Re: How can a tree hit by lingtning still live?

The electrical pulse delivered by lightning doesn't kill trees.  Note you 
have it spelled wrong in the National Geographic WWW reference, but people 
correct the spelling the address works. What happens is the resistance to 
the electrical flow generates a lot of heat, quickly, and water in the 
tree sap literally boils, turning into steam and expanding many times, the 
exact principle that runs steam engines.  The expanding steam literally 
blows the bark off the tree.  In some cases the wood can exploded by the 
steam. You use this principle to pop popcorn.  The water inside the 
popcorn grain is heated and turns to steam.  The sudden increase in 
pressure, held in by the hard endosperm, causes the grain to explode, 
greatly decreasing the density of the endosperm in the process.  Of course 
you use the stove or microwave to generate enough heat to pop the popcorn, 
but you could use an electrical current.  If you have an electric stove or 
a toaster, resistance to electrical current causes the element to heat and 
glow red.    

Not all trees struck by lightning die because under some circumstances the 
electricity is conducted to the ground without generating enough heat to 
damage the tree.  You can see lightning scars on many old trees, where 
lightning caused some damage, but not enough to kill the tree. Lightning 
rods on houses are designed to conduct a lightning strike to the ground 
safely so the resistance doesn't start a fire.