Over a short period of time you'd never get the same amount of energy out. However, if you get an average ~20milliwatts of power from a tree throughout a 100 year life time, when you'll get over 17 kilowatt hours of power from a single plant.
However, the real question like with all green power sources is how much land it uses up.
As Kim Stanley Robinson pointed out in his Mars trilogy of books, renewable energy is actually a type of geoforming. The more windturbines we build, the more we effect the flow distributions of winds. Quite literally, if we supplied all of Earths power needs by wind then there'd be so many turbines over the planet that we would begin preventing near-ground airflow.
Equally, at current efficiencies you'd have to cover all the land on the planet to even remotely hope of powering human civilization and in the process you'd destroy all life on Earth. Finally, tree powered Humanity would be kind of cool, but again you'd cover the entire planet in trees and harvest power at much lower efficiencies than solar.
So, in the case of tree power you're much better off doing what some power plants are. Use fast-growing trees, cut them down every 6 months and burn them. It's actually been shown that growing and burning trees produces less CO2 than growing them sequesters, although in the long run unless you put all the leaves and what not in a mine they'll eventually rot and get back into the air or end up in a forest fire or compost or some such eventually making it carbon neutral.
However, the real question like with all green power sources is how much land it uses up.
As Kim Stanley Robinson pointed out in his Mars trilogy of books, renewable energy is actually a type of geoforming. The more windturbines we build, the more we effect the flow distributions of winds. Quite literally, if we supplied all of Earths power needs by wind then there'd be so many turbines over the planet that we would begin preventing near-ground airflow.
Equally, at current efficiencies you'd have to cover all the land on the planet to even remotely hope of powering human civilization and in the process you'd destroy all life on Earth. Finally, tree powered Humanity would be kind of cool, but again you'd cover the entire planet in trees and harvest power at much lower efficiencies than solar.
So, in the case of tree power you're much better off doing what some power plants are. Use fast-growing trees, cut them down every 6 months and burn them. It's actually been shown that growing and burning trees produces less CO2 than growing them sequesters, although in the long run unless you put all the leaves and what not in a mine they'll eventually rot and get back into the air or end up in a forest fire or compost or some such eventually making it carbon neutral.