Whatever Happens, Babies Are Coming: seedlings in dry river beds for winter Tanzawa

It is still at the proposal stage for a possible new project for forests in rural Kanagawa about which I said a bit last week. The theme is to assess the effects from frequent storms et al, probably due to climate change. A sudden torrential rain for a short period of time has become common these days, which could have effects on environment. Landslides and debris flows could often occur to destroy communities downstream. Especially afforested cedars where the network of root system is somehow simple and its forest floor has lesser biodiversity, the new disaster risks many be materializing easily … Such questions are certainly worth looking at. Let us see how the theme evolves in 2026 and beyond. Having said that, mini floods are habitual for rivers running down from Tanzawa Mountains even before the climate change days.

Once it collapsed, it was like this.

There is a theory the name Tanzawa 丹沢 is from classic Korean circa 1AD. According to this story, the name of the place means “many small streams.” Apt. Then, once the storm comes, these not so long but rapid flows frequently change the course. It has created wide riverbeds in deep mountains. The feature is due to the fragile soil of the area thanks to the continuing crash of Philippine, North American and Eurasian Plates. In such wide dry gravel bars, there come pioneer plants, such as Euptelea or cat’s claw, which do not care about the crumbly stone filled soil. These species should be gone once the soil becomes stable and the dominant species for the climate of the area, such as ring-cup oak, will conquer the pioneers. Alas, such transition has not happened in Tanzawa’s riverbeds.

I think this is Japanese hornbeam in winter.
Yeah, it’s another pioneer plant along mountainous streams,
but I think even this one has some limit …

Very wide dry riverbed

Euptelea in bloom

Still, it does not mean we can find only pioneer plants in Tanzawa’s riverbeds. At least baby trees sprout in a gravel-filled space, even if they will be wiped away once a storm comes. From late autumn to early spring when Kanto Region is in a dry season and Tanzawa Mountains are ‘sleeping,’ we can leisurely find variety of seedlings and rosettes there. Thinking whose babies they are is like a treasure hunt in deep mountain. For example, these are the kids I found the other day in Yadoriki stream.

Rosette for Philadelphia fleabane.
It is a naturalized plant from the US.
I noticed there are several such plants of
 foreign origin in the riverbed.
For example, maybe,

Lysimachia? also from the US, and

Sonerila dongnathamensis?
If so, it is from Thailand.

Oriental false hawksbeard. It’s Japanese native.

Plume poppy. ditto

Hydrangea macrophylla. ditto

Stephanandra incisa

Deutzia crenata.
Come to think of it,
they all love forest edge with full-sunshine.
Typical feature of ecotone, maybe …

Trachelospermum asiaticum

I think it is winged spindle.
Though now it is familiar as a garden plant,
we can commonly find it in mountains.
Our ancestors used it for painkiller.
For such usage,
the tree must have been on a stabler soil ...

Japanese Spiraea.
It also loves rocky soil, and is loved by gardeners.

I know they will be crashed by rocky debris tumbling down from the upstream, when the rainy season comes. Still, some baby maples turned their color into vivid red in dry rocks. Hmmmmmmm … this may could be an inspiration for Bonsai art. If you have a chance to visit upstream rivers in Tanzawa, just look down on your feet. Those babies are betting on the chance of their survival in this very harsh condition. Impressive.

Crashed …

Japanese maple baby

If you find 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/

Quiet conqueror: Yadoriki Water Source Forest, early spring 2021 やどりき水源林

Euptelea polyandra in March 2021 for Yadoriki Forest

The last time I’ve been to Yadoriki Water Source Forest やどりき水源林 was October 2020. The place was under heavy reconstruction from the destruction by typhoons in 2019. Early this month, I’ve returned there. The works are still on-going, but several parts are open to hikers.

Japanese green alder (Alnus firma)
 in March 2021 for Yadoriki Forest

The prefecture has almost completed the repair works for the forestry road from the gate of Water Source Forest. We can walk a paved road almost to the end of the former route. The collapsed section is detoured by a new cutting through the western slope of Mt. Nabewari 鍋割山 (ASL 1272.4m). The debris of landslides 2 years ago still remain, but they definitely become a small part of the course. I think finally families with kids can walk there now. Though, we forest instructors have recognized that the prefecture, i.e. the landlord, does not intend to recover the pavement fully that before reached to the starting point to the trail to Ameyama Pass 雨山峠 (ASL 957m). Anyway, there is undeniably an improvement.

The collapsed part of the previous route is detoured.

The work is still going on …

Yadoriki Stream 寄沢, which caused flash floods and debris flows in 2019, is undergoing a substantial intervention. The Prefectural Office flattened the riverbed with heavy machinery and digging artificial water way in the middle. We seriously doubted how long such synthetic river can last if another monster typhoon hits the area again … In 2019, the Open Space near toilets suffered heavy erosion to be reduced in half. The place is still off-limit. We hope the site becomes accessible by summer holiday. But … could we find a place for kids to play with water, I wonder …?

This is the flattened riverbed.
 We cannot see the stream from this point,
 but a fissure at the foot of these destroyed logs
 is artificially dug water way.

Woooooooow.
 The stream looks like a road now …
 the construction work is going-on.

The afforestation expanded on the western slope of Yadoriki Stream is receiving an intense forestry by thinning cedars and cypresses. The prefecture told us the place is accessible only for professional foresters who contracted the work from the Office. In 2019, Yadoriki Stream was flooded with broken and uprooted afforested trees. So, doing professional forestry up there to stabilize the slope certainly has a good reason. They say the work will continue at least until summer this year. We will be able to have a quiet autumn walk in Hadano Forestry Road 秦野林道 this year …

The trolley line for forestry to the western slope is
 fully operational now.

We found lots of Astraeus sp. as well.
 They love gravelly place so that encountering them
 in Yadoriki of under-construction may not be surprising.

Despite of massive civil engineering, I personally find the nature of Yadoriki Forest is recovering strongly. After the typhoons in 2019, I felt sad to find many decimated points where before beautiful mosses secretly but cheerfully sprouted their capsule to procreate. Now they are coming back, if not fully. Impressive. In Chinese character, mosses are written as 苔. It’s a hieroglyph. The top part which looks like a hat means “row of grasses.” The middle symbolizes “plow”, and the bottom is “mouth.” When a farmer starts his/her work in the spring, the first thing s/he normally does is plowing the ground like opening the mouth of soil. So, the Chinese character for mosses means “it’s the beginning of vegetation.” Yeah. Yadoriki Water Source Forest was covered with mountain debris two years ago. Aside from the endeavor of humans restoring the place, tiny mosses may be quietly taking a lead for the recovery of the forest ... Petit conquerors!

I think, they are Palamocladium leskeoides.
 Such delicate apparitions of mosses were
 gone after monster typhoons of 2019
 … Now, they’re back!

The beloved Racomitrium japonicum are recovering in Yadoriki.
 Hurrah!

If you find 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/