Describing the Forest

Describing the forest can involve students in a learning process in which they accumulate and integrate a complex set of concepts and field skills. The sequence of skills includes:

• classifying
• counting
• measuring
• mapping
• calculating (areas, volumes, flows, rates)

Each set of concepts and skills builds on the previous set, leading the student through a developmental process. Completion of this developmental process will prepare students to study the major components or elements in a forest, including the soils, plants, animals, water, air, and people. Then, a similar integrative developmental process can be taught to prepare students for understanding the forest as an ecosystem in which the living and non-living parts interact through the exchange of energy and materials (to be introduced in the next section).

A. Classification

Objects in an adopted forest are described by placing them in categories such as trees and shrubs, birds, and rodents, or dry snady and wet clay soils. Teachers can make use of existing taxonomies or classification systems, as suggested below.

1. Plants

A good plant taxonomy book is a necessary companion to describing an adopted forest. One of the best guides for native plants in western Washington is Plants of the Pacific Northwest Coast by Jim Pojar and Andy MacKinnon. This book is available at most bookstores, including the University Bookstore. It is easy to use by amateurs and has rich descriptions of how Native Americans used plants prior to the arrival of Europeans. We will also use Trees to Know in Oregon to show how to identify native tree species common to the Northwest.

A good first exercise is to learn to identify all the trees, shrubs, and common herbs in an adopted forest. This can be accomplished by taking plant identification field trips on which students collect specimens to be brought back to the classroom for mounting and display. Study of seasonal changes in plant morphology is an important part of plant identification to be accomplished by field trips designed to show seasonal changes.

Grouping plant associations into vegetation types is an important skill for studying a forest. This is best learned by examining an actual forest and grouping similar types or sizes of plants, e.g., grasses and forbes, bushes, conifer trees, hardwood trees, etc.

2. Animals

There are several good guides to animals in the Pacific Northwest. But, since most animals are not observed that frequently in the forest, and birds are the most visible animals, Peterson's Western Birds of North America is recommended. Guides to other animals can be used when needed, such as the Audubon Field Guide to North American Mammals. By far the greatest diversity of animals in a forest is found among insects, so an insect guide may be useful for advanced students interested in entomology.

Development of accumulating lists for all animals observed in the field is a good exercise to accompany field trips that are scheduled for other purposes. Contests can be structured to enhance student interest in adding species to the list of sightings.

3. Soils

Simple soil classifications can be made by digging soil pits and examining the soil profile and its color, texture, pH, and essential plant nutrient content. Procedures for digging a soil pit and describing soil properties will be distributed as part of this course. This is a good exercise for students, especially when the adopted forest contains different kinds of soils to be compared. We will also examine the sorts of animals, primarily invertebrates that live in soil.

4. Air

Descriptions of air quality can be an application of what students learn when studying the atmosphere as part of basic science. The most important concepts for understanding forests are composition of air, especially oxygen, carbon dioxide, and nitrogen. There are important relationships between plants and animals (including people) through the exchange of carbon dioxide and oxygen, since forests are major sources of the oxygen people need for healthy living. The cycling of carbon from its form as a gas in carbon dioxide to its part in organic matter making up life is already taught as part of photosynthesis. But the role of carbon in global warming could receive more emphasis. Trees are sinks for atmospheric carbon and can reduce the threat of global warming by taking carbon from the air and storing it for long periods of time. Air pollution can also be studied, but it will be very difficult for students to observe its effects on a local forest unless there is severe damage from a nearby pollution source.

5. Water

Students can apply to study of an adopted forest what they learn from basic science about the composition and behavior of water. Primary classification skills are in identifying the state and behavior of water in a forest. Building and monitoring rain gauges can measure the quantity of water entering the forest. The movement of water through soil or its loss through runoff can also be studied. The depth of water in soils can be measured during various seasons, as the presence of standing water can be used to designate wetlands.

6. People

Students can learn to classify people according to their physical and ecological relationships to a forest. Sometimes people are grouped by categories of "stakeholders." At a minimum, there are neighbors who reside near the forest, residents who may live in the forest, and those less easily identified who depend on the forest for wood from its trees, water rom its streams, oxygen from its plants, and pleasure from its beauty or opportunities for recreational hiking, picnicking, or other relaxing pursuits. Very important parts of the relationship of people to a forest are people's perceptions and attitudes toward the forest. Students can study these human attributes by surveying neighbors, residents, and others who depend on the forest.

B. Counting

After students have learned to differentiate objects by placing them in categories, they are ready to practice counting. Two types of counts are useful for describing an adopted forest: the number of different kinds of things (e.g., plants, animals, soils, or stakeholders) and the number in each type. A count of the number of different kinds of living things is necessary to assess biological diversity found in a forest. Students can count the number of different kinds of trees, shrubs, and herbs to describe the diversity of vegetation. Similarly, they can keep records of sightings to describe the diversity of birds or insects.

Students can describe the abundance of each type of object by counting how many times it occurs. Such counts are useful for making frequency distributions of trees or other objects by size within each type. Counts are necessary to describe the age structure of a forest. Measurements of tree diameter or height (to be described below) can be used to classify trees into size classes, and counts of the number of trees within each size class describes the structure of a forest. This is useful for teaching about natural competition and survival, since seedlings or young are abundant and only a few survive until they are older and large. Just as there are lots of polliwogs in a pond and only a few adult frogs, so the forest floor is often covered with small seedlings and yet there are only a few very large trees.

C. Measuring

Progressive learning from classification to counting leads naturally to measuring. Measurement invl\olves assigning a numeral to an observed quantity, length, volume, speed (distance covered per unit time), or rate (occurrence per unit time). Measurement requires a scale with uniform units such as inches or centimeters, quarts or liters. Most measurements in the United States use English units (inches, feet, yards, square yards, cups, etc.). Since most of the remaining of nations uses the metric system, students should learn to use both the English and metric systems of measurement. And, most importantly, they will need to learn how to convert from one to the other. Assessment of an adopted forest provides a wide range of opportunities for applying and practicing these convesions.

D. Mapping

Making and reading maps is an important skill for living. Maps represent (re-present) important features of land areas in terms of spatial relationships. Maps are always selective in what their makers choose to represent. Hence, students can learn about the way maps leave out some features while including or emphasizing other features. This will teach students that maps always are made with a purpose. By making a map of an adopted forest, students will learn both how to read the purposes of maps, and use them appropriately. Maps also provide opportunities for measuring distances and areas.

E. Calculating

Study of an adopted forest also provides students with opportunities for learning and applying a wide variety of calculations. Maps are ideal for learning how to calculate areas. Percentages can be learned in a concrete context by calculating the percent of the area in each vegetation type in the forest or the percent of the large trees in each species. Students can learn to calculate volumes by exercises such as multiplying the area of the forest by the number of inches of precipitation measured in a rain gauge. They could even construct special catchments so that they could calculate the amount of water soaking into the soil and compare it with the amount of runoff from the surface. This would enable students to learn how to do original research on an important regional problem - how increasing flooding is caused by runoff from roofs, driveways, streets, and other impervious surfaces. Students could also learn to calculate rates of change by measuring plant growth between time intervals or the amount of precipitation between selected times.