15

There is a sign, at the Eden Nature Park & Resort in City of Davao, Philippines, that says this:

Of concern to all! A tree is worth $193,250

According to Professor T.M.Das of the University of Calcutta. A tree living for 50 years will generate $31,250 worth of oxygen, provide $62,000 worth of air pollution control, control soil erosion and increase soil fertility to the tune of $31,250, recycle $37,500 worth of water and provide a home for animals worth $31,250. This figure does not include the value of fruits, lumber or beauty derived from trees. Just another sensible reason to take care of our forests.

From Update Forestry Michigan State University

enter image description here

The figure, sometimes incorrectly quoted as $196,250, is cited at various green blogs, and sold on a bright red poster at Singapore Zoological Gardens, but i haven't been able to find the study behind it.

So is a tree living for 50 years worth $193,250?

  • 5
    What Nation's currency is that? And when? – Ladadadada Apr 26 '13 at 16:06
  • 4
    @Ladadadada Given the attribution to Michigan State University, it seems like (although not certain) that the currency would be U.S. dollars. – Beofett Apr 26 '13 at 16:37
  • 2
    Whats with that myth that trees produce the oxygen we breathe? – Stefan Apr 26 '13 at 16:45
  • 7
    It sounds like the real claim is "The tree generates X resources in 50 years" which is ENTIRELY DIFFERENT than saying "A tree is worth X." I just threw away a dot-matrix printer which helped me, over the last ~20 years, produce, sell, ship, process several thousands of dollars worth of products. That doesn't mean the printer is worth thousands of dollars. (Unless someone wants to offer me that price--I'll go dig it out of the trash). A tree is worth what someone will pay for it. – Flimzy Apr 27 '13 at 23:18
  • 4
    With a few exceptions (such as the desert southwest), most suburban USA properties have a lawn with one or more trees. If each tree were worth $193,000, then the current financial crisis in real estate could be easily solved by homeowners simply refinancing or selling trees. If that solution sounds like nonsense, so is that high appraisal of the value of a tree. – Paul May 2 '13 at 2:19
9

David Bennett from the Aboriginal and Torres Strait Islander Commission has a great article on this topic in Tropical Rainforest Research, under the title of "Valuing a Tree: The Ethics of Environmental Evaluation." The gist of it is that converting trees to currency is not an exact science. A number of assumptions could go into such a calculation, producing a range of values.

Bennett quotes the exact number from T.M. Das (in Singapore dollars by the way, which converted to US currency comes out to $158,739 / 50 years). About this metric he writes,

This method is crude, of course. It indicates only an average functional value for a hypothetical tree. The functional value of a given tree of a given species may be more or less than this amount. The point remains that the economic value of a tree cannot be reduced to its materials.

By comparison, an article in the Journal of Arboriculture 29(2): March 2003 indicates that the city of Davis, California

maintained nearly 24,000 public street trees that provided $1.2 million in net annual environmental and property value.

By this measure, a tree brings 50$ per year, and $2,500 over 50 years. The value in this study includes: "electricity (kWh/tree) and natural gas savings (kBtu/tree), atmospheric CO2 reductions (kg/tree), air quality improvement [NO2, PM10, and VOCs (kg/tree)], stormwater runoff reductions [precipitation interception (m3 /tree)], and property value increases [∆ LSA (m2 /tree)].

If I was wanting to be precise about the numbers, I would at least quote a range between these two estimates.

  • 3
    and how much does it cost that city to plant, water, prune, and replace those trees? I know the city I live spends a lot of money on that (well, not so much watering as I live in a rather wet climate). Don't have figures, but wouldn't be too surprised if that came close to the $50 per tree per year figure, especially given the wastefulness of typical government agencies. – jwenting May 1 '13 at 7:10
  • Agreed. The Arboculture article provides a much more detailed estimate than that of Das. – denten May 3 '13 at 17:40
  • 3
    @jwenting, denten quoted a net profit, so labor is already paid. – Cees Timmerman May 16 '13 at 9:52
  • @DuckTapeAl fixed – denten Feb 9 '17 at 22:04
11

Nancy Beckham explains in Trees: finding their true value about how the valuation was done.

It was published in Indian Biologist, Vol XI, No. 1-2, 1979, by T.M. Das, a journal which is edited by... T.M. Das.

Prof Das's system looked at a number of factors, one of which was oxygen production. The net accumulation of one gram of carbon in a tree was compared with the net production' of 2.66 g of oxygen. This oxygen production was related to the weight of a tree, using a correction factor for the amount of leaf shed every year and the age of the tree. The oxygen was valued at the prevailing Indian market rate.

Of course, what its components would be worth (or rather what its outputs are worth) in its purest form is a nonsense method of valuing anything.

There are various ways of defining economic worth, but it is clear that none of them are going to value a average, unspecified tree at $193,250, when its replacement and market price cost is so much lower. On the other hand, particular trees may be valued at higher than that price.

You must log in to answer this question.

protected by Community May 30 '13 at 21:25

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged .