Strangler figs are remarkable organisms. Germinating in the canopy of another tree, their roots gradually wrap around the host, growing down towards to forest floor. Once in the soil, the interwoven structure of the fig begins to grow and swell. Over time, the strangler fig does what its name suggests, it strangles the host tree. Strangling is bad news for the host, however, new research suggests that strangler figs may actually provide some benefit to larger host trees, at least for part of its life.

Cyclones are a force to be reckoned with. Their punishing winds can quickly topple even the sturdiest of trees. This is exactly what happened in 2013 when Cyclone Oswald struck Lamington National Park in Australia. Many trees fell victim to this storm but not all. Survival was not random and an interesting pattern started to emerge when researchers began surveying the damage.

The hollow center of an ancient strangler fig where its host tree once grew and has long since rotted away.

They found that large trees hosting strangler figs survived the storm whereas those without were more likely to be uprooted. It appears that hosting these parasitic figs just might have some benefits after all. There are a handful of mechanisms with which strangler figs could be helping their hosts. First is that figs spanning multiple trees may provide stability for the host and its neighbors. Another could come in the form of additional leaf area. The canopy of both the fig and its host tree may help reduce the impact of the cyclone winds. Additionally, once they make it to the soil, the roots of the strangler fig may act as guy-wires, keeping the host tree from uprooting. Finally, The interwoven roots of the strangler fig may act as scaffolding, providing additional structural integrity to the host tree.

More work will be needed to see which of these are the most likely mechanisms. The mere fact that this parasitic relationship might not be so one-sided after all is quite interesting. What's more, by keeping large tree species alive through devastating cyclone events, the figs are essentially keeping legacy trees alive that can then reseed the surrounding forest. This could explain why host trees have not evolved any obvious mechanism to avoid strangler fig infestation.

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It is no secret that orchids absolutely need fungi. Fungi not only initiate germination of their nearly microscopic seeds, the mycorrhizal relationships they form supplies the fuel needed for seedling development. These mycorrhizal fungi also continue to keep adult orchids alive throughout their lifetime. In other words, without mycorrhizal fungi there are no orchids. Preserving orchids goes far beyond preserving the plant. Despite the importance of these below-ground partners, the requirements of many mycorrhizal fungi are poorly understood.

Researchers from the Smithsonian Environmental Research Center have recently shone some light on the needs of these fungi. Their findings highlight an important concept in ecology - conservation of the system, not just the organism. Their results clearly indicate that orchid conservation requires old, intact forests.

Their experiment was beautifully designed. They added seeds and host fungi to dozens of plots in both young (50 - 70 years old) and old (120-150 years old) forests. They continued to monitor the progress of the seeds over a period of 4 years. Orchid seeds only germinated in plots where their host fungi were added. This, of course, was not very surprising.

The most interesting data they collected was data on fungal performance. As it turns out, the host fungi displayed a marked preference for older forests. In fact, the fungi were 12 times more abundant in these plots. They were even growing in areas where the researchers had not added them. What's more, fungal species were more diverse in older forests.

The researchers also noted that host fungi grew better and were more diverse in plots where rotting wood was added. This is because many mycorrhizal fungi are primarily wood decomposers. Nutrients from the decomposition of this wood are then channeled to growing orchids (as well as countless other plant species) in return for carbohydrates from photosynthesis. It is a wonderful system that functions at its best in mature forests.

This research highlights the need to protect and preserve old growth forests more than ever. Replanting forests is wonderful but it may be centuries before these forests can ever support such a diversity of life. Also, this stands as a stark reminder of the importance of soil conservation. Less obvious to most is the importance of decomposition. Without dead plant material, such fungal communities would have nothing to eat. Clearing a forest of dead wood can be just as detrimental in the long run as clearing it of living trees.

Research like this is made possible by the support of organizations such as the Native North American Orchid Conservation Center. Head on over to www.indefenseofplants.com/shop and pick up an In Defense of Plants sticker. Part of the proceeds are donated to this wonderful organization, which helps support research such as this! As this research highlights: What is good for orchids is good for the ecosystem.