The Plum Orchard: taking care of Ume plum trees in Yokohama

I know I’ll be busy in June. June is the month when Ume plums are harvested. After picking, the fresh fruits must be processed promptly for pickles, liquors, compotes, etc. I’ll be BUSY in the kitchen filled with sweet scents of plums … Though, none of these fruits are from Niiharu Citizen Forest 新治市民の森. Reason is simple. We Lovers of Niiharu 新治市民の森愛護会 have problems to collect enough quantity of Ume plums. It’s not because 70 ha of Niiharu Forest does not have plum orchard. It has 3 orchards of Ume. Nor it’s due to Lovers do not have access to these 3 places. Lovers have requests from the City of Yokohama and the landlord to take care of the sites. Yet none of these places bears adequate fruits.

Though, every year these two Ume trees
 for pink and white flowers are beautiful
 at the entrance of Niiharu Citizen Forest.
 They are private property, not a part of the Citizen Forest.

A tree standing at the entrance of Ikebuchi Open Space いけぶち広場 is the only Ume plum tree producing sufficient plums for about 3 jars of Ume liquor. One of the senior Lovers, a lady who’s in charge of such matters, prepare them in June. During high summer when we spend uber-busy weekends to mow the forest floors, her liquor’s waiting at the end of the day as a prize of hard work. Needless to say, the jars are empty by November. Pity. “You see, we had more Ume fruits until 10 or so years ago.” “Oh, yeah. Niiharu Forest has 3 orchards. We were very busy allocating enough time to collect fruits.” “Why can’t we have such amount of prize these days? They even do not flower much these days.” That’s the problem.

The only productive Ume tree in Niiharu.
 It flowers again this year.
 I hope we can have some fruits from it …

The only profusely flowering Ume orchard in Niiharu, out of three.
 The place too has pretty flowers constantly as this year.
 But the amount of fruits out of them is limited.
 The trees here are for flowers, not fruits、I guess.

Actually, roughly 3 or 4 years ago, the City of Yokohama had a problem of Plum Pox Virus. The disease started in 2009 in Tokyo and spread to Yokohama. According to the Ministry of Agriculture, Fishery and Forestry of Japan, the only possible treatment is to uproot and burn the affected trees. Er … worse than with COVID-19 for humans … The wards in the northeast of Yokohama, Tsurumi 鶴見, Kanagawa 神奈川, and Nishi 西 Wards found the infected trees. The City Office was super-alarmed. The greenery and private gardens there received administrative order to follow the direction of the Ministry. The City also arranged numerous training courses for professional and amateur gardeners how to take care of plum trees under the threat of virus. Hmmmmmm … now that I think about it, it was reminiscent of present-day policies about COVID-19 … Luckily, the other wards of Yokohama, including Midori Ward 緑区 where Niiharu resides, have not received the virus problem for plums, at least so far. But, the hub-bub became a nudge for Lovers to take action for Niiharu’s unproductive plum orchards.

In Japanese proverb, it is said that “The fools who cut cherry trees, the fools who don’t cut plum trees.” Surely, plum trees spread their branches and boughs to whichever direction disorderly as they like. They are often vigorous, if not productive. Left them to their own devices, between late March to early November neglected Ume trees have lots of leaves in a jumbled manner. The condition is certainly of “Closed spaces with poor ventilation; Crowded places with many people leaves nearby; Close-contact settings such as close-range conversations.” It seems to me, many viruses for illness love such conditions … To prevent the spread of plum pox virus, the first line of defense is avoiding such 3-C and wearing masks … er, no, “Prune, prune, PRUNE!”

Hmmmmmmm,
 once the way branches spread reaches this level of “whicheva,”
 it’s something of divine art work …

So, Lovers of Niiharu engaged in pruning Ume orchards last fall. It’s easier said than done, I tell you. Plum is deciduous tree but flowers early starting from January. Their life cycle allows us a tiny window to take care of the mess of branches. That is roughly 2 weeks of October to November, almost immediately after they’ve started shedding their autumn leaves. Inevitably, we abandoned the pruning for the 3rd orchard this time … “Well, trees are there. Give us a break.” The next problem was the method of pruning. All 3 plum orchards in Niiharu produce unsatisfactory yield. Seniors of Niiharu Lovers debated how much pruning to be done and settled with “HEAVY ones!” for the least fruitful orchard. We brought chainsaws in the orchard to cut the main boughs and pruned relentlessly for the remaining branches.

Cut here, here and here!

First, I hesitated, then, it became a sort of pleasure to CUT! “Hey, Naomi, prune that upright branch!” OK. Done, then, “Next one too!” But it looks not so tangled with the other ones … “No, no. You’ll see their next year’s growth surely collides with the neighbors.” Woooooow. With the thunderous sounds of chainsaws, one plum orchard in Niiharu became the place of very shortened trees with sporadic branches. It was a strangely relaxing scenery, with piles of cut boughs and branches on the ground. Will they flower coming spring? I’ve waited.

Hair cut!

We’ve cut this much …

Then, this February, those remaining branches have pretty 5-petal flowers, smelling nice. Hurrah! “It takes several years before we know the result of hard pruning, Naomi.” OK, OK, OK. But the resilient plum tree orchards could resume producing lots of flowers, and then fruits. Maybe it’s after COVID-19 becoming a familiar seasonal ailment, like flu …I keep crossing my fingers for everything.

Wow! Blossomed!

Year 1 after heavy pruning …

If you find a problem in the greenery of north-half of Yokohama, please make a contact with

Office for the Park Greeneries in the North 北部公園緑地事務所
Yokohama Municipal Government Creative Environment Policy Bureau 横浜市環境創造局
Phone: 045-311-2016
FAX: 045-316-8420

Niiharu Administrative Office / Satoyama Exchange Center 新治管理事務所・里山交流センター
Phone: 045-931-4947
Fax: 045-937-0898
Email: info@niiharu.jp
http://www.niiharu.jp/

Flower arrangement with living cedars: Pruning in Hakone 箱根

Hakone Sengokubara 仙石原

Last year’s monster typhoons threw Hakone 箱根 into a mess. Lake Ashinoko 芦ノ湖 overflew. Town’s roads system was destroyed by landslides. Railroads lost their tracks with collapsed mountain slopes … One year has passed since then. Fortunately (or not), according to this analysis, Japanese have accumulated the know-how to swiftly deal with such problems. The transportation system in Hakone has restarted its normalcy this July, 3 months earlier than the original schedule. Recently, I’ve been there. Yeah, in spite of the COVID-things, Hakone is resuming its tourism business. Traffic congestions were here and there. Impressive.

Fukuzumiro 福住楼,
 one of traditional Japanese hot-spa inns in Hakone

Though, the effect of Japanese oak tree wilt (; my post on August 23, 2019) is remaining in Hakone. The area was the first in Kanagawa Prefecture where we noticed the dying trees, some 3 or 4 years ago. Several mountain slopes in Hakone are now covered with desiccated brown patches that are definitely-not autumn leaves. Sad. Despite of ferocious typhoon winds last year, those dead trees keep on standing … It is remarkable, certainly. But, how long will it take for Hakone to recover mountains covered with healthy greens? I wonder.

The restored train operation,
 and unrestored mountain with oak tree wilt
 in Hakone

Hakone is also seeing the problems of overpopulated Shika deer. Tanzawa 丹沢, Hakone’s eastern neighbor, is having this problem for years. When we enter Tanzawa mountains we must cover our foot against vampire leeches carried by deer population (; my post on 14 July 2017). Shizuoka Prefecture 静岡県, the western neighbor of Hakone, also having the issues with the animal. Hakone has spared such challenges so far, but it could be a matter of time if its adjacent areas are full of deer (; my post on 21 July 2017). Actually, when we mow the forest floor in Hakone, saplings and young trees are often become lunch for hungry deer. As the place is the National Park, the authorities are more alarmed if such popular tourist destination having bold mountains and pestering vampire worms as her neighbors.

Lunch for deer

So, one day when we pruned the boughs of young pollen-free cedars (my post on December 16, 2016), the Prefectural office asked forest instructors to have a novel measure to protect the trees. Trees can withstand a bit of bites on their body, but once stripping of their skin becomes substantial enough, it dies. Voracious deer don’t care if a forest is dying due to their eating habit. So it comes the novel way to protect the young trees. We covered the foot of pruned cedars with its removed boughs, just like wearing skirts. Our intention was, by protecting trunks of young trees, deer cannot gnaw barks of the forest. “You see? Christmas wraths made of cedars keep its green for at least 2 years. The protection we made today would last for some time. Trees can grow stronger meanwhile.” I see. “You try to have a viewpoint of hungry deer. They come here and try to chew the vegetation within the reach of their mouth.” I imagined myself entering the forest on all fours and extending my neck to have a lunch. “Well, this lower space looks appetizing.” i.e. We had to cover that part. We fastened the branches leaned on a trunk by tying them with a longer cedar bough. They were flexible enough to be a securing band. “We cannot do this with cypress, you know.” It was a fun operation. We were becoming more artistic to make an interesting barrier around the trunks. It was like doing a flower arrangement in a forest.

Cedars wearing skirts

This installation is figurative,
 don’t you think?

We don’t know if our approach is effective to protect the forest from insatiable herds of deer. In any case, something is happening for forests of Japan. This fall, we’ve heard so many news about hungry wild animals, like deer, serow, bear, boar, … wondering into human settlement for food. It’s rainy fall this year. Winter is approaching …

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/

This (or another) side of a mountain 1: Afforested area in the southwest slope of Mt. Nabewari 鍋割山

Rejoice! My broken right wrist is improving! Now I’m able to operate a chainsaw! I’ve found out a maneuver for a chainsaw is a very good exercise as rehab. “Take a full-grip, and operate with a slow movement of both right and left wrists.” It means substantial weight-training for hands and arms. Perfect. One morning after a forestry activity the day before, I was surprised to find out a lighter feeling around my operated wrist. Hmmmmmmmmmmm. Life gives me lots of new findings … And so, recently I have visited several deep mountains for thinning and pruning. I have another new discovery: soil.

Kanagawa Forest Instructor Association has a field for forestry in a slope of Mt. Nabewari 鍋割山 (ASL 1272m), at around ASL 800-900m. According to FAO (2015), Japan places ourselves as World #2 for forest coverage of the territory with 66%, next to Finland (73.1%). 40-70 years ago, when the government gave a generous subsidy for commercial afforestation, people planted cedars and cypresses with gusto, which makes 40% of Japanese forest afforested area. It means quite a lot of our forests, 10,290,000ha to be exact (2017), were planted by human. You see? Japan does not have a wide territory, nor for a “vast expansion” to plant trees like in Siberia. Inevitably Japanese afforestation expands to the places like “What on earth were they thinking when they introduced these trees in such a remote area!?” Frankly, the area for Mt. Nabewari is one of such places.

This is the entrance to our field.

To be fair, not all of these “strange” places for afforestation went through commercial deforestation and haste afforestation with allergen, aka coniferous trees. For one thing, during the total war of the 1930s and the 1940s, Japanese Imperial Force did not bother long-term management of the mother land so that they just ordered to cut, cut, cut the trees “to build fighter airplanes, or the like, by wood”; were they crazy? In 1945 when the war was over, many slopes of Tanzawa 丹沢 were miserably bold (for this topic, pls. see my posts in September 22 and October 27, 2017). Planting something ASAP for avoid landslides at least was, and is, a reasonable option. In any case, very fragile soil of Tanzawa does not need to wait for a totalitarian Japanese Empire to have frequent deep-seated slope failures. So, it may be such considerations, not greedily pursuing profit from cutting trees, that made our grandpas to afforest such places that requires at least 2 hours mount climbing to reach for forest instructors with car-access privilege.

It’s not in the forestry field for the Association,
 but on Hadano Forestry Road 秦野林道,
 some 2K away from the activity site.
 On the last days of this July,
 it was a perfect mountain slope,
 but in mid-September, after several visits of typhoons,
 the place was like this.
 The scree was spreading over the forestry road.
 I guess it would be tricky for a car to maneuver this point.
 The other side is a tumbling-down valley for some 50 meters.
 Yes, there is a crash barrier in a spec same as for the downtown
 … Good luck for drivers.
 This is Tanzawa.

To reach to the forestry field,
 we proceed along the Ushirozawa gorge 後沢.
 Sometimes, we had to mend the road to go further.

The area Kanagawa Forest Instructors are taking care of for these 10 years is a public land owned by Kanagawa Prefecture. It expands the west side of a ridgeway hiking course to the peak of Mt. Nabewari. Across the narrow 1m wide trekking road, the east side is owned by the national government and populated by natural broadleaved trees, not afforested coniferous forests like in the west side ... There must have been some story behind it … Anyway, if you aim for the peak of Mt. Nabewari from Yadoriki Bus Stop 寄, you’ll find such area between Kurinoki-bora 栗ノ木洞and Ushirozawa Nokkoshi 後沢乗越. (If you take a standard hiking course, it takes about 3 hours of continuous uphill to the area from the bus stop.) Unlike hiking roads, inside of a forest does / should not have a treaded route by visitors. Sure enough, the forest floor for the field of Kanagawa Forest Instructors is close to “natural.” And that’s the thing I was surprised.

The spot where the forest instructors operated some 10 years ago
 … Now the place has at least sunshine reaching to the ground.

Peeking into the national side,
 the east side of the ridge way to Mt. Nabewari

The ridge way from Yadoriki to Mt. Nabewari

The ground we entered was steep and scree-covered slopes with not much variety in vegetation. The cypresses are clinging to the ground with their roots spreading bare on the surface. I could not be optimistic for those surviving that would one day become gigantic trees protecting the ground to collapse. My senior instructors told me the area is receiving heavy pest damage by deer so that the floor is dominated by plants hated by the animal. Hmmmmmm. … I moved up the slope almost crawling, and thinned and pruned not-so-well growing cypresses on the poor soil. “Don’t cause rocks to fall. It’s a very dangerous area …” Of course … Even at around ASL 800m, the heatwave of this summer attacked us ferociously. It surely was an adventure … The condition of the land might be due to heavy deforestation some 80 years ago, or it had been like that for millennia. I have not been deep into the national side, but just at a glance it seemed the floor for the broadleaved trees in the east slope was not much different. What instructors do in the west side was thinning and pruning to make the growing condition somehow better for the afforested trees. Sisyphean task (literally, yeah)? Could be. At best, it would take a very long time to have a tangible result from our activities … But if we don’t do it, the outcome shall be worse with serious land collapse. I recalled the episode in Tokyo where in 2005 a deer-infested and impoverished cedar forests collapsed and destroyed water supply network for Okutama Town 奥多摩町 (Takatsuki, 2015). That’s we have to avoid happening here …

* Seiki Takatsuki. “On Deer Problem: the direction of unbalanced nature.” Yamakei-shinsho, Tokyo, 2015. 高槻成紀 「シカ問題を考える：バランスを崩した自然の行方」ヤマケイ新書：東京、2015.

From this photo, you may think it’s not bad for the forest floor.

But the most dominating plant there in August
 was this pretty Boenninghausenia japonica.
 It’s a relative to oranges.
 When you pick them, it smells nice …
 Even though, with some reason deer hate it,
 and so the flower survives in this forest.

This is another spot the instructors operated several years ago.
 Could you see the soil condition?

Anyway,
 the prefecture built barriers to prevent deer from coming in.
 The effect of it is …
 The place is too wide to close off, perhaps.

This is the place we did thinning and pruning …

A diedback cypress tree due to, this time, bear-infestation.
 An Asian Black Bear (Ursus thibetanus)
 peeled off a swath of cypress bark to lick sweet sap.
 They effectively prosecute gardling for this tree.
 The leading nature photographer of Japan,
 Gaku Miyazaki 宮崎学,
 wrote in his blog the bears did not attack a tree randomly,
 but carefully chose weakened ones for their tasty treat.
 He continues, as such,
  observing many diedback cypresses would be
 an indicator for the health of the forest.
 Thank god,
 we did not find many bear-diebacks on that day …

With my recovering wrist, I am now venturing into Doshi Village 道志村 for thinning activity as well. Very broadly speaking, Tanzawa and Doshi areas belong to the same geological range, called Fossa magna that has very unique characteristics in Japanese archipelago. Though, strikingly, Tanzawa and Doshi are damned different each other. Next week, let me tell you my adventure in Doshi forest this year.

Broad-leaved forest along the ridgeway to Mt. Nabewari

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/

Baby sitting: pruning the trees in a water source forest of Kanagawa

In order to take care of afforested forests for water source, there is a cycle of jobs. Preparing the ground, planting seedlings, mowing, pruning, thinning … if the forest is for commercial logging, the final task is deforestation, then, the new cycle of ground preparation begins again. This week, I show you a bit of pruning for Japanese cypresses we’ve done recently. After our activity, I’ve felt a kind of “accomplishment” similar to a sense we have with a warm shower after a jog. Observing our job done gave me really a good satisfaction. It’s not smugness, believe me. Let me start telling you my pruning adventure to nurture the afforested forest for water source in the climate of Kanagawa Prefecture.

At the first stage before planting, the ground must be prepared. There may be a landslide, or deforestation by commercial logging. The space is cleared and the soil is to be plowed for baby trees to settle in. Additionally in Kanagawa prefecture it is a “MUST” these days to construct 2m high meshed barriers enclosing the vacant area in order to prevent the invasion of deer which love to devour baby trees for lunch.  Then, we plant seedlings. Recently it is more common in Kanagawa’s public land to plant broad leaved trees after harvesting of coniferous trees, hoping to create quasi-natural forest of our climate. Since mountains of Kanagawa are steep, the baby trees are often planted at the corner of rectangle whose sides are shorter in ridge and valley sides than for the sides of slopes. Reason? The canopy of trees planted nearer to the ridge grows wider to the direction of valley, which would reduce sunshine for the leaves of trees placed to the next lower place. In order to prevent the effect, we often keep the distance between the seedlings to ridge-valley direction. If they are the babies of coniferous trees, the standard in Kanagawa is 3000 of them per 1ha. For the areas of more intensive commercial forestry in southern Japan, it’s more common to plant 6000-8000 seedlings in 1ha. 3000 “would be optimal here,” I’ve heard from the professionals. We mark the corners of rectangles, and dig a hole there deep enough for the roots of a seedling can be stored with about 0.5 inches of soil covering their basis. We next “do a circle” around the baby tree to tread down the ground to support the seedling standing. I love this process, as it’s like a dancing for babies to grow well. 😊 The planted seedlings are indicated by a bamboo cane tied to their fragile trunk for propping up. These sticks become a mark when we mow the field to avoid chopping them off accidentally.

The seedlings are planted this way in the mountains of Kanagawa.

The seedlings of broad leaved trees
we’ve planted the other day.
The meshed fence behind them is enclosing
the afforestation area, protecting inside from deer lunch.

First
we dig a hole deep enough to cover the roots of a seedling.
The excavated soil is temporary stored
in the upper side of the hole,
and gently moved back to the hole with the seedling.

Stomp-dancing around the seedling.
We gently grab the baby tree and pull it up slightly
while we do a circle around it.

Loosely tie the seedling to a bamboo cane
to support it standing, and as a mark.

Ideally, mowing for an afforested area is done at least once a year during summer for the first 5 years of baby trees. During this period, the seedlings are still small and the weeds dominate the place in Kanagawa’s summer, which could prevent the toddler trees to receive enough sunshine for photosynthesis. For coniferous seedlings, once they become tall enough to escape from the overpowering grass, it is the time of the first pruning. To create straight and long logs for human consumption out of Japanese cedars and cypresses, it is important for a tree to have enough time, 2-3 years, covering sections by epidermis after pruning especially near the root. (Nearer the root, fatter the trunk, so that pretty lower bottom of a tree can provide more substantial logs. Got it?) Moreover, the dead boughs could create a huge hole on a tree’s trunk when we neglect the care for them. The crucks created by dried out branches attract pests and viruses, such as Cerambycidae, that will kill the tree eventually. It is important pruning cedars and cypresses regularly for at least their first 20 years, starting from their 5^th-8^th year.

The no-pollen cedars of their 5^th year summer.
The ground is completely covered with grass and shrubs
but now they are tall enough to receive sunshine by themselves.
The mowing of the place is completed this year,
and probably next year or so we will do the first pruning.
In Japanese forestry lingo,
the first pruning is called Suso-harai 裾払い,
“rear foot sweep” that is from sumo technique.

The traditional theory of afforestation in Japan is, cypresses are for drier place so that it is standard during your hike finding them near ridge after a cedar forest. (People do not follow standard always, of course. 😉) The point to differentiate cedars and cypresses is ground litter. Japanese cedars shed the old branches by themselves. When you find branches of coniferous trees on the ground in Kanagawa’s mountain, the trees around you are cedars. Often they are along the mountain stream, or near the valley. When humans harvest the tree in desired size, their natural discarding could be too late for sections to be wrapped completely with the outer skin. Or, the left-out broken boughs could be an entry way for diseases. Thus, pruning. On the other hand, Japanese cypresses do not drop their bough even when the branches are desiccated.  Cypresses renew their tiny 1-2mm leaves during fall to winter, leaving the boughs sticking out of the trunk. The lifespan of leaves of Japanese cypresses is about 6 years. After summer their 6^th year leaves fall off from the branches and cover the ground underneath.

The stems separated from
the fallen branches  of Japanese cedars

Trekking road in Mt. Oyama 大山
running in the Japanese cypress forest.
Could you see the difference with the above photo?

With these characteristics in mind, pruning is important especially for the health of coniferous forests. A forest of cedars et al without proper pruning is a dark place. Being it cedars or cypresses, the withered boughs and branches block the sunshine reaching to the forest floor. It becomes difficult for undergrowth to take hold when only the tree top receives enough power of sun. In such forests, the trees grow lanky with insufficient development of roots. The slope becomes vulnerable for soil erosion. For example, decay of fallen cypress leaves is VERY slow. In a dark cypress forest, it’s like walking on leaf-confetti without much hurdle of ground-growths. Furthermore, as you may expect, the cypress leaves are too small to stop water flow when it pours over a steep slope. There is this academic paper 林試研報 about substantial soil erosion in cypress forests. It fares better for forests of cedars without pruning whose ground is covered by shriveled branches scattered all over. But their effect is not much for soil protection. In contrast, proper pruning create space within a forest for sun light reaching to the ground. With rain and sun, the dormant seeds of grass, shrubs, and trees will sprout. They eventually protect the soil and forest to be washed away by storms. The trees grow with deep roots and store water underneath. Pruning is vital for maintaining water source forests in Kanagawa.

The cedar forest in the northeast slope of Mt. Oyama.
I think Atsugi City does a good job
for keeping the coniferous forest by pruning and thinning.
The sun light comes in here,
but still the undergrowth is limited at best.
In this photo, we can identify lots of retaining walls
made of thinned logs to prevent soil erosion.
Creating hierarchical structure in a forest is really difficult …

The height of the pruning depends on the objective of the usage of trees. When we plan to harvest a coniferous log for a pillar of standard Japanese house, we prune off branches and boughs sticking out the lower 6-7m part of a tree until its 20-25^th year. For a material suitable for repairs of gigantic temples in Nara or Kyoto, people nurture a cypress for decades or centuries by pruning the lower boughs nearer to withered branches deprived of enough sunshine by the leafs spreading above them. Kanagawa prefectural government does not recommend volunteers pruning with ladders at the height higher than 2m. So, we tackle with the branches within our reach. For creating a beautiful trunk of a tree, best pruning seasons are October-December and March. During dead-winter, trees dramatically reduce their water intake from the ground and their body becomes hard enough to make the operation difficult. When trees drink a lot during late spring to early summer, their vascular bundle is expanded with lots of liquids running inside. When a part of the system of bundle is terminated abruptly in the middle, which is pruning, the vascular organ is exposed suddenly to the outer world with its mouth wide open. For a tree epidermis, it’s difficult to cover the large wound completely. The tree will have a hole under the bark at best. Otherwise, the trunk keeps a cavity, not good for health of a tree or housing material.

This is one way of
reaching to the higher branches.

One weekend of this November, we entered a public forest located in the steep somma of volcanic Mt. Hakone 箱根火山. The place is a water source for Sakawa River 酒匂川 where many parts were afforested by coniferous trees decades ago. We forest instructor trainees have come this area several times as a part of the curriculum. Due to very rainy autumn this year, there were mini-landslides here and there in the area. I noticed several mini-ponds off the mountain stream where a couple of large cedar trees stood in a pool. The waterway had come that far during last storms … Our instructors told us due to 2 consecutive typhoons in October, there occurred numerous mini-land failures, although they did not triggered disaster downstream. Now the prefecture is busy in restoration works for the stability of the collapsed hills. The forest we pruned away this time was populated by 14 years’ old Japanese cypresses. They are still young with 20cm or so diameter. I noticed they preserved their withered branches at very lower part of their trunk. … They could not have their 5 years’ old pruning … the branches and boughs congested the forest. Inevitably, the entire place was very dark despite of a fine fall Sunday. Not much undergrowth was found except sasa bamboos whose roots expand horizontally over the shallow depth of the soil. I a kind of understood the reason of mini-slides in the area.

Could you figure out a mini-land slide over there?

Lots of dead branches are sticking out
from the lower trunk of young cypresses.
Although it was a windy day,
not much air stream penetrated into
the maze of tree boughs.

Our task was to prune off the branches, and mow sasa bamboos to make space for more deep rooted vegetation growing with sunshine. The forest expands over very steep slope which makes pruning the branches sticking to the direction of ridge way easy, but I had hard times to deal with those spreading to the valley side. I, a short Japanese woman, cannot reach them from the front … Properly done, pruned-off part will leave a round cut end surrounded by branch seat which is a part of the trunk. Cutting into the branch seat damages epidermis that would cover the cut end otherwise. I could manage preserving branch seat, but my cut end looked oblong when I had to reach to a valley-side branch from the ridge way direction. Moreover, the young cypresses were surrounded 3-4m long sasa bamboos poking from their roots. Although the bamboos were leggy at about 1cm in diameter (as this place does not have enough sunlight), they block the access to a tree. Worse, they could make the slope more slippery, and our movement around a cypress became more dangerous. “Woops. You have not sawed the bough straight.” “If you find the branch large, first provisionally cut it about 10cm from the branch seat, and then prune it away completely at the mouth of branch seat.” My seniors advised me. Hm. I found the 2-step approach worked well. Doing mowing and pruning at once for each tree on a steep slippery slope required patience and concentration. That was a very meditative task ...

This poor cypress was surrounded by
sasa bamboos and kept its lower twigs
poking out all over.
It would be a candidate for a thinning …
but today, we come here for pruning!

This is a good example of proper pruning for a coniferous tree
(; the photo was taken in cedar forest in another occasion).
Could you see the cut end is round?

I managed to do proper pruning this side
… and the other side is remaining …

Within 3 hours, roughly 80 volunteers of us pruned off the 1.6ha of young cypress forest. From the below, we could see the ground now receiving more sunshine, and the chilly autumn air started to flow among the trees. I hope the forest does not have torrential rain any more this year, but only drizzling or snow. If so, I imagined, early next spring when snow starts to melt slowly, spring ephemeral with enough sun-shine could show their head out of the ground, and start doing their job of stabilizing the soil of cypress forest. By and by, the water stored beneath the cypresses will join Sakawa River and come to Yokohama safely … I felt an accomplishment of our job. It might be self-satisfaction, but there is a scientific logic connecting pruning in the forest of deep-mountain and safe drinking water in a megalopolis. Calling our feeling “smug” could be very cynical and smug, I guess.

We mowed only sasa bamboos and left shrubs,
hoping for multilayered plant structure to materialize in the forest …

The sun light is coming in now!

Kanagawa Water Source Authority

1194 Yasashi-cho, Asahi-ku, Yokohama, 241-8525

Phone: 045-363-1111