Giáo trình tiếng anh chuyên ngành lâm nghiệp ( dành cho sinh viên đại học lâm nghiệp)

TRƯỜNG ĐẠI HỌC QUẢNG BÌNH
KHOA NGOẠI NGỮ

GIÁO TRÌNH
(Lưu hành nội bộ)
TIẾNG ANH CHUYÊN NGÀNH
(Dành cho sinh viên Đại học Lâm nghiệp)

Tác giả: Nguyễn Thị Hồng Thắm

Năm 2017
0


TABLE OF CONTENTS
INTRODUCTION
Unit 1: THE ROLE OF TREES............................................................................ Page 1-3
Unit 2: THE DEVELOPMENT OF CONSERVATION........................................ Page 4-6
Unit 3: IDENTIFICATION OF TREES (I)............................................................ Page 7-9
Unit 4: IDENTIFICATION OF TREES (II)...................................................... Page 10-12
Unit 5: TREE SIZE AND TYPE CLASSIFICATION....................................... Page 13-16
Further Reading: TREES AND FORESTS........................................................ Page 17-20
Unit 6: FOREST AND FLOODING.................................................................. Page 21-24
Further Reading: WINDBREAKS..................................................................... Page 25-26
Unit 7: CREATING A NEW STAND............................................................... Page 27-31
Unit 8: DIFFERENT TYPE OF CUTTING....................................................... Page 32-36
Unit 9: FOREST MEASUREMENTS DEFINED............................................. Page 37-39
Unit 10: FOREST HARVESTING.................................................................... Page 40-42
Further Reading: TREES DISEASES................................................................ Page 48-53
REFERENCES........................................................................................................ Page 58

1


LỜI NÓI ĐẦU
Tiếng Anh chuyên ngành Lâm nghiệp là giáo trình được biên soạn theo khung
chương trình giáo dục đại học ngành Lâm nghiệp. Giáo trình được biên soạn theo
hướng giới thiệu các từ vựng, thuật ngữ thường được sử dụng trong chuyên ngành
Lâm nghiệp. Ngoài ra, giáo trình còn giúp sinh viên củng cố, ôn tập một số điểm
ngữ pháp cơ bản trong tiếng Anh. Qua đó, sinh viên có cơ hội trau dồi vốn từ vựng,
ngữ pháp và phát triển các kĩ năng nghe, nói, đọc, viết thông qua các bài tập vận
dụng và thảo luận.
Tiếng Anh chuyên ngành Lâm nghiệp được biên soạn, chọn lọc theo các chủ đề
trong ngành lâm nghiệp, giúp sinh viên làm quen với vốn từ vựng cơ bản trong
chuyên ngành và luyện khả năng đọc hiểu và dịch văn bản chuyên ngành, tạo định
hướng nghiên cứu tài liệu chuyên ngành bằng tiếng Anh trong tương lai.

2


Unit 1:

THE ROLE OF TREES

For hundreds of years people have planted trees to serve the needs of future generations
for timber and tree products. In Europe and Asia forests were planted by rulers, church leaders
and farmers – for the people. By planting trees they particularly and symbolically showed faith
and hope for the future.
Trees are fundamental to life and the processes that maintain healthy soil, and clean air
and water. There is evidence which shows that in regions where the trees are cleared to less than
30% of their original surface area, other sustainable life processes begin to collapse. Rivers silt

up, soils wash away, and air quality declines. James Lovelock, a renowned ecologist, claimed
these breakdowns in natural systems will in turn affect other word bio-areas continent or cyclones
may occur more frequently. It will be sad if these things happen before we change from
consumers to producers.

I/ Comprehension
1. What do people plant trees for?
2. What do European and Asian people want to show by planting trees?
3. What are fundamental roles of trees?
4. What will happen to the area when the trees are cut down?

II/ Grammar
ADJECTIVE + PREPOSITION
Exercise 1: Complete these sentences with the correct preposition
1. It‟ very nice ................... you to let me use your car. Thank you very much.
2. Why are you always so impolite ………….. your parents? Can‟t you be nice ……...….. them?
3. It wasn‟t very polite ………….….him to leave without saying thank you.
4. I can‟t understand people who are cruel to …………. animals.
5. Why do you always get so annoyed …………….. little thing?
6. We enjoyed our vacation, but we were disappointed ………….…. the hotel.
7. I was surprised ………….….. the way he behaved. It was out of character.
8. These days everybody is aware ……………….. the danger of smoking.
9. Mr. Davis spends a lot of time gardening. His garden is very well-kept, and he‟s very proud …
……..…. it.
10. Bill has been doing the same job for too long. He‟s bored ……..………it.
Exercise 2: Fill in the gaps with words in the box
boundary ; slopes ; verges ; sanctuary ; shelter ; indigenous
pressures ; surrounding ; reptiles ; uncontaminated ; backbones
3

1.……….. forests involved over millions of years with all the …………. of natural selection
operating, so that finally what we see is a highly refined complex which is beautifully honed to
survive in the ………….. environment.
2. If the forest is large enough it will offer ………… to indigenous mammals, birds and ………
………. .
3. Forest may be established in the areas such as: creeks, gullies, farm ………….., ridges and
places with …………. greater than 15, and roadside …………………. .
4. Your garden is the natural forest that are the …………. and security for the whole landscape.
5. Like your food forest and structural forest, this assembly of trees and their organisms provides
…………… and protection, and maintains air, water and soil in ……………. states.
Exercise 3:
Expressing purposes: To-Infinitive
1. A tree uses sunlight. The purpose in using it is to combine carbon dioxide with water to form
carbohydrates.
2. In countries with inadequate rainfall we irrigate the land. Our object in doing this is to supply
enough moisture for satisfactory plant growth.
3. We should add fertilizers or manure to the soil. Our aim in doing this is to encourage plant
growth.
4. Tile drains may be laid in or on the land. The reason for this is to remove surplus water from
the fields.
5. We apply inorganic materials to the soil. Our object in doing this is to increase the supply of
one or more of the essential nutrients such as nitrogen, phosphorus, and potash.
Expressing conditions
1. Take one clause from each of the two columns below to make one sentence. Make sure your
sentences make sense:
If you don‟t understand the trees,
If a soil is badly drained,
Crops are often lost
If you don‟t take notes,

If agriculture fails,
You get better crops
Most trees die
People get sick

it can become waterlogged
you will never be a good forester
the world will starve
if the farmer does not look after them
if they don‟t get enough water
if they don‟t eat proper food
you won‟t remember the lectures
if the soil is fertile

4


2. Now say what you think would be the result if the circumstances below actually happened.
Complete the sentences, giving your opinion:
Example: My car/not/start
If my car didn’t start …………………….
a. drought/hit/my country
b. My land/flood
c. Lose/my note
d. My country‟s population/double
e. There/be/no rice/my country
f. we/not/test/new plant varieties

5

Unit 2:

THE DEVELOPMENT OF CONSERVATION

In very early pioneer days, trees were cut down with no thought of replacing them.
However, the significance of trees was indicated as early as the 1620s by the Plymouth Colony,
when an ordinance was passed prohibiting the felling of timber on any colony land without
official consent. A little later in Pennsylvania, William Penn, the governor, ordered that, for every
5 acres of forest land cleared, 1 acre was to be left uncut.
After the United States was established, laws with penalties were passed by several states
to prevent thoughtless waste of the forests. In the early 1800s Congress authorized the president
to protect live oak and red cedar timber in the state of Florida and to use the Army and Navy for
enforcement. During this same period the first step in forestry was taken by the government by
providing for the growing of live oaks in the southern states for ship timbers. A federal act also
provided for preservation of nearly 250.000 acres of forest land in Florida, Mississippi, and
Louisiana. According to another act passed in that decade, any person cutting down or destroying
living red cedar, live oak, or other trees on federal land could be punished by the government.
These laws and regulations, through which the government tried to control the forest land, helped
call attention to the importance of forests and led to the development of conservation at the state
level.
In January 1867, the first state committee on forest protection was appointed in Michigan,
and Wisconsin followed in March of that year. Two years later the State Board of Agriculture of
Maine appointed a committee to develop a state policy for the preservation and production of
trees. Minnesota created a law in 1871 that granted bounties to encourage the planting of forest
trees. The first Arbor Day, a day in late April or early May observed by the planting of trees was
celebrated the following year in Nebraska.
The federal government adopted the Timber Culture Act in the early 1870s. It provided
that the government would donate 160 acres of land to any person who planted 40 acres of that
trees with trees not more than 12 feet apart and kept the trees growing and healthy for one

decade. This act, however, was repealed after 10 years because of serious abuses; too many
recipients of these grants were not honoring their commitments by failing to follow the rules and
regulations pertaining to the grants.
In many instances, while employing fire to prepare their land for cultivation, the settlers
disregarded caution relating to neighboring land. Gross carelessness often resulted in destruction
of property well.

I/ Vocabulary
1. Look at paragraph 1 again. Which word has the same meaning as:
A. harvested
C. importance
B. without thinking of
D. banning
6


2. Look at paragraph 3 again. Find the synonym of the words:
A. agreement
C. give hope and courage
B. conservation
3. Look at paragraph 4 again. Which word has the same meaning as:
A. 10 years
B. parliament

II/ Put the appropriate word in the blank
protection
growing
timber
laws
destruction

conserve
cut
significance
fell
prevented

1. The…………………….…of Eucalyptus on waste land is becoming popular.
2. In Sweden, machines have been used to……………….….trees.
3. It is very important to……………….….all the valuable wood species.
4. Shifting cultivation causes a lot of forest……………….… .
5. Nowadays, most of people are aware the…………………of forests.
6. Forests……………..…….is a very important subject for us.
7. Long, long ago, trees were………………………with no thought of replacing them.
8. …………………..consumption of Japan has been increasing since the Second World
War.
9. Everybody should respect the……………….………. .
10. New forest laws have……………..……people from destroying forests.

III/ Comprehension
A/ True or False?
1. Trees were cut with thought of replacing them in very early pioneer days.
2. The importance of trees was known in the 17th century.
3. Before USA was founded laws with penalties were passed by several states to prevent
thoughtless waste of the forests.
4. In the early 10th century, live oak and red cedar timber in the state of Florida were
protected.
5. Red cedars were grown by the government in southern states for ship timbers in the early
19th century.
6. In some states of America, about 250.000 acres of forest land were preserved by a

federal act.
7. Any persons cutting down one acre of living red cedar, live oak or other trees on federal
land could be punished by the government.
7


8. In the early 19th century police were used to enforce forest laws and regulations.
9. In 1896 the state Board of Agriculture of Maine appointed a committee to develop a state
policy for the preservation and production of trees.
10. These early laws and regulations played an important role in the establishment of
forestry in USA.
B/ Answer the questions:
1. In very early pioneer days, why were trees cut with no thought of replacing them?
2. What was the content of the ordinance passed in 1620?
3. What did William Penn order?
4. In the early 1800s, what did the congress authorize the president to do?
5. When was the planting of trees started?
When was the timber culture Act adopted and what was its content?

IV/ Grammar
+ Some verbs in English must be followed by the - ing form:
Forexample: He admitted taking my book.
+ Others are followed by the infinitive, “to”:
Forexample: He agreed to lend me his book.
+ Verbs followed by a particles like „in‟, „from‟, etc. are followed by the -ing form:
Forexample: He insisted on going to a film last night.
Exercise : Make sentences from the following notes. Think whether you should use the
infinitive or the – ing form after the verbs.
1. He/suggest/read/chapter 5/before/we/go/lecture
2. The rain/not stop/fall/until yesterday evening

3. He/wants/spend/more time/study.
4. A good farmer/try/set/objectives.
5. Peter/prevent/harvest/his crop/bad weather.
6. I enjoy/listen/music.
7. He/not mind/work/weekends.
8. He/forget/hand in/essay/ last night.
9. There/nothing/that shop/worth/buy.
10. It/no use/leave/your work/last minute.
11. I/miss/watch/college football match/last week.

8


Unit 3:

IDENTIFICATION OF TREES (I)

Trees are woody plants, but not all woody plants are trees. A tree usually grows
upright to at least 20 feet (15.5 metres) at maturity and has a single stem, often called
bole or trunk. The stem supports limbs and leaves, forming the top or crown. Other
woody plants are vines and shrubs. Vines may have woody stems but do not have a
distinct crown of upright branches. Shrubs may have several woody stems growing
from a clump, and they usually are smaller than trees.
Trees generally develop a typical shape when they grow in an open area. Trees
that grow in crowded forests usually have trunks of greater clear length. Essentially, we
have no timberline resulting from high elevation in the East, but at timberline and at
higher mountain elevations in the West many trees are knurled, twisted, and sometimes
prostrate. Such tortuous form is the result of many factors, including thin soils, limited
growth periods, deep snows, and continuous exposure to strong winds. However, under
favorable conditions, most species develop characteristic shapes. Several field trips

with a good identification manual showing local species should enable an
inexperienced person to become rather proficient in identifying trees.
Identification features are also found in bud, flower, fruit, leaf, twig, and bark
structure. The precise botanical characteristics by which trees are classified (primarily
flower parts) are too small or fleeting to be useful in field identification for those with
little experience. The gross features (shape, leaf, and bark structure, buds and twigs) are
more useful for quick field identification.

I/ Comprehension
A/ Multiple-choice
1. A tree usually grows…………… .
A. vertically
B. horizontally
C. downward
2. A tree usually has…………… .
A. two stems
B. one stem
C. some stems
3. Vines has got……………… .
A. great crown
B. small crown
C. complex crown D. indefinite crown
4. The branches of a vine are…………… .
A. big
B. long and thin
C. not upright
D. hard
5. When growing in an open area, trees often have a………… .
A. nice form
B. popular form

C. great form
6. The tree that has to compete for light often has …………. .
9

D. dense form


A. a long stem
B. many branches
C. thick bank
D. a
beautiful
crown
7. The tree that grows on very adverse place generally has…………. .
A. a long stem
B. a usual shape
C. an unusual shape
D. a dense brown
B/ Answer the questions
1. All woody plants are trees or not?
2. At maturity, how high is a tree?
3. How many stem does a tree have?
4. What does the stem support?
5. Do vines have distinct crowns?
6. How do trees develop when they grow in an open area?
7. What kind of trunk does a tree often have when it has to compete for light?
8. Why are some trees knurled or twisted?
9. In what conditions do most species develop characteristic shape?
10. In order to have quick field identification what should be used?

II/ Vocabulary
Put the appropriate word into the blank:
stem
crown
shape
branches
light

knurled
factors
identification
bark
characteristics

1. …………………..is very important for the growth of trees.
2. Trees…………………...is a subject that we are going to study next week.
3. The……………………………..of this tree is very thick.
4. Many………………………affect the growth of a tree.
5. After the flood, the………………………..of the river banks changed so much.
6. This kind of Pine has got a lot of………………….….. .
7. We used to play under the…………………………….of this old, big tree.
8. The…………………………....of this bamboo is 10 metres long.
9. Yesterday, a car run into that tree, but only the……………………….is damaged.

10


III/ Paragraph writing
Match the following clauses together, using and, but, when, after, so and because.

a.
b.
c.
d.

the next evening he needed them
he arrived at the canteen
they did not please Andrew very much
Last night Andrew lend Robert his lecture
note
e. Andrew needed his notes immediately
f. He had waited for an hour

11

Robert could not attend
Robert finally arrived
he went to the canteen to look for
Robert
Robert has not returned them
Robert was not there
he decided to wait


Unit 4:

IDENTIFICATION OF TREES (II)

Trees and other plants often have several common names, which vary with
locality or local use. To make specific identities world-wide, botanists employ

Latinized names, which remain constant since Latin is a language that no longer
changes. The scientific name consists of two parts: the genus (a collection closely
related species) and the specific epithet or species (a collection of individuals so similar
that they suggest common percentage and produce like offspring). The generic name
always appears first and is capitalized, while the specific name follows and begins with
a lowercase letter. Because general and regional guides to field identification of trees
and government publication that describe local or native trees are readily available,
only a few of the important commercially significant trees of the major forest regions
will be studied in this chapter. Most of these are valued for their wood products.
Prior to studying individual tree species, it is necessary to know that trees are
divided into two main groups. These are the conifers (gymnosperms) or softwood trees
and the broadleaf (angiosperms) or hardwood trees. Conifers have mostly needle-like or
scale-like leaves and bear their seeds in cones or cone-like structures. The conifers or
evergreens do not shed all their leaves annually, with the exception of larch and bald
cypress. Deciduous trees, those that shed all their leaves in the fall, generally are broadleaved hardwoods.
The term hardwood and softwood can be misleading because the wood of some
hardwood trees is softer than that of some softwood trees. For example, the wood of
yellow poplar and basswood is much softer than that of the longleaf pine.
We will first study the conifers, which are very widely distributed in the various
regions and are very significant in the production of lumber and paper.

I/ Vocabulary
Find word or combination of words that means:
1. some (paragraph 1)
6. types (paragraph 2)
2. definite (paragraph )
7. accurate (paragraph 1)
3. the same (paragraph 1)
8. sawn wood (paragraph 4)
4. before (paragraph 2)

9. easily to be seen, bought (paragraph 1)
5. classified (paragraph 2)
10. different (paragraph 4)

12


II/ Comprehension
A/ Find an appropriate word to fill the blank
1. He is a very famous……………. . (paragraph 1)
2. These trees do not………….leaves in the autumn. (paragraph 2)
3. In old time, people used to………to construct bridges. (paragraph 4)
4. ……………….….is often used to produce paper. (paragraph 4)
5. It is difficult to store the…………...of this tree, because their germination capacity is
decreased by the time. (paragraph 2)
6. To conserve valuable………..….resources is a task of great importance. (paragraph
1)
7. This kind of trees are often…………………on high mountains. (paragraph 4)
8. Names of trees………………with different regions. (paragraph 1)
9. The generic name always……………………first. (paragraph 1)
10. ………………..….do not shed all their leaves annually. (paragraph 2)
B/ Choose A, B, C or D.
1. Trees and plants have………… .
A. very few names B. many names
C. two names
D. one name
2. The scientific name of a tree has……….. .
A. only one part
B. two parts
C. four parts

D. many parts
3. The specific name stands………….. .
A. first
B. in the middle
C. last
D. anywhere
4. ……….is written or printed in capital letters.
A. the generic name B. the specific name
5. Trees are classified into………. .
A. three types
B. four types
C. two types
D. several types
6. Conifers are often……………… .
A. hardwood trees B. softwood trees
7. Most of softwood trees do not change their leaves……… .
A. in autumn
B. in spring
C. in summer
D. in winter
8. The wood of………..hardwood trees is hard.
A. all
B. most of
C. some
D. many
C/ Questions
1. How many names do trees and other plants have?
2. Why do they have many names?
3. Why do botanists have to use Latin to name trees?
4. How many parts does the scientific name consist of? What are they?

5. How are trees classified?
13


D/ Reading test
Complete the following text by filling in the blank spaces with the expressions given
below. A dotted line………requires a phrase to be added and a straight line
requires a word.
the leaf
very carefully
plant groups
identifiable
some other plant

of
how
for example
grass
doing

the surrounding environment
unfamiliar plant
functions
smell

If you want to identify an…………………, use your natural senses. Feel the
texture of the leaves. Then
the plant- crush the leaves and see if the scent
reminds you
other plants you know. All the mints are

by smell,
and so are the lavenders, eucalypts and citrus. Taste……………. and spit it out, and
again see what it reminds you of;
the oxalis family all have the same
acidic taste, so do the sorrels. (Notes: it is very hard to poison yourself by
simply a test taste and then spitting the leaf out.)
Look at the plant……………… - all the thyme family have small hairy leaves;
other……………. can be similarly recognised by sight. Now you can probable see that
this plant is like……………………. you know. Think about it and then check its
growing place.
Examine ……………………- soil, aspect, slope- and the plant‟s habit- tree,
shrub, herb or
. Identify its yields and
- mulch,
groundcover, shelter food, and so on.
Now tell yourself where and

you would use it in a permaculture

design.

14


Unit 5:

TREE SIZE AND TYPE CLASSIFICATION
Tree age and size can be described in a general and approximate way by use of
such words as seedling, sapling, pole-size, mature, and veteran. A stand of trees can be
even-aged or all-aged.

A forest made up principally of one species is a pure stand, while one composed
of several species is a mixed stand. Trees are also classified by the positions of their
crowns relative to the general level of the forest canopy, the covering created by the
crowns interweaving each other.
Dominant: A tree having a well-developed crown that extends above the general
level of the other crowns and is exposed to full light from above and partial light from
the sides.
Co-dominant: A tree with smaller crown than the dominants that helps form the
general level of the canopy and receives full light from above but limited amount from
the sides.
Intermediate: A small-crowned tree crowded into the general level of the forest
canopy, receiving some light from above and virtually none from the sides.
Suppressed: A tree with poorly developed crown, beneath the level of the
canopy (overtopped), receiving very little light from above or the sides.
Foresters refer to a measure of the number and size of trees in a given area as
stand density. It indicates whether the forest is under stocked, medium stocked, or well
stocked. For example, if the canopy of a tract of timber is closed over as much as 40 to
70 percent, it is medium- stocked.

I/ Vocabulary
1. Look at paragraph 1 again. Which words have the same meaning as:
A. newly born tree
B. trunk
2. Look at paragraph 2 again. Which words correspond to the definitions?
A. unique
C. mixing with each other
B. a forest of different species
3. Look at paragraph 3, 4 and 5. Can you find the synonym of the following words?
A. face to the sun
B. layer of forest

15


C. actually
D. not any
4. Find out an appropriate word in the text to fill the blank:
a. How many…………does your nursery produce per year? (paragraph 1 )
b. I think these pines are…………….enough to be cut. (paragraph 1)
c. This stand is……….…….because it is made up principally one species. (paragraph
2)
d. This……………of pine grows very fast. (paragraph 2)
e. He has been a…………..….for twenty years. (paragraph 7)
f. The roots of this tree have………………….over a lot of land. (paragraph 3)
g. Dominant trees receive full……..…….from the sun. (paragraph 3)
h. Biomass production is affected by stand…………………. . (paragraph 7)
i. The economic…………………of Japan is admirable. (paragraph 7)
j. A given area of trees, which is consisted of species is called a……..……… .
(paragraph 7)

II/ Comprehension: True or false?
a. A pure stand is made up of different species.
b. Trees can not be classified by the positions of their crowns.
c. In a forest, each crown of each tree stays away from each other.
d. A dominant tree receives some light from the sides.
e. A co-dominant tree gets no sunlight from the sides.
f. A suppressed tree receives no light at all.
g. An intermediate tree does not have any light from the sides.
h. Stand density is the number and sizes of trees in a given area.
i. Basing on the crowns of trees that are relative to the general level of the forest
canopy, trees can be classified into four types.

j. If the canopy of a tract of timber is closed as much as 55%, it is medium-stocked.

III/ Grammar
The form of Definition
Definitions often take one of the following forms:
1. [ A] is / are, may be defined as [ B ] which [ C ]
E.g. A soil profile [ A ] is defined as a succession of soil horizons [ B ] which extends
from the surface of the soil to the parent rock.
2. [ B ] which [ C ] is / are called, is / are known as [ A ]
E.g. A succession of soil horizons [ B ] which extends from the surface of the soil to
the parent rock [ C ] is called a soil profile.
16


A
1. Photosynthesis

B

C

The process

Transforms light energy
from

the

sun

into

chemical energy

2. A soil profile

A

succession

of

soil Extends from the surface

horizons

of the soil to the parent
rock

3. Aerobic bacteria

Organisms

Can live in the presence
of air

4. Osmosis

Biophysical process

Take place through the
tissues of living plants

5. A leaf

Complex structure

Utilizes energy from the
sun in the manufacture of
food

6. Chloroplasts

Absorb

Bodies

sunlight

and

manufacture food
7. Stomata of plants

8. Chlorophyll

Minute openings on the

Lead to the interior of the

surface of a leaf

leaf and the chloroplasts

The chemical

Enable sunlight to convert
carbon dioxide into food
and other substances

17


Definition of Terms: Combine the items in Column A with the ones in column B to
make the correct definition of each term. You will need to add some necessary words
(articles, pronouns and adjectives, forms of the verb “be”) where appropriate.
Forest

Ecologically complex unit-community of trees and
undergrowth spreading, sometimes, over really enormous
areas.

Stand

Collection of trees which are more or less uniform (i.e.
more or less the same) in species, age distribution etc.

Type

Rather like a stand but more extensive- group of similar

stands defined by the species composition

Site class

Physical factors which affect the productivity of the
trees, concerning the thing like the soil, the slope and
exposure (wind, rain)

Size of tree

Height of tree and diameter.

Diameter of tree

Measured at one point three five metres from the surface
of the soil.

Cm dbh

Measurements used for the diameter of trees (dbh:
diameter at breast height)

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Further Reading: TREES

AND FORESTS

A mature forest cannot be precisely measured nor cost. However, it is clear that

forests have special functions. In addition to providing habitats for animals and
contributing to environmental stability, forests influence wind patterns, rainfall and
nutrients turnover.

The Function Of A Forest
The waru
The trees are the fixed elements of a forest and the associates of trees- fungi,
bacteria, squirrels, possums, insects, birds, and other animals- can be seen as the mobile
elements. The whole- the tree and its associates- can be imagined as a guild or waru
(the Australian Aboriginal word waru expresses the sense of all organisms belonging
together and working co-operatively.) the tree provides habitat for the animals (shelter,
food, nesting materials); in return animals carry out the tree‟s needs for pollination,
seed dispersal, pruning, cultivation and fertilising.
In permaculture, you are aiming to create landscapes and ecosystems that
function with the wonder, diversity and efficiency of a waru.
Trees and wind
Trees are “pruned” or deformed by prevailing winds and from this you can
predict local wind direction and intensity, and assess the need for windbreaks.
Heavy trees with large canopies, such as oak trees, rely mainly on their weight
to withstand severe winds. Trees with lighter canopies insert roots deeply into the
ground to anchor themselves. It is important to use anchoring trees in cyclone areas.
Wind carries a “load”. It carries ice particles, sand, dust, bacteria, viruses and
seed. Trees with small fine leaves can “trap” the load and deposit the nutrients for their
own growth. Because fine-leaved trees are often found on the edges of forests, you will
sometimes find that the edge facing the prevailing wind has richer soils than the edge
on the leeward side.
Typically, in a forest about 60% of the windstream is deflected up and over the
trees. The remaining 40% that enters the “edge” or forest closure is absorbed and
warms the forest with its energy. Within 100m the wind dies. At this point in the forest
the air is clean, warm, still and slightly humid. This is a perfect growing place.

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The deflected wind is compressed in a region up to 20 times the height of the tree
canopy. If the air is humid, it will be compressed and cooled, and it will rain.
The forest edge is essential to the lift of the wind. The species growing on the
edge are dense, small-leaved and thick-stemmed, and can withstand the force of the
wind. The edge must be kept intact because if it is destroyed the plants in the forest
may suffer from windburn and abrasion, and diseases and weeds can enter the forest
and destroy its integrity.
Trees and temperature
Forests can be seen as nature‟s air conditioners because they clean the air and
modify extremes of humidity and temperature.
Trees absorb the sun‟s light energy and turn it into chemical energy.
If leaves are dark green or reddish in colour, as often found in the tropics, more
light as absorbed and local temperatures are reduced.
Trees transpire water into the atmosphere as humidity. (one medium-sized elm
will transpire 7000 litres of water on a clear day.) this evaporation is accompanied by
cooling so that by day it is cooler in and near a forest than it is in unvegetated areas. At
night, in humid conditions, water condenses on the leaves and warms the surrounding
air.
In very dry areas, the evapotranspiration from trees will humidify air which is
uncomfortably dry; in very damp areas, water captured by trees dehumidifies the air by
absorbing water.
Trees and precipitation
Where the air stream is very humid (i.e. coasts and islands), air flows rapidly
and condenses on leaf surfaces. In these conditions dense rainforests will grow and the
condensation from leaf surface can be 80-86% of the total precipitation.
Trees pump moisture into the air as they transpire- up to 75% of precipitation is

returned to the atmosphere in this way. The Tasmanian Blue Gum, Eucalyptus
globulus, which averages about 60 trees to a hectare in a natural mixed forest, pumps
4000 litres/ day. This is a huge return of moisture to the airstreams.
The environmental effects of forest removal are dramatic, both in the local area
and further field. It has been calculated that as much as 60% of inland water comes
from forest transpiration. Hence, forest removal in one area may relate directly to
drought in another area.
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Forests protect the soil from erosion. In one heavy deluge up to 80 tones/ hectare of soil
can be lost from bare earth. In addition, the topsoil and subsoil start to dry out if water
runs across the surface and off the land into waterways. Dams and rivers silt up and
eventually flood, carrying the valuable topsoil downstream.
When it rains………
When it rains over a forest the impact of each rain drop on the soil is reduced
and the rain is spread as a film of water, bound by surface tension, over all the leaves of
the trees. It is caught in stems and bark, in webs, flowers and insect nests. The amount
caught is influenced by the crown thickness and density. For 100% of rain falling, 1015% is caught by the tree canopy, branches and trunks of deciduous trees; more is
caught in evergreen trees. This is called interception.
The rest of the rain- the throughfall- drifts through the canopy as mist and
droplets. It contains organic salts, dust, plant exudates, insect droppings and sheddings.
It is nutrient-rich and is directed towards the outer plant canopy (also known as the drip
line) and the underlying feeding roots.
Before the water reaches the roots however, the organic humus layer of the soil
acts like a great water blotter and soaks up 1cm of rain for every 3cm of depth. This
moisture is held for later use, when the soil begins to dry out again.
In the underlying 40-60cm of soil, the throughfall is filtered into water and air
channels, nests and burrows, and is absorbed by soil fungi and bacteria, and of course,
the tree roots. This water is first bound by particles of clay and humus and then the

excess percolates slowly through the soil. At any time some of this water is valuable to
soil organisms and plant roots.
Once all this has been accomplished, water starts to flow very slowly to rivers
and the sea. And when it does, it is clean.

I/ Vocabulary
1. In paragraph 3, line 1, the word “that” refers to:
A. permaculture
B. landscapes
C. ecosystems
2. In paragraph 6, line 2 , the word “their” refers to:
A. trees‟
B. leaves‟
C. loads‟
3. In paragraph 7, line 3, the word “its” refers to:
A. 40%
B. forest closure‟s
C. windstream‟s
4. In paragraph 8, line 2, the word “it” refers to:
A. tree
B. region
C. height
5. In paragraph 9, line 4, the word “its” refers to:
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D. B & C
D. nutrients‟
D. forest‟s
D. air

A. edge‟s
B. plant‟s
C. forest‟s
6. In paragraph 11, line 1, the word “it” refers to:
A. tree
B. sun
C. light
7. In paragraph 14, line 1, the word “which” refers to:
A. areas
B. evatranspiration C. air
8. In paragraph 16, line 1, the word “they” refers to:
A. trees
B. moistures
C. air
9. In paragraph 23, line 2, the word “it” refers to:
A. rain
B. throughfall
C. canopy

II/ Comprehension:
1. Can a mature forest be precisely measured or cost?
2. What is the definition of the term “waru”?
3. How can you predict local wind direction and intensity?
4. How can trees withstand severe wind?
5. Are fine-leaved trees benefit? Where can we find them in a forest?
6. What is the perfect growing place?
7. What tree species usually grow on the edge of a forest?
8. Why can forests be seen as nature‟s air conditioners?
9. When does air flow rapidly and condense on leaf surface?

10. Can trees pump moisture into the air? When?
11. How can trees help the soil?
12. Which acts like a great water blotter?

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D. weed‟s
D. energy
D. trees
D. precipitation
D. mist


Unit 6:

FOREST AND FLOODING

Under normal conditions, streams establish channels sufficient to carry the
water discharged into them. However, prolonged torrential rains and rapidly melting
snow can fill streams beyond their capacity. The resulting overflow causes damage to
property and in some instance loss of human life. Flood damage usually is correlated
with population density along main rivers. Rapid rise of water in headwater streams
(tributaries) results in flooding of the main rivers, the destruction of bridges, buildings,
and roads, and the deposition of debris on land and in buildings.
During our country‟s development, large areas of forest were cleared from the
water-sheds of rivers such as the Ohio, Mississippi, Missouri, and Columbia river
basins, to make way of farming, industry, and urban areas, thus making them more
prone to flooding than before, and local and downstream flood control much more
difficult. It became necessary to build levees, usually walls of dirt or of sandbag
construction, to prevent excess water from spilling ever the banks. Good forest

management regulates runoff, which moderates extremes in stream flow in headwater
regions and, in turn, helps prevent downstream floods.
In this chapter, the science called ecology was defined and various aspects of
ecology were touched upon, such as the ecology of forest wildlife, the impacts of
human activity upon the environment, possible interaction between climate and the
forests supply and forests, and so on.
Rainfall removes dust from the atmosphere, provides the water necessary for
tree growth, replenishes the underground water table, dissolves nutrient materials in the
soil, sometimes creates erosion, fills the river headwater streams, and may result in
disastrous floods. Lack of rainfall, wind and barren soil caused the famous Dust Bowl.
Forests are affected by climate and in turn produce some effects upon climate.
Air and ground temperatures within forests differ somewhat from those outside. Forests
affect the speed of air movement. Shelterbelts protect agricultural fields from winds and
snowdrifts, while windbreaks protect farmsteads by changing wind direction and
reducing wind speed. Ground litter retards flow of rainwater and also serves as a
thermal insulator, reducing the rapidity of changes in forest temperature. Excessive
conversion of forest land into agricultural fields has contributed to soil erosion, silted
streams, and contributed to the need for levees.

I/ Vocabulary
A/ Find out the word in the text which means
1. set up (paragraph 1)
2. enough (paragraph 1)
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3. lengthened (paragraph 1)
4. over (paragraph 5)
5. a certain area that supplies water for a river or a stream (paragraph 2)
6. causes (paragraph 1)

7. the start of a river or a stream (paragraph 2)
8. control (paragraph 2)
9. fills up again (paragraph 4)
10. too much/ too great (paragraph 5)
B/ Put the right word in the blank (use the words in the text)
1. One million dollars is………………………to plant one thousand hectares of forest.
(paragraph 1)
2. The………………….…..of this water pump is 500 cubic meters of water per an
hour. (paragraph 1)
3. People living in the down region of Mekong river are often threatened with…….....
…… . (paragraph 1)
4. Last year, he took part in a………………….management workshop which was
organized by FAO in Bangkok. (paragraph 2)
5. Forest……………………..is one of the main causes that lead to floods. (paragraph
1)
6. The presence of forest………………....the flow of streams. (paragraph 2)
7. Rainfalls………………....the underground water table. (paragraph 4)
8. Excessive……………….…..of forest land into agricultural fields is happening in
most of developing countries. (paragraph 5)
9. People in the poor countries are killing themselves by……………....their forests.
(paragraph 5)
10. The population………………..of America is 365 persons on a square kilometer.
(paragraph 1)

II/ Comprehension
A/ Fill in the blank with one word from the text
1. Streams…….establish channels sufficient to carry the water discharged into them.
A. always
C. sometimes
B. often

D. never
2. Flood damage is usually correlated with the…….. .
A. forests along the main rivers
B. shelter belts along the main rivers
C. population density along the main rivers
D. construction along the main rivers
3. ………results in flooding of the main rivers.
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