Magnolias in the wild, Part 2

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Rootstock

10 min readApr 30, 2019

This photographic journal shares highlights from an expedition I carried out in August 2018 with Dr Henrik Sjoman from the Gothenburg Botanic Garden and SLU Alnarp. Our research looks at the variation in functional traits in populations of Magnolia obovata, Magnolia salicifolia and Quercus mongolica var. grosseserrata, trees that frequently co-occur in Japan and the Kunashir Island in spite of their different evolutionary strategies. We selected our study sites based on an expedition I carried out to Kyushu and Honshu islands in April 2018 with Simon Hannus, and both expeditions were generously supported by The David Colegrave Foundation, The International Dendrology Society, The Merlin Trust, The Royal Horticultural Society, The Rhododendron, Camellia and Magnolia Group, and The University of Sheffield.

The story starts in Gifu University’s Takayama River Basin Research Station, high in the Japanese Alps. Henrik and I arrived in Tokyo on the 1st August and drove across to the eastern slopes of Mt Norikura, where we met Dr Yoshitake Shinpei and his colleagues to begin our research.

The Takayama research plot, a woodland that is recovering from clear fell approximately 30 years ago

We recorded the area and fresh mass of 6 leafs from a minimum of 8 trees of each species at each site, as well as the volume and fresh mass of a wood core sample taken from each tree

After being dried at 40'C for 48 hours, the leafs and wood samples are re-weighed and the Leaf Dry Matter Content, Specific Leaf Area and Specific Stem Density are calculated. We also carried out transect studies, soil samples and recorded allometry data for every tree we studied.

We frequently found plants thriving in places the horticultural literature says they shouldn’t: here a Magnolia obovata seedling is growing in a rocky, droughty scree

Miscanthus sinensis dominated the woodland glades

Evaluating the data after a long day in the field

Cardiocrinum cordatum in a roadside verge

Clethra barbinervis frequently co-occurred with Magnolia salicifolia and often with Magnolia obovata

Henrik searching for a large Cercidiphyllum we’d just driven past. At this point there was a transition in species as C. cerdiphyllum gave way to C. magnificum

Rudbeckia (a North American species) was frequently invasive in roadside verges

Schizophragma hydrangeoides in the evening light

Viburnum wrightii on the edge of a waterfall

Our next stop was Kyushu University’s Shiiba Research Station in Miyazaki Prefecture on Kyushu Island, a fascinating landscape that sits on the faultline of two geological regions, high in the mountains. Because of its unique location and climate (it is the only cold temperate place on the island of Kysuhu) it has a flora that has elements of both warm and cold temperate bioregions: amongst the Magnolias and Rhododendrons, for example, we saw some Gardenia seedlings. An extraordinary place. We met Dr Takuo Hishi and his team and headed up to our study site, an abandonned copper mine at about 1,200m.

The view across Miyazaki Prefecture from the abandoned copper mine

Magnolia obovata — note the enormous root plate scrambling over the top of the rocky soils

Magnolia obovata as we more frequently found it, on woodland fringes. Pieris japonica is the shrub that’s regenerating: the deer eat everything else

Henrik with a magnificent Stewartia monadelpha. The photo doesn’t do it justice- the bark was practically glowing in the woodland

Carrying out transects to assess the effects of excluding deer from the woodland. The fence shows the dramatic impact of deer browsing, note how sparse the understorey is outside the fence

After our work in Shiiba, we drove north to Fukuoka, working in a very different climate. Here the climate is classified as warm temperate, although many cold temperate species that we would recognise are also distributed. Our target was Aburayama Forest, a forest that ranges over a large mountain to the south west of Fukuoka, about 450m at its peak.

On the way through the central plains of Kyushu we saw many lilies in full flower, scattered over the roadside rocky screes

We visited Aburayama Forest at a time when conditions were challenging: hot and high humidity. Nevertheless, another highly productive couple of days, quickly collecting plant material and recording transect data. Here, Henrik emerges from the undergrowth with M. salicifolia material with Fukuoka in the distance behind him

I was particularly pleased to see this tree again: on the outskirts of the city, here’s a Magnolia obovata that’s self seeded into the top of a concrete retaining wall, the very conditions that everyone says Magnolias hate: highly droughted, alkaline soils and lots of reflected heat. Promising for urban foresters.

Sadly we had to work very quickly in Aburayama as a typhoon was approaching and we didn’t know when we would need to take shelter in the city. Worse: as we sheltered from the storm that passed over the next few days our flight was cancelled, delaying our next leg on to Kaisho Forest, near Seto. This meant that our time there would be shortened too.

Once we had rescheduled our flights we met up with Professor James Hitchmough and headed into the forest. Because of the typhoon that had just passed and another on its way, we only had a day in the field here, so we made it a long one, getting into the forest as early as possible and staying as late as we could. The worst problem though was finding Magnolia salicifolia. Here, the individuals that we had found in the spring proved extremely difficult to positively identify as they were hybridising naturally with Magnolia stellata. Great to find a large and robust population of an endangered species but really problematic for us given our shortened time frames- the result was that we had to exclude this species from the study for this site, a great shame in the end.

James and Henrik getting excited by the bark of Quercus variabilis, the Japanese cork oak

Recording transects and gathering tree data in Kaisho. Here, we are looking at a Magnolia obovata growing on the very edge of a stream bank.

From Kaisho Forest, our next stop was Kyushu University’s forest at the Ashoro Research Station in Hokkaido. Here the typhoons worked in our favour, giving us an extra day to explore before meeting Professor Masaaki Chiwa and Dr Takuma Nakamura.

Flying in to Sapporo late in the evening

Invasive Rudbeckia again, here in the eastern plain of Hokkaido at about 150m

Another North American invasive on the roadside, Evening Primrose

By contrast here are two native species to Hokkaido that pose problems in northern Europe: Reynoutria spp. and Sasa kurilensis underneath the birches

We found a bear sanctuary near a ski slope- sadly the tours weren't running (too late in the season?) but it did suddenly make us very aware that we’d been wandering around the woods checking out the Schizophragma without perhaps enough precautions. The next day James drove us to a camping supply shop and invested heavily in bear sprays and bells

Ski slopes waiting for snow, with Cryptomeria japonica

Typical forestry scene: larches and oaks, with Sasa underneath and Schizophragma hydrangeoides climbing a trunk

Another Campanula by the side of the road: I’ll add species names once I’ve checked the flora.

Arriving at the research station, our first step was to collect the plant materials as quickly as possible and then process them in the laboratory along with all the material we collected in Aburayama and Kaisho.

Preparing oak leaves at Ashoro Research Station

James gathers transect data with the Ashoro Research Station team, led by Dr Takuma Nakamura. This was pretty quick given the extent of the Sasa- nevertheless, some seedlings were identified that were fighting through the herbaceous layer

Acer palmatum var. matsumurae, co-occuring with Magnolia kobus and Magnolia obovata

Magnolia obovata on the edge of a larch plantation, with Magnolia kobus seedlings emerging too

Magnolia obovata and Magnolia kobus against each other for comparison. Note the size of the M. obovata leaves.

Betula platyphylla and Sasa kurilensis: the habitat that launched a thousand ships in the 1990s (think how many designers recreated similar landscapes in European towns and cities)

Here we’re heading back down the mountain, with birches and Petasites underneath

After collecting the plant material and doing our transects, we headed back into the mountains whilst the material dried in the oven. With 48 hours at our disposal we searched for the biggest mountains within driving distance to see if we could find any Pinus pumila habitat. Lucky Henrik had that umbrella to keep the bears away

Driving up through the passes to find a place to start climbing

James, Henrik and me at Lake Onnetoh, preparing to climb Mt Akan-fuji

At the base of the mountain we were immediately confronted by Picea glehnii forest: a tough climb

Pinus pumila. We’d been inspired to find it after reading Tony Kirkham and Mark Flanagan’s books and it was a nice moment to take stock and think about other plant hunters who had explored these islands north of Honshu

Returning back to base. Note the Sorbus commixta starting to turn red on the right hand side

After eight days with James and all too little time in the field, it was time to say goodbye and start the last leg of the expedition. We returned to Sapporo, James to fly back to Sheffield and for Henrik and me to fly to Sakhalin. After arranging a meeting at Hotel Lenina with Dr Liuba Kameneva and Dr Ilya Bogachyov from Vladivostok Botanic Garden, we then met up with Elena Linnik from the Kurilsk Nature Reserve at Yuzhno Korsakov, and boarded the ferry that would take us to Kunashir.

Magnolias in the wild, Part 2

Written by Harry Watkins