Tom Moertel, who blogs at http://blog.moertel.com/, emailed me the following comment on my lament about Mt. Lebanon trees. With his permission, I'm posting it below:
Presumably, it costs less to repair sewers if the sewer people don't
have to accommodate nearby trees. Removing "big, tall, healthy, straight trees," then, is probably some administrator's idea of saving money. It is, unfortunately, very likely to be a bad idea, one that costs the community more than it saves.
According to the Georgia Forestry Commission, "Healthy trees can add up to 15 percent to residential property value." In a recent report to the National Urban and Community Forestry Advisory Committee, university researchers found that trees in residential neighborhoods are associated with increased home values and property-tax revenues, each good tree representing a one-percent increase in a home's sales price, and in some cases considerably more:
Research comparing sales prices of residential properties
with different tree resources suggests that people are
willing to pay 3 to 7 percent more for properties with tree
resources versus few or no trees. One of the most
comprehensive studies of the influence of trees on
residential property values was based on actual sales prices
and found that each large front-yard tree was associated
with about a 1 percent increase in home sales prices
(Anderson and Cordell 1988). A much greater value of 9
percent ($15,000) was determined in a U.S. Tax Court case
for the loss of a large black oak on a property valued at
$164,500 (Neely 1988). Depending on average home sales
prices, the value of this benefit can contribute
significantly to cities' property tax revenues. [2, p. 64]
To apply these findings to Mt. Lebanon, consider a middle-of-the-road property, having a taxable value of $145,600. When a street-side, healthy tree is removed from such a property, the studies suggest the loss is associated with, on average, a one-percent or $1,450 reduction in taxable value to the community (not to mention the larger loss in resale value to the property's owner). If it takes on average twenty years before a replacement tree reaches maturity, the community loses
about $962 in present-value tax revenue over this period.
Ignoring the immediate loss in home value and "curb appeal" to the property's owner, and ignoring the aesthetic loss to the neighborhood, if we look only at the collective pocketbook of the county, municipality, and school district, we have good reason to question the tree-removal policy. It seems unlikely that the community will ever save enough on sewer maintenance to break even on the lost tax revenue -- and tree-removal fees -- that each healthy-yet-removed street tree represents.
In any case, it seems that the community has grounds to ask its representatives to examine the costs and benefits of the tree-removal policy more carefully. From all outside appearances, it looks like we are squandering both our trees and our money.
Using 2006 millage rates from  and assuming future
real-estate appreciation and millage increases will offset
typical discount rates, the present-value net loss per
tree is $962 for a median-valued home:
20 years * $4,810 tax revenue per year * 1% loss per tree
= $962 loss in tax revenue per tree