20 years after the discovery of “pollen-free cedar”… Is Prime Minister Kishida’s goal of “halving the number of pollen-free cedar trees in 30 years” feasible? | FRIDAY DIGITAL

20 years after the discovery of “pollen-free cedar”… Is Prime Minister Kishida’s goal of “halving the number of pollen-free cedar trees in 30 years” feasible?

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Will the day ever come when Japan will be free of cedar pollen…

The season of hay fever continues to be a painful one for hay fever sufferers.

Last year, Prime Minister Kishida convened a cabinet meeting to discuss measures to combat pollen allergy and set a goal of reducing artificial cedar forests by 20% over the next 10 years and halving the amount of pollen produced in the next 30 years. Toyama Prefecture is leading the way in planting pollen-free cedar trees.

Hay fever is a social problem,” said Prime Minister Kishida (PHOTO:AFRO)

In 1992, during a pollen dispersal survey, pollen-free cedar was accidentally discovered at a shrine in Toyama City for the first time in Japan, and 20 years later, in 2012, the prefecture succeeded in commercializing pollen-free cedar. But why did it take 20 years after the discovery? It seems to me that if you want to take cuttings, all you have to do is cut off a little branch of the pollenless cedar you found and plant it in the soil. ……

I don’t think it’s simply because it’s pollenless that it’s good. If it is to be used in forestry, it must grow fast, be of good quality, and be resistant to snow and other damage. It took 20 years to cross the pollenless cedar we found with other superior cedars to create a satisfactory variety.

says Mr. Masami Saito, Director of the Forest Resources Division of the Forestry Research Institute, Toyama Prefectural Agriculture, Forestry and Fisheries Research Center.

Even pollenless cedar has female flowers. Pollen from cedar trees was collected from all over Japan and crossed with the female flowers of pollenless cedar trees to produce a pollenless cedar of superior growth and quality. The pollen collected amounted to 330 varieties!

The resulting variety is called “Tateyama Mori no Shine.

But, it is not so easy to take cuttings and multiply the number of trees.

It takes time to grow the parent trees; in order to take 100,000 cuttings each, at least 10,000 parent trees must be grown. Until we had the parent trees we needed, we had to grow both seeds and cuttings.

When we grow seedlings, only half of them become pollenless cedar. After three years of cultivation, the trees are finally ready for planting. Cuttings can be shipped in one year.

The parent trees have grown, and in the last one to two years, we have finally become able to increase the number of trees by cuttings alone,” he said.

A 20% reduction in cedar plantation forests in 10 years is a mountain of problems.

Currently, 100,000 pollen-free cedars are produced annually in Toyama Prefecture. So far, they have shipped about 28,000 pollen-free cedar saplings to Fukui, Niigata, and Ishikawa prefectures.

In addition to Toyama Prefecture, the Forest Tree Breeding Center of the Forestry and Forest Products Research Institute has developed 147 varieties of small pollen-free cedar and 55 varieties of small pollen-free cypress by the end of FY ’23 in cooperation with the prefectural governments. As a result, 15 million trees a year are being replaced with pollenless cedar and small pollen cedar.

Since 28 million to 30 million cedars are replanted in Japan each year, roughly half of them are pollen-free or low-pollen cedars. The government has set a goal of replacing 70% of the cedars to be planted with pollen-free or low-pollen cedar in the next few years. This is a promising measure against hay fever, isn’t it?

No, the area of Japanese cedar planted forests is enormous, so this is far from enough.

The number of cedar planted forests in Japan is about 4.4 million hectares, and the number of trees to be planted per hectare is about 2,500. If one calculates from this figure, 15 million trees is only about 0.14% of the total.

The “scions” from the parent trees are grown as cuttings. If grown from seed, it takes three years before they are ready for shipment, but with cuttings, they are ready to ship in one year.
Harvesting the grown pollen-free cedar. Landscapers and farmers are growing pollen-free cedar.

Toyama Prefecture, the pioneer of pollen-free cedar, has planted 220 ha of pollen-free cedar so far, but the total area of cedar planted forests in Toyama Prefecture is about 48,000 ha, of which only 0.5% is pollen-free.

This is far too small. ……

Is it really possible to reduce cedar planted forests by 20% in 10 years?

A 20% reduction is an enormous number. I think there will be many problems. First of all, if we leave the trees as they are after logging, landslides will occur, and seedlings will have to be planted.

How do we secure the manpower for logging and planting seedlings? How will we secure the seedlings? We have to solve all of these problems, so I think it is a big challenge.

After securing growers, the goal after two years is to produce 200,000 pollen-free cedar trees per year.

Cedar trees were actively planted between 1950 and 1970. This was due to the increased demand for lumber during the postwar reconstruction period. However, since then, inexpensive timber has been imported from overseas, and the demand for domestically produced timber has only declined. Is it necessary to plant cedar trees now?

People often say that it is better to plant hardwoods, but it takes time for hardwoods to grow. Until they grow to a certain size, they require a lot of work, such as clearing undergrowth. Also, hardwoods do not grow straight, making them difficult to use as lumber. Japanese cedar grows quickly and has a high landslide prevention function and carbon dioxide absorption function. Cedar plantations are necessary to pass on forestry to the next generation.”

The cedars planted 50 to 60 years ago have now grown so large that they are just about ready to be cut down.

As if to coincide with that time, it is now possible to increase production of pollenless cedar trees simply by taking cuttings.”

Toyama Prefecture’s goal is to produce 200,000 trees in two years. What are the challenges now?

“The challenge now is to secure growers for the increased production of saplings.”

We would like to encourage them to do their best to reduce pollen production as much as possible.

  • Interview and text by Izumi Nakagawa

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