Bamboo shoots in the new era? 2023 bamboo shoot harvesting in Kanagawa Prefecture

 

A bit strange this spring is not limited to cherry blossoms. The case in point is bamboo shoots, aka Takenoko. I don’t know how professional Takenoko farmers do for stable production of their produce. But, in general in Kanagawa Prefecture, bamboo shoots that can be harvested from bamboo forests managed by volunteers have a sort of pattern in annual yield. It alternates bumper and poor years. We volunteers dig bamboo shoots not for harvesting ag produce, but for controlling the wild spread of bamboos that can damage the ecosystem of entire forest. Poor year is poor year, and we accept it philosophically. Last year, 2022, was a bumper year. This year was not much. OK. Then I noticed a bit strange thing in bamboo forests. It’s not about bamboo shoots but the ground.

As I told you in my post for May13, 2016, for digging up bamboo shoots, we remove soil around the shoot, then strike down the root part. How deep we have to dig is actually not much regardless of the size of the shoot. It’s about 20cm or so deep and we reach the connection point of the shoot and its underground rhizome. When we meet with that joint, it’s time to strike and remove the shoot from the rhizome. This year, I noticed when we dig the ground around a shoot, the soil that is moist is top 5cm or so at best. Below that, it is dry. Sometimes my hoe finds even crumbly underground around the rhizome. That’s strange. Yeah, it’s easy when the root does not stick to the ground when we harvest a bamboo shoot. Thank God. But I feel a slight discomfort. Bamboo forest is a dim place. Botanically speaking, bamboos are not trees, but extremely tall grass many of whose leaves remain bushy and green all year long. They shed older leaves gradually, just like evergreen trees. Their leaves tend to remain on the ground but not so fine as cypresses so it can keep rainwater that reach to the ground more. Bamboo forest is a dim and humid place. Its ground tends to retain water. But this year …

Could you see the crumbling soil around the shoot?

March 2023 was an average year for Yokohama in terms of precipitation. According to the stats from Yokohama Meteorological Station, we had 140mm rainfall for March 2023. 1991-2020 average is 139.5, so we had a bit more rain last month than the average. Not bad for Takenoko to come out. Though the way rain fell may not have been the same as, say, 40 years ago. Below is the scatter plots I’ve created from the precipitation data for Yokohama.

To keep the graph easier to see, I intentionally dropped the March 1st data since in 2003, when Yokohama had a huge rain, 153.5mm to be exact. The horizontal axis is for days of March for 2023, 2022, 2003, 1993, and 1983. Each colored dot is amount or H2O dropped from heaven. 2023 rain has light green, 2022 is pale blue, 2003 is tangerine yellow, 1993 smoky green, and 1983 is marine blue. Don’t you think dots for 2003, 1993 and 1983 spread more for the entire moth, but 2023 and 2022 colors tend to gather around a particular day or a week?

Lifting!

The other day in a public seminar, Prof. Kishi of Keio University speculated on the influence of global warming on riskiness of large flood for Tsurumi and Tama Rivers. He doubted the possibility of an increase in total amount of rain our area receives in a year because of climate change. But the way for the clouds gathered above our head may have become different from those of yesteryears, he said. Sea waters are warmer and the westerlies meander that mix warm and cold air above unexpected way. He guessed it may make a linear rainband formed more easily than the time of less warming era. So, “When it rains, it pours,” and in-between days are very dry … Is the soil around bamboo shoots affected?

Raining …

For Japanese ordinary supermarkets, roughly 90% of bamboo shoots are imported from China and South-east Asia. So, pricewise, the effect of climate change may not appear much and Japanese could enjoy meals unnoticed the difference in bamboo forests around us. In any case, bamboos in Japanese residential areas now are nuisance, which invade non-bamboo forests and wither the other vegetation ... Er … they may be telling something to us silently …

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/