Gaia: On recovering the power of soil in Tanzawa Mountains

Let’s return to bok-bok black soil. Whether its black Hoei Scoria, or red Kanto Loam, the strata made of volcanic projectiles are not good for flora to grow. There are certain kinds of species, so called “pioneer plants,” that can first take roots on such harsh conditions. They cannot grow fast and big, but they make the best of the terrain they are given, make seeds or spores, and die down. Their bodies decay to be organic matter and prepare better, if slightly, soil for their offspring to flourish more. After few generations of pioneers, the piled up dead-body become a part of Gaia where more delicate species are possible to take roots with organically richer condition … That’s the way volcanic soil turns into bok-bok. OK, you know, vegetables do not do it alone, don’t you? They have helps from bacteria, worm, insects … I mean something other than flora. The more such hands are available, the faster the road to Black Bok Soil is.

What we’ve observed the other day told us in Tanzawa 丹沢 it took more than 300 years for the forest to have 15cm petit bok-bok above 50cm Hoei Scoria. Er, I did not tell you last week. Where we dug was an afforested area. The forest is made of roughly 70 years old cedars. I don’t know if the place has been for the last 300 years for forestry where deforestation was regular ... Anyway, I was taught one thing about Japanese afforested area with conifers. In general, biodiversity of habitants in floors and below is generally lower in such forests than in forests of deciduous trees. The number and variety of bacteria et al is smaller for artificial forests of coniferous trees in Japan. According to Junichi Aoki (1995), biodiversity of Japanese forest floors can be ranked like

1. 🌞 Well-preserved natural forest or protected forest surrounding old temples and shrines
2. 🌟 Matured mixed forest that may have started as resources for daily use in pre-industrial rural villages
3. 🌲 Young mixed forest or coniferous afforested area
4. 🌷 Parks, residential gardens, school yards
5. 🚗 Roadside planting

* Diagnostics of Environment Using Soil Biota as Indicators. Jun’ichi Aoki, in “Impact Prediction on Natural Environment: result and manual for research methodology,” Environmental Affairs Department, Chiba Prefecture, 1995, 197-271. 土壌動物を用いた環境診断。青木淳一、「自然環境への影響予測-結果と調査法マニュアル」千葉県環境部環境調整課、1995、197-271。

Does coniferous afforested area really have not much habitant in their soil? The other day this June, we, Kanagawa Forest Instructors, actually counted how many kinds of bugs we can find with our naked eyes in a soil of Tanzawa’s afforested area. Yeah, it was not so exciting expedition.

It looks really rich the soil is, doesn’t it?

We dug and collected 4 sets of 50cm*50cm soil of forest floor for cedar trees of about 100 years old. As it was in Tanzawa, we dug only 10cm deep. It was its top soil, not reaching to Hoei Scoria. Before our research we also set for 48 hours traps of tin cans with baits, like sugar, chicken meat, and cheese. We carried both of these samples indoors and counted how many species we can find from them. We strained our eyes for about 1 hour on the soil spread over white plastic table cover, and found

<Group A>

Enchytraeidae (earthworm)

spiders

Acari (mites, ticks)

Springtails

Ants

Rove beetle

<Group B>

Oligochaeta (earthworm)

Thrips

Lithobiomorpha (stone cetipede)

Larva of moss

Weevil

Beetle

Larva of beetle

<Group C>

Diplopoda (Millipede)

Geophilomorpha

Symphyla

Gammaridea

4 traps, with sugar, chicken meat, cheese, and nothing

50cm*50cm

We dug it with this shovel, and carry it in a plastic bag.

Those in Group A can be easily found even in City Parks or road side flour beds along artillery motorways. Group B resides more environmentally rich area, and Group C is picky creatures live only in sufficiently biodiverse forests. We could not find many animals in Group C. No Opiliones (Harvestman), Scolopendridae, or shellfishes / slugs … That was somehow disappointing as we were deep in Tanzawa Mountains. “Yes, this June is really wet. Creatures in soil must have been suffocated with water, and moved to the other drier corners we don’t know.” “In any case, it is an afforested forest, though relatively old one.” “Indeed. Biodiversity is supposed to be poorer than for natural forest.” Er, yes. But I just thought the soils in Tanzawa Mountains are in any case handicapped by thick Hoei Scoria thanks to Mt. Fuji nearby. That would be the best they can do at this moment of geological time … Can we tell them “well done”?

The soil was spread over this plastic cover for us to search.
 Before that, we checked what’s inside the trap.

We’ve found a cricket and a beetle!

The place we dug the soil.

Lessons learned from this adventure, I presume, is, we really have to treat gently the tierra of forests in Kanagawa Prefecture. Thanks to “Rediscovery” of charms in natural forests, and our proximity to downtown Tokyo, these days many many people hike our mountains. Not all of them know the fragility of the nature in Tanzawa. One day, I’ve met a group of senior citizen hikers, about 10 granddads near the peak of Mt. Oyama 大山 (ASL 1252m). In that area, rangers and forest instructors are busy monitoring the environment with lots of deer fences and observation equipment. In the 1980s, we Japanese first recognized that part of forest affected by acid rain from Megalopolis, and dying out of gigantic beeches whose barks were eaten by deer and sawfly (Fagineura crenativora). Keeping healthy soil is vital for the place to recover the damage done. The Prefecture builds and maintains lots of deer fences to fend off deer. The office also prepares good trekking roads expecting humans do not deviate from nice road, aka discouraging humans from invasion. But … At that time, those supposed to be sensible senior adults were criss-crossing the fragile slope of the mountain, off the hiking road, laughing excitedly. “Hey, this way is far faster!” OK, they may have recalled the adventure they had 60 or more years ago when they were kids. But, now they were far heavier adults, probably having grandkids. Their stamping impact on the soil was definitely greater than before. Trudging the forest floor by humans depletes the top soil the most heavily, completely different from what bears do. It destroys the ecosystem underground, and weakens the vegetation depending on the nutrition from the ground. Once the flora becomes unhealthy, so does the animal world sitting above the food chain. Impossible outbreak of insects, like sayfly, would recur. By the way Tanzawa needs at least 300 years to recover 15cm of humus-like soil from Hoei Scoria. Did those grandpas know what they were doing? I doubt that.

This is human power.
 Just walking, we can gouge mother earth this much.
 Could you see the difference in height of the surface
 between the road and the roadside?
 Also, we find lots of big roots running across the road.
 They were once underground,
 but now all the soil over them was gone.
 Pathetic, actually.

So I tell you. Please know our forests are fragile. Don’t deviate from hiking road unless there is absolute necessity. Happy summer hiking season. Oh, I of course told them “Please do not deviate from hiking route. This is a protected area, blah-blah-blah.” They looked a sort of dumbfounded, being told to behave well by a stranger WOMAN in deep-mountain. They were typical of Japanese male, taking it for granted silent females. Heck. Come to think of it, Gaia is a goddess.

If you find an environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121 〒243－0121　厚木市七沢657

Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

The Power of Mt. Fuji: soil in Tanzawa Mountains

Any living things need nutrition to grow bigger, right? For a tree, in general at least, that food comes from the ground, aka soil. So, as a corollary, people of Japanese forestry say we can “measure” the “power of soil” by seeing the height of a tree. Especially in areas where afforestation was done some 70 years ago, “tree” means cedars and cypresses in Japan. And we can find a bit sorry 70 years’ old trees here and there in the forests of Kanagawa Prefecture. Is it the matter of our soil?

In theory, those trees planted during the 1950s to the early 60s should be now tall enough to produce standard materials for housing. Alas, in 1964 Japanese logs lost the battle of international competition after the complete import liberalization. As it did not pay, people have not cared the afforested area sufficiently. Now supposed-to-be good enough construction materials are found in congested mountain slopes. No proper thinning was done, which made them lanky and not tall enough for 60 or 70 years old cedars. Cypresses have lots of scars on their trunks as they have not received appropriate pruning when they were young. Such regretful features make market value of timber from our forest even lower. Yap, it’s a man-made result. Even so, in the first place for Kanagawa, was our land rich enough to nurture trees to grow faster and bigger in 70 years? Did it have a potential to be a good forestry area when that afforestation policy was started 80 years ago? The other day, I had a chance to see how the soil in afforested areas of Tanzawa Mountains 丹沢 is. That was shocking.

I’m afraid to say this forest in Yokohama
 shows ample signs of neglect.

Geologically speaking, Kanto Region is generally covered with Kanto Loam, the stratum made of 25-40% silt and clay. The origin of it is volcanos surrounding Kanto Plane. For Kanagawa Prefecture, especially Mt. Fuji 富士山, Mt. Hakone 箱根山, and Mt. Ashitaka 愛鷹山 contributed a lot with their eruptions during Pleistocene era that was some 2.58 million to 10 thousand years ago. They spewed out massive amount of volcanic ash and granule whose size in general is Ø 2 mm or less. They have been winded up countless times for these millions of years, which made their ingredient, iron, oxidized. So, Kanto Loam is often called Red Soil, Akatsuchi 赤土, in Japanese. Loam stratum itself is very heavy clay that was not so good for vegetation to grow. No matter, Japanese flora has tried to live on it for a very long time. They have gradually turned the red cray into black soft humus. (More to it, next week.) This black top soil is named with onomatopoeia as Black Bok Soil, Kuro-boku-do 黒ボク土, as farmers felt its texture “Bok-bok.” So, the Japanese bok-bok black soil started with volcanic ash. It is different from chernozem in the continents. Bok-bok or not, humus is good for agriculture and forests to grow, right? So, the thicker the bok-bok soil, the larger the trees are.

Kanto Loam in Niiharu Forest.
 As it is heavy in clay,
 we can use it, for example,
 for constructing kiln for charcoal baking.

Peculiar feature of the soil in west Kanagawa is, Kanto Loam is covered heavily with scoria stratum originated from Fuji 1707 tephra. In October 1707, present-day Sizuoka Prefecture 静岡県 was attacked several big earthquakes, including the one of M 8.7. Then, on 16 December, the south-east slope of Mt. Fuji around timberline opened 3 volcanic mouths. As of July 2019, it is the latest eruption of Mt. Fuji. Now there remain craters called Hoei volcano 宝永火口. At that time, Mt. Fuji spewed out for 2 weeks humongous amount of ashes and granule that was estimated to reach 20km high in the atmosphere. People in the downtown Tokyo still find about 2cm of scoria stratum in their soil. Niiharu Forest 新治市民の森 has about 5cm of scoria beneath. Yokohama’s South Forest, like Yokohama Nature Observation Forest 横浜自然観察の森, has 15cm of them. But it was the present-day Gotemba City 御殿場 in Shizuoka, and West Kanagawa that received, literally, tons of it. For western Kanagawa Prefecture, the thickness of scoria reached 80-30cm.

Yokohama Nature Observation Forest in January.
 OK, the place was almost denuded in the 1960s
 for a development of golf course. (Oh, yes.)
 So, their trees of oaks like Quercus serrata are relatively young.
 Yet the place has certainly thicker scoria stratum than in Niiharu,
 and it shows in its vegetation, I think.

Niiharu Forest in May.
 Er, I tend to be partial when it comes to Niiharu Forest.
 But I really think the depth and biodiversity here is
 richer than in the larger South Forest of Yokohama.

Scoria is made of porous pumice. It cannot retain water or nutrition. If you’ve ever been to Mt. Fuji, especially from Gotemba side, you notice its slope is a “desert.” It is the area where Hoei scoria is piled up more than 1m. The thicker the scoria, the more difficult for soil to establish bok-bok soil is. So, we still have hear-say that after the 1707 eruption those ancestors of landlords in Hadano City 秦野市, the main entrance to Tanzawa mountaineering routes, dug up their bok-bok soil covered by 50cm scoria in order to continue their farming. It is said that many people migrated to Edo, aka Tokyo, as refugees to survive. The downtown was also covered with volcanic ashes. They starved to death. Famine continued for many years. According to the statistics recorded by the feudal lord of Odawara 小田原, their territory could not recover the production level of agriculture until the early 19^th century. If farm land with human intervention was in such condition, forests in deep mountains must have fared worse.

Observing Hadamo Basin from Take-no-dai 岳ノ台 (ASL 899m).
 Could you imagine people dug up this entire area
 to recover the black soil below the 50cm of scoria?

Recently, we forest instructors had a training session to learn methodology recording soil conditions in forests. We entered a prefectural forest in Tanzawa Mountains, and vertically dug 1m the slope to create a cross section of the soil.

Digging.
 Could you figure out red below? It’s Akatsuchi.
 And black sandy thing we’ve dug out is scoria.

The result was this stratum we’ve dug out.

The border between red and black is somehow clear, and we can figure out a layer of larger pumice on it. Those are volcanic bombs reached first here before scoria ashes fell over slowly. Also, the top part of red soil is a bit brownish. It is a former top soil before the eruption. The current top soil can also be divided in two. The deeper part is a mixture of more scoria and less fermented organic matter. The soil just beneath the surface has more organic matter approaching to bok-bok.

“Wow, this part has only 15cm of black soil.” “Yeah, below is the scoria … let me see, hmmmmmmmm, it has 40cm of the width.” “And finally, there comes the Kanto Loam.” “Could you see almost no root end in the scoria?” “Yeah, plants must go further deep to Kanto Loam in order to have some water and minerals …” “Otherwise, they remain in the 15cm of top soil.” Oh my Buddha. More than 300 years later, the hummus of the area is only 15cm deep. It takes really LONG LONG time for volcanic ashes to be good enough for flora to survive ...

I was a sort of convinced why those afforested areas in Yadoriki Water Source Forest 寄水源林 show apparent slowness in the growth of trees, compared with Doshi Water Source Forest 道志水源林. The northern limit of Fuji 1707 tephra to reach is the Northshore of Lake Yamanaka 山中湖. Doshi Forests situate in the north of the lake. The depth of scoria in Doshi village was less than in downtown Tokyo, if any. They were spared. It is so amazing to imagine why they are different. Tanzawa and Doshi are less than 20km apart. Maybe the wind? Maybe the form of ridges of Tanzawa Mountains? It’s like a very thin boundary between life and death when Mother Nature completely dominates the scene. Awesome … Then, lately I also had a chance to check the process of creating top soil. I’ll tell you my adventure for this next week. It was also a thought-provoking experience, I tell you.

Typical 50-60 years old trees in Doshi Village

About 50 years old trees in Yadoriki.
 Could you see the difference from the above trees?

If you find an environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121 〒243－0121　厚木市七沢657

Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

Singin’ in the rain: Forests of Kanagawa during rainy season

It might be a matter of taste, but people often say rainy days are depressing. Yeah, we need fine weather to be uplifted … or do we? I personally think forests of wet season are very attractive. Uplifting? Don’t know. But they are certainly therapeutic. During Baiu 梅雨, the time of rain from June to July in Kanagawa Prefecture, the trees are receiving rain drops almost daily. The forests show fresh greens washed frequently by showers. Still the plants develop their leaves to catch energy from sun. Soon, they’ll be ready for glaring sunshine of late July till mid-September. They are waiting. They look so pure.

For me, forests in Kanagawa during Baiu are good place to be meditative. The exquisiteness of fresh emerald surrounds us with infinite variation of hues. From canopy, sometimes we receive fluttering ray of sunshine that can be quickly replaced by water drops with the smell of leaves. Thanks to the weather, not much noise from human activity arises. Chirps of birds sound clearer without much car exhaust. Several ornithologists taught to us forest instructors birds love rainy days as fewer predators, humans included, are active. In Niiharu 新治, it’s easier to enjoy bird songs this time of year with little sonic distraction from surrounding housings. In Yadoriki Water Source Forest やどりき水源林, the echo of Yadoriki Stream 寄沢 quietly fills mountains where fewer hikers come. Wherever, some plants emit their fragrance more when they breathe air of higher humidity. Touching carpets of wet moss, I find they are really soft … If you’re lucky to meet with green fruits of Japanese pepper (山椒 Zanthoxylum piperitum), you can try your fifth sense with their peppery and citrusy taste. We can entertain our 5 senses in the forests during Baiu time. Amazing.

A couple of brambling (Fringilla montifringilla)

The first Tricyrtis flower for Niiharu this year

Recently, I’ve been to an installation by teamLab in Tokyo, near Olympics’ Village (under construction). It seems to me they tried to create synthetically an experience walking in a forest with “streams” and “ponds.” OK. I got it. Though, going up barefoot along artificial river running over soft synthetic floor cannot match with my memory of walking along pure Yadoriki Stream. Sure, losing my way in a room of floating balloons was dreamy experience, and we can enjoy occasional fragrance of lavender in their dark narrow corridor. But sensation we can receive from the in-betweens of leaves and branches in Niiharu’s deep forest was more pensive with purified smells of fresh greens. It was certainly mesmerizing looking up projection of decaying flowers created by AI and signals from our cellphones. But finding flowers of spotted bellflower (Campanula punctate) or Ground-ivy (Glechoma hederacea Subsp. Grandis) in raining open air is far more comfortable … Can we ever create such delicate color coordination of Saururus chinensis with computer programs?

Floating balloons of synthetic world

Spotted bellflower (Campanula punctate)

Buds of flowers for kudzu
 (Pueraria montana var. lobate)

Saururus chinensis

I love walking in forests during rainy season. … Oh by the way, the average date for summer period of rain to end is July 21^st. Japan Meteorological Agency forecasts 2019 is a normal year in this regard. 2 more weeks to go, then. 😄

If you find an environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121 〒243－0121　厚木市七沢657

Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

Growing up in a (concrete) jungle: swallow chicks in Yokohama

I digress. Recently, I’ve noticed I’m getting attentive for signs of living creature (humans inclusive) in our environment. (Thank you Niiharu Citizen Forest 新治市民の森 and Yadoriki Water Source Forest やどりき水源林!) Tiny bugs on leaves of planting along boulevards, silhouette of birds flying between buildings, poops covering pedestrian road … One ordinary morning this June, I suddenly realized droppings of birds spread over a part of our familiar pedestrian tunnel below one very busy arterial road in Yokohama. Every day, we city folks hastily commute to catch packed morning trains via that tunnel made completely with concrete. I didn’t “see” the droppings there till that time. I was a sort of taken aback, and moved my sight to the ceiling of the tunnel. There, barn swallows constructed their home, and 4 chicks sat inside VERY silently. They avoid any attention from us humans busily coming and going below their home. Or, in this regard, perhaps they did not want to be detected by any natural enemy, and kept perfectly quiet until their parents brought meal. The way they closed their beaks tightly with determination was … CUTE, CUTE, CUTE!!!!!

Here they are.

Don’t you feel strong will in their shape of mouth?

Since then, every morning I observe, or glance, them. I am amazed they literally grow bigger daily. I think the place was perfectly safe. The tunnel has only smooth concrete surface, and snakes et al cannot manage climbing up to the ceiling. Unless humans try to destroy the nest, they’ll have happy childhood. Soon, they leave their nest with their parents and join a community of swallows near water. (Where is it for them?) They stay there until the flock move to Southeast Asia for wintering. Every morning commute becomes a bit of fun for me these days. 😄 Barn swallows (Hirundo rustica gutturalis) is listed as “nearing to be endangered species” in Kangawa Prefecture. Hey kids, keep your mouth shut to survive, OK?

If you find an environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121 〒243－0121　厚木市七沢657

Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/