Christian Barthod 1
The exceptional damage caused in France by the two storms of December 1999 has led forestry partners to re-examine some of the major choices that had been made and to attempt to draw some conclusions from this important crisis. In particular this situation has made it necessary to re-examine the inventory and monitoring data needed by decision-makers and managers, to note the fragility of the soil when faced by the heavy machinery used in emergencies and to re-evaluate certain options or strategies in the protected area network sector. Furthermore, all the potential consequences of climate change, of which one characteristic is an increase in the intensity and frequency of storms, must be analysed and taken very seriously particularly in the areas of forest health, the development and exploitation of the forestry sector, regeneration strategies and urban forestry. These considerations lead to the search for a world perspective with regard to the impact of major catastrophic events on forestry policies and the strategies of the actors involved.
On 26 and 27-28 December 1999 two storms whose intensity would probably not be repeated in more than a century swept across the water-saturated soil of most of the French countryside. With gusts of wind across vast land surfaces that exceeded 140 km/h on average and even reached 198 km/h or more in some areas, these two storms caused the greatest windblow of timber in human memory in Europe. Parts of Germany and Switzerland were also affected by this exceptional climate episode.
The volume of fallen or broken timber amounted to 150 or 170 million cubic metres in France alone and damage in excess of 50% affected approximately 7% of the nation's wooded areas. Based upon the traditional economic estimation methods used in forestry, the cost of the forestry damage in the country has been estimated at six billion euros, namely one-third of the total damage caused in France by these two storms.
Over and above the complex management of a serious crisis, this painful and even traumatic experience for a large number of forestry owners and managers led all of the partners concerned to ask themselves some basic questions that in the absence of this type of experience often receive conventional answers.
Reasoning in terms of wooded surfaces or forest volume is very convenient and widely accepted by foresters as well as by public opinion. Our forestry inventories are principally built on these bases. Ecologists have strongly emphasized the complex nature of most forestry ecosystems, both natural and slightly artificial, and the need to characterize the biological nature of different types of stands, but decision-makers and managers need simple criteria in order to make their choices. Since 1993, the debate with regard to criteria and sustainable management indicators has revealed the great difficulty in basing even a purely qualitative argument upon a limited number of ciphered indicators that are scientifically pertinent, technically measurable and have a financially acceptable cost. Following storms on the scale of those that occurred in 1999, our awareness of forestry resources must of necessity be modified again: how can the parameters that contribute either alone or more frequently in complex interactions to the fragility of forests be identified and measured? How can forests be described in terms that make it possible to clarify the choices that decision-makers and forestry managers must make individually and collectively in space and time?
The problems relating to the permanence of the options in forestry land use and the degradation of certain forestry ecosystems are being faced once again. It might be legitimate in certain areas to take advantage of this occasion to reassign certain wooded lands to uses other than forestry. The damage caused by the storms might provide a selective opportunity for restructuring landholding and the revision of the overall development choices for certain farming and forestry territories. In a country whose afforestation rate can reach 70% in certain vast areas, and where forests still grow by approximately 80 000 ha per year, shouldn't clearing in conditions of reversibility be considered legitimate as long as it meets a definite need of local populations?
In a more general manner however, the question arises in a practical and often unresolved fashion with regard to the reversibility or final irreversibility of one or two forestry revolutions concerning certain degradations caused by the settlement of soils during the carrying out of urgent exploitation or untimely work in the primitive habitats of threatened species. The massive weight of the modern forestry machinery that is utilized for urgent work on water-saturated soils presents very serious problems in point of fact with regard to the physical degradation of soils due essentially to the degradation of the structure rather than to erosion, in temperate climates at least. Soil capital is one of the most important and most threatened elements in managing the consequences of massive storms. Are forestry managers always fully aware of this?
The management plan options for the disaster-stricken forests have had to be vastly revised in the hope of finding a new equilibrium between forest plots in the process of being regenerated, those being improved and those still to be exploited. The debate concerning the types of treatment to be applied (regular high-forest, irregular high forest and a combination of coppice and high forest) was thus considerably stimulated on this occasion. However, did one really have the means of perceiving all the consequences for the industry of a gap in resources, species group by species group, as well as the forestry options that are individually taken by tens of thousands of proprietors? What would be the impact upon the need for increased competitiveness in the production, mobilization and wood transformation network in favour of forestry that is closer to nature and regeneration processes that are as natural as possible?
The group of independent scientific experts appointed by the Forestry Ministry to identify the forests' sensitivity or resistance factors in the light of scientific knowledge and the damage that had occurred as a result of storm hazards, was unable to demonstrate the intrinsic superiority of one type of forestry as opposed to another, irrespective of the proprietors' objectives and constraints and the characteristics of pre-existing stands. This group of experts was nevertheless able to draw up a table indicating the comparative advantages in terms of stability of regular high forest and selective high forest treatments. For an individual proprietor, the comparison will always depend on the property's surface area, the state of the stands and the forestry percentage of the private patrimony. How could a real plurality of choices be expressed in forestry development based upon the type of risk that an individual manager might accept, one that develops all the available scientific and empirical knowledge regarding the sensitivity and resilience of forestry ecosystems?
Another difficulty arises from the fact that some forestry strategies are only relevant at the collective level of a large forestry area, whereas individualism remains a predominant trait among many private landowners. Experience has taught us however that collective memory is short and that collective good intentions are often quickly forgotten in returning to a "normal" situation. Given the foundation of a crisis of this nature, how can a favourable context be created for a deep, collective and durable evolution of forestry organization between public and private landowners on the one hand and forestry and wood industry managers on the other?
Resorting to natural regeneration and the pragmatic development of natural accretion have emerged as a privileged means of achieving restoration at least in public forests. If the option of natural regeneration is not chosen, restoration by reafforestation would provide an occasion for re-examining the choice of species that are not available and for exercising extreme vigilance regarding the question of origins, as well as furthering the use of improved forestry material as long as the management project is consistent with the genetic superiority of this material. Although psychologically very understandable, the desire of managers to re-take the initiative as soon as possible might very well lead to underestimating certain problems, thereby creating new ones a few decades from now.
It is a known fact that by initiating new genetic forestry cycles, storms are the driving force behind diversification in structure, species and habitats. Consequently, an economic catastrophe need not necessarily be an ecological catastrophe; it might even turn out in the long run to be a positive factor in certain areas as far as biodiversity is concerned. Disturbances frequently constitute the essential part of the natural plantation dynamic but they are most often only one of the factors affecting the evolution of the ecosystem through their interaction with the soil, the specific makeup of the forest, its condition when a crisis occurs and of course the actions undertaken by managers with regard to the damaged lots.
The impact of storms of this magnitude can therefore not be analysed without taking into account previous forestry management and the choices that had been made with regard to actions undertaken on the damaged lots for exploitation and regeneration. Furthermore the time gap between major disturbances as well as the probability of one disturbance following another (e.g. a storm followed by a proliferation of bark beetles in coniferous plantings, or a storm followed by a fire feeding on plants that had fallen to the ground) could in the absence of decisive human intervention profoundly modify the structure and physiognomy of the ecosystems that depend upon it. And finally one must not underestimate the impact resulting from the massive pressure exercised by large herbivorous mammals that are capable of involving the forest in a regressive cycle following the wide opening of stands following a storm. How can we step back a little from the pressure created by emergencies and imagine forests that have healed their wounds over the course of several decades or even a century and thereby begin to implement coherent long-term choices?
The bibliographic data available at the European level indicates a clear tendency toward an increase in the number of storms that have occurred since 1865 when the first systematic networks for meteorological measurements in Europe were created. However, at the same time, the evolution with regard to planting characteristics (the growing percentage of coniferous trees, the increase in dominant height resulting from high forest treatments, the increase in volume per hectare, the aging of stands and an insufficiently dynamic forestry ...) must not be forgotten. How can we be certain under these conditions about the absence of a precedent for these extreme climate events?
Following these massive storms, the question of climate change has arisen for the partners in three different forms. The first deals with the problem of evaluating the risk of large-scale storms and the ability of promoting forestry that minimizes the impact of this type of storm. Even if scientific experts do not have sufficient evidence to prove that storms such as those that occurred in December 1999 are a tangible demonstration of climate change, it is equally certain that present climate models would appear to indicate an increase in such extreme events and therefore of large-scale storms. It would therefore be reasonable to take this type of risk into account.
The second form deals with questions concerning the evolution of forest carbon stocks and the coming into force of the Kyoto Protocol. How can we deal with the contradiction between the desire of some parties to increase forest carbon stocks within the framework of an increased storage policy or for reasons of maintenance (and restoration, if need be) of forest biodiversity on the one hand, and on the other the frequently-mentioned need of energizing forestry and reducing volume per hectare in order to minimize storm risks, as well as for reasons related to certain industrial needs?
The third form finally, with regard to rebuilding operations on 400 to 700 000 ha, deals with the ability of foresters to promote the creation of stands that are capable of withstanding major climate changes (the increase of average temperatures, the foreseeable evolution of the hygrometric system and the increased possibility of extreme events). The climate models that are presently available are not on a level that would be useful for managers. There are only very few countries, such as Switzerland, that have taken the risk of mapping those stands that are most susceptible to climate change. Apart from the signing of the 1992 Convention and the 1997 Protocol, our societies are not apparently in a hurry to implement a strategy based upon the principle of precaution. But can foresters wait for the rest of society before finally taking action?
The impact that the two storms have had on the health and vitality of the remaining stands is far from negligible even if the cool and rainy climate conditions during the two years that followed the storms considerably limited the plant care risks of entomological origin, in addition to the withering that followed a period of drought. The root systems nevertheless had frequently been seriously weakened, there was resulting root rot, trees or clumps of trees were suddenly brutally isolated and the average physiological state of a certain number of trees was deficient and will undoubtedly remain so in the future. An additional amount of wood can definitely be harvested after limited windfalls or from clumps of withered trees; in certain very selected areas with coniferous trees this can amount to as much as 30 to 50% of the trees that were initially knocked down. How can we anticipate future problems and develop the appropriate strategies in response to them?
The impact of the two major storms that occurred in December 1999 resulted in the need to re-examine certain earlier choices that had been made with regard to the network of protected forest areas and the full reserves in particular. It was therefore decided to include very largely damaged stands in this network thereby allowing for the free expression of the genetic forestry cycles' natural dynamic. It will furthermore be necessary for some types of habitats to replace certain protected areas in the network in order to guarantee the maintenance of representativeness on the bases that had previously been agreed upon. It will also be necessary to evaluate the situation resulting from the disappearance of a certain number of corridors between large forest areas (damaged forest plots or wooded hedges that have been destroyed). Finally, we must recognize that in the absence of an overall view and an anticipated expertise, some decisions that were urgently taken concerning managed reserve territories were not always appropriate. As a preventive step, should we not develop some prospective thoughts with regard to intervention or non-intervention options in a protected area network that had suffered large-scale damage?
These major storms have also radically changed the underlying base of urban forestry. The urban public is traditionally very hostile to programmes that involve the ongoing renewal of the parks and forests that serve it on a weekly basis for relaxation. On numerous occasions the managers of these areas have had to abandon technically justifiable projects, resulting in the excessive aging of stands that were part of programmes dating from the nineteenth century. In this manner the outlying forests of Boulogne and Vincennes and the park surrounding the Chateau of Versailles in the immediate proximity of Paris have suffered gravely as a result of the storms that literally devastated their overage stands whose renewal had been continually postponed for a later date. The renewal programmes that had been refused for decades were in point of fact inescapable and people strolling in these parks have had to get used to seeing landscapes that were radically different from those they had once loved, often finding surroundings that were more in keeping with the original development projects for these outlying parks and forests. How can the need for renewing the stands that accommodate the general public be made more visible and more credible?
During the course of the past three decades, scientific experts have continued the work begun by certain pioneers in this field and focused their attention on the influence of weather disturbances upon the natural dynamics of forestry ecosystems throughout most of the world. The thoughts expressed by Europeans during the past 20 years with regard to the advantages of irregular high forest treatment have been supported by some of these analyses and have highlighted the possibility of taking into account the resilience of forestry ecosystems within the strategy of a forestry manager.
It should be emphasized that well beyond Europe forestry policy, decision-makers and forestry managers throughout the entire world have shown an increasing interest in the link between disturbances, natural dynamics and forestry projects.
This has often been demonstrated owing to disconcerting experiences with regard to traditional forestry cultural plans or unforeseen large-scale events that obliged decision-makers to reason at spatial and temporal levels that they never imagined they would have to deal with other than in theory. French foresters were thus convinced that, given the geographic situation of their country on the one hand, and the considerable differences between the types of stands and forestry in France as compared to those that characterize Central Europe on the other, they were relatively protected from catastrophic windfalls in spite of the fact that France had suffered a number of storms in the past that had caused several million cubic metres of windblown timber. The great Yellowstone fire of 1988, seen at first as a major catastrophe that had reduced more that a century of protection efforts to nothing, was later revealed to be an opportunity for a renewed and dynamic approach to the great North American forestry landscapes. The great fires in Borneo (1983) or the Yucatan (1989) resulted in extending the tropical forest, whose evolution had appeared to be largely dominated by micro-disturbances and approaches that seemed to be reserved for the boreal forest.
However, beyond these events that depart a priori from the conceptual framework of forestry managers and that raise doubts regarding "certitudes," there are others that make us attempt to understand the functioning of a complex ecosystem in order to be able to develop a viable forestry project. In North America it was only upon the completion of important scientific studies that the great proliferation of spruce budworms was understood to be playing an essential role in the specific composition and irregular nature of the natural forest stands. In Europe the blight that occurred in vast forestry areas at the end of the 1970s and the beginning of the 1980s forced the scientific forestry community to undertake a huge research effort with regard to the dysfunction of the temperate forestry ecosystems that resulted in placing the complex interactions between climate stress, soil and planting characteristics, and in certain cases a large range of pollution types, into perspective.
In each of these cases, the improvement in scientific comprehension led to a deeper awareness of the limits of forestry plans inspired by the farming paradigm, to a redefinition of human capacities and intervention modalities and to the validation of the theoretical and historical foundation of the nineteenth century French forestry school, which has often been forgotten or reduced to an empty slogan, namely, "Imitate nature and hasten its work". Nevertheless these important events that create crises also result in emphasizing the cultural dimension of every forestry policy since they cause serious questions to be asked with regard to what professional actors can accept as "normal" or "manageable" or otherwise, as well as concerning the uncontrolled eruption of natural forces that cause harm to practices and projects.
When forests are owned for the most part by a very large number of family proprietors, as is the case in France, part of the orientation of government policy is to maintain confidence in the sector, particularly in its capacity to intervene whenever a catastrophic disaster exceeds what the insurance sector is able to manage, which is quite limited a priori in forestry. In order to carry out long-term investments and create stands, policy planners must be firmly convinced that it is both possible and well worth the trouble to act, that the expected result is worth far more than the measures and energy that would be invested in implementing the project and that the future can be predicted. Major catastrophic events thus have the power to undermine the very basis of this conviction and to destabilize the values that guide strategic choices. It is for this reason that forestry policies must rediscover their hidden cultural foundations and use them for the well thought-out wagers they undertake with regard to what they will never fully control.
Events as catastrophic from the point of view of forestry policy and the actors concerned as the great storms that occurred in France in December 1999 are very ambivalent. They are at the origin of a severe economic and technical crisis, as well as of a long-lasting loss of motivation on the part of forestry proprietors and managers, unless convincing answers can be found both individually and collectively to the problems and questions that have been identified. In addition, they oblige public and private partners to re-examine certain forestry options or practices that are largely due to historical legacy particularly in the form of a scientific, technical, social, economic and cultural context that is occasionally out of date. They would be able in this manner to provide a more solid basis and new energy to forestry policy from the moment that a shared vision with regard to the major concerns and constraints emerges. The shock of seeing devastated forestry landscapes forces us to become aware of all the utilitarian, ethic and aesthetic values that are an integral part of the conservation, protection and rehabilitation of our forestry heritage.
1 Sous-directeur des espaces naturels, Direction de la nature et des paysages, Ecology and Sustainable Development Ministry, 20, avenue de Segur, 75007 Paris, France [email protected]