It's important to separate in the debate the forest cultivation for providing goods from the conservation of important ecosystems. It's true that in some countries of Europe it's quite mixed but it's not a global tendency. Every forests provide multifunctional services but not in the same way.

It's not only a matter of climate change. In farming forests, non native species are often the only solution to provide renewable materials in enough quantity, quality and in a sustainable way. It's clear that the invasive species must be forbidden by laws, it's another debate. The substitution of fossil materials by the renewable ones must increase if we all want to improve the future of the planet.

The new question asked by Andreas, I think, is if non-native tree-species are an option to replace native trees in threatened ecosystems. I think there should be a lot of evidences (clear climate tendencies, demonstrate non-adaptation...) to take a decision like that. If it’s possible, we all agree that it’s better to plant farming forestry in abandoned agricultural lands and to plant adapted provenances of native species in threatened forests ecosystems.

Hi, Kenneth,

Thanks, I see the point. "Threat" is meant in terms of outcompeting native (tree) species by non-native ones. Yes, I am aware that the term "native" and "non-native" is relative in time of climate change and shifting species ranges.

Hi Svetoslav,

please regard the named tree species Douglas and Grand fir as examples for the promotion of all non-native or neo-native species (sensu Miller et al. 2007). I guess that your remark is going more in the direction that passive adaptation (see link below) with spontaneous forest ecosystem dynamics should be more included in forest management and planning in the face of climate change. I am absolutely of your opinion. However, forestry follows also commercial aims, and thus foresters has to look for adaptive, productive and valuable tree species that could be intergrated in regional ecosystems without outcompeting most of the other tree species. To find here an opiomal solution may be one of the key challenges in (future) forestry.

http://onlinelibrary.wiley.com/doi/10.1890/06-1715.1/epdf

Article Adaptive forest management in central Europe: Climate change...

Article Is Close-to-Nature Silviculture (CNS) an adequate concept to...

There is a difference between a non-native species and invasive. A non-native species is any species growing in a new ecological zone while an invasive species is a species growing in a new ecological zone and has a potential to cause harm to the native species in terms of changing the habitat, altering the ecological functions and services and out-competing the native species.

I, therefore, think that it's the invasive species that are harmful to the forest ecosystem. We did a study on Psidium guajava, as an invasive species in Kakamega tropical forest, the only remnant of the once great Guinea-congolean rainforest in Kenya, and indeed we found that P. guajava, has allelochemicals which enable it to outcompete the native species. It's a threat to the biodiversity of the forest. this could apply to other invasive species, in another forest.

Article The Allelopathic Impact of Psidium guajava L., Leaf Extracts...

It can only be an option if restorative programme is clearly followed in replacing the cut or the then used to be species. non native species can as well be a threat and even turn out to be invasive

Dear Prof Bolte Sir,

Very interesting debate on native  and non-native species with respect to climate change. Yes,  non-native species are clearly distinguished from invasive species as rightly pointed out by   Rashid C.A Kawawa.  Invasiveness is a negative trait acquired by an invasive plant species to invade natural ecosystem.

If a native plant species being to acquire more adoptive features to face drought and to face other stress conditions  than a   non-native species in a same environmental conditions then  natural conservationist (s) and Conservation biologist will award bonus to the native species.

Why we prefer native species or endemic one to keep in the corridor of native world   as member  just because of balanced ecosystem functioning and services in a hormonal manner in the nature.

In general, a non-native species (except naturalized one)  as well as invasive always provided negative role towards modifying ecosystem structure and functional behaviour of invaded ecosystem. 

In a changing environment under changing climate, a non-native species will  adopt more adoptive traits  all those adverse character to hamper structural and functional traits of a native species. So, based on my experience,  traits of non-native  and invasive plants will be termed as threat to an ecosystem where they are.

Many factors will influence the invasiveness of an introduced species. I believe it is necessary to address the issue with a solid understanding of biological invasion theory (see. Catford et al 2009).

A good debate native v/s non native rather invasive species  as adaptive measures for climate change. There is  very purpose growing non native/ exotics for commerce or economic gain/ raw material for forest based industries which native species not provided. Rarely any non native species introduce fin natural ecosystem or biodiversity area or even in plantations reached to reproductive cycles. The question of climate change adaptive scenario all conservationist will go for native species blindly or without any argument. But whether this issue is having so much impact as this process is going on as per need by different country and generally no country allow non native species in natural forests/ or native vegetation due to presumed threat. It will economics will direct the decisions for this issue too.

Related to this question is use of native species but from different seed zones. About 15 years ago the Mono Lake Committee had been planting Jeffrey Pine (Pinus jeffreyi) in stream restoration efforts on the east side of the Sierra Nevada in the Mono Basin, but when local seedlings were no longer available from the US Forest Service, we began using seedlings from a similar-elevation seed zone from the Stanislaus National Forest on the western slope. This change caused some concern, however it was hypothesized to introduce genetic variability to the population that could ultimately be beneficial in facilitating adaptation to climate change. The change in seed source also coincided with the onset of drought, and seedling survival declined, so it is unknown if the non-local seed source contributed to the poor survival, but it is possible those seedlings were poorly-suited to local conditions.

It's important to separate in the debate the forest cultivation for providing goods from the conservation of important ecosystems. It's true that in some countries of Europe it's quite mixed but it's not a global tendency. Every forests provide multifunctional services but not in the same way.

It's not only a matter of climate change. In farming forests, non native species are often the only solution to provide renewable materials in enough quantity, quality and in a sustainable way. It's clear that the invasive species must be forbidden by laws, it's another debate. The substitution of fossil materials by the renewable ones must increase if we all want to improve the future of the planet.

The new question asked by Andreas, I think, is if non-native tree-species are an option to replace native trees in threatened ecosystems. I think there should be a lot of evidences (clear climate tendencies, demonstrate non-adaptation...) to take a decision like that. If it’s possible, we all agree that it’s better to plant farming forestry in abandoned agricultural lands and to plant adapted provenances of native species in threatened forests ecosystems.

Very interesting debate.

In Galicia, NW Spain, we have a similar controversy concerning Eucalyptus. It is an “exotic” fast growing species considered by some as a threat. My opinion is that Eucalyptus mustn’t replace native species, like Quercus. But on degraded land (for example by wildfire), where Quercus does not exist anymore, a fast growing species, capable of sequestering carbon and protecting soil from erosion may be a good solution.

I have seen a similar situation in Cape Verde, concerning acacias, exotic species well adapted to arid climate and capable of growing on steep slopes, prone to erosion.

Another situation to be considered is cultivated forests, which, as Carlos Tejedor says, can provide raw materials and fuel to replace fossil fuels.

Dear all, thanks for this really inspiring debate! I have learned a lot.

In the general assessment of non-native tree species one point seems to be very relevant:

- Integrative or segregative approach in forestry:

In Germany with an integrative approach, the idea is mainly to use non-native tree species in managed forests not in mono-species plantations or for restoring degraded landscapes, but to admix them to native species like European beech. There is a clear tendency away from monospecies stands with uniform stand structures no matter if you have native or non-native tree species. In a segregative approaches with a clear distinction between commercial plantations like e.g. Eucalyptus and non or very extensively managed forests with native tree species for e.g. nature conservation issues it is clear that you have strong conflicts with using non-native species in native forests with the priority for nature conservation.

Regards, Andreas

You can see my MS on ResearcgGate " Prosopis juliflora debate........" P.juliflora was introduced in India around 1857 , due to its tremendous colonizing ability , the species has spread in entire arid and sem-arid regions , which are approximately 49% of country's geographical area.Till 1970s , state forest departments of various states were using the species in their plantation activities . Once environmentalists declared the species as an noxios weed , under pressure state forest department of varous states stopped its plantation.Even eradicatuon programmes have been started in some places without success.Now question is - 70% rural folk in arid and semi-arid parts of the country are still dependent of its wood for fire energy , how the issue is going to be solved if we eradicate this species. No body has any answer ! I sincerely feel that exotics are not such bad thing as being claimed in many countries of world now a days.You have to nake aंbalance of exotics and indeginous species while going for plantation / afforestatio programmes according to environmental and socio-economic set up of the area where plantaion are being taken up.

Tahnk you Andreas.

I think it's a question of scale, we must have an integrative approach at a regional level, not necessarily at forest level. We must find a regional balance between plantations for providings goods and forests for nature conservation. There will allways be environementals externatilities and economy in both systems but everyone should have its own priority. In Spain, there are very few cases of forests economically viable and managed extensively. In the world, the supply of sustainable raw materials from plantations is increasing in an important way.

Que interesante debate.

En Chile, ese debate se extiende por más de 20 años y obviamente no existe una conclusión al respecto. Entre los años 1974 y 1992 aproximadamente se plantaron un poco más de 2 millones de hectáreas con especies exóticas (Pinus radiata y Eucalyptus globulus principalmente) en suelos de aptitud forestal, pero también hubo sustitución de bosques nativos.

A partir de ese recurso forestal exótico, se desarrolló una industria de productos forestales que hoy está entre las 5 más grandes del mundo, principalmente en la producción de celulosa y papel, pero también en tableros, madera y otra serie de productos.

Esta situación "exitosa" por una parte, conlleva también costos sociales y ambientales, los que las compañías forestales han comenzado a mitigar a partir de los requerimientos de los estándares de certificación forestal exigidos en los países desarrollados para la adquisición de productos forestales.

Luego de esta larga historia, 2 consideraciones que me parecen relevantes:

1. No es aceptable en la actualidad sustituir bosques naturales por plantaciones industriales, sin importar si las especies son o no introducidas.

2. Las plantaciones industriales, son absolutamente necesarias para el abastecimiento de productos de la madera y su eficiencia en el abastecimiento de la demanda es indiscutible. Este tipo de recurso "artificial" necesariamente reduce la presión sobre los bosques naturales a nivel global, aunque no necesariamente a nivel local. 

At a point where there are hardly any pristine ecosystems left in the world, when talking about native and exotic species we should also consider the state of the ecosystem prior to colonisation by exotics and the disturbances that lead to their spread. As very correctly pointed out by Prof. Tewari above very often forest managers/ environmentalists get carried away by declaring such exotics as detrimental to the environment without carefully analysing the socio-economic and ecological outcomes of eradication programs. 

The attached publication might help you in thinking on those lines.

Best wishes,

Niyati

Article What influences the plant community composition on Delhi rid...

i know along roads they replanted with foreign seedlings here in ireland and there was a lot of steam about non-natives and why they couldnt use / develop our own seed bank infrastructure and we were destroying our native breeds, be warned 

The answer depend, as always on place and time.  

Maybe there are areas in Europe with more frequent droughts (Andalusia?) but generally climate change takes many tracks ( e.g. attached). On the mentioned Douglas please see my earlier Q&As on the RG.

Article Pinus mugo Krummholz Dynamics During Concomitant Change in P...

First the discussion can't be led without respecting the legal Framework. In Germany and the whole European Union today we also have to respect Habitats Directive and Birds Directive. So space for using nonnative tree species is already restricted. Second we have to notice, that also native tree species react to climate and other environmental changes in a way we still not know exactly. Example: The abandonment of stray use in Germany, the increase in atmospheric nitrogen Deposition, changes in the distribution of rainfall during the year and the extension of the vegetation period by two weeks have changed the growth of beech so strongly in the last 50 years that we have to think carefully about what we can expect from native and nonnative tree species. Douglas fir is not a remedy for all problems.

Thanks for this remark, and I can follow the statement that Douglas fir or other non-native species should not regarded as solution for all problems due to climate change. However, this may be also true for recent native species and habitats which is sometimes forgotten. And some mediterranean non-native species may be the native species of the future in Central Europe. Thus, climate change can disturb the entire paradigm of nativeness and naturalness which is one fundamental of nature conservation legislation in Germany and European Union. There is great chance that we will have shifting and novel habitats with recent native and future native tree species, and nobody will know how birds and other faunistic elements will respond on this. The static view on nature is one of the challenges of nature conservation in the face of climate change and dynamics approaches seems to be needed. I found a really nice paper on this problem in Journal of Applied Ecology.

Cheers,

Andreas

I agree with Prof. Toe , in Thar desert , India , Prosopis cineraria , also known as king of desert trees , a native of the region , is facing problem of mortality since more than 15 years. To describe the reason many researchers shooting arrow in dark ( a common proverb in India), but no body could reach any logical conclusion till date. Problem is there with this great multipurpose species but what is the reason , no body is able to define.

Kenneth... I only gave a comment to the question, wether nonnative tree species might be a solution in forests. I do strongly underline climate change being a great Problem to our civilisation.  But this also cannot be solved alone by greening cities with alien species. Eg. facade solar systems might reduce heating of buildings in the sun by about >10% and give an additional Input into our basket of renewable energy at the place of consumption...

this can be literature

Article Invasive non-native plants have a greater effect on neighbou...

I would suggest to use autochthonous species and adapt the management due to the concept of leaf area carrying capacity. We did a project some years ago for drinking water protection forests. See e.g. https://www.researchgate.net/publication/258623446_A_modelling_approach_to_adaptive_management_of_water_protection_forests_under_climate_change_scenarios?ev=prf_pub

The project website is here: http://www.ccwaters.eu/

Article A modelling approach to adaptive management of water protect...

For a long time (as founder of Torreya Guardians) I have been advocating a paleobiological approach to determining what is a "native" tree in this century of rapid climate change. Here on Researchgate you can access the Feb 10, 2017, paper in Science journal titled, "Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems."

https://www.researchgate.net/publication/313518513_Merging_paleobiology_with_conservation_biology_to_guide_the_future_of_terrestrial_ecosystems

I disagree with the level of detailed research the authors advocate (I opt for a cheaper, more natural history, site-by-site consultation approach). See also my online analysis:

Paleoecology and the Assisted Migration Debate: Why a Deep-Time Perspective Is Vital (Torreya taxifolia as Exemplar)

http://www.torreyaguardians.org/assisted_migration_paleoecology.html

Article Merging paleobiology with conservation biology to guide the ...

@ Cony Barlow

The paleobiologic approach sounds useful to me. However, the environment has not been particularly stable over the last 11 thousand years (as postulated in your article) everywhere (attachment 2). Further the reader of your article may appreciate some background reading on the mountain gorilla (attachment 1) featuring prominently in the illustration of the paper in Science. Finally, in places,  land use change is dominating  over climate change as driver of biodiversity change (attachment 3). The latter may also apply to the gorilla environment.

Article Sharing natural resources: Mountain gorillas and people in t...

Article Fine resolution distribution modelling of endemics in Majell...

Article Pinus mugo Krummholz Dynamics During Concomitant Change in P...

I think they can always be an alternative in whatever situation in which you need to forest bare or wasted lands

I thing this could also be useful for the discussion.

Native species coexist with existing biodiversity to form a stable and resilient ecosystem. Nonnative species once  established may turned to be invasive or exploit resources at the cost of others, hence biodiversity may decrease in course of time until a new stability regime gets established. Some nonnative species like eucalyptus once touted as "green gold" turned into an environmental problem in some regions in India. Alien species   may even induce depletion in the water table and that may, according some researchers, invite drought situation. 

Hello

I'll like to read about this ongoing discussion from the perspective of animals living in such an ecosystem. Any idea or suggested reading will be appreciated!

Future environment will be different and we cannot be specific about the changes to happen. Hence ,a priority setting approach can be an effective strategy. Case studies exist where non natives monterey pine (P endangered in its small native range, have naturalized along the north coast of California.Rather treating them as undesired, this could be a potential solution for climate change initiatives particularly with non- natives in the introduced region. Rather than relying on historical approach, the above approach may prove to be fruitful in the present era of uncertainty.