I suppose it depends on the goal.. In the Himalaya, where broadleaf forests were targeted for fuel and fodder,after a point, the degradation cascaded into a cycle of forest fires and selective regeneration of conifers. In the process, underground water resources have been affected. This in turn affects river discharge. In such cases, I think restoration to a previous state is relevant and feasible.

Since the goal is major and appropriate forest cover is the only valid method, time scales should not matter much, for a fifty year restoration effort will yield results for centuries.

Other areas will naturally have different challenges, goals, time scales and levels of degradation. In principle, Heraclitus' assertion is true, but while the water might have flowed on and the cells of the man changed, yet essentially, the river remains the river and the man is still the man...

I think it's an interesting question, even on a broader scale. I mean, not only for the restoration (or conservation!) of forests, but also grasslands and other ecosystems... I believe you can't conserve the systems of yesterday, only the processes of tomorrow. And the question is: where to give space and opportunities for species....

So, in your case, I think you can restore beach forests, but they won't be the same in species composition as the ones that were destroyed. Ground layer flora won't be the same, nor will the fauna..... What are the alternatives? Well, restore the forest, accept it will be different because it's history is different....

Panta rei....

Thanks Rense and Peter. At the heart of this seems to me to be a two conflicting ideas. Firstly to have the comfort of the word 'restore' - in the sense of fixing things, redemption, taking an ecosystem back to a better past - it's a concept which we like, and perhaps our customers/funders like it too. The second is our knowledge that reverting to a previous system is or may be impossible. So in Rense's sentence '...you can restore beach forests, but they won't be the same...' we see this conflict in play. Personally, I think the use of the word 'restore' is often deceptive, to others and to ourselves, and we would be much better to think and talk more openly about transformation or change, rather than restoration which isn't actually restoration

Thank you for these views, Duncan. I have neither funders nor customers, so am quite free of the taints associated with this.. :) however, the word 'restore' in a Himalayan context is crucial, since vast sums of money have been and are being spent to 're-green' and 're-afforest' the mountains, without any concept of either what benefit 'greening' will do or what a 'forest' is (the Indian Ministry of Environment and Forests has had two rounds of a competition to define "forest" outside the dictionary sense which no one has won so far.). So if one talks about restoration, it means to try and re-introduce components of forests including those that do not have immediate commercial returns, eg., might be 'non-timber trees', but have some role in the total ecosystem required for stabilizing groundwater. So I would not be averse to using the word 'restore', for want of a better target! This, of course, in a Himalayan context. Elsewhere, the potential of our race to misuse things, whether resources, words or life itself, is limitless, so it should come as no surprise that the concept of restoring ecosystems has received attention from people for whom 'restoration isn't actually restoration'.....

Incidentally, my father let some 5 acres of tea plantation re-grow undisturbed around our house 60 years ago and it is quite a respectable forest today, largely indistinguishable from reserve forests which have not been disturbed for over a century. So there are cases where we can 'restore' forests to something very closely resembling the original model.

I think that restoration is posible, the things is that our rol is not to take the forest to it's previous status but to assist it's recovery to a point where the forest could continue recovering by it self. If we assimilate Restoration in this way I think it's possible to speak about restoration

A contrarian might take this angle, in an ever changing world restoration and indeed species conservation is an exercise in futility. Human mediated change is ubiquitous and unavoidable at some level, but at another we have control over it. Also it is widely agreed that the community unit concept in ecology is not realistic (such that certain species always co-occur as some kind of super-organism). The historical dichotomy is simplistic, and although species do respond to change individualistically for the most part, there are many exceptions e.g. mutualisms. Some interactions are well understood and can be managed. We should view this in the context of evolutionary history. For example, if we do rat control on an island where the endemic species are not adapted to rat predation, e.g. Pinzon Island in Galapagos, we are likely to get increases in any remaining endemic snails, a number of bird species, some plants etc. etc. These are likely outcomes (as shown in other island based rat control programs). After 100s of years with rats present, we will not restore the pre-rat-invasion state. I say "so what", we at least can conserve much of this evolutionary history, and this has value. In the face of inevitable human mediated change, I would prefer a more conscious approach that does not let ecosystem components disappear due to a lack of thought or action. Our species (or indeed all life on earth) will eventually disappear, but it would be a shame to bring about change to a poorer world without many species we value, or our own early demise if it were avoidable.

Restoration = setting the structure and functions of the previous  ecosystem, process by which a disturbed ecosystem is returned to previous disturbance structure and function.

This process is practically impossible because of so called hysteresis which translate in a single word Heraclitus assertion. So, restoration is resumed to establish a general structure, functionality, dynamics and self-standing behavior of the previous ecosystem.

Any attempt to "restore" an ecosystem is subject to a "reclamation" rather than returning to its original state.

A reclamation means to develop a series of activities designed to change biophysical skills of the ecosystem, the new resulting from these actions ecosystem being different from the previous one.

The reclamation is an approach that aims to achieve a similar end point of restoration, but not identical to it. This end point is achieved by re-foundation of an ecosystem that develops following the same path as in case of restoration so that it integrates functionality, composition and dynamics similar to that of the original system.

Wheaton, J.M., Sear, D.A., Darby, S.E., 2004, Uncertain notions of natural targets in river restoration. Glasgow BGRG Conference (manuscript - INTERNET) and Breen, P., Lake,S., Rutherfurd, I., 1999, Stream Rehabilitation: Priorities and Possibilities – Presentation Notes. Cooperative Research Centre for Catchment Hydrology, Victoria,

even if they refer to rivers, explained very suggestive the differences between the two concepts.

We can’t actually restore but save what exists after destruction and to protect what is not destroyed. Multidisciplinary studies implying the anthropologists (for participative management of the population around the forest to be restored), the biologists and ecologists ( for impacts of the destruction on animals, etc.) are thus needed. It is on basis of the combined information, that you could restoration of the population and the government. Best wishes.

Hi Duncan.

Yes, it is very difficult to obtain the 'original' system, but beyond the semantics, definitions, connotations and implications that surround "restoration", humanity has no choice except restore nature and natural resources that once supported vibrant life forms on earth (in a given region), including mankind. The implication of restoration is far-reaching. For example, when you restore a native keystone tree species in a degraded landscape, you are restoring at least the following critical natural components: 1) the tree itself; 2) soil fertility; 3) water resources; 4) biodiversity; 5) local micro-climate; and, 5) local livelihoods. On top of this, you are also sequestering CO2 (in the soil, in the biomass and necromass, etc.), thus mitigating climate change. Never mind if you don't get the original stuff, but go on restoring biological systems that have been the products of millions of years of continuous evolution. Evolution is the ultimate test for the viability (and positive interaction with other forms of life) of any biological material.

Paul, I remember reading some years ago that several reputed think-tanks in North America, when considering the phenomenon of a rapidly emerging middle class in China, India and other "Third World" countries, had agreed that the world did not contain enough resources for everyone to lead a North American lifestyle. So, perhaps instead of seeking to modify the ecosystem to suit the lifestyle, it might make more sense in the long term to modify the lifestyle (read consumption patterns) to suit the sustainable productivity of the global ecosystem.

Thanks for all your responses. I think I come closest to Paul's view that we need to consider restoring processes rather than historic biotic assemblages - but I remain concerned that by using the word 'restoration' without making this clear, I worry that we're kidding ourselves and others that the future doesn't have to be very different from our recent experience.

Does "restore" really mean to return something to its exact earlier state? Even when restoring a building or painting I think most people accept that it will never be returned to the exact original condition.

Nature abhors a vacuum. Any piece of land left vacant will be colonised by plants and animals. It may take a long time for the succession to move on from the early species poor communities, but more diverse communities will eventually assemble until the local climax condition (which is itself a constantly changing entity) is reached. The aim of restoration for conservation is to assist (speed up) that process in order to provide habitat for particular species, usually species that prefer the later successional communities. So the target community is defined by the niche requirements of the species of concern (which are usually broad enough to enable restoration interventions to be fairly generic). Restoration can also be targetted at other ecosystem services, such as water supply or soil stabilisation, in which case the species used are less important.

One could have a similar objection to the word "conservation", but most people don't get hung up on the semantics.

Semantics aside, (the trouble is) we are restoring too little and extracting too much. We are massively wasting human labor for the benefit of the few. Society needs to work on diverting the sweat of a Congolese or an Ethiopian miner from slaving away at a few tens of grams of diamond or gold to restoring the landscape, soils, water and biodiversity. Can we afford to go on 'worshiping' diamond and gold while humanity's survival is at stake through not 'restoring' the ecosystem? An equally important question is: Do we have to go on reproducing ourselves only to exploit every nook and corner of mother Earth? In both of these perversions lies our demise because humanity succumbs to its own abundance, as well as to the values it attaches to the material world.

An extant forest that has not been restored will also change over time. Restoration processes simply result in the end-points of change being more similar.

To understand a process, whatever is it, we need a very clear definition. This or that definition may be resumed in a single or much more words. The semantic is very important when we, all that gave an answer to Duncan's question, need to understand the same thing(s) with the same word(s).

Let resume what all of us said. Practically we agree with the fact that "restoration" isn't or can't be possible. So, we need another definition of that Duncan asked.

Perhaps the Duncan's answer is in Forest Management Practice and one of its basic principles = continuity. According to this thesis a forest - being understood as a sum of component stands - has a function, derived from social and economic demands.

Here we need a particular explanation: it can be distinguished two categories of forests: one is "the natural forest" the other one being a "natural modified by human intervention forest". The first is characteristic in few places in the world (some Amazonian forests, some Equatorial Forests in Africa or South America, some Siberian Forests). The second represents all other forests on the Earth. Do we want to "restore" this second category or do we want to "restore" the first category?

In the natural forests case we cannot make more or less philosophy. That forest still follows the destiny established by the universe.

In the "natural modified by human intervention forest" the continuity thesis is divided into other two ways: one of a permanent "conservation", the other of a cyclic resetting.

Conservation means to keep the structure of the existing stand and to extract - for the social and economic needs - only the individuals that (in our understanding) lost their contribution to the self-stability of the stand (that is sick individuals, too old to ensure reproduction or attributed function, etc.).

Cyclic resetting is to extract permanently a quantity of individuals that is equal with the average annual growth in biomass, while ensuring the installation of the new generations (see forestry principles). According to this procedure the foresters have care to keep a target composition of species which is very closed to the actual structure of stands. In fact this is a permanent "reclamation" and not "restoration".

Someone can say that a forest is not only the community of the static beings. It's true, but the walking beings have an adaptability much more evident and demonstrated by millions of years of evolution

The idea of restoration should certainly be questioned, Duncan, because baselines and attractors are constantly shifting, now more than ever, and even an ecosystem in a "pre-disturbed state" was likely disturbed and shaped by past human activity. But restoration still has merit for specific ecosystem services or species.

For my masters thesis I am studying ecosystem services "recovery" in logged coastal rainforests of British Columbia. This is a system with very infrequent stand-replacing disturbances. Individual trees may live >1000 years (and be >90m tall), fire intervals range over 4000 years and stand structural development may endure at least1500 years (based on much more than just the growth of trees!).

Shifting attractors rule out structural recovery to a pre-logged state. The forests were shaped by a past climate and past aboriginal land management (controlled burns and small-scale aboriginal forestry), much less practiced today. However, restoration is used in this system to target particular ecosystem services. As a single example, to promote salmonid population recovery (an ecosystem service of high cultural and economic value on the coast) broad leaf pioneer alder trees are removed from stream sides so conifers can establish, stabilize stream banks and recruit large woody debris.

A 6 min video on streamside restoration on BC coast (http://clayoquot.org/about/films)

Also, I just finished an enlightening book on this subject by science and environment writer J.B. Mackinnon called: The Once and Future World 213 pg. 2013. Highly recommended.

Hello Duncan! Happy New Year!

The question you ask has been well answered by a number of respondents. What "restoration" is really capable of is not a return to what there was, but a revitalization of the same sorts of ecosystem services as were present in the duration of recorded history. Natural succession can accomplish that if the devastation is not too great. If devastation has been great, then management intervention is required, first to start the new process of succession in the desired expected trajectory, and then to accelerate it.

The founder principle suggests that the early stages of succession start off as somewhat chaotic ... "what gets in, can establish" but as complexity in terms of diversity and interactions increases, the successional trajectories converge in similar biomes. The eventuating communities would be expected to be different from each other from place to place within any given biome, and different from what was there before. Nevertheless, one would expect increasing similarity in general physionomy (ecosystem functionality) as succession marched on with the assistance of management or not.

Cheers, Peter

For ecosystems in a state far from historic norms and where acute degradation has been recent, I find the term "rehabilitation" to resonate with policy makers and the broader public. I believe this concept is also quite harmonious with the ideas presented by Peter in his most recent post.

The trouble is who knows for sure what the 'original' complexity contained, looked like or interacted with the then biological, chemical and physical environment? Would be good if we settle for, at best, crude approximations and start restoring and/or conserving what is left. By the way, who defined "restoration" first, and what did they exactly say?

That's a neatly phrased question.

Even a "pristine forest" changes in composition over decades and centuries with succession and gap dynamics and over millenia in composition. It's not the same but even the pre-Socratics would recognize continuity of conceptual entities like Heraclitus, Ephesus and the Cayster River - none of which resemble their ancient states. Restoration should not simply be about ecosystem functionality or ecosystem services, it should also be concerned with form and structural integrity; restoring a forest, comprising a mix of co-evolved species from that bioregion, not necessarily the precise composition of forest that occurred there previously.

Yes Panta rei (all is changing) ....how much should we put back the ecological clock?.In my opinion there is no reference state for a system to refer restoration to. The usual state of affairs in living systems like forests is one of systems fluctuating around some trend (increasing or decreasing) or stable average; however, sporadically, this condition is interrupted by an abrupt shift to a radically different regime. Disturbance can be deemed as an event causing departure of a living system from the ‘‘normal range’’ of conditions typical of its basin of attraction. The apparent paradox that disruption of the existing order (i.e., disorder) and persistence (i.e., order, stability) always coexist in living systems such as forests is addressed by the concept of resilience, defined as the amount of disturbance a system can absorb without shifting into an alternative state and losing function and services. Such a concept seeks to explain how disorder and order usually work together, allowing living systems to assimilate disturbance, innovation, and change, while at the same time maintaining characteristic structures and processes. Restoration should go along with this line as it should address the resilience capacity of a system. The main aim of restoration could be then restoring this capacity in order to maintain characteristic structures and processes of systems within the same basin of attraction.

To stimulate discussion on definitions in ecology-biology:

1) What is the exact definition of 'reproduction'? To 'remake/copy/replicate what already exists'? In that case 'exact' reproduction does not exist given the physical dynamics of nature. Each newly produced individual is unique in physical expression and is therefore not reproducible....

2) What is the exact definition of 'survival'? To maintain what already exists? In that case, (exact) survival does not exist given the continuous physical dynamics of nature. Each biological unit is unique in physical expression at each spatiotemporal moment..

3) What is the exact definition of 'restoration'? To remake/copy/replicate what existed in the past? In that case, 'exact' restoration does not exist given the physical dynamics of nature. Each biological unit, including an ecosystem is unique in physical expression at each spatiotemporal moment.... How much terminology in science is truly 'precise' to capture the true nature of nature...?

Thus, Heraclitus wrote ‘No man ever steps in the same river twice, for it's not the same river and he's not the same man.’ In other words, aspirations to revert to a previous state may not be feasible under changing circumstances

I sometimes think: 'Nature' is smarter than 'humans', so why not leaving environments grow without human intervention. Perhaps it's to nature to restore, not to humans not always having sufficient background knowledge.... . Perhaps it would be interesting to compare plots with versus without human intervention, but then again we need time and patience (>100 years) to get appropriate data...

I recently read about stream restoration following coal mining. When the artificial streams are plotted over landfills of the mining waste the water get polluted with toxic trace elements. In natural streams, which are older then a few years, these elements have all been washed away long ago, allowing the stream to reach its current pure condition. When Marcel Lambrechts talk about patience he reminded me how different nature's "patience" is from human patience capacity. We want the restored stream to be pure right now, not in 30-300 years of slowly diluting pollution.

I think we should add a time-frame to the discussion of restoration - how fast do you expect results to match your goals.

I would be willing to give 5-10 years of grace to restoration projects, if only to let the trees grow back a bit. However, it is hard to hold coal mining companies accountable for their damages 10 years after the fact, and this would be true for any other project. 10 years is a long time in human scales, very very short in nature scale.

Yes ...Lachezar, I agree "We have to start the restoration from ourselves first and then turn to nature". That is why the priority setting of Donella is of paramount importance.

Duncan, I stumbled on this thread late in the game and see that it has turned very philosophical:) However, your primary statement comes up quite often... "what are we really restoring?" I caution that being bogged down with semantics allows stream to erode, invasive species to thrive, and other species to go extinct. Restoration should not be viewed as an endpoint with tightly defined parameters (species composition, growth, biomass, etc.), rather it should be examined at larger spatial and temporal scales that focus on ecosystem services and functioning. In restoration, we plant native species because they are likely to do well and have various functions in the system. The specific goal may be to get certain plants in the ground BUT the real goal is to provide structure, habitat, trophic stages, and options for future dynamic needs. Restoration attempts needn't be forced, or tightly constrained but should simply aim to provide conditions that are and will be better than they are now... and all this can be done by helping nature along, even if just a bit.

Non-linear dynamics has teach us that when trying to repeat a process, minuscule variations in initial values will lead a system far from the intended destination. This happens with restoration ecology. A restored area will never match the exact initial conditions of a previous ecosystem so what is to be obtained is a NEW ECOSYSTEM. Yes will be my answer to the question that if it is worth restoring. An artificial restoration will accelerate the recovery of a perturbed area, but the end will be not necessarily what is intended, that is something to be taken into account.

Thank you everyone for your comments.It's been very interesting following the discussion, and I'm very comfortable with many of the ideas - for example Jonathan's - suggesting that our aim in restoration is to restore and maintain the functions structures, trophic stages and future options.

But, where I think we still need to critically consider the value of the word restoration is where it seems likely to mislead. If we can fix the functions using the biota native to the location, then restoration is undoubtedly a valid word. But what if we can't? Is the ambition to replace the American chestnut with a blight resistant chinese-american chestnut hybrid really restoration - or rather transformation?In other words, as Octavio describes, a new ecosystem. As the world changes fast over coming years the nature of a functional ecosystem seems to me likely to move further and further away from our inherited natural or native systems. That to me means that we'll be using the word restoration when we really mean 'a transformation to a state which functions similarly but has many different actors'.

In a scientific discussion we can fairly freely re-define any term we want, as long as we're clear about it. But to the non-specialist world, using 'restoration' when we mean 'adaptation' or 'transformation' in this way seems likely to become more misleading and eventually backfire on the credibility of the adaptive work we want and need to do.

Duncan, you are so correct. Managing public lands must include adaptation to novel ecosystems that are currently evolving rather rapidly due to human-induced climate change. Maintaining historic landscapes (pre-human) on a large scale simply won't be possible.

The flux of time and physics, and its dynamics, shows us that restoration is scientifically impossible. There is continuous 'adaptation' to a renewed set/cocktail of physical factors...

I was reading today the New Scientist and found this article about "future ecosystems" that could be made after restoration with non-native species when the original ones are gone forever (extinction!):

http://www.newscientist.com/article/mg22129581.700-when-is-an-artificial-ecosystem-no-longer-a-fake.html#.UxfFfVRdX0o

As Robin Chazdon has put in the Preface of a recent book by Eliane Ceccon (Restauración en ecosistemas tropicales: fundamentos ecológicos, prácticos y sociales., UNAM, Mexico, 2013): "Present century must be the century of restoration".

Restoration is a unavoidable urgent necessity in front of the unprecedented degradation that the environment has faced during the XX Century. This task is a must, it has to be made. There is no impossibility in doing restoration beyond the political will since it cost lot of money. However there is a practical "problem" that involves minute differences in the initial conditions of the restoration that could result in "novel ecosystems" rather than an exact copy of the pre-degraded one.

This is not an impossibility to restoration but has to do with the "success" in the restoration.. are novel ecosystems a failure? or a plausible and acceptable outcome?

Some reading are:

Anand, Madhur, and Rachelle E. Desrochers. "Quantification of restoration success using complex systems concepts and models." Restoration Ecology 12.1 (2004): 117-123.

Mayer, Audrey L., and Max Rietkerk. "The dynamic regime concept for ecosystem management and restoration." BioScience 54.11 (2004): 1013-1020.

Beisner, Beatrix E., Daniel T. Haydon, and Kim Cuddington. "Alternative stable states in ecology." Frontiers in Ecology and the Environment 1.7 (2003): 376-382.

Jentsch, Anke. "The challenge to restore processes in face of nonlinear dynamics—on the crucial role of disturbance regimes." Restoration Ecology 15.2 (2007): 334-339.

Hobbs, Richard J. "Setting effective and realistic restoration goals: key directions for research." Restoration Ecology 15.2 (2007): 354-357.

The very basic problem i had in merely trying to restore my 2 and 1/4 acre yard after decades of heavy machinery compacting the soil (lawn/grass mowing) and the constant removal of anything "wild" (weeding and insecticides) was to SIMPLY GET SOMETHING TO GROW, the land was so disturbed. I had to allow non-native weeds for starters and use non-natives to "recover" some kind of litter and soil invertebrate populations before anything native would grow. It has taken ten years to get native frogs, snakes and insects back, the bird species are still the same, so "restoration" was very different at different taxon levels. This reminds me of the classic work in the first restoration of Costa Rican cow pasture back into rainforest, the use of non-native trees to provide a transition from damaged land to land that could support propagules of more native flora and fauna. It DID REQUIRE HUMAN INTERVENTION and not a direct path! Daniel Janzen is a pioneer in this field and i would recommend searching for his early and more recent publications and work in this field.

I guess the lack of reference site is also the problem in restoration efforts for forest ecosystem. Most of the forests now today are secondary forest, as described by Chazdon and van Bruegel. Adding to this, is the high expectation on "restoration", that is why as Hobbs highlight it is important to set a realistic goals. I think nowadays it is more appropriate to call restoration as intervention ecology rather than restoration itself.

In degraded indigenous people's territories in Brazil we try to build a forest with a set of useful native plants and a set of fruiting plants which could support traditional game animals, such as big birds and small mammals. It is not restoring, but re-editing the native ecosystem. All terms sound pretentious, but the discussion between restoration, recuperation and rehabilitation does not ring a bell. Do I do agroforestation?

Native plants support native biodiversity which is an essential step towards saving your national heritage of wild creatures. It would also allow further re-wilding of areas in the future. Its better than sugar cane or soybean. The plant foods are probably also healthier for people to eat! Protecting human cultural diversity, that evolved in concert with native plants and animals is part of protecting the biodiversity of the planet. It would be a very boring planet if everybody wore the same tshirts and jeans. We need to stand against the urge to monoculturize the entire planet into one or two styles/crops someone else wants you to wear/grow. GROW NATIVE! then export it and diversify the food base for the planet. This lowers the risk of a food collapse which will eventually happen if we plant just a few crops that are over-tended by fertilizer, insecticide and no longer shaped by natural selection.

Re-forestation is something humans have been practicing for millennia, but often in selfish interest of mankind i.e. for timber or fuel. I think the introduction of historically native species to replicate primary woodland is a step in the right direction.

But the problem as i see it is how do we ensure the continuing management of projects such as these through not just the next 50 years but for many generations further down the line as we would have to replicate a mixed age structure and the colonising of habitat which takes hundreds of years.