My little sister is doing a school project on nature related topics. One thing that I can’t seem to find is how forests form? What stages does a baby forest go through to become a big adult forest? Please help?
Do a Google search on “crown forest” or “fire reforestation” for your best bets.
Basically, an area that can support a forest* is seeded by shrubs and fast-growing, but short-lived trees. As the bushes and smaller trees grow, they provide shelter for the young plants of larger and longer-lived trees. When the larger trees reach maturity, they provide a canopy that denies the smaller plants enough light to thrive and the mature trees simply crowd out the other plants.
*(Usually one that has just been burned off, or a farm that has been allowed to go fallow, although it could include a prairie near the edge of an existing forest where slight changes in climate have allowed the forest to spread.)
Here’s a diagram showing forest succession.
You can also try doing a search on “primary succession” - establishment of plant communities in bare areas such as lava flows, sand dunes, etc. - and “secondary succession” - re-establishment after fire, logging, etc.
The link provided by Colibri is as nice and as succinct an explanation of forest succession as I’ve seen. Of course with such brevity and simplicity often comes a dismissal of deviations and details. So, ringmaster, if your sister does use that website I’d caution her to recognize variations in succession in different geographic regions.
For instance, some areas never move beyond an intermediate stage, this is called physiographic climax (Woo hoo!! I never thought I’d get to use that term outside of my forestry classes!). As such, speaking of forest succession in terms of some inexorible progression towards some end stage may well be inaccurate.
You might also direct your sister to the following link which focuses on early succession of oak-hickory forests which make up a large chunck of the forests in the eastern half of the US and depending on your local may be a more appropriate starting point than refering to a spruce-fir forest.
And here I thought it had to do with guys like Johnny Appleseed.