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Origins of Mushroom Cultivation
Shiitake log cultivation
I would like to start this column by discussing the long history between the Japanese, mushrooms, and the natural environment.
Japan has been a world pioneer in commercially establishing the cultivation of a wide variety of edible mushrooms, including shiitake, enoki and maitake. And today, as "exotic mushrooms", these varieties have attracted global attention as healthy and delicious and the forest-based cultivation method continues to gain popularity as an environmentally-friendly and high value-added form of agriculture.

There are several factors behind this. One is that in Japan industry, government and academia have smoothly collaborated to research and develop mushroom cultivation. At the same time, Japanese civilization has cherished forests since prehistoric times. Moreover, we cannot overlook how much Japan has traditionally valued mushrooms as a natural bounty from the mountains, as exemplified in the food culture and the historical evolution of mushroom cultivation. There is one particular mushroom that was the driving force behind this: the shiitake mushroom (Lentinula edodes). We can safely say that it was shiitake log cultivation upon which the research and development of Japanese mushroom cultivation techniques and the foundation of its commercial development were built. And the history of mushroom cultivation in Japan can be said to have its origin in log-grown shiitake too.

In that context, I'd first like to talk about Japanese forests, in particular the highly unique "satoyama" type, to which mushrooms, themselves forest organisms, are inseparably related. The reason for this is that the history of mushrooms in Japan all starts in forests of satoyamas.

Statistics show that Japan's forests total 25 million hectares and make up approximately 70% of the nation's land. The total area of all forests globally is approximately 4 billion hectares. However, as much as 5.2 million hectares of the world's forests continue to disappear from the face of the earth every year. According to data from the Food and Agriculture Organization of the United Nations (FAO), the average percentage of forested areas around the world is approximately 27%. In comparison, Japan's percentage is 68.5%, the second highest among developed countries after Finland. Moreover, that such a small island country with a population of some 125 million is maintaining so much forest is, in a sense, almost miraculous. And, surprisingly, these percentages have remained largely unchanged for over 50 years.

In terms of composition, Japanese forests fall largely into three categories: old-growth forest, planted forests and secondary forest (natural forest). The first, old-growth forest, is completely untouched by human hands and comprises a mere 2% of all forests; that is all that is left of it in Japan. The island of Yakushima, the Ogasawara Islands, the Shirakami-Sanchi mountain range and the Shiretoko national park have been registered as World Natural Heritage areas for that reason, with their native vegetation and ecosystems still preserved today.
The second, planted forest, is managed by human hands regularly with the planting, weeding, pruning and thinning of primarily softwood saplings such as cedar, cypress and larch for use in building and other materials. This comprises about 40% of Japan's forests.

The third, secondary forest (natural forest), is one where trees have sprouted from tree stumps or seeds remaining in the soil and then grown naturally, or sometimes, with the help of people, in an area that has been impacted by human activity or a natural disaster. The term satoyama refers to various mixed forests that fall under this third category. Most secondary forests are made up of deciduous hardwood trees such as chestnut, beech, maple, and oak species such as sawtooth oak (Quercus acutissima), Mongolian oak (Quercus mongolica) and konara oak (Quercus serrata), and become more mixed with evergreen (glossy-leaved) hardwoods such as chinquapin and evergreen oak species the further south you go. Secondary forests make up 50% of Japan's forests.

A satoyama environment is generally an area located between mountains and an urban space and refers to secondary forest that surrounds human habitation. However, areas composed of this kind of forest but also intersected with agricultural land, reservoirs, waterways and grasslands are also part of the extended managed environment of a satoyama.

Forest (secondary forest) where virgin forest has been cleared and altered for human use by, for instance, replanting it with trees needed for everyday life is a "satoyama". Rice paddies and other agricultural fields and water storage systems are created around satoyama and are then properly maintained by human hands, forming a rich ecosystem where creatures such as insects and small animals gather and coexist with people. In other words, satoyama is not untamed wilderness flowing with untouched nature like an old-growth forest, but rather nature that has undergone varying degrees of human intervention. The forests of satoyamas are a complex world shaped by a diverse mixture of human and natural forces.

From the Paleolithic period 50-60 thousand years ago, through the Jomon period (ca. 10,000 BCE-300 BCE) and until to the present day, the people of Japan have lived with the bounty of the forest and developed a forest culture. The practices that have shaped satoyama over the millenia are believed to have begun with the start of rice farming in the late Jomon period. Amazingly enough, the land management decisions made at that time are the reason Japan's lush green forests and rich natural ecosystems still exist today.

Since then, the Japanese people have lived and enjoyed the great bounty of satoyamas as a managed forest for obtaining firewood, charcoal and compost, as a production center for biomass resources such as timber (a "tree farm" of sorts), and also providing hunting grounds and foraging areas for natural foodstuffs (classified as forest products in Japan) such as mushrooms, nuts, wild vegetables, and berries. All of these, including the clean air, fresh water, vegetables and mushrooms, are safe and are considered to be a bounty of the mountains and a renewable resource that must be protected for future generations.

Satoyamas play an important role in ensuring stable water supplies (they also help prevent floods and landslides, both of which Japan as a highly mountainous country is vulnerable to). The biomes of satoyama collect and purify water slowly over time, maintaining the quality of wells and springs critical for human civilization. Even the delicious fresh seafood prominent in Japanese cuisine is also thanks to the organic nutrients and abundant minerals in the soils of satoyamas, which are leached by rainwater and snowmelt and flow to the sea where they nurture rich fisheries. It can be said that Japan's unique longevity-promoting food culture is thus all built on the concept of satoyama. All thanks to the wisdom of the bronze-age society that diligently created satoyama for the mutual benefit of humans and nature, and developed forest-based agriculture where the forest resources are used in rice farming and human daily life.
Japan is also known for having more than 1500 endemic species of tree. As the Japanese archipelago is topographically long with steep and complex terrain, it has a variety of climatic zones to which a variety of forests are adapted. The climatic zones range from the subtropics of Okinawa in the south to the subarctic of Hokkaido in the north, and even vertically the small nation has steep topography with mountains over 3,000m high so a range of forest (vegetation and tree species) can be seen from lowland areas to alpine zones, giving Japan's forest areas diverse characteristics. And because the Japanese archipelago geographically falls within the Asian monsoon climate and is surrounded by ocean in all directions, it has a unique combination of relatively warm but well-regulated climate with abundant precipitation, making it an ideal environment for trees to thrive. Naturally, the topographical features of Japan have greatly influenced not only forests, but also the development of its agriculture.

Now, in the long course of human history, "agriculture" is not just the mere supply of food; it is also the cumulation of specialized knowledge and technology and other human wisdom from the continued protection of the environment in which various creatures coexist. And it also influences the formation of the unique local landscape, traditions and the culture of an area.

Throughout the world now, however, due to technological progress amid the global advance of modernization, changes in people's lifestyles and globalization are distorting the use of resources and local values in a myriad of ways. And because of a preference for excessive mass agricultural production, environmental issues such as deforestation and water pollution, soil degradation, the destruction of local culture and scenery, and loss of biodiversity are progressing on a global scale.
Meanwhile, there are regions that even to this day continue to protect the disappearing traditional agricultural practices and subsequently the knowledge, biodiversity and scenery born from it. There is a program that integrally preserves all this as a "local system" with the aim of passing it down to the next generation: the Globally Important Agricultural Heritage Systems (GIAHS) program.

Originally, GIAHS was an FAO project that started in 2002 in hopes of preserving the traditional agricultural systems that were disappearing due to development in emerging countries so that they could be passed down to future generations. That is why developed countries like Japan were not initially eligible to be part of the program. Now, though, the GIAHS has designated 72 areas in 23 countries, with 13 of those in Japan. There are very few global examples of places in developed countries like Japan where age-old cultures, traditions, customs and technology associated with the landscape and agriculture, forestry and fisheries industries, in the form of satoyama, with people and nature coexisting on a national scale, are still being passed down today. What's more, the World Heritage designation recognizes the fact that log cultivation of shiitake contribute to satoyama circulation systems.

The "Satoyama Initiative" from Japan was adopted at COP10 of the Convention on Biological Diversity in 2010 and introduced to the world as an exceptional recycling-based conservation system. Satoyama, which has now become a global standard, is thus a treasury of biodiversity even as it is not a completely natural or untouched environment of the sort traditionally uplifted as the ideal of environmentalist movements.

From here I want to address the role that mushrooms play in forest ecosystems. And yes, while mushrooms are a familiar and important ingredient for the Japanese, they are also a crucial member that supports Japan's satoyama ecosystems. What essentially enabled forests to grow on Earth and helped plants adapt to the harsh land environment four hundred million years ago when plants expanded their place of life from the sea to the land were fungi called endomycorrhiza, which already lived symbiotically in the root tissue of sea plants. These fungi, however, did not produce mushrooms.
Then, one to two hundred million years ago, in the course of the coevolution of plants and fungi, ectomycorrhizal fungi appeared emerged in concurrence with plant-based life forms. These mycorrhizal fungi help plants grow by supplying their roots with water from the surrounding soil and inorganic salts such as phosphorus, nitrogen and potassium. In return, mycorrhizal fungi receive nutrients such as carbohydrates from the plants, enabling them to grow. In this way, mycorrhizal fungi form a symbiotic relationship with the forest, compensating for each other's nutritional deficiencies. In fact, we know that virtually all land plants are connected in some way with ectomycorrhizal fungi. Some well-known mushrooms of mycorrhizal fungi include matsutake (Tricholoma matsutake), porcini (Boletus edulis) and, most famously, truffles, but there are actually many mycorrhizal mushrooms living in the Earth's forests. The number of varieties are estimated to be from 20,000 to over 25,000.

In addition to ectomycorrhizal fungi, there are other mushroom-producing fungi in forests. The most familiar ones include shiitake, oyster mushrooms, and button mushrooms. The mushrooms widely cultivated around the world and their relatives are called saprophytic fungi and grow on dead and fallen trees and leaf litter. When saprophytic fungi take nutrients from dead trees and leaf litter, they showcase a very special but underrated ability_emdash_decomposition. This is important because the cellulose and lignin that make up most of a plant's body have an incredibly complex structure and are difficult substances for other organisms to break down. However, some fungi have, through the process of evolution, acquired the ability to do just that. At the moment, the only organisms that can easily break down lignins by themselves are saprophytic fungi.

When you enter a forest, you will notice a layer of decaying leaf and plant matter that is soft and fluffy. And the thickness of that layer is somehow always constant. That is because fungi are tirelessly breaking it down. Consequently, the inorganic salts broken down and stored by saprophytic fungi are returned to the soil and reabsorbed by plants through mycorrhizal fungi. The recycling of matter on Earth by these such fungal functions has continued uninterrupted to this day.
It is actually largely the work of mushrooms such as mycorrhizal fungi and saprophytic fungi that has supported the vast forests that cover one third of the Earth's land area and sustained the existence of all organisms. That we humans can exist the way we do could also be thanks to mushrooms meticulously maintaining the earth. In actual fact, the mushrooms we see in forests are carrying out various functions as members of the forest ecosystem. Thus, in Japan's richly diverse forests, there are surprisingly many mushrooms, numbering over 6,000 varieties, that are known to be native. At the same time, this is also proof that Japan's nature and forests are rich and healthy.

Now the Japanese are known to be a mushroom-loving people. So when did the Japanese start eating mushrooms? And when did they start cultivating them? These are questions we will look at in the next issue.

^{Fujishukin Co. Ltd. is one of the most established and highly considered producers of spawn for log cultivation in Japan. The Japanese Exotic Mushroom Journal is proud to feature their expertise in an ongoing segment covering different aspects of log cultivation.}

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Origins of Mushroom Cultivation

Shiitake log cultivation