Rainforest or Not?

Essays, Stories, Adventures, Dreams
Chronicles of a Footloose Forester

By Dick Pellek

Rainforests or Not?


Discussing rainforests is not the same as explaining rainforests and reporting from a rainforest is not the same as reporting about rainforests. Likewise, discussing rainforests does not and should not imply that the reporter or commentator understands rainforests. If ever there was a case to separate out the lumpers from the splitters, the subject of rainforests is a good place to start.

Without deliberately denigrating the lumpers of facts from those who analyze and split facts into ever-smaller components, there must be a place to start in even deciding which side of the divide a putative commentator on rainforests will be.  Lumpers, in general, try to look at a picture and make sense of it, in a general way.  Splitters look at the same picture and implicitly divine that its structure, colors, and components make it special in ways yet to be deliberated.  A few rudimentary comparisons may make the point, using the mental picture of a rainforest as the case in point.

A rainforest, presumes the lumper, is composed is a forest where it rains a lot, presumably in the tropics where it is hot.  That, of course, makes it a rainforest.  That simplification is not an exaggerated one since the Footloose Forester has heard and read many variations of that very theme.  One time in Haiti, he even winced after a reporter from a Philadelphia newspaper wrote an exclusive about rainforests in Haiti, where they had never existed. One of the reasons that the Footloose Forester calls himself a splitter is because he firmly believes that a multitude of circumstances goes into the formula about what makes a tropical rainforest.  Even for a splitter, one must start with some presumptions and weave the various strands into a fabric of plausible identity.


On this map, not even the vast Amazon Basin is recognized as rainforest


To move from the lumper approach to the splitter approach still requires a starting point and a few fundamentals.

Tropical + Forest = Tropical Forest.  Rain + Forest = rain in a forest.  Rain + Forest + Tropics = rain in a tropical forest.  When the words are combined, rain in a tropical forest does not equate to a tropical rainforest.  Why not?

There are qualifiers and quantifiers that delimit what should be included in the definitions.  To be tropical the sole qualifier rests on a geographical location somewhere between the Tropic of Cancer and the Tropic of Capricorn, those imaginary lines of latitude north and south of the earth’s equator.

To be considered forest, the area in question should be composed of trees, palms, and/or bamboos whose canopies form a more or less homogeneous expanse and whose boundaries can be observed. The unique description of rainforest combines the essential ingredient of rain in a forest but with a minimum measured amount.  And that is where the lumpers and the splitters part ways when it comes to description.  Although this chronicle is a personal view of what a rainforest is and what it is not, the Footloose Forester has spent enough time researching putative rainforest characteristics to suggest some qualifiers and quantifiers.  Furthermore, living in and studying tropical forests on the ground helped to embolden him to offer clarifications.

First off, a rainforest can occur anywhere there is an accepted minimum amount of annual rainfall, distributed more or less continuously throughout the year, in an ecological entity that can be recognized as forest.  Heavy and uniform rainfall falling on the ocean in the tropics does not qualify, nor does similar patterns of rainfall in grasslands or cities, and urban areas.  Many experts put the minimum annual rainfall requirement as at least 2500 mm, or 100 inches per year.  Others put the minimum at 5000 mm at a basal altitude in the tropical zone, with different minima at various altitudes.  A worldwide standard has never been established, thus the debate and the confusion will persist.  Most experts would agree, however, that continuous recorded monthly rainfall is a vital characteristic to distinguish total annual rainfall in putative rainforests from total rainfall derived in monsoonal climates that have months or little or no rainfall.   

In 2017, RESOLVE.org published an interactive worldwide map of some 846 ecoregions showing variations in vegetation types and the color gradations that suggest that increasing or decreasing rainfall plays an important part in determining the boundaries. The organization that was founded in 1977 uses collaboration building as an institutional tool and supports policy initiatives to advance new learning, best practices, and (land) ethics. It is perhaps the very best resource for laymen and scientists to consult regarding characteristics of various vegetation types because, in addition to a detailed map, the publication offers taxonomic descriptors that are accompanied by photographs of each of the 846 ecoregions.  The reference map also has a handy legend that indicates that indeed there are rainforests in various places around the world, not all of them are in the tropics and not all of them are recognized as non-descript rainforests.  There are lowland rainforests, montane rainforests, coastal rainforests, and one monsoonal rainforest.  Qualifiers…and quantifiers went into the decisions to distinguish one from another. 

Lumping rainy places in the tropics into a few classification categories does not tell the story of the complexity of the biotic communities on the ground that cries out for a more comprehensive set of qualifiers that can only be established by recognizing sub-sets of parameters that distinguish one from another.  The discussions about rainforests may go on, but the RESOLVE map of worldwide vegetation should be considered a standard reference.

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