There was a recent post on the ISA Board asking about SULE. Steve Day had been kind enough to send me some background on it, which is provided here. The principal application seems intended to be development and hazard analyses, but it would seem to be applicable to valuation as well.

Any comments or experience from the KnotHole crowd?

"SULE was advanced by Jeremy Barrell in a paper entitled "Pre-development Tree Assessment" presented at the Morton Arboretum May 31-June 2, 1995 and published in a compendium of papers entilted "Trees and Builing Sites" published by ISA, Gary Watson and Dan Neeley, eds.

Barrell first published: Barrell, J.D., 1993. Pre-planning surveys: Safe Useful Life Expectancy (SULE) is the Natural Progression. Arboricultural Journal (UK) 17:33-46."

Reply to post by Scott Cullen, on March 18, 1999 at 07:34:59:

SULE is cited and briefly discussed in Matheny and Clark, 1998. Trees and Development. Savoy, IL: ISA. pp. 70-71.

Reply to post by Scott, on March 18, 1999 at 07:34:59:

It seems to me that Safe Useful Life Expectancy (SULE) is another way of saying the Service Life (SL)of the tree. Hopefully folks aren't reading too much into it. We do need to have a sense of how long a tree can be expected to provide benefits that warrant maintenance costs.

Some service lives are short such as Malus sp. and Sorbus sp. Others can be much longer in urban environments. I look at service life when I consider consequences of damage from butchering. On a young tree, a butcher job has at least diminished SULE/SL by 50%. On more mature trees, SULE/SL may have been reduced by a higher percentage, depending on species and decay rates.

Do ya like the fluttery leaves on an aspen? Go ahead and plant one, but expect a short service life, and plant something nice near it so when it dies there isn't a void in the landscape(in my area this is usually the case, your area might be different).

Make sense?

Best regards,
KWK

Reply to post by Scott Cullen, on March 18, 1999 at 07:34:59:

I have found a place for SULE in many reports. If a tree goes through the Visual Tree Assessment and beyond, and comes up in the hazard class, then the SULE is less than one year, or even "immediate removal is recommended".
Most trees aren't that bad off, and if it is relevant to the assignment, I like to give my opinion of the SULE. As others have mentioned, I base SULE on species, site disturbance, and individual health. That part is included with "as of now when consultant is looking".
The next part can deal with limitations on future disturbance, as in, "if grade changes are made within... . Should irrigation and turf be applied ... . When the trees to the windward side are cut down... ."
SULE seems like a good tool to warn against damaging the immediate ecosystem and expecting no harm to come to the tree individuals at risk. It might help people in a future civil law suit. I believe that trees will remain victims at construction sites until the people in charge of site designs get taken to task in court and their insurance companies lose many millions of dollars.

Reply to post by Peter Torres, on March 18, 1999 at 07:34:59:

I have been using the concept of SULE in both construction and hazard evaluation. It especially comes in handy with a tree failure report. In addition, I use it quite often in my mind (no jokes guys) during analysis of the best use of my municipality's funds for tree care. In large tree management cases (parks, open space, street trees) it is a simple form of triage. It is useful especially after reading the paper, in explaining plant health care to lay people.

Reply to post by Bill Cassel, on March 19, 1999 at 00:59:18:

I like the concept Bill. The little research I've done on SULE seems to position it much more as a decision making aid than as a prediction or measurement tool.

Reply to post by Scott Cullen, on March 18, 1999 at 07:34:59:

Hello there,
Would you please outline the various factors
considered when working out the SULE?

This is needed for a Horticuture course
assignment.

Thank you
Kay