chinese-elm-seedling-topTrees are such a beautiful part of our world. Not only are they gorgeous and soothing to look at, they provide us with oxygen and shade, shelter for animals, and are incredibly important to sustaining our ecosystem.

So, how do trees grow? Well, it all starts with a seed ...

Germination

Seeds can be carried by wind, animals or water to where they will eventually grow. Once the seed finds the perfect place to start the growing process, it relies heavily on the nutrients it has brought with it from the parent tree. The right mix of water, light, warmth, soil and nutrients the seed will sprout, and send its first stem up and its first root down—becoming a seedling.

Cell Growth

As humans our bodies—bones, skin, muscles, etc.—increase in size as we grow. But, trees don’t grow like that. Tree branches and trunks grow as new cells are produced under the bark. Tree growth does not take place at the base of the tree, but rather in the branch tips. Growth also occurs in the trunk but not upward. Instead, the tree increases in diameter. This happens because trees grow by producing those new cells in limited spots throughout the tree, called meristems, and this is where all the growth takes place.

Meristems at the tree's roots and at the tips of the branches are called apical meristems. Vascular cambium are meristems that cause the trunk, branches or roots to grow in diameter.

The Roots

Meanwhile, under the soil the seedling’s roots are anchoring themselves to the soil and soaking up water and minerals to provide fuel to continue the growth. Once the seedling has gained some strength, the stem breaks through the soil surface and, when its leaves are large enough, the seedling can start to produce its own food through photosynthesis—and continues the meristem growth process.

Hitting New Milestones

Trees are seedlings as soon from the start of the growing process until the tree reaches about 3 feet in height (this varies between species), and then it becomes a sapling. A tree will remain a sapling until its trunk reaches 2 ¾ inches in diameter, and then the tree is reclassified as a young tree. A tree is considered mature when it’s reached just under 12 inches in diameter.

Want to know more details about tree growth? Check out About.com’s video “How Does a Tree Grow in Nature.” These sources were super helpful in creating this article.

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(Photo Credit: http://blog.growingwithscience.com/2011/03/seed-of-the-week-chinese-elm/)

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