Science Week: Day 1

Original Post: The Curious Case of Brosimum alicastrum
Date: October 21, 2008 at 9:49 AM 

Brosimum alicastrum trees growing on the ruins of Coba in Quintana Roo.

Brosimum alicastrum trees growing in the home garden of a present-day Mayan family in Quintana Roo.

Fruiting branch of Brosimum alicastrum.  A red-fruited variety of the species is also common.

Many Mayan ruin complexes were discovered by chicleros looking for forage to feed their mules after a hard day of tapping latex. The preferred forage was the leaves and twigs of Brosimum alicastrum Sw. (Moraceae), a common rain forest tree known  locally as "ramon" (from the Spanish verb ramonear, i.e. to browse).  The chicleros would encounter a dense stand of ramon, start cutting the branches, and eventually notice that the trees were growing on the finely-worked stones and carvings of a Mayan temple. 

The relationship between Brosimum alicastrum and Mayan ruins becomes even more interesting given the utility of the tree.  The leaves are used for forage, the fruits and seeds are edible, the milky white latex is potable, and the wood is durable, yet easily-worked.  The dried, ground seeds contain more protein than corn.  Ramon seeds are currently eaten as survival food by rural communities in Quintana Roo, and there is much archaeological literature that suggests that the seeds were a dietary staple for the Maya in pre-Columbian times. The logical conclusion drawn by many investigators is that the dense aggregations ofBrosimum alicastrum found near ruins are, in essence, relict Mayan orchards. 

I spent five years studing the ecology of Brosimum alicastrum for my doctoral dissertation.  I have a different theory  (American Antiquity 48: 610-615) of why these trees grow on Mayan ruins. [NOTE: The fruits shown in the Wikipedia link are not Brosimum alicastrum. Not even close.]

Bird's-Eye View

Part of my fieldwork with Brosimum alicastrum (see The Curious Case of Brosimum alicastrum and Gas Exchange) involved climbing trees to get a closer look at their flowers. I opted for rope, ascenders, and a sit harness, rather than the metal spikes used to climb telephone poles, because I had to climb the same trees several times during the flowering season and I didn't want to damage them or effect flower production.

Was a wonderful way to get away from the mosquitos, although I did fall asleep (briefly) on my observation platform one time (I was roped in). [NOTE: It wasn't so much that I was worried about snakes in the canopy. I just forgot to take off my leggings before going up the rope when this picture was taken (thx, Lauro)].

Gas Exchange

I learned a lot about Brosimum alicastrum when I did my doctoral research (e.g. see The Curious Case of Brosimum alicastrum and MAB Report). I looked at the growth and reproduction of natural populations, conducted experiments on seedling establishment, and developed a matrix model to assess the long-term demographic impact of seed harvesting.  I also took greenhouse-grown seedlings into the laboratory and measured their photosynthesis, respiration, and transpiration under different light levels. Main finding: seedlings are very shade tolerant but they can also respond to abrupt changes in light levels (e.g. treefalls and canopy gaps).

I am basically a field person, but this high-tech lab stuff was quite fun and provided an amazing amount of detail about seedling physiology.  [NOTE: The Brosimum seedling is resting on top of a dictionary (Webster's 1964 College Edition; I still have it), with its terminal leaf enclosed in a brass and plexiglas assimilation chamber. Light source is a Sylvania 1000 watt metal arc lamp.  Flow rates were measured using a Beckman Model 865 infrared gas analyzer, two Wosthoff G27/3F gas mixing pumps, and an EG&G dew point hygrometer].

The Curious Case of Brosimum alicastrum

Brosimum alicastrum trees growing on the ruins of Coba in Quintana Roo.

Brosimum alicastrum trees growing in the home garden of a present-day Mayan family in Quintana Roo.

Fruiting branch of Brosimum alicastrum.  A red-fruited variety of the species is also common.

Many Mayan ruin complexes were discovered by chicleros looking for forage to feed their mules after a hard day of tapping latex. The preferred forage was the leaves and twigs of Brosimum alicastrum Sw. (Moraceae), a common rain forest tree known  locally as "ramon" (from the Spanish verb ramonear, i.e. to browse).  The chicleros would encounter a dense stand of ramon, start cutting the branches, and eventually notice that the trees were growing on the finely-worked stones and carvings of a Mayan temple.

The relationship between Brosimum alicastrum and Mayan ruins becomes even more interesting given the utility of the tree.  The leaves are used for forage, the fruits and seeds are edible, the milky white latex is potable, and the wood is durable, yet easily-worked.  The dried, ground seeds contain more protein than corn.  Ramon seeds are currently eaten as survival food by rural communities in Quintana Roo, and there is much archaeological literature that suggests that the seeds were a dietary staple for the Maya in pre-Columbian times. The logical conclusion drawn by many investigators is that the dense aggregations of Brosimum alicastrum found near ruins are, in essence, relict Mayan orchards. 

I spent five years studing the ecology of Brosimum alicastrum for my doctoral dissertation.  I have a different theory of why these trees grow on Mayan ruins. [NOTE: The fruits shown in the Wikipedia link are not Brosimum alicastrum. Not even close.]