[2 for 2028]

[quote author=Boston Card link=topic=12914.msg130502#msg130502 date=1443205373]
[quote author=stupac2 link=topic=12914.msg130468#msg130468 date=1443195665]
Sort of related, the house I bought this year has two of exceedingly large proportions redwoods in the back yard. There's nowhere that I can stand (including on my roof) where I can see their tops. I'd love to know how tall/old they are, but I'm not sure how to do that. I really like having them around (though it's too bad they're on the north line so they don't give a ton of shade), but holy crap do they drop a lot of cones/twigs/branches. It's like the pine trees I grew up with on the east coast, but times 20.

 
Measure your trees' shadows while measuring the shadow of an object of known height.  The shadows are proportionate to their height, so your trees' height = trees shadow length * object height / object shadow length.

BC
[/quote]

This method works great if one can measure a shadow cast by the top of a tree.  But if there's nowhere that Stupac can stand where he can see the tops of the trees,  that means there's also no place he can get to where he can measure the shadow cast by the tops of the trees.
[/quote]

You don't need a shadow.  Lots of ways to do it if you can reasonably see top of the tree from the ground somewhere.  I had to walk down the street to do it, but I was able to measure the height of a tree in my back yard before Sandy hit since I was worried that the tree could land on my daughter's room.

[2 for 2028]

[quote author=Boston Card link=topic=12914.msg130502#msg130502 date=1443205373]
[quote author=stupac2 link=topic=12914.msg130468#msg130468 date=1443195665]
Sort of related, the house I bought this year has two of exceedingly large proportions redwoods in the back yard. There's nowhere that I can stand (including on my roof) where I can see their tops. I'd love to know how tall/old they are, but I'm not sure how to do that. I really like having them around (though it's too bad they're on the north line so they don't give a ton of shade), but holy crap do they drop a lot of cones/twigs/branches. It's like the pine trees I grew up with on the east coast, but times 20.

 
Measure your trees' shadows while measuring the shadow of an object of known height.  The shadows are proportionate to their height, so your trees' height = trees shadow length * object height / object shadow length.

BC
[/quote]

This method works great if one can measure a shadow cast by the top of a tree.  But if there's nowhere that Stupac can stand where he can see the tops of the trees,  that means there's also no place he can get to where he can measure the shadow cast by the tops of the trees.
[/quote]

You don't need a shadow.  Lots of ways to do it if you can reasonably see top of the tree from the ground somewhere.  I had to walk down the street to do it, but I was able to measure the height of a tree in my back yard before Sandy hit since I was worried that the tree could land on my daughter's room.