http://blog.islaformosa.com/2007/09/war-on-betel-nut-and-betel-palms.html
Betelnut trees being the root cause for disasters has come into doubt following the devastating summer typhoon of 2009.
"In the absence of any official declaration of the underlying causes, residents have filled the void with speculation.
Taiwan’s forestry bureau says native subtropical trees had covered most of the deadly mudslide areas of Kaohsiung County in southern Taiwan, doing more to hold mountain sides intact than to loosen them. Villagers had planted mainly bamboo, mangoes, peaches and taro on the lower hillsides. They had shunned betel nut plantations and high-mountain tea, which are common elsewhere on the island and are notorious for destablising soil for lack of deep roots, an agricultural official said.
Other disaster authorities point toward Taiwan’s fragile geology and ecosystem, including repeated earthquakes, typhoons and an early 2009 drought that have left hillsides at increased risk, allowing even huge deep-rooted trees to fall last month.
“Taiwan is an important case study in climate change,” said Chern Jenn-chuan, deputy minister of the cabinet’s Public Construction Commission. “We can say that natural disasters will be more and more severe. We can be sure of that.”
The villagers claim:
"Decades of forestry, farming and over-population have loosened mountain soil all over the island, leaving it prone to massive slides."
http://blogs.reuters.com/china/2009/09/17/aggressive-land-use-set-off-deadly-taiwan-mudslides/
So once again it seems that betelnut trees, often scapegoated in these disasters, are not the culprit this time. In fact, there are a wider range of factors which would fit nicely in Jared Diamond's Collapse theories.
On top of this it is interesting that high mountain tea is also mentioned due to lack of deep roots. Why isn't there an anti-high mountain tea growing campaign from intellectuals?
So it appears that farming and deforestation in general are more likely the cause of landslides. Why do people believe the anti-betelnut lobby so blindly?