TropicalOkay, so the first thing I always thought of growing up is the idea of "the tropical rainforest" and immediately picturing the Amazon. I know, very original.
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Plants in forest biomes are responsible for roughly 75% of the world's gross primary production |
Cloud Forests, a unique type of wet tropical forest, is situated within cloud cover, providing non-precipitation access to fresh water |
Where we have one extreme, we're actually able to experience another. As cloud forests have a unique atmospheric water reservoir, tropical flooded forests have theirs at ground level. This biome isn't necessarily specific to tropical areas, but are very typical of them, creating idiosyncratic hot, wet habitats that we typically associate with swamps. Of course, this starts straddling the line of wetland vs. forest, so we'll stop there for this breakdown.
In addition to wet tropical forests, we have dry tropical forests as well. That's kind of a misnomer, since dry tropical forests can still garner hundreds of centimeters of rainfall per year, but they experience a dry season. During this season, broadleaf forest trees will lose their leaves, allowing for retention of water until the next wet season. The other type of dry tropical forest is coniferous, whose trees retain their leaves year-round, and are comprised of conifers that have adapted to variable climate conditions and low-to-moderate rainfall. |
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Additionally, the closer we get to the poles, the more extreme seasonal sunlight availability becomes. During these regions' winter months, sunlight is limited, perhaps only being provided for several hours of the day. Coupled with the drier conditions and lower availability of water stores, trees tend to go dormant, dropping their leaves and taking their resources back into their trunks and root systems until wetter, warmer seasons return.
BorealWhich brings us to our final broad category, the boreal forest. Growing up, I was taught this region as a taiga, but boreal gives us a little more information based on its etymology. The word comes Latin origins meaning "northern" or "of the north" occasionally in reference to mythical gods of the north wind. Taking this origin, we'd probably assume these forests appear in the northern parts of Earth, and this would be true! The boreal forests span the northern reaches of the planet, mostly Canada and Russia.
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Temperate deciduous trees drop their leaves in cold climate seasons when water isn't as readily available, generally being locked in snow and ice |
Boreal forests, also known as taiga, get their name from Latin origins and mythological gods of the northern wind |
Common CharacteristicsNow that we have a decent grasp on the spectra of forests that exist on our lovely planet, how is it that we know we're looking at a forest? How do we tell the forest from the trees?
Where I live, in the midwestern United States, I've learned that one way is to gauge the biome by its abundance of tree cover. That is to say, for a given amount of terrestrial area, how much of that area is covered by mature trees? The general rule of thumb I was taught getting into woodland ecology is 0-10% cover is a prairie, 10-30% is a savanna, 30-80% is a woodland, and 80-100% is a forest. You'd guess correctly that there is likely a lot of debate over where to draw the line between a woodland and forest, and I tend to agree that this distinction is hard to make. Suffice to say, if you're having difficult time seeing sunlight under the trees, you're likely in a forest! |
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We rise up another layer to the canopy, mostly comprised of avian species. As this is the highest portion of the forest for most of the trees, a lot of fruit growth appears here, attracting many species. The canopy can be used as a bit of a highway for creatures able to traverse the trees. This may sound a bit contradictory, but while the canopy sounds like the topmost layer, it's just where the majority of trees form a shield against sunlight from filtering into the forest. Due to this, we can understand that, while getting less sunlight, anything beneath the canopy is also protected from particularly high heat.
Beyond the canopy, we have the emergent layer, which, true to its name, is comprised of the trees that have emerged beyond the canopy of the forest. This layer is relatively inhospitable, being comparatively dry to the rest of the forest. In tropical forests, this area is also remarkably hot, not benefiting from the shade of the dense interlocking of trees granted by the canopy. Here, we'll find our tertiary avian predators, who will dwell away from the rest of the forest, diving into the canopy layer to feed on other smaller birds and other animals. Despite the type, these 4 layers of habitat should be distinguishable in a forest biome! |
Forests have 4 major layers teeming with different types of life which include the forest floor, understory, canopy, and emergent layer |
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