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Posts tagged ‘walnut’

Danish walnut beer

July 16, 2013

Gabriel Hemery

As with all good stories, this one begins in the dentist’s chair. In between garbled arghs and minuscule nods, my dentist and I ‘discussed’ my work as a silvologist and landed eventually on the topic of my research on walnut trees. It turned out that he called home the tiny island of Ærø in the Baltic Sea of southern Denmark, although he’d been practising in England for many years. There in the garden of his family’s property, he was the proud joint owner of a walnut tree and locally, he told me with a glint in his eye — and I’m sure a smile behind his mask — there was a local brewery that made a wonderful walnut beer.

Ærø walnut beer

Ærø walnut beer

I thought nothing more of the conversation until my next visit, six months later for a regular check up. He greeted me with the usual cheer while reaching into a sterile white cupboard to produce, with a flourish, a bottle of walnut beer. I was flabbergasted, not only that he’d remembered our conversation, but that he had so generously brought me a bottle to sample. He recounted with delight how he’d hidden the alcoholic drink during various inspections!

The 7% alcohol beer is brewed by the Rise Brewery and is called No. 5 Walnut Duke Hans. It is a bock type, made with various malts, aroma hops and walnut extract. The company describe the resulting dark beer as:

“a fantastic harmonious, maroon, strong bottom-fermented Bock beer with a delicate walnut flavour.

I really enjoyed my sample  — my first ever walnut beer — and was delighted to find that the brewers can supply by mail order.

Now, I need to find something to offer my dentist in return. Perhaps a bottle of my recently matured home-made elderflower champagne would go down well.

Basal Areas for common walnut

December 27, 2011

Gabriel Hemery

common walnut basal areas

There are no published Yield Class tables for common walnut Juglans regia – at least that I am aware of. A search on the European Forest Yield Tables Database reveals that data are only available for black walnut Juglans nigra in Hungary.

I wrote previously about research that I undertook exploring the crown sizes of major hardwood species – Estimating tree crown size. This work provides the next best available data on managing a stand of common walnut, in the form of basal areas for common walnut ref.

The table below shows the stem diameter (dbh), crown diameter (cd), crown/stem ratio (cd/dbh), number of trees per hectare (Nha) and acre (Nac), and Basal Areas (G) in m2 per hectare. These data were collected from trees grown in open conditions, and calculated for stand densities with zero crown overlap.




N trees per ha

N trees per acre

Basal Area m2 per ha















































































common walnut basal areas

Common walnut Juglans regia basal areas with dbh.

A growth rate of 1cm per year in stem diameter can be presumed, permitting this graph and data to be used in estimating suitable basal areas at different stand ages. If real dbh data is available, then the accurate growth rates will provide accurate basal area increase projections for a given site.

Gabriel Hemery


Hemery, G.E., Savill, P. & Pryor, S.N. (2005). Applications of the crown diameter – stem diameter relationship for different species of broadleaved trees. Forest Ecology and Management 215, 285-294. View abstract

Threatened walnut forests

October 17, 2011

Gabriel Hemery

The effect of excluding grazing in the walnut forests, Kyrgyzstan

Sheltering in the south-western Tian Shan mountains exist a unique yet threatened forest found nowhere else on Earth. These forests are the walnut-fruit forests of Kyrgyzstan.

Last month I attended an international conference concerning the sustainable management of the forests (see my travel photos). The walnut-fruit forests are considered a biodiversity hotspot of global importance. Estimates suggest that there are 47,000 hectares (Grisa et al., 2008) of walnut fruit-forest, although large areas are now in a critical condition for a number of reasons.

Socio-political change

Following independence from the Soviet Union in 1991, Kyrgyzstan’s infrastructure deteriorated, especially the administration, transport, industry and public services. With these socio-political changes the walnut-fruit forests became even more important for local people; providing fuel wood, timber and walnuts from the trees, and grazing land, hay, cropping (e.g. alfafa and potatoes) and other non-timber products essential to rural life. As a result, the pressure on the forests increased, and forest management became unsustainable.


The walnut-fruit forests are found in two distinct areas of Kyrgyzstan; in the Fergana and Chatkal mountains. They survive winter colds of -24oC in January, and summer heat of +36oC in June. Late Spring frosts are a problem as they damage shoots and flowers, sometimes leading to serious failures of the walnut crop. Most precipitation in the forested areas occurs in the Spring, while there are three very dry months between July and September. The threat from climate change is very real, where changes in precipitation patterns could significantly affect the health of the forests.

Six walnut forest types have been identified (more details):

  1. walnut with false brome grass
  2. walnut as [1] but with moister soils
  3. walnut with spruce and fir
  4. walnut and hawthorn
  5. walnut with maple and apple
  6. walnut in park-like conditions

Ownership and use of the forests

The walnut-fruit forests are owned by the state. They are used heavily by local people however under different agreements, which have become more structured in recent years. Families in the forest explained to me that where there was a history of use in an area of forest, this used to be enough to secure continued use in a neighbourly agreement with fellow users and officials. Now, most users are likely to pay a rent to the state.


A ban on walnut tree felling has been in place for a number of years, and is mostly successful. This has led in turn to heavy pressure on other tree and shrub species, where any fallen branchwood from any tree species is quickly cleared away for fuel wood. Wood fuel remains the main source for heat and cooking in most rural dwellings. The walnuts themselves are harvested for sale in markets across Kyrgyzstan. Of course, what are nuts for humans are reproductive fruits for the trees, and therefore unless collection is limited or controlled, then the forests will become increasingly senile.

Walnut forest and fuel wood collection

A camp in the walnut-fruit forest in Autumn, where the people collect walnuts for market, and wood fuel for the winter

The greatest threat today is from over grazing: with cattle, horses, goats and sheep. This is illustrated perfectly in an experiment in place near Shaidan. On a typically steep slope deep within the forest, the most common walnut type [6] (above) is prevalent: mature walnut trees spaced widely apart with no natural tree regeneration (complete absence of young trees) in the heavily-grazed sward. Yet, nearby a fence made from the brash of tree branches has excluded grazing animals in a plot of some one hectare in size. Inside the fence, the grass is tall and rich with dicot species, and a new generation of young walnut trees are present under the tall canopies of the mature walnut trees. The photo below illustrates this perfectly.

The effect of excluding grazing in the walnut forests, Kyrgyzstan

The effect of excluding grazing in the walnut forests, Kyrgyzstan. In the plot on the left grazing animals have been excluded, and now ground flora thrives and a new generation of walnut trees are emerging. On the right, the typical appearance of the 'walnut park-like' woodland caused by overgrazing.

Without real and determined action, which must necessarily combine the best silvicultural practise with the tackling of the socio-economic issues with local communities, the walnut-fruit forests of Kyrgyzstan will continue to be degraded. Ultimately their survival is under significant threat.

Gabriel Hemery

References and further reading

  • Grisa, E., Venglovsky, B.I., Sarymsakov, Z., Carraro, G., 2008. Forest typology of the Kyrgyz Republic. Intercooperation, Bishkek.
  • KIRFOR: Kyrgyz-Swiss Forestry Support Program
  • More of my Kyrgyzstan posts

Weekly photo challenge: fall

September 25, 2011

Gabriel Hemery

Walnut collecting family with donkeys in Kyrgyzstan
Walnut collecting family with donkeys in Kyrgyzstan

Fall (Autumn) in the walnut-fruit forests of Kyrgyzstan, I came across a father returning home with his two young children and a large horde of walnuts. Photo: DMC-GF2, 15mm (30mm 35mm equiv), f4.0, 1/125sec, ISO100, handheld.

For this week’s photo challenge and theme of ‘fall’, I thought that this image was very fitting. It’s a double entendre, as not only was the photo taken in the Fall (Autumn), but I was amazed how these three managed to balance on the donkey without falling!

I was pleased with the photo as all three of the family are looking at the camera, and I like the way the youngest is just peeping over her father’s arm.

This was a good example of the advantage of always having a camera ready; not just by having it in your hand or around your neck rather than tucked deep in a bag, but also by having it ready with the best settings. I normally prefer to shoot using as many manual settings as possible but I am not proficient enough to be able to take successfully a quick shot of the unexpected. So, I normally leave the camera on the ‘idiot’ or full automatic mode just in case I need to fire off a quick shot without thinking of all the settings I might need.

Deep in the walnut-fruit forests of Kyrgyzstan, miles from the nearest track passable by a 4×4, I was climbing a narrow path when the family group suddenly appeared around a corner. I asked quickly (with gestures only as I don’t speak Kyrgyz) whether I could take a photo, and after Dad’s nodding approval I managed to take just two frames as they carried on past.

See more of my Weekly Photo Challenges

Gabriel Hemery

Kyrgyzstan walnut fruit forest photos

Collecting firewood, Kyrgyzstan

Regular readers will have noticed that I did not post a feature last week. In fact I was in southern Kyrgyzstan visiting the beautiful and remote walnut fruit forests that nestle in the Fergana Valley, among the south-western Tian Shan.

In 1997 I spent three and a half weeks in Kyrgyzstan, which is one of the most mountainous countries in the world. In places it has very high biodiversity and yet is devastatingly desolate in others. Fourteen years ago I was collecting walnut seeds as part of a scientific expedition (read more).

This time I was invited back to this fascinating country to give a presentation at an International Conference discussing the future of the walnut fruit forests. Both meeting and travel were inspiring and I have much to write and share. For now, here is a short slideshow highlighting some of my favourite photographs from the trip:

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Gabriel Hemery

Growing walnuts for their nuts – the cultivar revelation

August 16, 2011

Gabriel Hemery

One walnut tree is not necessarily the same as another walnut tree.  Many people will have planted a walnut seed in their backyard waiting hopefully for the growing tree to produce a crop of nuts.  They will appear of course, as that is the wonder of nature, but the tree may be 20 years old before it crops.

Many people don’t realise that there have been available commercially for decades, many selected cultivars of different walnut varieties. No gardener would think of planting a wild apple or pear and expect a good crop of fruit of known quality.  It is just the same with walnut.  Choose a cultivar that has been bred for its nuts and you will be rewarded with consistent crops of nuts of a specified taste and quality.  Even more attractive is the fact that a grafted walnut cultivar may start producing nuts only 3 years after planting in the garden or orchard; compared to the 15-20 years for a seedling tree.

walnut fruit tree

walnut cultivar varieties

  • Fernor – A modern (1995) French variety.  Late to leaf, precocious flowering, lateral fruiting and blight tolerant. Its fruit is late to ripen, large size and of excellent quality.  In France, yields of 1 tonne per hectare at 6 years-old are usually attained, and 4-5 tonnes per hectare when mature.
  • FranquetteA traditional French variety, representing 75-80% of orchards (15,000 ha) in just two French production areas (ref).  Late leafing, good productivity, excellent nut quality.  It is a terminal bearer (1- 2 fruit per terminal) which requires only light pruning.  Yields are only moderate compared to modern lateral bearing varieties such as Fernor and Lara. Partly self-fertile, bearing fruit at 3-5 years. Late fruiting season, nut size mid to large. Resistance to blight.  It has a light blond shell, and its fruit has a delicate taste.
  • Lara – French variety (developed 1980s), good fruit quality, precocious and highly productive. Early bud break and fruit ripening. Average vigour, quite upright in habit and lateral bearing.
  • Ronde de Montignac – An old French variety.  Fairly vigorous growth, semi erect habit, light cropper producing small/medium-sized nuts with high quality kernels.  Late to leaf so it can avoid Spring frost damage.
  • Some other French varieties
    Marbot (preferred variety for fresh walnuts), Granjean (fleshy fruit with distinctive taste), Corne (good disease resistance, sweet taste, fine texture), Mayette (sweet rich favour) and Parisienne (vigorous and productive when mature, can be grown on less fertile sites).
  • American varieties – caution is required when planting some of these varieties in Europe due to problems from early leafing in Spring.
    Chico (excellent variety), Hartley (vigorous growth and productive fruiting), Pedro (good productivity and suitable for temperate climates).

Gabriel Hemery

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