The scientific (Latinized) name of the bald cypress is Taxodium distichum.

Lesson 27: Coniferous - The Pine

Week: 27

This lesson addresses three species of pine trees of the Pinus Genus: the white pine, the pitch pine, and the scotch pine. Pine trees are coniferous trees and therefore bear cones. They are also evergreens, keeping their needles all year-round. Pine trees have long needles in comparison to other types of conifers. White pines have clusters of five needles, pitch pines have three needles in each cluster, and scotch pines have two needles in each cluster. This is unlike the spruce tree (next lesson), where needles connect directly to the branches. The scientific (Latinized) name of the white pine is Pinus strobus, the pitch pine is Pinus rigida, and the scotch pine is Pinus sylvestris.

Lesson 28: Coniferous - The Spruce

Week: 28

This lesson involves the Norway spruce tree, which is an evergreen with branchlets that droop off their upward bent branches. Unlike the triangular pine needles grouped in fascicles, quadrilateral spruce needles connect individually to the branches in spirals. Due to its pleasing shape, the Northern spruce is used as the showcase Christmas tree in cities around the world. The modern scientific (Latinized) name of the Norway spruce is Picea abies.

Lesson 29: Deciduous - The Tulip Tree

Week: 29

This lesson overviews the tulip tree, which grows lovely tulip-shaped flowers in May, and maintains its characteristic cups around its fruit (cones) into winter. The leaf and its four lobes are very distinctive. The scientific (Latinized) name of the tulip tree is Liriodendron tulipifera.

Lesson 30: Deciduous - The Magnolia

Week: 30

This lesson looks at the decorative magnolia genus, which contains many species known for their beautiful blossoms. Magnolia species can often be told apart by their buds. This lesson focuses on the cucumber and the umbrella variants, which are prevalent in the eastern United States. The cucumber variant is named for its fruit, which resembles a green cucumber. The umbrella variant is thus named as its leaves grow at the tips of its branches and form an umbrella shape. The scientific (Latinized) name of the cucumber variant is Magnolia acuminata and of the umbrella variant is Magnolia tripetala.

Lesson 31: Deciduous - The Locust

Week: 31

This lesson addresses the black locust, a flowering tree with compound leaves and a slender trunk. The flowers of the locust are pea-shaped panicles, arranged around a central axis of symmetry. The scientific (Latinized) name of the black locust is Robinia pseudacacia.

Lesson 32: Deciduous - The White Flowering Dogwood

Week: 32

This lesson covers the white flowering dogwood tree, which grows leaves in whorls of three, square bark plates, and lovely blossoms and autumn foliage. The scientific (Latinized) name of the white flowering dogwood is Cornus florida.

Lesson 33: Deciduous - The White Mulberry

Week: 33

This lesson looks at the white mulberry tree, which has wavy looking bark and small brown-red buds. The red mulberry (rough top, downy underside) may be told from the white mulberry (smooth and shiny) by their leaves. The scientific (Latinized) name of the white mulberry is Morus alba.

Lesson 34: Deciduous - The Sycamore

Week: 34

This lesson addresses the sycamore tree, identifiable by its mottled bark and large branches. The rhinoceros beetle is a pest of the sycamore tree. The sycamore tree is also called planetree. The scientific (Latinized) name of the sycamore is Platanus occidentalis.

Lesson 35: Deciduous - The Willow

Week: 35

This lesson covers the weeping willow, which is readily identified by its drooping mass of slender branchlets. The scientific (Latinized) name of the weeping willow is Salix babylonica.

Lesson 36: Deciduous - The Beech

Week: 36

This lesson overviews the American beech tree, which can be characterized by its smooth, gray bark, spectacular fall foliage, and slender and sharp-pointed bud. The edible fruit/beechnut of the American beech tree is enclosed within a prickly burr. The scientific (Latinized) name of the American beech is Fagus grandifolia.