Even with flowers, leaves and Culm sheath characters experts misidentify Bamboos so don't hold your breath.

There are reportedly only four bamboos native to Belize:

Guadua longifolia
Merostachys pauciflora
Otatea fimbriata
Rhipidocladum bartlettii

And we are told that "Belize ... is well known for the Guadua longifolia populations along the Belize river and its tributaries on the Yucatan Peninsula." [In the author's view, the other three apparently weren't worth mentioning.]

http://www.inbar.int/ wp-content/ uploads/ downloads/ 2012/ 09/ inbar_working_paper_no35.pdf

This post was edited by missingtheobvious on Sun, Dec 22, 13 at 22:11

Any reason to believe this is a native species?

If you're asking me, then no, I'm not making any assumptions. But photos of those four bamboos might be a place for blakrab to start.

If the parts sort of like criss-crossing wire netting are actually coming off the bamboo then that would be a hint as only certain ones do this.

B. bambos?

Thanks, I could probably assume it's Guadua longifolia..

Whose relative, Guadua angustifolia, I think is currently being proposed as an economic timber bamboo.
http://www.guaduabamboo.com/

Here's another photo of some bamboo nearby in Honduras - that also look similar..
http://www.traveltourismhonduras.com/2010/08/lancetilla-real-garden-of-eden.html

Here is a link that might be useful: {{gwi:378882}}