PM Submission - Thomas Kearney - MCU18/0015

THE BURNLEY METHOD

The Burnley method has as its focus two simple elements. The first is the establishment of tree size.
Initially, this was determined using the formula for a cylinder (or2h), which requires the simple
measurements of height and canopy spread. The second element of the method involved establishing a
dollar base value for the tree. This was achieved by obtaining the retail price from appropriate
nurseries for purchasing a specimen with a volume greater than 1m3, using the formula for a cylinder.
The base value calculation was expressed as $/M3. The calculation was done by determining an
average value for at least three specimens from different nurseries.

In developing the Burnley method, it was intended that by multiplying the size and value components
together a basic tree value would be established, which would then be modified to allow for the
peculiarities of the tree and its location. The modifiers to be used were:

        I.      TREE SIZE (V) : With large trees, the values determined by the formula were
                unrealistically high. Accordingly, a modifier was developed (Table 1) to reduce the
                value.

        2.      USEFUL LIFE EXPECTANCY (E) : This modifier took into account the projected
                useful life expectancy of the specimen (Table 2).

        3.      FORM AND VIGOUR (FV) : This factor was used to assess the form and vigour of
                the tree (Table 3).

        4.      LOCATION (L) : This modifier was used to assess the tree's suitability for its
                particular location (Table 4).

The modifier tables were used to minimise the risk of significant discrepancies in tree values made for
the same tree by different arborists. The value of an amenity tree was then determined using the
formula:

        VALUE ($) = TREE VOLUME x BASE VALUE x (E) x (V) x (FV) x (L)

The formula developed is consistent with the mathematical principles proposed by Helliwell (1967)
where related variables are multiplied.


MODIFICATION OF THE BURNLEY METHOD

Following the use of the Burnley method, particularly in Victoria, criticism was made of the volume
modifier in particular, which was seen by many arborists as little more than a fudge-factor that
adjusted values without reason (Wycherley, 1991). This criticism was to be expected because the
rationale for use of the modifier had not been clearly identified in the original paper.




For use in conjunction with Computers II Assignment Sheet    © The University of Melbourne