Explaining the world one sketch at a time

Ponderosa pine and its bark listing out some of the fire protections it has

Ponderosa pine fire protections

Many trees and forests were built to live with fire and in many cases, fire is essential for a healthy ecosystem. Giant sequoias, for example, have cones that dry out during surface fires releasing their seeds so they can germinate at the ideal time to grow with less competition. Ponderosa pines have a number of ways they have evolved to live with fire. They have bark that when heated can split off from the tree protecting the trunk and reducing the spread of fire. They often lose lower branches, sometimes from smaller fires, reducing the likelihood of ladder fires that climb towards the crown. The shade they cast and the acidic soil they favour helps reduce understory plants that could catch fire beneath the tree and help a fire to latch onto the main trunk. They have deep roots that can remain intact after a fire allowing the tree to still gather water and nutrients even when surface roots are damaged. Some policies of suppressing natural fires have changed the balance of many forest systems and helped promote some of the recent mega-fires. More about the Fire ecology of ponderosa pines (pdf). Also see: identify a douglas fir, time hierarchy
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A bowl repaired with kintsugi with bright gold seams visible next to a flower


Kintsugi is the repair of a ceramic item, perhaps a bowl or vase, with a bright gold seam. Like wabi sabi, kintsugi reflects a view that wear and use of an object adds value rather than detracts. Rather than try to hide the past damage and the repair instead it is celebrated and enhanced. A bowl repaired with kintsugi might be seen as more valuable than one that had never been broken. An ebook might reload the same every time. A book, instead, accumulates its previous use in its pages and appearance — the slight bend in the pages, discoloration from fingerprints or sunlight, creases in the spine at frequently visited pages, a pencil mark here and there. The book itself hints at the story of its own life. A well-thumbed secondhand book can be a beautiful thing. You may have noticed some modern kintsugi in Kylo Ren's helmet.
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Two hikers look at distant lightning and count how long it takes to hear the thunder to estimate how far the lightning is away

Flash-to-bang method

How far away is the storm? The flash-to-bang method can help. When lightning is made by a storm the rapid heating and expansion of the air create the thunderclap. But because sound travels slower than light, there's a gap between seeing the lightning and hearing the thunder it produced. Using Distance = speed x time, by counting the seconds from seeing the lightning you can easily estimate how far away it is. Conveniently, the speed of sound in air is about 330 metres/second. So depending on your unit preference: every 3s you wait the thunder travels about 1 km every 5s you wait the thunder travels about 1 mile Give it a try at a safe distance from your next lightning storm. Also see: thunderclap or rumble, thunder clouds, dirty thunderstorm
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An urban area next to a more natural rural area showing how the urban area gets hotter than the surrounding land

Heat islands

Heat islands are urban areas that can have higher temperatures than surrounding rural areas with more greenery. Heat islands are caused by a number of factors including: the types of materials we use in cities for buildings, pavement, and roads that can absorb more heat than natural surfaces such as leaves or grass human additions to the sun's heat such as air conditioning, vehicles, cooking, or machinery that shapes of our cities that may restrict airflow to carry heat away the mass of our buildings that can absorb heat and release it gradually, even through the night More natural, often rural areas with greenery may reflect more light, release moisture and provide shade. There are ways to help reduce the effect of heat islands such as planting more urban trees, or using green roofs. Deciduous trees have the handy feature of providing shade for a house in the summer while letting light through in the winter when the leaves fall. Learn more about the heat island effect
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