Definition : Tree height and related terms Methods of measuring Tree height Tree height Measuring Methods

1. Tree height and methods of measurement
Submitted to :- Dr. D R Bhardwaj
Submitted By :- Bandana Dhiman
F-14-20-D
FOR- 615
Advances in Forest Biometry
Presented By : Dr. Bandana Dhiman
Ph.D. wood Sc. & Tech.
Dr. Y S Parmar UHF Nauni Solan (H.P.)

2. Tree height
• It is the vertical distance between the base of the tree and
the tip of the highest branch on the tree.
• It is not the same as the length of the trunk. If a tree is
leaning, the trunk length may be greater than the height of
the tree.
• Tree height can be measured in a number of ways with
varying degrees of accuracy.

3. • Bole height :- is the
distance between ground
level and crown point.
• Crown point :- is the
position of the first crown
forming living or dead
branch.
• Commercial bole height :- is
the height of bole that is
usually fit for utilization as
timber.

4. MEASUREMENT OF HEIGHT
 Total height of a standing tree is the straight line distance
from the tip of the leading shoot to the ground level,
usually measured on slopes from the uphill side of the tree.
Objectives
 Height of the standing tree is measured to find out its
volume because height is one of the important components
of tree volume.

5. METHODS OF MEASUREMENT OF HEIGHT
• Ocular estimate method
• Non-instrumental method
– Shadow method
– Single pole method
• Instrumental method

7. Shadow Method

8. • Christen’s hypsometer
• Smythie’s hypsometer
• Brandis hypsometer
• Abney’s level
• Topographical Abney’s level
• Haga altimeter
• Ravi multimeter
• Relaskop
Instruments used in measurement of height

9. Instrument based on properties of similar triangle
•Christen Hypsometer
•Smythies Hypsometer
Instrument based on trignometrical principle
•Relaskope
•Abneys level
•Brandis hypsometer
•Ravi multimeter

11. • Hypsometer is an instrument used for determining the
height of standing tree from observations taken at some
distance from the tree.
• Altimeters are generally altitude measuring instruments,
instrument has been devised to determine heights of trees.
• Clinometers are instruments which measure angle of slope.

12. • Height measuring instruments based on properties of similar
triangles are used in India.
• It consist of a strip of metal, thin wood or even card board
about 2.5 cm wide. It has two flanges or protruding edges one
at the top and other at the bottom. Each flange has a hole in
it, the upper one to suspend the instrument by some thread
passing through it and the lower one to suspend a weight
from it to prevent it from swinging.
• It is used with and graduated for a staff of known length. The
distance between the inner edges of the flanges varies with
instruments used in different countries. The one generally
used in India has this distance as 33 cm and is graduated to
read yards when used with a staff of 3.6 m(12 ft) .
CHRISTEN’ HYPSOMETER

13. CHRISTEN’ HYPSOMETER

14. • In order to use the instrument, the observer stands at a suitable
place from where both the base and the top of the tree can be seen
between the flanges after placing a staff vertically against the tree.
He holds the instrument vertically suspended from a thread and
moves the hand backward or forward till the top and base of the
tree seem to fit exactly within inner edges of the upper and lower
flanges respectively.
• In this position he sees the mark on the instrument where the line
of sight to the top of the staff intersects the instrument. the mark
reads the height of tree in yards if a 4 yards staff is used or in meters
if a 4 m staff is used. When the tree is more than 30 m in ht, the
divisions are rather close and mark where the line of the sight from
the eye to the top of the staff intersects the instrument is difficult to
read. this difficulty can be overcome either by increasing the length
of the staff or the instrument, though this will make them unwieldy.
METHOD OF USE

15. • It is made of flat card boards or thin sheet of wood rectangular or square in
shape and provided with a handle. On one side of the board is pasted a
squared paper normally of equal length and breadth with the squares
parallel to the edge of the board and of size large enough to give at least 3
large square in each direction so that each of its 10 divisions may represent
1m either way and the instrument may read heights up to 30 meters .
SMYTHIES HYPSOMETER
SMYTHIES HYPSOMETER

16. The vertical scale is called the base or distance scale and is graduated from
top to bottom. The horizontal scale is called the height scale and is
graduated from the side of the handle to the outside .
A plumb bob hangs from the top corner towards the handle side of the
squared paper. A part of the protractor is marked on the squared paper
showing angles from 0 to 90 °. This helps reading of angles made by the
plum bob with the vertical , which is the same thing as the angle at which
the board is held to the horizontal while sighting the tip or the base of
the tree .
On the other side of the board is pasted a table giving percentage deduction
corresponding to different angles of depression or elevation to be applied
to sloping distance for finding out the horizontal distance .

17. • In order to use the instrument in the case where the top of the tree above
and the base below the eye level, the observer should stand at a convenient
place from where the tip and base of the tree can be sighted.
• The distance of this point should be measured along ground. The instrument
use then pointed to the base of the tree with the handle towards the
observer and the angle of depression is read on the protractor. For this angle
of depression, percentage deduction is found out from the table given on the
back side of the instrument and applied to the measured sloping distance to
find out the horizontal distance. now, in order to get the height of the tree
below the eye level , the plumb bob should be held on the angle of
depression. then the ordinate for the calculated horizontal should be traced
till it touches the plumb bob. from this point abscissa should be traced down
till the height scale is reached .
• The reading on the height scale will be the height of the tree below the eye
level. then in order to get the height above the eye level , the top of the tree
should be sighted with the handle away from the observer.
METHOD OF USE

18. • The plumb bob should be held at that angle and the ordinate for the
calculated horizontal distance traced to the plumb bob and from there
traced along abscissa to height scale.
• The reading on the height scale will be height of the tree above the eye
level should be added to get the height of the tree. In case when the base
of the tree is above the eye level , both angles will be angles of elevation
and so the instrument will be held with the handle away from the
observer in both cases . The rest of the procedure will be the same except
that towards the end , the height obtained by sighting the base will have
to be deducted from the height obtained by sighting to the top .
• In case when the whole tree is below the eye level , both angles will be
angles of depression and therefore the instrument will have to be held
with the handles towards the observer in both the cases .the rest of the
procedure will be the same except that in the end , the height obtained
by sighting to the top will have to be deducted from the height obtained
by sighting the base .

19. • In India, Brandis hypsometer and Abney’s level, Haga
Altimeter and topographical Abney’s level have come
in use. More recently, Relaskop, Tele Relaskop, Barr
and Stroud dendrometer and Blume-Leiss
hypsometer are also being used.
INSTRUMENT BASED ON TRIGONOMETRICAL PRINCIPLES

20. • The instrument consist of a hollow metal tube about 14cm long and of
rectangular cross section. A wheel enclosed in a circular metal case is attatched
to it on one side. The object to be sighted is seen through the hollow tube
from the end marked a, which is closed except for a horizontal slit through
which the observer looks. The other end of the tube marked b is open with a
horizontal wire fixed there.
• The pivoted wheel attached to the tube is heavily weighted on one side W so
that when the instrument is horizontal the wheel is in zero position. The outer
rim of the wheel is graduated to show degrees which can be read through an
opening in the metal case by a magnifying glass in eye piece. The instrument
reads angles up to 60 ° above and below the horizontal. To prevent wear and
tear as a result of continous swinging of the weighted wheel, the instrument is
provided with a retaining spring which presses on the wheel. Only when the
spring is depressed, the weighted wheel swings freely.
BRANDIS HYPSOMETER

21. • In order to use the instrument as a simple clinometers, the observer
should stand at a convenient place from where the top and base of the
tree can be sighted.
• He should hold the instrument in left hand and press the spring with
forefinger. the top and base should then be sighted successively. in each
case, when the wheel becomes steady, the spring should be released to
look the wheel.
• The readings on the scale will give angles to the top and base of the tree.
The sloping distance from the observer’s position to the base of the tree
should then be measured and height of the tree calculated by any of the
formula of the tangent method applicable in the case.
METHOD OF USE

22. • The instrument is also provided with a table called brandis table
which gives the heights of trees directly. This table has been
compiled for a specific case where the top of the tree is above
and base below the eye level. The table gives the angles of
elevation to the top of the tree with an interval of 2°.
• For each of these angles, a set of angles of depression to the
base are given with interval of 5°.
Brandis table

23. • In order to use the table, it is necessary that the observer should stand at a
place from where the angles to the top of the trees is one of the angles
given in he table. this can be achieved by moving backward or forward
steadily so that the wheel does not swing very fast. when the top has been
sighted for any of the angles of elevation given in the table, the instrument
should be directed towards the base, having adjusted it to one of the angles
of depression given in the table.
• But care should be taken to see that the position of the observer is not
changed. With a fixed position and a fixed angle of depression, the exact
base of the tree may not be sighted and therefore the point where the line
of sight intersects the tree should be got marked by another man. The
height of the mark should be measured and noted down. Then sloping
distance should be measures along the ground. The height of the tree from
the top to the mark near the base is obtained from the table for the
corresponding distance and angles of depression and elevation. the height
of the mark is added to get the total height of the tree.
METHOD OF USE

24. • This is an invaluable instrument for forest officers and is therefore most commonly
used by them not only for measurement of heights of tree but also for contour survey
in forest surveys and alignment of roads. it consists of a hallow tube with an eye piece
fitted at one end and a short sighting tube fitted at the other. The eye piece consists
of two or three telescopic hollow tubes with a pin hole at the extreme end.
• The sighting tube is small detachable tube fitted with a horizontal wire across the
centre at the inner end, and a mirror behind the horizontal wire, but covering only
half of the tubes, so fitted that it makes an angle of 45°to longitudinal axis of the
main tube.
• The spirit level is fitted to the main tube in such a way that it can be rotated by one
screw or a wheel and a screw. when a wheel and a screw are fitted, wheel is for
quicker movement and the screw is meant for final adjustments. An index arm is also
attached to the spirit level and the spirit level is rotated, the index arm moves on a
graduated semicircular arc. the arc is graduated to read whole degrees. Each division
of the vernier scale represents 10°(minutes).
• The number of divisions coinciding with any division on the main scale on
semicircular arc, gives the reading in units of 10 minutes.
ABNEY’S LEVEL

26. • In order to use the instrument, the observer stands away from
the tree at the place from where top of the tree the base are
visible. then the top of the tree is sighted through the pin hole of
the eyepiece after pulling it out.
• This make the instruments inclined and the bubble is not seen in
the mirror. therefore while sighting the top, the screw is rotated
to bring the spirit level in the horizontal position, the bubble
appear on the edge of the mirror the spirit level is continued to
be move slowly to the position when the bubbles image is
bisected by the line of horizontal wire on the mirror and in the
other half, the tree top is seen touching the horizontal wire. At
this position ,the index arms reads the angles of elevation to the
top of the tree on the circular arc.
METHOD OF USE

27. This instrument is similar to Abney’s level except for minor differences. the
protector of this instrument is graduated both sides. one side gives the rise
and fall per chain horizontal distance and the other side gives the
percentage rise and fall. the instrument is used in combination a trailor tape.
Trailer tape is an ordinary tape 1 to 2 chains long on one side it is graduated
to read distance while on the other side it gives trailors addition
corresponding to various slopes recorded by topo Abney’ level. these
trailore addition s represent the distance which must be added to the
sloping chain length to make it equivalent to horizontal distance for a
particular slope read by topo Abney’s level.
TOPOGRAPHICAL ABNEY’S LEVEL

28. While using the instrument on sloping ground the first thing to be done is to
stand at one chain horizontal distance from the tree. In order to find out this
point, the observer stands at little more than one chain sloping distance and
sights the top of staff equal in length to his eye height. for this reading, the
trailor addition has to be found from the trailor tape .then one chain sloping
distance + tailor addition read, gives the point which is at a horizontal
distance of one chain one tree.
The top of the staff may be sighted once again from new position to se that
there is no change in the reading of the topo Abneys level. if there is any
change, the position is readjusted with the new trailor addition. from this
new position, the line of sight to the top will give height of the base from
eye level.
The height of the tree is then found out adding to the two readings in cases
where the top of the tree is above and base below the eye level or
subtracting the latter from the former reading in cases where the top and
the base are above eye level or subtracting the former the latter in cases
where the top and the base of the tree are below eye level.
METHOD OF USE

29. • It is a portable instrument for measuring heights of
trees or other vertical objects without the
trigonometric tables and formulae as required for
determination of heights by Abneys level.
• It consists of a gravity controlled, damped, pivoted
pointer and a series of rotatable scales on a
hexagonal bar in a metal, pistol shaped case. the
top of the case is slightly rounded at the rear end
of which eye piece s with a pinhole and towards
the font end a sight vane, consisting of a hollow
metal tube 1.5 cm long and 2m in diameter and
having two prongs R protruding from the opposite
sides inside the tube. the pronges are in a
horizontal line with a slight gap between the two.
• A little below the rounded top, the instrument has
inside it a hexagonal bar which can be rotated by a
turning knob on the front face of the instrument in
line with the bar inside.
HAGA ALTIMETER

30. • Relaskop is used for measurement of basal
area of crops. the instrument can also be
used for measuring diameters over bark at
any height and heights of tree. the
instrument has a rotating drum for slope
correction.
• This drum is used for height measurements.
four scales for measuring heights are
incorporated in the instrument having five
measuring bases. One scale gives percentage
inclination while the other three scales used
in collaboration of measuring bases 03,04
and 05. It gives directly height of the tree
when a horizontal stick of fixed length kept
at the base of the tree is exactly covered
with the selected measuring base.
RELASKOP

31. LiDAR
• LiDAR, an acronym for Light Detection and Ranging, is an optical remote
sensing technology that can measure distance to objects. LiDAR data is
publicly available for many areas and these data sets can be used to
display tree heights present on any of these locations.
• Heights are determined by measuring the distance to the ground from the
air, the distance to the tops of the trees, and displaying the difference
between the two values.
•

32. • In addition to using LiDAR to locate tall trees, there is great promise for using
LiDAR to locate old-growth forests. When comparing known old-growth sites to
second-growth in LiDAR, old-growth has a much more textured canopy because of
the frequent and often remarkably evenly spaced tree fall gaps.
• Finding equations that can predict old-growth forests of various types using LiDAR
and other data sources is an important area of scientific inquiry that could further
conservation of old-growth forest."

33. SOURCES OF ERROR IN HEIGHT MEASUREMENT
• Instrumental errors.
• Personal errors.
• Errors due to measurement.
• Errors due to observation.
• Errors due to lean of trees.

34. References
• Forest Mensuration And Biometry
A.N. Chaturvedi & L.S. Khanna
• Principles and practices of silviculture- L.S.Khanna
• Indian Forester : Manikanandan and Prabhu
• www.google.com