Why Do Madagascar Palms Have Some Cold Hardiness?

[PalmTreeDude]

Why do some Madagascar palms, for example  Bismarkia and Beccariophoenix alfredii, have some cold hardiness to them? They are not cold hardy in cooler zones like 8a/8b but they are cold hardy from where they come from. Most of Madagascar is north of the Tropic of Capricorn. Are they just like that? You would think that they would not be cold hardy at all. 

[PalmTreeDude]

BTW, I know some are not cold hardy at all. 

[Ben in Norcal]

My guess is elevation.  Never been there, but looking at the topography there is a large central plateau at 5,000 feet plus.

[sonoranfans]

Both are from the high plateau, Bismarckia at a bit higher elevation.  Consider parajubaea, grow  at high elevation also.  the natural habitat of both is also wet in the warm season and dry in cool season at that elevation.  they are both adapted to dry winters so their best coldhardiness will likely be in a dry cold.

[richnorm]

Also it is sometimes suggested that island palms sometimes provide surprising cold tolerance because they have been geographically marooned during ice ages.

 

[quaman58]

 Being located as many of us are in the northern hemisphere, we associate going south with getting warmer. But as Madagascar is in the Southern Hemisphere, I've noticed that palms from the northern part are often nearly impossible for me to grow. I always assumed being closer to the equator meant they needed too much warmth. I realize that's probably an oversimplification , but it's been my experience in many cases.

[Yort]

Because of the combination of altitude and land climate. Madagascar is a huge island, much larger than the state of California for instance. Both palms grow far away from the coast, where temperatures are hot in daytime but drop during the night. 

[Cikas]

Ice age is the reason. Climate was much colder 10000 years ago. Plants still have genes for cold hardiness evolved then. 

[Hillizard]

In the spirit of Earth Day 2018: The loss of Madagascar's unique palm trees will devastate ecosystems: http://theconversation.com/the-loss-of-madagascars-unique-palm-trees-will-devastate-ecosystems-78622 

[GottmitAlex]

Don't forget the Ravanea Hildebrantii.

 

[Dypsisdean]

Unless you have lived or spent time in a mountainous tropical location, the part elevation plays in temperature is not often appreciated. Even 500-1000 ft elevation is noticeably cooler than sea level. 3000 ft is easily 10-15º F cooler - into the upper 40s some winter nights. And when you get up past 4000-5000 ft. it can be downright cold at night in winter. This phenomenon seems more pronounced as you approach the two "Tropic of C&C" lines.

Someone I know camped out on Madagascar's upper plateau during winter and found a thin crust of ice on the top of his water bucket in the morning. So it appears as if palms from these higher locations in Madagascar are accustomed to occasional light freezes.

So, I'm guessing that a Madagascar palm's native elevation plays even more of a role in it's hardiness than it's native range (north or south),

[LJG]

Another reason is that Madagascar use to be further south but thanks to plate tectonics, it’s moving north. The plants have some cold-hardiness built into them from long ago. 

[Bill H2DB]

  I watch a good bit of the BBC news , and most of the time , when they have a report concerning 

something in highland Kenya , or Ethiopia , the locals are often wearing flannel shirts and light jackets .

  Kilimanjaro is the white mountain .

Within the last week or so , there was an article concerning Madagascar ( I've forgotten the content ) , and they were 

dressed similarly .

   Altitude really counts .   Look at Flagstaff , Arizona  e.g. , or the various climate zones of Costa Rica , etc.

   

[DoomsDave]

@PalmTreeDude, this is one of those profound questions.

There's a lot of habitats in Madagascar, including some in the high mountains. @LJG had occasion to visit some of them, and it looked cold up there.

Also, while nowhere near the size of Africa, Madagascar is still a big, varied place.

Finally, Madagascar has a shortage of the Armageddon pests and diseases that plague palms elsewhere, or at least that I've heard of. Mainland Africa, for example, has porcupines, giant spiny rodents that destroy all they can chew. There's no palm weevils, no phytopera rots. The worst palm pest is people, alas!