Saturday, February 1, 2014

Sanbon Sugi gets a physical.

If you've been following my blog, you may know that visitors can no longer see Jomon Sugi from the "front," because a health exam a little over a year ago found that the overhanging limb is hollow -- as it may have been for hundreds of years -- and was deemed hazardous to those standing below. But just how do you go about evaluating the health of a tree that's older than Jesus?

This January, I went to the local Forestry office and asked. Fully expecting to be shown a stack of papers and research reports, I was thrilled by the answer:
Why don't you come along and see for yourself?

The Patient: Sanbon Sugi
The next examination coming up was for a tree named 三本杉 -- Sanbon Sugi, or, literally, Three Sugi Trees, in English. This tree isn't on the list of milleniarians, but, according to the head of the research team, it received its name well before any of its famous Yakusugi associates. Not only does this threesome of inosculated (I'm impressed if you don't have to google inosculation!) trees stand along the
That's a bottle of
Mitake shochu behind
the inscribed stone.
Kusukawa Trail used by Edo-period loggers to access Yakushima's interior, but it's a holy tree. In fact, there is a small shrine recognizable by the carved stone nestled among the trunks. Over hundreds of years, the tree has grown up around this stone, so that the dedication is only partly visible.


Sanbon Sugi, measurement sticks
in place.
Once there, the head scientist bowed to the shrine, and then they set up tools for standard measurements, laying out tape measures and standing a ten-meter-high pole next to one of the trunks. We all backed away and tried to estimate the height of the tree -- not an easy feat in a dense forest. I counted out 24 meters to a space where I could see both the top and bottom of the tree, and then took out my cell phone (got to love smartphone apps!) to measure the angle. Others estimated how many ten-meter poles would be required to reach the top. The team leader, a local well-versed in both about nature and local lore, took out a surveying device that looked a bit like a mini-telescope that measured both and angles to calculate height. Most estimates fell around 24 meters, although both my cellphone and the surveying device gave something closer to 30m. The leader jotted down the height and environmental conditions and sketched the tree on the long form he carried.

Circumference is measured at the highest point 1.3 m above the ground.

Coins removed and returned
to the shrine. Did you know one-yen contain aluminum, which is bad for the environment?

Soil Observations: Testing the firmness of the soil. Note the book of swatches on the ground.
The next measurement was circumference (and thereby diameter) of each trunk. This is measured at 1.3 meters from the ground, so that the sprawling roots don't overblow the measurements. Then parameter of the roots. What trees (epiphytes) had taken up root on Sanbon Sugi. (It's not easy to identify a plant that's 12 meters up the side of another tree trunk!) and what plant species were growing in the area. The depth of hollow openings above the roots. A sound-test for hollowness. (All three trunks are hollow.) Estimating how far the branches extend in all directions. The presence of fungus on decaying limbs. (The form called for identification of the fungus, which is something I couldn't do with the fungus in front of my nose, and this fungus was probably 15 meters above. サルノコシカケ, polyporaceae, seemed like a good bet.) Things like that.


Lunchtime was the most interesting for me. I'd racked up a bunch of questions I wanted to ask, but found it was much more interesting to let the group talk about things I hadn't even considered.


In the afternoon we started the soil measurements, which take the most time. A couple holes were dug and the leader expertly documented the soil layers including color, granularity, stiffness, and a bunch of other factors I didn't understand. Apparently these things have been recorded for soils all over Japan, and you can look up the color in this little booklet that must be the world's most expensive book of swatches (to untrained eyes, just like you get for free from the paint store!) to find out the stage of erosion. While the leader concentrated on that the rest of the team took turns boring meter-deep holes by dropping a weight on the end of a sharp-tipped pipe. With each drop, the pole sank a few milleters or maybe even a couple centimeters, and the depth was recorded. The weather forecast had called for partly cloudy skies, but it was much chillier than most of us had anticipated, and I found myself cheering for the pole to sink faster as a shivered and waited.


While the team was documenting all the flora in the area, (omg, they're supposed to know the names of all those ferns?? Wow.) a family of monkeys -- apparently aquaintances of our leader -- stopped by to chat as they foraged nearby.


Sanbon Sugi (according to Yakusugi Museum texts)
Height: 23.4m
Circumference (of largest trunk): 4.9m
Elevation: 550m

Special thanks to the kind and knowledgeable folks in the forestry office and at the Yakushima Forestry Conservation Center.