The project

The aim of the project I am working on is to better understand how geography affects plant communities. (I think I’ve heard this referred to as phylogeography). Those differences could be differences between the pant communities, difference within a species, forest structure, carbon trapping capacity… Once the data is collected it can be crunched to look at any number of things; do trees grown in nutrient poor soils produce larger amounts of defense chemicals, etc, etc.

The soil types here vary widely and plant species do too. Guyane, small as it is, hosts some 1,200 to 1,600 tree species. New York State is almost twice the size of French Guiana and has fewer than 150 tree species. The number of species here depends on who you ask, the day of the week, the latest publication, etc. The variability in those numbers has a lot to do with the fact that there isn’t yet a good answer to the question, “What’s a species?”

The looks at plant communities in three distinct soil types:

× Bas-fond - low areas that are often inundated

× Terra-firma - richer soil that is generally not inundated

× Sable-blanc - white that are very low in nutrients.

The plan is to work in areas that have all three soil types, set up multiple plots in each of the soil types and repeat that protocol in different parts of Guyane. Trees as small as 8cm in circumference are identified to species within a small area. This gives a picture of the woody plant diversity.Trees 60cm and larger are i.d.’ed to family or genus within a larger area, provides a picture of carbon storage.

When I say, “we identify” I mean of course, they – they who are tropical botanists. The degree to which they can identify these plants is staggering. They look at the various characteristics of the bark, make a shallow cut and look at the sap, smell it, feel it’s texture, look up at leaves through binoculars, tap the trunk, feel the bark, see how it peels and so on and so forth. They can often identify a tree to species within seconds. When they have trouble, we collect a sample of foliage with pole pruners, a throwline or…a shotgun.

In the Midwest I was bothered by how many trees I was removing. Now I’m shooting them. This is one of those things that takes a little getting used to as an Arborist, but it quickly seems to make a lot of sense. Taking aim at the twiggy bits at the ends of a branch brings down small samples quickly. Sometimes all the botanists need is a single leaf for a positive i.d. I can get my throwline (a 2mm line with a weighted sac) over a branch 25-30 meters up, but it often takes a long time and brings down branches far bigger than what we need so in some ways the shotgun is a gentler tool. When we get to the reserve of Nouragues with it’s no shoot policy, I along with one other climber will take the place of the shotgun.