on one side of may house are very tall
eucalytus trees, approximately one
hundred and twenty feet. The wind comes
down a canyon, therefore the trees are
leanings towards my house. Naturally, I
fear a gusty storm, and one may drop.
I have an idea the expense may run into the thousands. My main concern is the contover-
in trimming methods. Topping versus thin-
ing. Can you lead my to some advice or
a book. Thank you

Reply to post by gael schafer, on November 30, 2001 at 04:48:19:

Thinning can be done to work with the trees form and maybe reduce the risk of failure.

Topping is a short term solution that may increase the risk of failure in th futur do to it's causing decay and fast growing branches that the tree puts out to replace lost foliage.

The attached link is a meta engine search I did on the subject. There is material there that will better help you understand why we now try to discorage topping.

Reply to post by JPS, on November 30, 2001 at 04:48:19:

Crown reduction is an established pruning technique that can make for a smaller, safer tree. Unlike topping, cuts are made at side brancches that can assume the apical growth. Cuts are made at an angle that promotes rapid sealing of the pruning wound.
An ISA Certified Arborist should be familiar with this technique. A further description is available through the ISA. It's a lot harder to do than topping, but it's a lot more effective at hazard reduction than thinning.

Reply to post by Guy Meilleur, on December 06, 2001 at 20:41:12:

Reduction or drop crotching is applicable on a case by case basis. Some trees will not lend themselves to this.

Another problem, especialy when the cuts are large (she wants to make a 100+ ft tree shorter) large wounds are usualy made and they cannot close up well. The with a branch wound there is a natural protective boundry not present with a reduction cut.

Reduction cuts are better then topping in that they leave a branch attached, but they do not eliminate sprouts and you still have a high probibility of large pockets of decay.

Reply to post by JPS, on December 07, 2001 at 15:13:14:

Crown reduction definitely not applicable for every tree, true. But neither is crown thinning, which might be done to reduce windthrow hazard but increase branch breakage hazard (see Scott's comments in the Ivy on Conifers thread under Ask the Experts.)

I've only reduced a couple of eucalypti, and those some time ago. To shorten a 100'+(?) tree, it's true that large cuts would need to be made, and some sprouting is likely. But as long as the side branch assumes the apical role the sprouting branches will be secondary and much better- attached than on a topped tree. Some sprouting is good and necessary, to replace the lost foliage, and it speeds wound closure.

"Where there's no natural boundary", it may be true there's no natural boundary when the cut is made. But if the cuts are made in the best possible locations, wound closure may be rapid enough to minimize decay.

bottom line is JPS's note that this is a case-by-case consideration. I only hope gael schafer gets good local help so this doesn't become a Legal Issue!

Reply to post by gael schafer, on November 30, 2001 at 04:48:19:

The best advice here is not about the method of pruning, but in finding a qualified arborist to check out the tree.

I am not an expert on eucalyptus, but as I understand it, there are many problems associated with this genus of trees. Someone who knows the trees and has worked with them is best qualified to judge the condition of the tree and determine the risks it poses. While the discussion of pruning methods does come in to the question at some point, the overall safety of the tree is the paramount issue.

The American Society of Consulting Arborists can recommend highly qualified arborists and consultants in your area. Their web site and database is at

http://www.asca-consultants.org

or contact the main office at

American Society of Consulting Arborists
15245 Shady Grove Road
Suite 130
Rockville, MD 20850
(301) 947-0483

The International Society of Arboriculture maintains a current list of ISA Certified Arborists. The searchable list can be accessed at the ISA Web site, at:
http://www.isa-arbor.com