(ABOVE: This used to be tree. Photo courtesy: Paul Orosco. BELOW: I stole this picture from the Internet as I couldn't find my own lightning photos... Anyway, this tree looks typical of a negatively charged lightning strike. A narrow stripe of bark is carved out.)
Trees struck by lightning rarely die from the actual lightning strike. The lightning usually doesn't penetrate the wood very well, and superficial bark wounds usually result. More than 90% of such strikes are of negative polarity.
Typically, the lightning strike resembles work done by a paint scraper. The tree looks like someone carved (as in the above stolen picture) out a thin stripe of bark. You can usually follow the lightning strike/missing bark trail from the top branches toward the base.
The lightning damage sometimes ends before reaching the ground. You might notice the bark channel stopping about 10 feet or so above the roots. If you see this, the lightning likely jumped to another object to finish its cloud to ground connection. This commonly occurs as lightning jumps from trees to homes or to metal fences, whatever conducts electricity more easily.
The tree usually survives the initial strike, but the now weakened tree is susceptible to bug infestation and disease.
As a second grader, I remember a 100 foot tall pine tree in our front yard in Orange, TX. The tree survived the lightning strike but died months later due to pine beetles.
(ABOVE: Paul Orosco took these pictures in Okmulgee. This could be the result of positive lightning. Either way, it's just as dead.)
About 2-5% of cloud to ground lightning strikes are positively charged, and they do much more damage.
Positive strikes are much hotter, last longer and carry much more electricity. House and forest fires are often caused by positive lightning. Tree also don't fare as well.
Aside from the one picture which I stole from somewhere, the tree pictures on this page are from 2NEWS viewer Paul Orosco. The properties of the tree and exact path of the lightning can obviously factor into how well the tree fares, but I'm guessing that Paul's pictures could be from a positively charged lightning strike.
And I'm fairly positive the tree is dead!