I was asked about forest regrowth after a fire, or any disaster really. Why do they grow back different from what they were originally?
I've been doing some research, it looks like it's just a high degree of random effects.
When a fire sweeps through a forest what regrows is called Secondary Succession. The picture up top helps illustrate this process. Pioneer plants quickly take hold and gradually change the landscape. Dependant upon which seeds spout first can change how much of the ground is shaded and the soil composition thus possibly creating a new set of conditions with new plant growth as the return of the forest begins.
Many times even as fires are tearing through a forest, the start of new tree growth is already happening. The heat from the burning trees pops open the cones on those trees, releasing seeds that have been waiting to get loose for years. Within 30 or 40 years, many won't even be able to tell there was forest fire there.
Scientist say that fire is a natural part of the forest’s regeneration system and that most forest trees need to be exposed to fire every 50 to 100 years to invigorate new growth.
But as I said above, it's a high degree of random effects. Weather patterns can also play a big role in how the new forests develop. If there is a drought after the fire, that could kill the newly released seeds and short-circuit any new growth, giving new species of trees a chance to grow in the area. Normal rains mixed with the nutrients left on the ground from the fire could be a great booster shot to getting the seeds off to a flying start.
I'm not sure how helpful this was, I certainly learn something new though! Hope you did too!
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