My understanding of hugelkultur is that it's not terribly appropriate in subtropical/tropical environment, as the soil biology/insect life has the ability to break down woody materials exceedingly fast. Tropics Usually have extremely poor soils as most of the nutrients are in the vegetation.
The tera preta soils of the amazon basin consist primarily of bio-char as it has the ability to soak up nutrients and hold them in a soil-like medium without the excessive rainfall leaching nutrients out of the soil. That might be a more appropriate use of permaculture locally (I'm unsure about your rainfall) and bio-char is equally inappropriate here in temperate climates.
Also, I feel like swales are a little over used and misunderstood. That much slope has got to be challenging.
Hugelkultur actually works very well in tropical climates.
Yes decay is faster but so is growth to replace it.
I'm glad to know that. I was under the impression it was less/marginally effective in the tropics. Thanks for that feedback