What is a Tree Worth?

Drouin's trees are valuable for many reasons.

Trees provide habitat for urban wildlife. They reduce energy costs by producing shade in Summer and protection from cold winds in Winter. Properties in treed streets sell more easily and a tree on the nature strip can add thousands of dollars to the sale price of a house. Trees absorb carbon, airborne pollutants and noise. They 'exhale' oxygen, mitigate water run-off and reduce the level of the water table. Well treed suburbs and towns are known to have lower health costs and reduced crime rates.

Fortunately, in Australia and here in West Gippsland, we are catching up with many other places around the world and beginning to think of urban trees as assets rather than liabilities.

But, just how do you calculate the monetary value of a street tree? (If you 'Google' that question, you get hundreds of very technical answers.)

An example relatively close to home is the Urban Forest Tree Evaluation Fact Sheet from the City of Melbourne which provides a formula for providing the monetary amenity value of a tree;

Value(V)=Basic Value(B) x Species(S) x Aesthetics(A) x Location(L) x Condition(C).

Basic value (B) is taken from an internationally acceptable set of figures which provides a monetary figure for each square inch of basal trunk area.

The Species factor (S) is a score determined by analysis of the rate of growth in a particular environment.

The score for Aesthetic value of a tree, (A) is determined by its impact on the landscape if it was removed.

The Locality score (L), is evaluated from a range of localities such as undeveloped bush or open forest to the city centre or main boulevard.

Condition (C) is calculated from a table that lists factors like 'solid and sound trunk' to 'advanced infestation, decay or dieback', etc.

So, let's apply V = B x S x A x L x C to a well-known Drouin tree, (hope you're keeping up?), the Bill Kraft Giant in Albert Rd, (E. cypellocarpa).

    Base Value B

This tree's diameter at breast height is 223cm. The given table for determining the Base Value does not go this high, but extrapolation from the table gives a Base Value B = $248,200.

Species Factor S

Eucalyptus with a long life span, S estimated as 0.9. (could be higher).

Aesthetic Value V

A solitary feature specimen tree, A = 1.0

Locality L

Outer area/residential street, L = 1.5

Condition C

Rating from table C = 1.0

Determining some of the above values is a subjective process but I believe I have been conservative. The basic value figure is an estimate made in 2012 and was extrapolated from a table which did not cover a tree with trunk diameter as large as this.

Thus, the value of the Bill Kraft giant Mountain Grey Gum in Albert Rd is …

V = B x S x A x L x C

   = 248,200 x 0.9 x 1.0 x 1.5 x 1.0

   = $335,070

A Chilly McNeilly Wetlands

The Drouin Amateur Weather Station recorded a minimum of -4.7°C on Sunday morning. Brrrr. Between warming the fingers to press some buttons, I captured a few shots at McNeilly Wetlands, (map, earlier blog post)….

(Click on images to enlarge or open in a separate window)

Plenty of seating available

Even the canines wore coats.

A frosty handrail

A scene that caught my eye

Another scene - sans ducks!

This White-faced Heron sought a sunny perch

Trees in China

By Judy.

I have always thought of China and its capital Beijing as being industrial, smog emitting, high density living and void of trees. ….but I was wrong.

We have just returned from time visiting our son in Beijing and we were surprised by the value the Chinese put on trees. There is an evident priority plan to plant trees along highways, main arterial roads and in every available space alongside roads. The green of the city is evident everywhere you go, alongside the huge highways and amongst the tall, densely positioned buildings and apartments.

We saw many mature trees being planted alongside roads after being transported on the backs of trucks. Some trees would have been 1.2m to 1.5 m in trunk girth and perhaps 10m high. …planes, poplars, elms, willows and pines. And most times there is also a secondary planting of smaller trees like gingkos, cherries, pears. Yes it’s well organized and they are laid out in lines or avenues but the predominant feel of driving in China is ‘trees’ and ‘green’.

The second thing we noticed was the value placed on old trees. Old trees in parks or reserves are all labelled. The younger trees of 150 years have a green metal name plate, and older trees of 300 years have a red metal name plate, all with the tree’s number and details and sometimes a Q code for those with smartphones who read Mandarin, to learn about the tree. 

It is obvious that the Chinese value old trees because old trees are kept well into and through old age despite being wind or disease damaged. Huge metal poles are used to hold up limbs, leather straps are bound around a trunk to hold it together, huge metal or wooden constructions are built to hold up a tree and its canopy, which become in themselves a work of art or sculptural masterpiece. Sometimes fences or rails are necessary to keep people away from trees but this is because so many people want to touch them, not because of fear of prosecution if a limb should fail!! Old tree roots are carefully protected with attention to the area around the tree base; metal, wood or concrete slats to protect and give good drainage.

I would like to think that in West Gippsland we value our old native and planted trees and do all we can to keep them into their vintage years. We don’t need to start replanting as the Chinese do, YET, but we do need to stop chopping down and at least have a neutral rather than negative removal/replacement rate. And where appropriate supporting and keeping old trees into their twilight years.

We have a lot to learn from other nations!!

Judy Farmer