Why do some trees drop their leaves every fall (deciduous), while others hold onto their leaves year-round (evergreen)?
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There are tradeoffs between the two strategies. In the winter, leaves are a liability because they vastly increase the surface area of a tree, leading to increased water loss from evaporation and providing more places for snow to accumulate.
On the other hand, having to grow new leaves every year is challenging because leaf growth requires the use of soil nutrients. In nutrient poor soils these will not be available year after year. Leaves also become less efficient at photosynthesis as they age.
Evergreen trees have evolved leaves with minimal surface area (what we call needles), this reduces some of the concerns with water loss and snow accumulation in the winter, but even evergreen trees have to replace their needles eventually.
In the fall, you may notice needles on evergreen trees turning yellow or brown on the interior of a branch. If the young needles on the outside are still green, but the older needles on the inside are dying, the tree is probably just replacing the oldest cohort of needles.
Needles typically last 2-5 years, depending on the species. If the brand-new needles on the tip of the branch have died, though, the tree is likely to be affected by disease, pests, or drought. This is a much more concerning situation.
Different strategies will win out depending on the soil conditions and climate. Plants have found so many incredible ways to adapt to the challenges of our world!
The above photo was taken on the traditional land of the ǔmssk̇ǎaṗiiṗiik̇ǔni, Kootenai, Selis, and Qlispe People. 📍
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Some ice is obvious—maybe you picture a glacier or a frozen lake—but other ice is much harder to find.
For example, many surfaces in the world around us are porous—able to be penetrated by water. Wood is porous, as are cracks in a mountainside or asphalt in your driveway. We can see the water on the surface, but there can be a lot of water hidden out of sight.
How do animals know when to start preparing for winter?
NPS / Jacob W. Frank
It’s not just from memory of years past—even young born that spring, who have never seen a winter, know to start readying. For many animals the answer lies in a part of the brain known as the pineal gland.
The pineal gland, which receives light information from the retina, produces melatonin only when it’s dark. As nights grow longer during the fall, melatonin will accumulate in the bloodstream. The increased melatonin levels trigger a series of changes, including the autumn molt.
Leave No Trace Principle #3: Dispose of Waste Properly♻️
Pack it in, pack it out! This saying is common among backcountry hikers, but is good advice for everyone. Whether you’re hiking or relaxing, be sure to properly dispose of all trash and food scraps. (1/4)
While it may be tempting to toss apple cores, banana peels, and orange peels on the ground, they do not decompose well in many places.
They may get eaten by wildlife, and potentially cause harm to the animal or contribute to habituation. (2/4)
If you see trash where it shouldn't be, please pick it up!
It takes everyone to keep the 🌏 clean. (3/4)
What runs but never walks, murmurs, but never talks, has a bed but never sleeps, and has a mouth but never eats?
... a river! 💧
When you watch the crystal-clear rivers and creeks of Glacier, they seem to have a life of their own.
Thanks to melting snow, creeks and rivers flow fast in the spring—their water level rises, and they run brown with debris. As snowpack diminishes late in the summer, some creeks dry up entirely, and rivers shrink back to reveal their rocky shores.
At first glance, it may look like trees lined up against a vibrant sky. But hold on, is that a reflection?
This photo shows off a delightful phenomenon—rock flour—responsible for the color of many of Glacier's lakes and streams.
What is rock flour?
To answer that, you have to start with Glaciers. Glaciers are distinguished from other bodies of ice by the fact that they move. As they move, they grind and scrape the ground beneath them, pulverizing rock into particles so small they resemble flour.
When this flour-like substance finds its way to water, it gets suspended throughout and is very slow to sink.
How does rock flour turn a lake blue?
While rock flour is a terrible gluten-free alternative when baking, it excels at reflecting turquoise and blue light.