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/