Respite Cascade, Victoria, Australia

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This photograph shows one drop in a roughly 400 meter (1300 foot) long cascade that flows down a very steep hillside. Dense vegetation, enormous fallen trees and woody debris along the sides of the stream allowed access at only two spots along the short but difficult hike. This is one of them. It is normal for rivers and streams in old growth forests to contain lots of logs, tree limbs and other forest debris, but the amount here is exceptional. This is because the entire area burned in Victoria's Black Saturday bushfires in February 2009. Fourteen years later there is significant regrowth and the enormous mountain ash trees, some more than 114 meters (375 feet) high, are starting to fall. When this happens a single tree and its branches smash everything in a surprisingly large area. This generates even more debris, some of which finds its way to the water during heavy rains.

Until recently fires seldom occurred in wet rainforest environments like this. Human caused climate change is creating more severe droughts more frequently, and today fire is a significant threat. Essential oils that give eucalyptus trees their fragrance are highly flammable. They also produce large quantities of flammable material on the forest floor in the layer of leaf litter. This makes it easy for a fire to get started and spread quickly. In addition the outer layer of bark on eucalyptus trees dies each year and peels away in long thin strands that can be many meters long. These are often seen hanging from tree trunks, on the branches of all foliage in these forests, and on the forest floor. These quickly take fire high up into the canopy and form burning embers that can be cast 30 kilometers (18 miles) ahead of a fire. Fires in Australia have been measured traveling up to 72 km/h (45 mph). Eucalyptus trees have some ability to re-sprout after a fire and their seeds often survive fires, but today's more frequent and intense fires limit the ability of these forests to regenerate. Not only does climate change create more severe and frequent droughts, but rains between them are also more intense. Heavy rain on on a severely burned forest creates landslides and heavy runoff that is full of mud and wood.

As damaging as fires are, logging has historically been far more damaging to these old growth forests. Fortunately a landmark supreme court judgment in November of 2022 found that the state-owned logging agency, VicForests, has broken the law by failing to protect endangered species. Accordingly, all logging of Victoria's native forests stopped at the end of 2023. Since Australia's mountain ash forests have the highest biomass carbon density of any forest on earth, this court decision is beneficial for the world's climate and our forests, not to mention the diverse species of plants and animals that these forests protect.