After 11 interviews with experts on native reforestation, holistic orchard management, water retention landscapes, perennial crop agriculture and more, I learned a lot of new things about the state of the world’s forests and the tools and knowledge we have to regenerate them. I wrote this article originally as a special episode for the podcast, so be sure to check out the Reforestation and Agroforestry series if you’d prefer to listen to this information and hear clips from the people interviewed.
To wrap-up the series in this article, I’ll break down some of the information and statistics that will help you understand the major role that forests play in maintaining a healthy climactic balance on earth. I’ll also break down how both past and current practices have put forests at risk all over the world and how many well-intentioned projects are causing unintended damage. I’ve also catalogued many inspiring examples of productive and healthy reforestation and agroforestry projects, to hopefully offset some of the difficult realities you’ll learn about in the beginning.
Personally, I learned a ton in the research for this article as well as from the perspectives of the people I had the pleasure to interview. Before you read further I just want to make it clear that I got all of this information from the most reliable and up to date sources that I could find. None of these statistics are my own, but for the sake of keeping things easier to read, I’ve put links to all of the articles that I pulled information from at the bottom of the page. I really encourage you to check these resources out because there’s so much more mind blowing information than I could summarize here from sources like national geographic and research papers from professors at Rutgers University. So let’s explore the world of forests from the beginning.
Forests and their services
Forests cover approximately 30% of the world’s terrestrial surface and provide essential ecological benefits to the entire planet. They are often credited as one of the greatest defences we have against climate change and loss of biodiversity. Tropical forests alone are responsible for around 34 percent of photosynthesis occurring on land. Tropical forests are also where about 50 percent of all terrestrial species are found.
All types of forests also store tons of carbon through a complex network of methods that build on one another. The leaf litter and mulch that forests constantly shed helps to sequester carbon in soils and creates habitat for mycelium, insects, and bacteria that build rich nutrient dispersal networks and feed all the plants around. The root networks of the trees not only hold the soil in place to prevent erosion, it also allows for greater infiltration of water. Surprisingly, this vast network of roots and their symbiotic relationship with mycelium is also how forests store most of their carbon. You might logically think that the organic matter that accumulates on the soil’s surface–such as in leaf mulch–is what breaks down and stores most of the carbon, but nearly half of the sequestration actually happens much deeper as fungal networks work with tree roots to exchange the minerals that they break down for the simple sugars that the trees produce through photosynthesis. Since these exchanges happen deep under the topsoil, the organic matter doesn’t oxidize and instead stays buried as it breaks down into its elemental parts. To put it in perspective, the world’s forests contain more than 55% of the global carbon stored in vegetation and more than 45% of that is in the soil.
The effect of forests in preventing the freezing of soil is of major importance in increasing the amount of water that percolates into it, particularly during the spring months. The humus layers, we think of as characteristic of any healthy forest in cold climates, absorb between two to four times their weight in water. The water-holding capacity of humus rich soils is much higher than mineral or compacted soils. Forest soil, with its decaying organic layers acts as a huge sponge capable of absorbing much more water per unit area than soil out in the open. In turn, the shade from tree canopies protects and cools the ground temperature of soils below during the hot and dry months, which is no small matter. It’s estimated that the loss of moisture through evaporation from the surface of the soil out in the open on a windy day may be five times as great as the loss of moisture from forest soil of similar character under the protection of canopy cover. I could go on and on about all the services and gifts of forests from wildlife habitat, water transpiration and “seeding” the clouds to increase rainfall, to say nothing of the fuel and building materials in wood.
One of the ecological functions that often gets credited to forests is the creation of oxygen. I’ve seen all kinds of sources that claim the Amazon is responsible for 20% of the world’s oxygen that I believed it too. It turns out though, that that’s just not the way the oxygen cycle works. Trees can only produce as much oxygen as the CO2 they take in, and given that the percent of carbon dioxide in our atmosphere, even at current elevated levels, is only about ½% of the air we breathe, it’s just not possible for plants to make a major contribution to the 8% of oxygen in our air. On top of that, most plants actually absorb oxygen at night when their leaves are not photosynthesising in a process called cellular respiration, to the tune of just over half of the oxygen that they release during the day. When you consider all the oxygen consumed by all the animals, insects, and bacteria that forests support, the net amount of oxygen that they create is actually around 0. It’s mostly a closed loop system. The largest producers of oxygen are actually a tiny species of phytoplankton called Prochlorococcus which live near the surface of the ocean and are so small that millions can be found in just one drop of water. Unlike other plants which usually oxidize when they die, releasing much of their embodied carbon to the atmosphere, these phytoplankton drop to the ocean floor and decompose in an anaerobic environment so their carbon is trapped below the sea. Even through these methods, it’s taken millions of years of geologic time to create the 8% of oxygen that we now rely on with this cycle and even a major disruption wouldn’t likely have an effect on the percentages in our atmosphere for millions of years after. The Amazon rainforest alone contributes around 20 percent of the oxygen produced by photosynthesis on land—which may have incorrectly slipped into public knowledge as “20 percent of the oxygen in the atmosphere. So even though forests may not be net oxygen producers, they still have a major role to play in their effect on the atmosphere as they do have the capacity to store huge amounts of carbon, both in their biomass and in the soils they foster.
Different types of forests
Though I’ll continue talking about forests in general terms throughout this episode, I want to make sure that I distinguish between the different types, because they certainly aren’t all the same and depending on what type of forest we talk about, they might behave quite differently as ecosystems.
Tropical forests are the ones that get a lot of press these days, and for good reason. They’re among the most endangered ecosystems on our planet and in the last few years they’ve been disappearing at an accelerated rate. These are the jungles and rainforests that occupy the area closest to the equator mostly in South America, central Africa, and southern Asia. Most of the carbon pools in forest vegetation are located in tropical forests to the tune of about 62%. These are also incredibly biodiverse regions with as much as 90% of terrestrial species living at least part of their lives here. One thing that surprised me to learn about tropical forests before I visited them myself was that they’re also characterized by pretty poor soil and not much of a topsoil layer at all. This is due to a number of reasons including water access from regular rains near the surface of the soil and because photosynthesis is so constant, the nutrients that drop to the forest floor just get sucked right up by plants and stored in the canopy. The consistent damp and warm temperatures in the tropics also accelerates decomposition and anything left just gets eaten up by the riot of life in these ecosystems.
Further away from the equator you’ll find Temperate forests. There are a lot of sub classifications and differences within the three main categories, but we won’t go into too many specifics. One type of temperate, or subtropical forest I’ll mention are Mediterranean forests which is the environment in which I live now. They’re characterized by dry arid summers and rainy winters. They tend to be dominated by pine, oak and other drought tolerant tree species and shrubs. Though Mediterranean forests only account for about 1.5% of the world’s forests they’ve served as essential ecosystems and sources of economic exploitation by humans for thousands of years. They also register lower water-retention potentials than other evergreen forests.
Finally moving to the farthest regions from the equator we have Boreal forests. There are only two seasons here: a short, moist, mildly-warm summer and a long cold dry winter. Most of the carbon pools in forest soils are located in boreal forests, accounting for 54%. They also account for the largest percentage of virgin forests left on earth, predominantly in areas of Russia, Canada and Alaska. The densest areas of tree coverage are also in the boreal forests near the Arctic. Despite their dense coverage, cold climates have just 24% of the tree species, whereas the tropics and subtropics support almost 43%. The rest are distributed throughout other places, including temperate zones.The ground is comprised of a very thin layer of nutrient-poor, acidic soil, and the canopy lets very little light through so there is usually little growing in the understory. Evergreen conifers with needle leaves that can stand the cold, like pine, fir, and spruce trees, live here. Coniferous forests in general, though less biodiverse than their tropical counterparts, retain about 10% more water than broadleaved forests or mixed forests.
The state of forests all around the world, in general, is pretty grim. The Earth loses on average 18.7 million acres of forest per year and about 15 billion trees. Most of that is due to human activity. It’s estimated that about 5 billion new trees are planted or sprout annually, yielding a net loss of 10 billion. For reference, the trillion tree project has so far planted 13.6 billion trees in roughly 14 years. While that’s a valiant effort and we certainly need programs like this, it’s not even enough to offset the deforestation of a single year. An exhaustive recent study has calculated that there are about 3 trillion trees on the planet today, which sounds like a lot, but this represents only 45% of the total number of trees that had existed before the rise of humans meaning that the Earth has lost more than half of its trees since humans first learned how to wield the axe.
Deforestation however, is not evenly distributed. Most modern deforestation is concentrated in a few key areas around the world. Countries with significant deforestation in the last few years included Brazil, Indonesia, Thailand, the Democratic Republic of Congo and other parts of Sub Saharan Africa, as well as parts of Eastern Europe.
Here’s a break-down of some of the most affected areas and a few of the main drivers of forest loss.
Brazil, Peru, and Bolivia, representing the Amazon rainforest, are mostly threatened by the expansion of cattle ranching, soy, and illegal logging. For the last decade, deforestation in the Amazon had been slowing down, but in recent years, for a number of different reasons, it has seen a rapid increase. Remember the Amazon fires from summer 2019? Those were mostly concentrated in these three countries.
Indonesia, representing the largest rainforest in Asia, at the moment is threatened primarily by the expansion of the palm oil industry and illegal logging.
Russia, which has the largest forests on the planet at around 12 million km2 or 70% of the world’s boreal forest, is even larger than the Amazon rainforest. Russia’s forests contain more than half of the world’s conifers and represent more than 10% of all the biomass on Earth. It is estimated that 20,000 km2 are deforested each year, with areas nearer to the chinese border being the ones most affected, since it’s the main market for their timber. Deforestation in Russia is particularly unfortunate because the forests have a short growing season due to extremely cold winters and so they take longer to recover. An estimated 25% of the world’s untouched forests are located in Russia.Sadly, these forests are also at a high risk of fire with over two thousand miles of woodland lost each year to the blazes.
Mexico is seeing rapid loss of its few remaining tropical forests, often to avocado plantations. Even though this is agroforestry, the loss of native habitat is threatening many endemic species including the monarch butterfly.
Papua New Guinea is increasingly threatened by logging and palm oil.
Sudan has seen 500 miles of trees cut down for home cooking and heating among industry threats.
Nigeria, which was once a vast land covered in forest. Today has only around 6% left due to the use of wood for cooking and heating. The rates at which Nigeria is losing its forest is one of the highest in the world.
Vietnam has the second highest rate of deforestation of primary forests in the world, second to Nigeria.
Other Southeast Asian countries where major deforestation is ongoing are Cambodia and Laos, which border Vietnam.
The most common pressures causing deforestation and severe forest degradation are agriculture, unsustainable forest management, mining, infrastructure projects and increased fire incidence and intensity.
Though it’s easy to point out that many of the countries with the highest rates of deforestation in the last few years are generally lower income regions (for example, Nigeria, Indonesia and North Korea have the world’s current highest rates of deforestation), and that China and the United States have the lowest, it’s worth pointing out that 90 percent of the continental United States’ indigenous forest has been removed since the 1600’s. China and Europe have also removed the vast majority of their forests over the last few hundred years. They simply cut down their forests a long time ago and are finally realizing the negative effects. These regions also represent some of the largest markets for imported timber and are, in many ways, driving the deforestation of other areas. It’s worth knowing too that as a general rule, the planet’s forests are being cut down at an even rate with population growth. The World Resources Institute estimates that most of the world’s remaining indigenous forests are located in Canada, Alaska, Russia and the Northwestern Amazon basin
The Amazon is the most biodiverse ecosystem on land, and climate change and deforestation are putting that richness at risk. Unlike coniferous forests in other areas of the world such as the Western US, The Amazon and other tropical rainforests didn’t evolve as fire ecologies and the bark and foliage of the trees there can’t withstand a serious burn like many of the trees of temperate regions which evolved with regular fire cycles. The 84% increase in fires from last year, due mainly to man-made fires, seems to be caused by direct policy changes since Brazil’s recent elections. In other places the causes are not as well known. In the last few months, Australia’s fires have seen 14.7 million acres burned, with drought and high prolonged temperatures seeming to be the main culprits, though human interference has resulted in arrests and fines as well. The scary part is that weather extremes like this are predicted to increase in years to come due to climate change.
In the United states, California’s fires have been the point of scrutiny and speculation for over a decade now. Though 2019 was not as devastating as the previous two years, California has seen more than 20 million acres burned since 2017 alone. In this case, though extreme weather conditions and drought have played a factor, many people are looking at the way fires have been increasingly suppressed in the last few decades and claim that regular controlled burning (which native peoples in the area have been known to practice since long before european settlers) would decrease the fuel load and prevent larger, uncontrolled, and devastating burns. There’s a fantastic talk by Paul Hessburg that explains this in much more detail that I highly recommend.
Ultimately, forest fires have quite a few factors that make their control difficult. Undoubtedly humans are behind the most severe and damaging of them. Between incentives that encourage active burning, short sighted management practices that create the conditions for huge uncontrollable fires, or even the climactic impact that our industries have on irregular weather patterns and warmer temperatures, we need to take a hard look, not only at the effect these actions are having, but the legacy that this destruction will leave behind for generations to come.
Reforestation efforts, and why they’re not always the solution
It would seem though, that there is some good news in all of this mess. For the first time in decades, some areas of the world have seen a net gain in forest cover.
Forest restoration is still the best large scale climate change solution available today. Major reforestation programs around the world are more important now than ever. The global tree restoration potential report found that there is enough suitable land to increase the world’s forest cover by one-third without affecting existing cities or agricultural land. However, the amount of suitable land area diminishes as global temperatures rise. For example, even if global warming is limited to 1.5 degrees Celsius, the area available for forest restoration could be reduced by a fifth by 2050 because it would simply be too warm for certain tropical forests. It turns out that more than half the potential to restore trees by this criteria can be found in just six countries: Russia with 151 million hectares of non-disruptive reforestation potential.
The USA with 103 million
Canada with 78 million
Australia with 58 million
Brazil with 50 million
China with 40 million.
Those countries have so much potential because they’ve already removed a major portion of their forests. As far as the top tropical forest restoration hotspots go, all the major ones are in Africa, with Rwanda, Uganda, Burundi, Togo, South Sudan, and Madagascar topping the list. Since so much land has been degraded due to extractive agricultural practices spreading around the world, reforesting some of the marginal cropland and pasture lands could bring great opportunities to regenerate that land and restore the diversity of species at low cost and low risk. There are also a whole range of benefits to local people that come from forests economically, socially and health wise.
An Ecological Economics study found that degraded ecosystems cost world agriculture $6.3 trillion a year. Research in Latin America and Africa shows that every dollar you spend on forest restoration means $7 to $30 in benefits. Unfortunately, instead of investing in ecosystem regeneration, around the world industry and governments are subsidizing things like logging and annual crop agriculture that lead to native forests being cut, and not subsidizing or protecting the forests that are being lost.
Facts like that used to make me think of developing countries in other parts of the world that are slashing the tropical forests for cattle ranches, palm oil or soy plantations, but it’s a big problem in North America as well. An example I read pointed to the case of North Carolina, which is home to some of the most bio-diverse forests in the continental United States. There they give landowners property tax breaks to sell their forests for logging, but there’s no incentive to conserve them. It turns out that we’re not even at the point of arguing for incentivizing forests. We’re still struggling not to encourage their destruction.
While of course, reforestation projects are incredibly important there’s still vital importance in protecting existing forests and, of course, phasing out fossil fuels. For as much ecosystem service potential as new forests have, they would still take decades to mature, with most of their effects only coming on gradually.
Before I go and give all the carbon capture credit to forests, I need to point out that grasslands in fact have a greater potential for carbon sequestration than forests if managed correctly. This comes as a surprise to a lot of people because we don’t think of grasslands being nearly as lush or vegetated, but here’s how it was explained to me so I finally understood. Forests are like a snapshot of decades, if not centuries, of carbon capture. You see it all at once. Grasslands however, usually only show the carbon capture of a few weeks or months because they’re constantly being eaten and trampled down where they decompose and turn into soil or manure (if naturally managed). Since they can go through this growth and die-back cycle multiple times in a year, they can account for more net growth and soil building than an old growth forest which is not growing as vigorously. In some cases, reforestation projects are planned to be installed in what would naturally be grassland, and while a forest is a better option than an industrial farm, grasslands are also critically endangered ecosystems and their preservation and regeneration should be considered just as important as forests in the correct context.
Joseph W. Veldman, of Iowa State University, and his colleagues in an article for the October issue of BioScience, in which the authors argue that “forest and tree-focused environmental policies and conservation initiatives have potentially dire ecological consequences for undervalued ecosystems, such as grasslands, savannas, and open-canopy woodlands. So long as carbon stored in trees is valued above other ecosystem services, the conservation values of grassy biomes will remain threatened by agricultural conversion, fire exclusion, and ill-placed tree planting.”
Problems with many reforestation efforts
So the solution is obvious, right? We should just support reforestation programs and start planting trees right away. The more the better, right? Well it turns out that it’s a lot more complicated than just planting trees everywhere we can. The majority of reforestation projects are centered around planting monoculture plantations of commercially marketable species, primarily for lumber. These programs are responsible for most of the forest gain in the US and China in the last handful of years and these timber plantations come with a lot of their own risks. Monoculture plantings of trees, just like any other crop, are devastating for biodiversity and animal habitat. They are also very susceptible to pests and diseases like in the case of the japanese beetle kill zones in the western US. Since they’re often occupied by fir and pine species planted as close together as possible, they can also create a major fire risk. Because these plantations are at odds with nature they also require a lot of management and resources to maintain. Though they look very green and lush from a distance and they do serve a few ecological functions like soil retention, they’re just as unsustainable as any other industrial farming method. I’ve even heard them referred to by members of the permaculture community as “green deserts.”
Even the most well intentioned reforestation programs from nonprofits have often been ineffective. Many of them start out by setting lofty goals and set out to plant trees in order to meet arbitrary numbers and quarterly targets. “Trees planted” are also not equal to “trees grown.” Many species take a minimum of three years to become established with high rates of failures before that time. It’s important to keep track of the trees over time and make sure that they’re surviving and multiplying.
In a few cases, poor understanding of the ecosystems which we’re trying to reforest can lead to unintended consequences once the trees have been planted. Take for example China’s green wall initiative. A massive reforestation belt along the southern edge of the Gobi desert which was planted to stop the advancement of desertification which has been encroaching rapidly for decades. Though the concept was sound, the trees that were planted were mostly fast growing, non-native species. Once established, they began to drink up so much water with their deep roots that the water table has now dropped to dangerous levels in those areas.
Or take the example of Japan after WWII. During the war, huge swaths of forested countryside were cut down to provide energy for Japan’s war efforts. After the war, there was a huge demand for timber, mostly to aid in reconstruction, which resulted in even more forest loss. When the government finally began reforesting, it did so in a way that prioritized commodities over biodiversity, and today the country is paying a steep price both ecologically and financially. An astounding 44 percent of Japan’s total forest cover was converted to one-or-two-species forest plantations, and as a result, they have whole countrysides devoid of biodiversity.
Natural reforestation can be difficult in a lot of areas though. New forests take time to get established. Different tree species grow at different rates, with natural forest species growing far more slowly than plantation trees such as pines and eucalypts. Trees also grow at different rates in different climates. Carbon accumulation also slows to zero net gain as the trees mature. To continue storing carbon, plantations have to be felled and replanted, and the wood has to be stored so the accumulated carbon isn’t lost to the atmosphere, like burning firewood.
Ultimately, no matter how many trees we plant, we still need to limit emissions in order to stop climate change. There’s no scenario in which even a completely forested world would undo the damage of all the pollution and CO2 we’ve released since the beginning of the industrial revolution.
What Does it take to regenerate a native forest?
So if many of our current reforestation efforts are falling short, what does it really take to regenerate a native forest? According to a study focusing on the Brazilian Atlantic forest, which is a unique ecosystem in itself, certain aspects can return surprisingly quickly, as soon as 65 years. But for the landscape to truly regain its native identity it would likely take a lot longer – up to 4000 years. Animals are very important to the successful regeneration of cleared areas. Typically, 80% of the tree species in a mature tropical rainforest are animal-dispersed. The researchers found that it took just 65 years for a forest to recover to just this level. Another indication of forest regeneration is the existence of a high proportion of shade-loving trees. This is because immediately after trees are felled, the land tends to be repopulated by opportunistic species that thrive in the Sun. Shade-lovers take considerably longer to find their way back into the forest – about 160 years. It’s recovering the proportion of native species that are unique to the original forest which takes the longest time – the model predicts this will take up to 4000 years.
Native species that are unique to the Atlantic forest in Brazil have been isolated over the years into separate plots of forest due to deforestation. As a result, their seeds take a long time to disperse to the few protected areas that still remain. “If endemic species do not germinate and grow, the forest cannot recover fully. Ensuring healthy genetic diversity requires drawing from as wide a genetic pool as possible. It also requires creating physical connections for travel that allow the exchange of genetic information across the landscape. In practice, creating corridors of habitat between isolated islands of intact and restored ecosystems that restore connectivity.
To use a different ecology as an example, in the case of the West Coast of the US, restoration may mean removing trees from the landscape.” Future foresters, according to Forest Ecology and Management, should try “first evaluating the potential for natural regeneration and then gradually eliminating barriers.”That may be a valuable lesson for the mission of re-growing the global forest: sometimes it’s less a perspective of taking action than of removing obstacles and getting out of the way.
One way to restore function is to recreate disturbance regimes, or episodes of temporary environmental change, that encourage historical succession patterns. The trouble is that restoring the vegetation is only one part of the puzzle. Animals, insects, bacteria, fungi and others all play a crucial role in the resilience of an ecosystem. Even one missing element can throw the whole system off balance.
The good news
All of the interviews in the podcast series covered very different approaches to reforestation. Some with the goal of native forest regeneration, others focusing on healthy polyculture orchards and profitable species, while others were trying to integrate a mix of the two. Ultimately I learned so much from this project, not only about how some people, both amatures and experts are tackling the problem, but that we already have solutions and positive models to follow to combat the problems outlined in the research at the beginning of this episode. The problem of deforestation and poor reforestation projects are not coming from a lack of information or a lack of good examples to follow. The bigger questions that will determine the future of our forests, and all of our precious ecosystems for that matter, are whether we can implement these methods in time to deter the worst effects of climate change, biodiversity loss and mass extinction.
There are a few key questions that I would love to hear from you about in order to understand how you think about these topics and get some ideas that perhaps I hadn’t considered
Can agroforestry systems feed the world?
What percentage of your diet would you be willing to replace with tree and perennial plant foods?
In your opinion, do tree and perennial foods offer enough nutrition and calories for the space they occupy to meet the world’s food needs? Do they have enough nutrition to replace many of the meat and animal products that many of us eat in excess?
What priority should reforestation be given in land management policy? For example, would you like to see tax breaks or subsidies offered to forestry programs in your country, or do you think it would be better if these projects continue to be bootstrapped by nonprofits and private businesses?
I would love to hear your thoughts and opinions on these questions and any other thoughts, ideas, or even critiques of the information presented here. You can contact me directly at info (at) abundantedge.com, through the contact page on this website or by leaving comments below. I’d especially like to hear if you enjoy these podcast summary articles so I know whether or not to keep writing them. I look forward to hearing from you
Check out each of the interviews in this series to be inspired that there are many people working, not only to restore native healthy forests, but who are finding ways to make it profitable too.
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