The tallest Armstrongii in the Top End ?

[greysrigging]

A pic, taken by local photographer Jacci Ingham, of an amazing Cycas Armstrongii. Multi heads and about 7m ( 22' ) tall ! Armstrongii are locally common in the Top End of the Northern Territory, but this one appears to be a giant among its peers.

 

[redbeard917]

Wow. How old, would you guess? I wonder if it is the parent of many of the smaller ones nearby.

[paquicuba]

Is that forest recovering from a fire? 

[greysrigging]

At least 150 years old and perhaps 200 or even more years according to local commentators. ( growth rates in the Top End of about 2" a year. ). And yes, the Top End bush burns seasonally and many native plants have evolved to withstand the annual burn. In recent decades, however, the introduction of exotic grasses such as Gamba Grass ( for cattle grazing ) has dramatically increased the fuel loads in the bush resulting in hotter more intense fires which are detrimental to these amazing plants such as the one pictured.

https://www.ncbi.nlm.nih.gov/pubmed/28308128

Edited September 4, 2018 by greysrigging
Spelling error

[greysrigging]

Top End bush after seasonal fires....

[TexasColdHardyPalms]

That should be older than 200 years. 

[Tracy]

On 9/4/2018, 4:04:28, TexasColdHardyPalms said:

That should be older than 200 years. 

If the estimate of height growth per year is accurate at 2" per year, an age of 200 years would yield about 33' in height, so the calcs work out.  Interesting, as I would have guessed older as well, but have to defer to the local knowledge.

On 9/4/2018, 2:30:54, greysrigging said:

At least 150 years old and perhaps 200 or even more years according to local commentators. ( growth rates in the Top End of about 2" a year. )

 

[TexasColdHardyPalms]

The math is works out but it took MANY years for a wild seed to germinate and develop a caudex large enough to go vertical. I haven't grown armstrongii but I presume it grows much like angulata, another tall, northern AU cycas which I have grown. In cultivation they grow faster than a revoluta but slower than a taitungensis.  I have revoluta and taitungensis seeds that squirrels ran off with 8 years ago and planted that are only a baseball size caudex.  Granted we don't have year round heat which will make a substantial difference, but not double the speed.

[epiphyte]

Impressive specimen!  In your second photo... is that Pandanus spiralis in the background?  

[greysrigging]

37 minutes ago, epiphyte said:

Impressive specimen!  In your second photo... is that Pandanus spiralis in the background?  

Yep.... locally common and usually a sign of low lying ground that gets seasonally waterlogged.

https://nt.gov.au/__data/assets/pdf_file/0008/200024/pandanus.pdf