Update on the treehouse bridge in the redwoods of the Santa Cruz mountains

[David Eather]

Shouldn't there be a forestry or similar department you could ask for advice?

[Martin Eastburn]

Is the cable(s) around the tree adjustable for growth ? Or will the blocks start to dig in.

Martin

[Danny D.]

Martin Eastburn wrote, on Tue, 17 Feb 2015 16:03:06 -0600:

Not adjustable, at least not in the sense that we built that into the design.

So, eventually, the blocks will dig into the tree.

[rickman]

Are these bolts going to support the weight of the bridge? That seems a bit awkward with the long length of the board. Does the support board run under the bridge to be supported at the other end?

I think rather than drilling into the tree, I would make use of the various branches and wrap a line around the tree trunk like a lasso somewhat higher up than the walkway. The branches will keep it from sliding down the tree without being tight. Drop the line to the walkway or even pass it under and back up on the other side to the same or another tree.

[Danny D.]

rickman wrote, on Tue, 17 Feb 2015 20:17:21 -0500:

The bridge is already supported. It's supported by a 3/8-inch suspension cable on both sides. The bolts are simply for redundancy, and, because the treehouse, when built, will add additional weight, even if/when the cable is suspended for the treehouse itself.

We haven't decided what to do with the branches yet.

[Martin Eastburn]

Redwood branches tend to die off and fall out from time to time. Not all but here and there. Some are 4-6" in diameter. Consider that but end coming down on you, your car, your shop. One punched through my shop roof and kept out the rain with all of the green junk on top.

I had to cut it off on top and on the bottom - punch out the disk and replace the roof boarding. Glad it was in the shop.

Martin - relocated from my 100 or so tall tree home site.

[bob haller]

Run your perspective design by a college arborist and mechanical engineering department, to assure safety, for both you and the tree.

are redwoods a protected species where you live?

[Danny D.]

Martin Eastburn wrote, on Wed, 18 Feb 2015 23:26:19 -0600:

Some of those redwood branches are as thick as trees, so that's a valid concern. We may need to reinforce the roof, against them falling on it.

[Danny D.]

bob haller wrote, on Fri, 20 Feb 2015 05:26:09 -0800:

In California, it is my understanding that EVERY tree is protected if it's large enough to measure 1 foot wide at about chest height.

If you cut down a tree, you have to get a permit; even if it were dead or dying.

The permit, I'm told, is free, but, generally you have to plant an equal number of trees to replace the ones you cut down.

If you remove trees without a permit, they can fine you, or let you go (up to them).

That's what I remember about a conversation about an oak tree in my yard that was blocking the view anyway.

[Joe Gwinn]

The reason is that humans ganged up on and killed critters that dared to take a human. Over the last say 50,000 years, this enduring bit of Darwinist pressure had a big effect. Five or six people with spears are quite capable of killing a lion.

Joe Gwinn

[G. Ross]

A dozen years ago we owned a lot (around 4 acres) with many large trees. One huge oak had a horizontal limb about 2 feet in diameter and I dreamed of putting up a spiral stair and a platform on the limb, just for fun. We wound up selling the lot instead of building a house on it, and I went by to look at it a last time and the limb had fallen off and was lying on the ground.

[Scott Lurndal]

I've encountered mountain lions (aka cougar, puma) in both the Santa Teresa foothills and the Marin headlands. They're sized similar to a medium sized dog (24" to 36" at the shoulders, 65 to 180 pounds depending on gender and age).

The lions mainly hunt from dusk to dawn, which is one reason that human-lion encounters are rare. The lions are also not interested in humans as prey.

[Jim Thompson]

I encountered one in my back yard. Awakened by the dog barking very strangely, I stuck my head out the arcadia door to encounter mountain lion with my dog standing on top of his dog house shaking like crazy ;-)

Mountain lion took off like a bullet. ...Jim Thompson

[Roy]

Cougars have attacked bicycle riders, people on horseback AND people just walking in the woods. They are NOT harmless pussycats. Google for more up-to-date data on these animals. ==================

[Danny D.]

I helped my neighbor with the 75-foot by 16-foot wide (at the tree) bridge today, so I figured I'd show you some shots from below:

Notice in that picture above that there is a "widowmaker" of about ten feet long hanging in mid air, ready to fall. Also notice that the "sucker" was cut flush, and the boards screwed to it ...just because we could.

We're close enough to the big redwood to touch it now!

Here's a view, looking down, at the big tree, inches away from it:

That's a milestone after so much work starting at the other end.

I tried to get a picture to take the whole thing, from under:

But, the best I can show you in a single pic is a side view: