Violent Destruction Brings Opportunity & New Life

When our general manager in Peru, Fernando Rios, emailed me in early November 2020 saying that a storm had felled hundreds of trees at our Santa Cruz Forest Reserve, I took it in stride. Storms happen, trees fall. I've been in the rainforest when a storm blows in. It can be a scary experience. The forest canopy overhead is whipping back and forth, dead and live branches snap and fall. Trees tip over and the sound of crashing resonates near and far. The air is filled with swirling leaves, seeds, insects and debris. The prudent thing to do is to get out of the forest and into an open area as fast as possible, before something lands on top of your all-too-fragile skull.

As it happens, the afore-mentioned storm brought down a large tree next to our main facilities at Santa Cruz, flattening one set of bathrooms and neatly bisecting the kitchen and caretaker quarters. I wasn't too upset about the damage, the structures were old, not optimal, and in need of being "built back better", as it were. And with flights to Peru opening up again between the US and Peru (as of 1 November), it was an opportunity to travel back to the Amazon and escape the political and media circus surrounding the US elections. Of course, the process of getting to Peru during Covid-19 was quite the experience in and of itself.

Top: One of two sets of toilets/showers at the inland facilities at Santa Cruz. Happily no-one was answering the call of nature when nature called!

Bottom: Several tonnes of tree trunk sliced right though the kitchen and caretaker housing structure. The freezer was definitely a goner, even though it missed a direct hit.

It wasn't until I arrived in Iquitos on 24 November, and then at the Santa Cruz Forest Reserve on 25 November that the enormity of the damage of the windstorm started to sink in. Fernando's statement that hundreds of trees had come down, referred to JUST along the main trail from the river to the inland facilities. In talking with several sources, the true picture started to emerge. In the early afternoon of 1 November, the windstorm swept from northeast to southwest across some 30-35 kilometers (~18-22 miles). Fernando was returning to Iquitos by speedboat from Santa Cruz, and when the storm hit, it was only by having the small speedboat protected in the lee of a larger ship that it wasn't swamped. While the windstorm itself lasted about 30 minutes in any given area, the waves whipped up on the Amazon itself took hours to subside, and once the waves died down and Fernando was able to safely return to Iquitos, he saw dozens of boats along the banks that had been swamped and sunk.

The red oval indicates the rough area that was most impacted by the windstorm.

In Iquitos itself, roofs were blown off, and several people were injured by flying debris - most notably tin roofing sheets. One of our employees and his sister threw a rope across a roofing beam in their house and hung on for dear life to prevent their roof from blowing off. Plantations of bananas, plantains (the cooking bananas) and yuca (manioc or cassava) were flattened throughout the impacted area, and Cecropia (a fast-growing early successional tree) forests on river islands looked like a steam-roller had run over them.

In preparation for reconstruction of the kitchen and caretaker quarters, we had sent a smaller crew to Santa Cruz prior to my arrival to clear away the debris and open up the main trail to the river. All the remaining trails were mostly impassible (except with very frequent and very extensive detours) upon my arrival.

One of the trail "shelters" on the main trail from the Mazan River to the inland facilities at Santa Cruz.

I was still totally unprepared for the level of destruction that I witnessed. Hundreds of trees "down", was just the tippy-top of the tip of the iceberg. While I expected the damage to be more extensive in second growth areas dominated by fast-growing and largely weak-wooded trees, the level of damage in both secondary and primary forest appeared to be similar. Roughly 50% of ALL trees had suffered some kind of damage - minor tippage, breakage of fronds or small branches (at minimum), and tens of thousands of trees suffered major damage - completely tipped over, snapped off (from ground-level to 15-25 meters [~40-60'] above ground level), or with loss of major limbs and portions of their crown. It would have been absolutely terrifying and incredibly dangerous to have been in the forest during the storm.

Blocked trails at the Santa Cruz Forest Reserve

In some areas, the forest would appear to be largely intact, but a short distance later, it was reminiscent of the damage of a Category-5 hurricane. Windstorms of this nature are rare, but not unheard-of in the Amazon. A 2005 event in Brazil featured a 200 km-wide by 1000 km long (124 x 620 miles) front of squalls that killed an estimated half-billion trees. While strong winds are a part of such storms, the real damage seems to be done by micro-bursts, or mini-tornados, that form during the storms. These twisting winds are responsible for many of the snapped trees - imagine taking a head of broccoli and twisting the top part while holding the bottom part firmly. Eventually it snaps. With many of the snapped-off trees, the results of the twisting action is clearly visible.

Apparently intact (left) and lightly damaged (right) forest at Santa Cruz. Catastrophic damage is shown below.

These pictures are just a small sample of the forest damage encountered on site

In the Amazon, when one tree goes down, it seldom goes down alone. The forest canopy is linked with numerous vines and lianas (woody vines), so if a large tree snaps or tips over, not only are the trees directly in its path flattened in the process, but many other trees "tied" to it by lianas may also be pulled down in a chain reaction. As I was writing this, I started to wonder if "tens of thousands of trees" might be a gross exaggeration. After all, how many trees are actually at the Santa Cruz Forest Reserve? We have about 232 ha (~573 acres) of protected land on site, and an article published in the top-tier journal Science (a Fireside Science summary is referenced here) estimated some 565 trees per hectare (2.47 acres), or a mere 490 billion trees across the Amazon as a whole (better deduct a few billion trees per year to account for deforestation, though). The Santa Cruz site is thus home to some 130,000+ trees, and if 50% of them suffered some damage, that amounts to 65,000 trees. Of those, I'd guess that at least 20K-30K, if not more, suffered major damage, so I'll stick with my "tens of thousands" assessment.

It will take weeks to completely clear all the trail network. On this relatively short trail, 3 guys with machetes and two chainsaws required a full two days to re-open the trail. Weakened trees will continue to fall, as will woody debris that is hung up in other vegetation, so additional trail maintenance will be required for months. Here, Rider works the chainsaw while Lider sharpens his machete.

So, does this signal a rainforest apocalypse? By no means, though the damage is certainly significant. As previously noted, such events are rare, but not unprecedented. If, however, climate change means an increasing frequency of violent windstorms in the future, that could have significant impacts on forest structure, biodiversity, carbon storage, and the resilience of the Amazon rainforest to respond to natural and human-created challenges.

There are several immediate short-term consequences.

  • A very large increase in woody debris on the forest floor, as well as standing woody debris in the form of snapped off trees (some of which may branch out and recover). Populations of wood-eating insects will explode, as will the number of fungi that grow on dead wood. Other animals that feed on these insects and fungi will also benefit.

Less than two months after the storm, tiny wood-boring beetles (known locally as gorgojos) are already hard at work on fallen trees, producing little piles of sawdust as they excavate tunnels through the wood. They will be rapidly followed by colonizing fungi, termites, isopods, centipedes and a host of other organisms taking advantage of the new habitat and food sources.

Top row: Armored millepedes are common detritivores in the Peruvian Amazon. In addition to being armor-plated, they also produce cyanide compounds as a deterrent to anything that might wish to eat them.

Bottom row: Not all wood-boring beetles are tiny. Batus barbicornis are large and spectacular Cerambycid beetles. If you are counting appendages in the photo at left, it is a mating pair. The following day I passed the same spot and found the single adult and a presumed larvae pictured at right (and no, the larvae can't possibly grow that fast!).

While most of the action of fungi is invisible to the naked eye, the spore-producing bodies (the mushrooms, toadstools, and whatnots) can be quite conspicuous. Many fungi are heavily fed on by beetles and fruit-flies which help to spread the spores widely. Marasmius species (lower left) have very delicate stalks and come in a wide flavor of colors.

  • A significant increase in the amount of light reaching the forest floor. This is very important in terms of promoting the growth of light- and warmth-loving early successional plants, and also promoting the growth of primary forest seedlings that might have been waiting in the understory for years or even decades for their chance to reach for the sun.

Understory herbaceous plants are already flowering and will see their populations explode in the coming months. Many of these have incredibly hard seeds that can survive for years in the soil, but which germinate rapidly when the soil is heated by the direct sun. The warmth is an indication of favorable conditions for growth - lots of sun and lessened competition for light and nutrients. From left to right by row: Heliconia velutina, Heliconia stricta, Heliconia schumanniana, Heliconia juruense, Heliconia orthotricha, Costus sp., Costus erythrophyllus and Costus (?)amazonicus. Most of these are pollinated by hummingbirds.

  • New micro-habitats have been created that will favor certain sets of organisms. Tip-up mounds provide a dryer and lighter habitat for many plant species. The dirt "walls" created also provide nesting opportunities for bird species that excavate nest holes in banks - kingfishers, puffbirds, and motmots. Meanwhile, the soil cavities created where tree roots were yanked out of the ground often fill with water, providing fish-free locations for frogs to lay their eggs. Such bodies of water are also rapidly colonized by a wide variety of insects that have aquatic life-stages - mosquitos, damselflies, dragonflies, water beetles, and others.

A large tip-up mound (left) with close-up showing dozens of germinating seedlings (center). At right, a water-filled hollow beneath the roots of an overturned tree.

  • Sun-loving butterflies and other insects will see favorable conditions, and can be expected to increase dramatically in numbers. Many of these insects feed (as adults or larvae) on plants that are favored by higher light levels.

Morpho species of butterflies are notoriously difficult to get pictures of. The instant they land, they fold their wings and "disappear". When they fly, the iridescent upper surfaces of the wings appear to flash with each wingbeat. Several species were common at Santa Cruz during my November/December 2020 visit - here two different species give you brief looks (and hey, this was done on a cheap cell phone, I don't have multi-thousand dollar video equipment!)

More butterflies! Here are Parides sp. (cattle-heart) butterflies feeding on Palicourea (Rubiaceae - coffee family) flowers.

Left to right from top: Rhetus periander, one of the common and spectacular butterflies of the Amazon (this one has lost part of a hind wing), Heliconius doris, a common and long-lived butterfly, an Ithomid butterfly (or mimic) feeding at a Coussarea flower, and finally, a caterpillar that screams "don't touch me!"

  • The distinction between primary and secondary forest will be blurred as fast-growing secondary species take off and dominate large tree-falls in primary forest areas. At the same time, undamaged primary forest seedlings that have become established in secondary forest areas will have a chance for a year or two of rapid growth, followed by several years of slow but steady growth, all of which will take them closer to becoming a dominant part of the canopy.

A grab-bag of pictures - left to right on top: A pair of true bugs (Hemiptera) feeding on new growth, Gustavia sp. flower - an understory treelet found in both primary and secondary forest, a young Cecropia leaf in the process of expansion. The fast-growing cecropias can reach 10 m (30') in two years or less of growth.

Bottom row: leaf-flushes and flower cluster of Brownea grandiceps, a common small legume tree of primary forest. With higher light levels, we expect a profusion of new growth and flowers.

  • Lastly birdwatchers, entomologists, botanists and herpetologists will have a couple of years where they have a much easier time of viewing or encountering canopy-dwelling birds, insects, epiphytes (bromeliads, ferns, orchids, etc.), frogs, lizards and snakes!

On a very practical basis, construction of replacement facilities has also been made easier by having a number of high-quality timber trees come down in the storm. We are actively scavenging the wood (and will be able to continue doing so for several years) without having to cut any standing trees. Since many of these trees are close to where the new construction is taking place, it is also relatively easy to transport the cut timbers to where they are needed. Field station construction methods are nothing like what most people are familiar with, and are the subject of this related blog. Enjoy!

The bottom line? Windstorm events like the one documented here may negatively impact many species, but also provide abundant opportunity for many other species. The damage itself is neither good nor bad, it is simply a natural event that helps to maintain the incredible biodiversity for which the Amazon is rightfully lauded. In two years, a first time visitor to the rainforest probably won't notice the damage. In ten years, most of the damage will be noticed only by very observant persons, and in thirty years, only a tropical biologist (or local resident) familiar with the flora and fauna will be able to tell that a significant event happened. Change happens, even in the Amazon.

And how often do you get to encounter a new Phylum of organisms? This horsehair worm (Phylum Nematomorpha, Genus Gordius) was encountered on a trail after a night rain. Gordius species are parasites on crickets, grasshoppers, cockroaches, mantids and some other insects. They effectively sterilize the host and occupy most of the body cavity. Normally they emerge when the insect host is in water, where the Gordius "worm" releases eggs that hatch into microscopic swimming "wormlets" that infect other insect hosts when they are ingested. This one was probably 30 cm (12") in length. Imagine that packed inside of a cricket. There are two records of Gordius species being coughed / vomited up by humans, but let's not go there...

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