Cover Image
close this book Forestry training manual Inter-America Region
View the document Information collection & exchange
View the document Acknowledgements
View the document Trainer guidelines
close this folder Training program overview
View the document Training program goals:
View the document Advance information
View the document Forestry observation guide for site visit
close this folder Getting ready
View the document 1. Stock the library
View the document Reference material listing
View the document 2. The training site
View the document 3. Plan the field trip
View the document 4. Tree planting site
View the document 5. Soil erosion site
View the document 6. Transportation
View the document 7. Materials
View the document Conducting the training program
View the document Weekly evaluation form
View the document Session I day one
View the document Daily schedule for technical training
View the document Session II special projects
View the document Session III The forest of the world, peace corps forestry goals, the individual volunteers' roles
View the document Session IV Language class
View the document Session V Exercise I: Record keeping
View the document Session VI Exercise II
View the document Session VII Flowers, seeds, the beginning
View the document Session VIII Spanish language class
View the document Session IX Non-verbal communication
View the document Session X Basic site selection, planning and layout of a nursery
View the document Session XI Spanish language class
View the document Session XII Cultural values
View the document Session XIII Soil preparation, seed bed sowing, and reproduction by clippings
View the document Session XIV Spanish language
View the document Session XV Communication through illustration
View the document Session XVI Fertilizers, watering and containers
View the document Session XVII Spanish language
View the document Session XVIII Protection and record keeping
View the document Session XIX Individual interviews
View the document Session XX Planting trees
View the document Session XXI Spanish language session
View the document Session XXII Introduction to extension
View the document Session XXIII The principals of pruning and thinning
View the document Session XXIV Spanish language
View the document Session XXV Volunteer's role as an extensionist
View the document Session XXVI Pacing, plane table, rustic transit and compass
View the document Session XXVIII Spanish language
View the document Session XVIII Forestry extension
View the document Session XXIX Forest menstruation
View the document Session XXX Spanish language
close this folder Session XXXI Working with groups as an extension worker
close this folder Unasylva
View the document Can farming and forestry coexist in the tropics?
View the document Some observations about agricultural plantations and agri-silviculture
View the document Session XXXIII Spanish language
View the document Session XXXIV Lesson plan and use of visual aids in teaching
View the document Session XXV Small research projects
View the document Session XXXVI Individual interviews
View the document Session XXXVII Soils
View the document Session XXXVIII Spanish language
View the document Session XXXIX Community analysis introduction
View the document Session XL Soil erosion
View the document Session XLI Spanish language
View the document Session XLIII Watershed management
View the document Session XLIV Spanish language
View the document Session XLV Review of expectations - mid way
View the document Session XLVI Spanish language
View the document Session XLVII Species report
close this folder Session XLVIII Forestry issues
View the document Exotic vs indigenous species
View the document Exotics vs indigenous - Ecuador
View the document Exotic vs. indigenous species - Paraguay
View the document Session XLIX Spanish language
View the document Session L Field trip overview
View the document Session LI Ecology teams give presentations
View the document Session LII Individual interviews
View the document Session LIII Review of field trips
View the document Session LIV Project planning: goal setting
View the document Session LV Spanish language
View the document Session LVI Resources
View the document Session LVII Compost heap - insect collection - light gaps
View the document Session LVIII Spanish language
View the document Session LIX Cultural shock - are we ready for it?
View the document Session LX Grafting and fruit trees
View the document Session LXI Spanish language
View the document Session LXII Professional approaches to interaction with host country officials
View the document Session LXIII Final interviews
View the document Session LXIV Graduation

Session XXIII The principals of pruning and thinning

Learning How to Make and Use a Diameter Tape

Total Time: 4 hours

Goals:

- To have trainees learn the principals of pruning and thinning.

- To have trainees understand the concept of a diameter tape and its use.

Overview

In this session, participants will come to understand the principals of both pruning and thinning of trees. They will have actual "hands on" practice in pruning trees and thinning a woodlot. Participants will make a diameter tape and learn how to use it. They will measure trees with diameter tapes before thinning.

Exercise

1. Pruning and thinning theory and practice.

2. Make a diameter tape and learn how to use it.

Materials

Flip chart, marker pens, tape, pruning saws, ban saw, standard dressmaker measuring tape (metric), indelible pens.

Exercise I Learning How to Make and Use a Diameter Tape

Total Time: 1 hour

Overview

A diameter tape is a simple tool for measuring the diameter of a tree at breast height (DBH). The trainees will first learn how to make a diameter tape. After having made diameter tape, trainees will learn how to measure tree at DBH.

Procedure

Time

Activities

 

1. Participant who has taken this on as a special project teaches other trainees how to make diameter tape. It is inexpensive and trainees can teach others how to make and use this tool. The directions should be similar to those listed below. Measurements are also included.

Description

A diameter tape, although it measures the circumference of a tree, is calibrated to read out the diameter measurements. The tree is measured at breast height (DBH);

i.e., measure tree diameter at 4 1/2 feet above ground level.


Fig. 12

Thus a tree that measures 135.09 cm in circumference has a diameter of 43 cm.

Method:

Using attached scale mark off dress maker tape every 3.14 cm with indelible marking pen. Allow to dry

 

Diameter Tape

 

C=<p > D

1

=

3.14 cm

2

=

6.28

3

=

9.43

4

=

12.57

5

=

15.71

6

=

18.85

7

=

21.99

8

=

25.13

9

=

28.28

10

=

31.42

11

=

34.56

12

=

37.70

13

=

40.84

14

=

43.98

15

=

47.13

16

=

50.27

17

=

53.41

18

=

56.55

19

=

59.69

20

=

62.83

21

=

65.98

22

=

69.12

23

=

72.26

24

=

75.40

25

=

78.54

26

=

81.68

27

=

84.83

28

=

87.97

29

=

91.11

30

=

94.25

31

=

97.39

32

=

100.53

33

=

103.68

34

=

106.82

35

=

109.96

36

=

113.10

37

=

116.24

38

=

119.38

39

=

122.53

40

=

125.67

41

=

128.81

42

=

131.95

43

=

135.09

44

=

138.23

45

=

141.28

46

=

144.52

47

=

147.66

48

=

150.80

DAP Diametro altura de pecho (diameter at breast height [DBH])

Exercise II The Principals of Pruning and Thinning

Total Time: 3 hours

Overview

In this exercise trainees learn the principals of pruning and thinning. Trainees also practice actual pruning and thinning.

Procedure

Time

Activities

 

1. Technical trainee gives lecture on

45 minutes

pruning and thinning with the use of saws and axes. If a trainee has extensive experience in pruning and/or thinning, he is asked by technical trainer to demonstrate proper techniques to other trainees. If no trainee has this specific experience, technical trainer does demonstration.

 

2. Technical trainer now takes trainees to

1 hour

nearby stand of trees in need of pruning and trainees prune trees.

 

3. Trainees also thin a few trees from a

1 hour

stand that needs thinning.

 

4. Technical trainer supervises trainees

15 minutes

and summarizes at end of exercise.

 

Explanation of these activities is outlined on the following pages:

Materials: Bow saws, axes, diameter tapes (made in previous exercise).

PRUNING (Poda)

Objectives of Pruning:

1. to produce knot free wood,

2. to allow easy access to the forest,

3. to decrease fire hazards,

4. to increase value of stand,

5. to improve the aesthetics of the forest.

Products - Firewood

Advantages:

1. make clear wood production,

2. less taper in tree,

Disadvantages:

1. growth rate decrease.

Methods

1. It is best to use a pruning saw attached to a pole if higher limbs are to be cut.

2. Use an ax or a machete (on lower limbs) only if worker is really proficient in the use of these tools. Limbs must be cut flush with stem of tree which requires great skill with a machete or an ax.


Pruning - percent of crown to be removed


Pruning - cut should be flushed to the hole of the tree.

Undercut - to avoid stripping bark off tree trunk.

POSSIBLE PRUNING SCHEDULE

Schedule depends on:

1. species

2. growth rate (site)

Example

1st pruning age 6 - 7 years

2nd pruning age 8 - 9 years

3rd pruning age 10 - 12 years

Economic considerations:

1. For what products are the trees being grown?

2. Are prices for pruned trees (or logs or lumber from pruned trees) higher than for unpruned trees?

THINNING

Objectives:

To provide growing space to selected trees (crop trees) so that these trees have the highest annual growth increment possible.

Products:

1. firewood

2. pulpwood (or wood for chips)

3. posts

4. poles

5. rafters

6. small saw logs

Methods - mechanical (systematic)

1. row removal

2. removing every other tree


Fig 15

- Either system removes 1/2 the trees.

- Both systems can easily be used on young trees.

- Easy to implement and supervise.

Marking for Thinning

Depending on local custom either "leave" or "take" trees are marked. Trees are usually marked at eye level and on stump (all marks facing the same direction).

a. Ax markings are easy, but they can easily be changed.

b. Paint is better but more expensive.

- There should be very close supervision of cutting and removal work.

- Loggers tend to want to remove as much volume as possible.

D + X Method

The average diameter in inches + some factor (X=1 to 8) is equal to the average spacing as expressed in feet.

Example:

Average DBH=12"

factor = 6

12+6 = 18

Average spacing should be 18 feet between trees.

A good marking method should consider:

1. crown growing space,

2. position of tree in stand structure,

3. defects: rot, top breakage, forks, crook, etc.,

4. root space,

5. openings in stand.

It is best to leave dominants and codominants with room to expand their crowns; remove intermediates, supressed and defective trees. If a systematic thinning was planned with two thinnings per rotation, the results might be the following: (consider a plantation originally planted 2 meters by 2 meters, 2500 trees/hectare).

- Removing every other row would leave 1250 trees/hectare spacing 2 meters by 4 meters.

- Removing 1/2 the remaining trees would leave 625 trees/hectare with spacing of 4m X 4m.

- It is generally thought that there will be between 600 - 700 crop trees per hectare at the final harvest, however this depends greatly on the species used.

Economics of Thinning

Costs:

marking

falling & bucking

yarding & loading

transport

administration

Total Costs

Price of Materials

price of material

Total Cost

Profit

- The largest cost will probably be transport. The closer to market, the better.

- Keep yarding costs down by keeping maximum yarding distance as small as possible (+/-200 meters to loading site).

- If labor is cheap, hand falling and bucking might be less costly, although slower.

- If machinery is expensive, using animals for yarding will probably be less costly, although slower.