My tree is a Douglas Fir (Pseudotsuga menziesii), which is quite different
from a pine tree. Doug Fir is the strongest North American softwood
species. Based on 23 years experience with antennas in it, there is not a
significant pitch problem and the tree is is excellent health according to
my arborist who inspects and maintains it annually. Since this tree was
topped, we're dealing with the lower 95' of a 150' tall tree. As I
mentioned in the original post, I've never observed more than about 6"
mvement at the top which occurred during our record setting wind storms last
winter (85+ MPH gusts). This tree is also surrounded by 100-150' high Doug
Fir and Cedar trees that provide a very good wind block in most directions,
especially the prevailing wind direction. And, of course, the windload that
I'm adding at the top is insignificant compare the the wind load of the
branches.
I really appreciate all of the comments about this installation. I'm know a
lot more about trees, including their growth habits and maintenance, than I
do about steel. My primary concern is ensuring that the tower movement
doesn't result in metal fatigue. The info provided, both objective and
subjective, will help me decide how to proceed.
Thanks & 73,
Clay W7CE
> ----- Original Message -----
> From: "kd4e" <kd4e@verizon.net>
> To: <towertalk@contesting.com>
> Sent: Wednesday, May 09, 2007 6:31 AM
> Subject: Re: [TowerTalk] Tower in Tree
>
>
>> You need to know which type of pine tree you are
>> working with, some are very sturdy and some very
>> weak.
>>
>> Ask a local who is familiar with the trees in
>> your area which are the most and least sturdy.
>> The water oaks here in FL are almost indestructable,
>> the scrub oaks are something else entirely.
>>
>> From most pines you will also suffer large quantities
>> of pitch all over your tower making climbing dangerous
>> and service a nightmare.
>>
>> Test this latter factor out by leaning an extension
>> ladder against your pine tree for a couple or three
>> weeks. I made this mistake. Yuck!
>>
>> Oh, and in lightning-prone areas pine trees are known
>> to be lightning magnets - one of the sources of
>> lightning storm wildfires - we had 193 such fires
>> here in Florida as of last count. If the tree burns
>> it will likely take your coax, rotator, and antennas
>> with it even if your tower survives.
>>
>> Just some factors to consider - variables change
>> with geography.
>>
>>> Finally, although I put a 50 footer in a maple tree...I would have
>>> some trepidation about a 100 footer in a pine tree. The top of that
>>> thing is going to move in big winds a LOT. That means that you'll
>>> need to have progressively looser chains, as you go up the tree,
>>> to allow more flex/wiggle room. And THAT means you'll have to have
>>> a method for tightening those chains, when you go aloft to work on
>>> things.
>>>
>>> Plan on climbing this 4 times a year, to make sure the chain isn't
>>> digging into the bark of the tree.
>>>
>>> n2ea
>>
>>
>> --
>>
>> Thanks! & 73, doc, KD4E
>> Personal: http://bibleseven.com/kd4e.html
>> Ham QTH: http://mysite.verizon.net/kd4e/
>> _______________________________________________
>>
>>
>>
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>
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