Seijun Nishihata travels the globe as a plant hunter. At the Sora Botanical Garden Project, a vast horticulture nursery, he manages greenhouses of plants that grow in various environments around the world, including temperate zones, deserts, and cold regions, and selects the plants needed by his clients for delivery in Japan and overseas. In the import and export of plants, he minimizes stress on plants by providing comparable conditions to the temperature and humidity of their native environments. In the second installment of this series, he talks about the plants of cold countries and the beautiful scenery and unique features that they display despite their harsh environments.
Relationship of Temperature and Humidity to Biological Diversity
While there are many countries in the world with a variety of climates, let’s start first by talking about cold countries since this article will be published in winter. And let’s say that “cold countries” refer mainly to the arctic and subarctic regions.
Many Japanese people have the impression that winter is cold and dry. However, many regions around the world have low temperatures and high humidity. These regions would include, for example, Scandinavian countries and countries in the southern hemisphere such as New Zealand, Fiji, and Patagonia.
Countries with warmer climates, such as those in the tropics, generally have a greater diversity of not only plants, but also animals, insects, and birds, whereas cold countries have fewer species of plants and organisms since they must adapt to the cold. Unsurprisingly, there are far fewer types of plants growing naturally in the boreal and subarctic regions than in the tropics and subtropics.
Shaped for Enduring the Harsh Winter Cold
The vegetation that we most commonly associate with cold countries would probably be coniferous trees such as fir trees and spruces, which are used for Christmas trees.
These trees do not grow among different varieties of flowering trees and plants, but rather they inhabit forests where there are coniferous trees as far as the eye can see. When you go to the mountains of Russia, you will only see coniferous trees. Even in Hokkaido, the forests consist of fir-like trees such as the Yezo spruce. These trees often have similar shapes.
From my experience, the plants inhabiting cold countries under extreme conditions tend to have a lean shape. For example, we know that fir trees and spruces get snow, and while their branches hang down to support the weight, the branches are less likely to break than other trees. Likewise, the birch trees seen in abundance in Hokkaido are long and thin, and they stand serenely like bamboo trees to prevent snow from accumulating on them.
In other words, trees take on the most efficient shape for the climate. In contrast to the tropics, where there are many conspicuous and diverse plants, the plants of the boreal and subarctic regions tend to be simpler and more uniform.
Only Plants Acclimated to the Environment Survive the Conditions
Up to this point, I’ve talked only about plants in the subarctic zone, but for places with even harsher environments where trees cannot grow, the area is likely to be limited to lichens, such as moss, that cover the ground and flowers and herbaceous plants that grow crawling on the ground. It's an environment where there is no diversity and only selected creatures can grow. You can actually see this kind of situation even in high-altitude mountains. As you climb 4,000 to 5,000 meters upward, even temperate or subtropical mountains begin to resemble a subarctic environment.
Altitudes above the timberline become an environment where trees cannot continue to grow. That’s why trees no longer grow as large as they do in cold countries. The environment acts to dwarf growth, and only a bare minimum of plants can grow. One reason hindering plant growth in such an environment is partly because of a lack of nutrients in the soil, but it is also true that the vast majority of plants on earth require a certain temperature level in order to grow.
Most plants begin to grow when the temperature is above 15°C, but as the temperature drops below that, growth either slows down or stops. In Japan, the growing season for plants lasts about half a year from spring to autumn (from March to October). However, in colder countries, for example, it gets colder faster, so the warm season only lasts for a few months. In other words, plants in the boreal and subarctic regions require less time to grow than other plants in the world. This make trees tighter and smaller since they must adapt to the environment. When you include temperature and climatic conditions, you can say that air helps determine the shape of a plant.
A Memorable Speech in Russia
In 2018, there was an international conference held on the theme of “green infrastructure” in the Russian city of Voronezh. I was invited to speak there in front of other speakers and plant experts from all over the world. The following is an excerpt from that speech:
“People like colorful things. Diversity in all kinds of trees, flowers, and grasses is highly treasured. Coming from Germany to Japan, Philipp Franz von Siebold is reported to have said, ‘Spring in Japan is wonderful and so beautiful. Spring in the country where I was born does not have such colors.’ I don’t know if he actually said those words himself or if they were simply attributed to him, but nature in Japan is blessed with diversity and an abundant array of colorful plants and vegetation. This is because while Japan is predominantly temperate, it also encompasses a variety of climates as a result of the great distance it extends from north to south.
However, people here in Russia live in the subarctic zone. And like Northern Europe, Russia has fewer plant varieties. In saying this, I don’t mean to brag about Japan. Rather, I’d like to point out that forests with such a large scale of coniferous trees that can withstand the harsh winters can only be found in this cold country. I feel that this is wonderful element not found in my country. As I walked around the streets, I could see many types of flowers being planted and beautiful landscapes with rows of identical trees, which I thought were marvelous.”
When I talked about this aspect, there was a very positive reaction, and when I finished many people came up and complimented me by saying, “That was a great speech.” At the end, I even received an award for best speech, which has become a fond memory for me.
Now, when I think back on it, some people may prefer things that have an air of color and energy that give a place its own atmosphere and ambiance. However, people can also be attracted to landscapes that may be simple but have a core and strength, and things that have a dignified presence.
For example, people native to Germany felt a strong vitality and wanted their leaves to remain vibrant even in harsh winters, so they developed a culture of decorating evergreen trees. This custom spread mainly in Germany and Scandinavia and is said to be the origin of the Christmas tree.
Decorating your home with plants symbolizing eternal life and energy invites happiness. Within that, there must be a kind of respect for trees that survive in the harsh cold. To Japanese people, this would be similar to pine trees for Japanese people. When you see it from this perspective, you realize that no matter where you go in the world, people's hearts do not change, and that everyone is connected in some way.
