Blight at 2,000 metres

Is all well with the representative tree of Japan’s alpine zone?

This just came in from Hakusan, the home mountain of the Hyakumeizan author. The photo below shows a creeping pine tree (haimatsu, Pinus pumila) affected by some kind of blight or rust that has turned the tips of its branches a reddish colour.

None of the experienced local mountaineers in the photographer's group could recall having seen creeping pines in this condition before, at least on this mountain. Several more haimatsu thickets in the area of San-no-mine, a subsidiary peak, were blighted in the same way.

Haimatsu is the representative tree of Japan’s mountaintops. “The scent of creeping pine” (Haimatsu no nioi) is the title of an essay on the joys of mountaineering by Kojima Usui, the founder of the Japan Alpine Club. On Hakusan, haimatsu thickets extend from the summit regions, at about 2,700 metres, down to about 2,000 metres, the tree’s lower limit, where this photo was taken.

According to a botanical garden’s website, the tree, when cultivated, “is susceptible to tip blight, rusts and rots. Pine needle scale can be a serious problem in some areas. Sawflies, moths and borers may appear.” That said, these afflictions shouldn't be much in evidence when haimatsu is growing in its natural habitat. Unless, perhaps, the habitat has changed. This year, Japan’s rainy season came late. Less rain fell than usual, while temperatures were much hotter than average.

Image courtesy of Kita-Nihon Shinbun

On Tateyama last year, the haimatsu withered in the vicinity of Jigoku-dani when the valley’s fumaroles started to emit more sulphurous volcanic gases than usual (photo, right). But this was apparently a localised problem.

Volcanic gases are unlikely on long-dormant Hakusan. More plausible culprits for the blighted haimatsu could include industrial pollution (see Yellow sand, black snow), rapacious caterpillars or competition from other plants.

It may be that the Hakusan blight is also a localised problem. Or something more widespread may be going on. Has anybody else seen haimatsu thickets that are affected like this on other Japanese mountains?

Update on 24 July

The same group of mountaineers who sent in the Hakusan photos went to the Karamatsu/Goryu area in the Northern Alps on the following weekend. These mountains are a good distance inland and further north than Hakusan. 

And there (see photo right) they found more evidence of the haimatsu rust or blight. The "rusty" bushes were at a height of 2,300-2,500 metres and were mixed in with healthy bushes. So this is not an isolated problem.

Update on 27 July

Hanameizan reports that most of the haimatsu bushes on Amida-dake (in the Yatsu-ga-take range) are tinged with rust (see picture right). Also, he adds, some other conifers and bushy plants appeared to be scorched.

Update on 26 August

Hanameizan is just back from a long hike from the Japan Sea Coast to Karamatsu: "From Nihon-kai to Karamatsu (Tsugami Shindo), the haimatsu tips were burned pretty much everywhere. Will be interesting to see whether the state worsens or improves next year," he reports (see picture below).