New mwember question about a cottonwood

Hi, My name is Ralph Fravel and I live in St, Paul, MN. Two days ago I found TCI during a Google search about tree climbing and am very impressed with the content and spirit of this site. The reason for my search was that I am having a 95 year old cottonwood removed from my yard. It's a majestic one with two large 14\" limbs branching from the trunk at about 20 and 25 feet, and then three 18-20\" limbs forming a crotch at about 30-35 feet. After talking with the arborist who is removing the tree, I have decided to only drop the limbs and leave the trunk and enough of the crotch limbs to construct a small platform on the top of the crotch limbs.

I know this isn't really a \"climbing tree\" but I was wondering if anyone had experience with how to preserve such a tree trunk. The arborist told me that if I remove all the bark and then paint or oil seal the wood, as well as protect the trunk area from moist conditions, that the tree should be solid for 15-20 years.

I'm excited about using this \"tree\" which is very close to the house to learn basic skills and techniques before heading into our woods where we have some 40-60 foot ash, maples and oaks. Thanks in advance for any help you can give me.

I don't buy it. The roots hold the trunk up, they need to be alive. You can't control rot in the roots after the tree dies. Some species like American Chestnut or Honey Locust have extremely rot resistant wood and roots. Cottonwood is not in that category, it's on the far other end, not very dense wood that's quick to fall apart after it dies. Any chance you'll reconsider killing what sounds like a magnificent tree? You'll be able to hang out in it much more securely as a live tree.
-moss

Thanks Moss for your quick reply. I should have been more clear that this tree has already died and we have to remove it because limbs are threatening our garagge. We just moved back to this home after a six year job-related absence and I understand the tree has been dead for about one season. The trunk measures about four feet in diameter and is straight as an arrow. Based on your input, I'll do some more checking around with other tree people here as well. Thanks a lot and good climbing.

I'll second moss on this one. Cottonwood has a low density wood and a low lignin content, so the Wood Handbook (USDA Forest Products Laboratory) lists it in the least decay resistant category:
(page 18, table 3-10 in: http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch03.pdf). This tree is likely to get scary fast.

Ok, it's dead already. If that's the case then the roots are probably already compromised. There are some ice climbers in my neighborhood woods who've been climbing in the off season on a dead red maple with ice picks. Sooner or later it will fall over hopefully not while they're on it.

For the cottonwood it's a tough call as to when it will become unstable. I suppose you could put some guy lines on it to keep it standing until the crotches start to fail.
-moss