| Made4 and Aleksa, one thing to keep in mind.....while I agree that the rain forest canopy is a complex ecosystem, most neotropical orchids do not grow in the rain forest. The rain forest concept might apply to the Indonesian and Asian rim orchids. I'm not that familiar with the Indian Ocean/SouthPacific regions so I'm not commenting on them. Maybe someone else can do that.
In South America there are few orchids (but some) found in the area us dumb Americans visualize as the equatorial rain forest of the the Amazon region in the state of Amazonas, Brazil. Largely the Brazilian orchids come from the Atlantic coastal and the adjoining inland area that is partially mountainous and partially semi arid rolling plains with large outcroppings of limestone cliffs. This area also is the home of numerous rivers that support strips of larger trees and vegetation, but the key here is that these riverine environments are geographically separate from each other and make up a small part of the overall landscape. True many orchids are found in trees along the rivers, but many grow on limestone outcroppings, in scrub vegetation along the Atlantic coast, and in the mountain areas separating the two. The cloud forest species of Peru, Ecuador, Bolivia, Columbia , and Venezuela do grow in trees, but it would not be correct to view these as rain forest environments where the canopy essentially dominates everything by shading the ground.
So forget the mythical, movie view of canopies teeming with pooping life that support orchids below. When you look at the scrub areas (for instance), orchids tend to favor certain scrub trees..why? You could make a case that birds poop in those trees, but my observation of birds is that they poop whenever the urge comes not over certain tree species. There is something special about those trees that allowed the evolution of orchids and that something had to be more consistent than a crow with a poop urge.
I'm not defending Geoff Hands theory in Orchid Review. I'm just saying it makes some common sense. Both the author and Orchid Review are British. I have no special knowledge of Geoff Hands. The article describes him as a grower with over 45 years experience and current grower of over 2000 orchids. Additionally, his biography suggests he is respected in British orchid circles. He says (spelling is his),"I was dissatisfied with explanations claiming that orchid roots trap leaf mould particles, or that bird droppings provide fertiliser". He made some rain water collections in Thailand to help prove his theory that tree sap is exuded from stomata and when it rains this sap (containing sugar and plant nutrient elements) is washed down. It was an amateurish effort with minimal analytical chemistry support, but seemed to substantiate his theory as far as it went.
Hopefully someone with the financial backing and research skills required will pick up this work because I do not think we know how orchids get their fertilizer. I'll be happy to go to Brazil and do it if you all will bankroll me. I spent a month there and loved the country and people and most of all the Amazon. Two of the weeks were spent in Manaus. Since third grade geography I've loved the Amazon. Believe me folks it makes the Mississippi River look like a creek.
renata, if you PM me your e-mail address I will try to scan the article and send it to you.
Why don't you describe the areas of Bahia, Minas Gerais, Rio de Janeiro, and Espirito Santo for us.  |