Decades After Being Abandoned, Indian Eucalyptus Plantations Look Nothing Like Surrounding Forests

[hatrack]

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Eucalyptus plantations in southern India that were abandoned and left to recover for nearly 40 years are still far from resembling the primary forest surrounding them, a new study has found. This, researchers say, suggests that once disturbed for long, forests may never bounce back to their original forms. In India, eucalyptus has often been the tree of choice when it comes to restoring degraded forests: it grows quickly, is hardy, and requires little care. But can these plantations, when left alone and allowed to regenerate, grow into the forests they replaced?

To find out, researchers turned their attention to the southern stretch of the Western Ghats in India. In the past century, large parts of wet evergreen forest in what is now Kalakad-Mundanthurai Tiger Reserve (KMTR) in Tamil Nadu state were cleared to make way for plantations including tea, coffee and cardamom. Vast forested areas were also felled for eucalyptus plantations, with the timber mainly to be used as fuelwood for the tea industry. However, with the establishment of KMTR in 1988 and a subsequent logging ban, many plantations were eventually abandoned and the area has been on a path of recovery ever since. Some plantations have now been regenerating for nearly 40 years.

In 2016, Ashish Nerlekar, lead author of the study published in the Journal of Tropical Ecology and a doctoral student at Texas A&M University, looked at one such eucalyptus plantation in KMTR with his colleagues. The plantation had been abandoned for 36 years as of 2016, and was surrounded by primary, old-growth forest.

“Because it’s the Western Ghats and because there has not been any major disturbance after abandonment, I thought the plantation would be very close to the primary forest,” Nerlekar said. “I was expecting some degree of structural resemblance in terms of species richness and so on. I was also expecting to see at least 20 to 30 percent of the trees characteristic of the primary forest in the plantations.” But as it turned out, this wasn’t the case.

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https://news.mongabay.com/2019/02/abandoned-plantations-in-forested-areas-may-not-recover-fully-study/

[KY_EnviroGuy]

1. Interesting article, thanks! I wonder if long-term climate change has been considered.

Another thing that comes to mind is that the plantation's eucalyptus trees may be dominating the forest canopy, which would seem to inhibit new tree varieties from getting established.

Sounds counter-productive, but perhaps if they thinned the eucalyptus trees it would give other species room to grow...

[JayhawkSD]

2. Forty years is insufficient time for evaluation.

The "primary old growth forest" to which comparison is being made took centuries to become what it is. Forty years is the blink of an eye. Complaining that a forest which has been regrowing for less than the lifetime of a very young man does not look like a forest that is older than civilization is twaddle.

[Zambero]

4. Eucalyptus naturalizes better than many species

A number of exotic species will grow well when introduced elsewhere but will fail to regenerate, allowing native species to recover over time. Eucalyptus species are a notable exception within Mediterranean and tropical climates. Another consequence is that the oils and resins from Eucalypts repel many native wildlife species, rendering that particular habitat a virtual biological desert. I recall walking through a dense mature Eucalyptus stand in Laguna Beach CA, and not seeing or hearing a single bird in the process, just eerie silence.

[Nitram]

3. I find it hard to understand why someone with an iota of knowledge about ecosystems was not employed

to plan this re-forestation project. The last thing you want to plant is a non-native tree. Eucalyptus does not provide food or prime habitat for native insects, birds and other wildlife and, once established, a eucalyptus stand prevents the growth of native trees.

[JayhawkSD]

8. Something's wrong. I married a redhead and the children don't look like me.

They have red hair. How can that be?

See article, "...are still far from resembling the primary forest surrounding them." Duh.

[Botany]

5. It is very hard to put the genie back into the bottle

The damage done by non native species to the ecosystems is massive.

Would think that collecting local ecotype seeds, then geminating them,
then growing them on in containers or in the ground in nurseries, then
transplanting them into the disturbed areas, along with removal of the
eucalyptus trees would be a good project. For all the "stuff" i hear about
round up it is a very good tool in ecological restoration.

thanx for posting!

[littlemissmartypants]

6. Interesting. Thanks. nt

[Thyla]

7. I had to find the paper to find the exact species

Although I could of guessed it was E. globulus.
I'm not overly sure what they were expecting as the water requirements for Tassie blue gums are well documented and a brief look at seasonal totals in the region show it on the lower side so it would seem to me they just out compete the natural species for water and resources which again is a known trait for some Eucalyptus species.
Solution would seem simple, log the timber and repopulate with natives.

Seems like a lot of fuss over common sense.

But from the sounds of it they are not concerned about them spreading to the primary forest which is good probably because they don't spread unless they have the right climate so that is another nail in the invasive eucalyptus myth.

[Nitram]

9. The reason eucalyptus gained a reputation as an invasive is that all over the earth

humans cut down forests and replaced them with Eucalyptus. It is man that is the invasive species.