But according to Professor Yves Coppens, leader of the Lascaux scientific team, the caves are beginning to heal the damage on their own, a happy but puzzling situation.

“The Grotte de Lascaux is holding its own and no intervention is needed at the moment,” said Coppens. “The black marks are going away and we are happy, but still vigilant and a little disturbed that they are disappearing without us knowing why.”

I’m no scientist, but I never fail to be impressed by the ability of an ecosystem to restore itself if left to heal without human intervention. There are more things in heaven and earth than are dreamt of in our philosophy, after all.

The forests have long formed a vital part of the region’s economy, with a number of industries – construction, paper production, and lumber treatment in particular – building their businesses on wood. Tens of thousands of people across Aquitaine rely on the forests for their employment.

As a consequence, the two storms, ten years apart, were devastating. And while the post-1999 reforestation project saw the land managers reforest with an aim to reproducing the woodlands that were there before, the 2009 storm is being used as an opportunity to rethink the future of the woods.

Currently under debate is the notion of reforesting using a mixed strategy that would see some species of tree introduced to Aquitaine – having been previously assessed for environmental suitability – with a view to increasing the range of woods available.

Some of the forest’s users need short-term high yields for their production needs, while others are seeking longer term growth.

And for the statistics fans among you, here are some facts and figures on the Aquitaine forest from the Forest Industry website:

Aquitaine, the first forest region in France in terms of surface area

• Almost 1.8 million hectares, i.e. 42 % of the regional territory (60 % for the department of Landes, ahead of Gironde, 46.4%).
• A forest which is largely privately-owned, with almost 92% of private ownership. 128,000 owners hold more than one hectare of forest, i.e. 1.64 million hectares. Three quarters own more than 10 hectares. 2700 owners hold more than 100 hectares.
• 3 forest areas: the cultivated forest of Landes de Gascogne, the entire Dordogne Garonne with its woodlands, the Adour Pyrénées zone with its mountain forests.
• A species which is largely dominant, the maritime pine represents 49 % of the volume of standing timber and 91% of felling in the region. The regional hardwood forests have made progress, while the storms in 1999 and 2009 have impacted the softwood forest.

Aquitaine, the first French region for forest production

•  70% of the national harvest of softwood in private forests.

Aquitaine, the first French region for forest certification

•  11 250 owners have obtained the PEFC certification, i.e. a total surface area of certified forests of 918,000 hectares (figures from the Aquitaine PEFC).

Aquitaine itself represents half of the certified surface area of private forests in France.

•  932 works and exploitation enterprises are employed in the Aquitaine PEFC, which is a particularity of the region.

The Aquitaine paper wood forest activity: 34,000 employees, in addition to the foresters, mainly in rural areas

•  34,000 industrial jobs, which makes it one of the major regional economic sectors.

• 32,000 owners holding more than 4 ha, means that many people are committed to ensuring the continuity of forest investment, the upkeep and the protection of the forest.
• 15% of the national lumber production. The region represents 75% of national maritime pine lumber.
• A complete range of transformation industries: lumber and parquet and panelling production units, which often constitute the only employment opportunities in rural areas; factories producing packaging, panelling, paper pulp, paper and cardboard, woodwork, furniture and, more recently, products destined for wood construction, energy wood and green chemistry, including the first French biorefinery in Tartas, the Tembec factory.

Aquitaine, the first French region for forest production

• 70% of the national harvest of softwood in private forests.

Aquitaine, the first French region for forest certification

• 11 250 owners have obtained the PEFC certification, i.e. a total surface area of certified forests of 918,000 hectares (figures from the Aquitaine PEFC).

Aquitaine itself represents half of the certified surface area of private forests in France.

• 932 works and exploitation enterprises are employed in the Aquitaine PEFC, which is a particularity of the region.

The Aquitaine paper wood forest activity: 34,000 employees, in addition to the foresters, mainly in rural areas

• 34,000 industrial jobs, which makes it one of the major regional economic sectors.
• 32,000 owners holding more than 4 ha, means that many people are committed to ensuring the continuity of forest investment, the upkeep and the protection of the forest.
• 15% of the national lumber production. The region represents 75% of national maritime pine lumber.
• A complete range of transformation industries: lumber and parquet and panelling production units, which often constitute the only employment opportunities in rural areas; factories producing packaging, panelling, paper pulp, paper and cardboard, woodwork, furniture and, more recently, products destined for wood construction, energy wood and green chemistry, including the first French biorefinery in Tartas, the Tembec factory.

Famed for high end labels like Chateau d’Yquem, Sauternes is one of the more versatile sweet wines, complementing a range of flavours from foie gras to fresh fruit.

The Sauternes appellation falls roughly 25 miles southeast of Bordeaux, and follows both the Garonne and its tributary, the Ciron. The combination of the Ciron’s cool spring waters and the warmer Garonne promotes the misty conditions that help promote the noble rot for which Sauternes is famous. At the beginning and end of the day, the Sauternes vineyards are swathed in mist that helps the Botrytis cinerea fungus to grow. But in the heat of the day, the sun dries the grapes, keeping then safe from other, lesser, forms of rot.

The noble rot helps promote sugar production in the grapes, taking them along the road to becoming raisins, and is the same method used to produce other well-known dessert wines, including the local Monbazillac and Hungary’s Tokaj.

A combination of Sémillon, Sauvignon Blanc, and Muscadelle grapes are used to create Sauternes’ distinctive flavours, which include honey, peach, and apricot. The wine is notable for its golden hue, which darkens progressively as it ages.

Try spooning chilled Sauternes over sliced peaches, apricots, or melon, for a light summery pudding.

Photo via www.vinography.com and © George Ross.

In Offenburg the Roth family bookshop (now in the same family for five generations)  offered a five course dinner, which included a splendid foie, cooked to perfection, and flavoured with a little of the preserved ginger one usually finds in Japanese restaurants.

In Heilbronn the Bergerac wines were carefully chosen and in Aachen I was happy to see my old friends from the Schmetz am Dom bookshop, which is in the square by the magnificent cathedral and the somewhat intimidating presence of Charlemagne’s tomb.

Walter Vennen, who runs the shop with his wife Barbara, took me a marvelous restaurant called the Alt-Tor, for a 6-course feast of Spargel, the white asparagus which makes eating in Germany such a pleasure in the month of May. We had the asparagus in a vinaigrette salad with pine nuts and what  though was avocado until I ate it and found a delightful green asparagus ice cream; in soup (flecked with a pink soy foam); with hollandaise sauce and veal stuffed with liver; au gratin and then finally as a white ice cream. The people who award Michelin rosettes should check this place right away.

After a very happy evening in Munster, (asparagus with wiener schnitzel) we are now in Cologne, one of my favourite German cities, and about to head to an old castle in the countryside for another reading.

Each of the readings so far, in Hamburg, Hanover and Berlin, has been sold out, and Germans are such devoted book-lovers that they pay 10 and 12 euros to come and listen to authors read aloud.  I suspect that the audiences were swelled  by the presence of my friend Margarete von Schwarzkopf, herself a literary star in Germany from her very popular book programmes on NDR radio. Margarete reads in German and I read in English, and I try to answer questions in my schoolboy German while Margarete deftly interviews me and translates what I meant to say.

The other attraction is, of course, the wine that is usually served at these occasions, and at Berlin’s Thalia bookshop on Friday night I was delighted to find one of my favourite Bergerac Sec white wines from Chateau des Eyssards, along with Monbazillac and a splendid  Pecharmant from l’Ancienne Cure.

Lots of questions about how the French react to the Bruno books now that they are about to be published in French, and others about the French Presidential election. One questioner in Hanover wanted to know if I would still call my cockerel Sarko if President Sarkozy loses his bid for re-election. Sarko’s name stays, but if the opinion polls are right to predict a victory for the Socialist Party candidate my chicken coop will still reflect French politics, since we now have a pair of pheasants and the cock is named Flanby, the nickname for Francois Hollande.

Its vine covered terrace with lovely views has always been an enchanting place to lunch or dine in summer, but the cooking seems suddenly to have gone into overdrive. The chef’s specialty, Ravioli de Langoustines, is excellent and if like me you enjoy kidneys the cassoulet de rognons is an absolutely splendid dish.

You are always served a tureen of the home-made tourain soup, and this is one of the best versions I have tried. In careless hands it can look and taste like old dishwater but this version is excellent with lots of egg whites and garlic, not too much bread and a very hearty taste.

This is the kind of excellent local restaurant that is disappearing elsewhere in France, with good solid regional and traditional cooking, enlivened by some extra dishes.

The wine list is sound. You will not go wrong with the Chateau Jaubertie.

For more restaurant recommendations in the Dordogne, see the restaurant page.

The Domaine de la Vitrolle – just outside Limeuil on the road to Le Bugue – is a charming small chateau, used as a secret Resistance HQ by Andre Malraux in the summer of 1944.

The current owners have turned the chateau into a charming hotel, with  rooms in the chateau for 110 euros per night for a suite and 85 euros for a room, all decorated in 19^th century style with some fine antiques.

The grounds contain more than 20 self-contained gites, which are available 760 euros per week for a two-bedroom flat with sitting room and kitchen, plus a delightful annex with four rooms and its own chapel.

Set amid orchards and vineyards and overlooking the river, the Domaine de la Vitrolle has figured in several Bruno novels, inspiring the Domaine in Dark Vineyard and the scene of the summit in The Crowded Grave.

For a vin de table, it now produces remarkably good Merlot and Semillon thanks to a gifted winemaker, John Alexander.

It is also number 8 in the rival list from Focus magazine.

Because reheated coffee is terrible, but disposing of good coffee such a waste, I have taken to repurposing all of my abandoned coffee into a refreshing espresso granita, a trick my elder daughter taught me last summer.

Simply decant a full-sized cafetiere of abandoned (or freshly-brewed) strong coffee into a plastic container suitable for the freezer, and mix in two tablespoons of sugar. Increase the sugar to taste, especially if you are adding more than one cafetiere’s worth to the container. Cover, and stick in the freezer. Every few hours – or when you remember – drag the tines of a metal fork through the freezing coffee, separating the granules. If you start the process at breakfast, your granita should be ready come supper.

While the paperback edition of The Crowded Grave won’t be coming out till next year, my publishers have sent me a copy of the cover, seen above.