The Importance of Looking Down (From the Archive)

I am a firm believer in the idea that if you want to understand the future of a tropical forest - look in the understory (see Regeneration Surveys). Repeated observations of marked seedlings are the crystal ball (maybe Ouija Board is a better analogy) of forest dynamics.  A species may be represented by a large number of canopy trees at the moment, but if it doesn't have any seedlings or saplings established in the understory, it's days are numbered. Want to assess the sustainability of forest use? Count seedlings. Want to make imperceptible, lasting changes to forest composition? Selectively weed the understory (see Tembawang). 

When you walk through a tropical forest, the natural tendency is to look up.  To scan the crowns for flowers and fruits (if collecting herbarium specimens) or to marvel at the size of the canopy trees (see Size Matters). Nothing wrong with this, but there may be more to be learned by looking down. [NOTE: The sapling with the orange flagging is Grias peruviana (see Grias Predated, Umberto Pacaya, and Varzea Still Life); I still have that machete].

Science Week: Day 2

Original Post: The Importance of Looking Down
Date: April 7, 2009 at 5:58 PM 

I am a firm believer in the idea that if you want to understand the future of a tropical forest - look in the understory (see Regeneration Surveys). Repeated observations of marked seedlings are the crystal ball (maybe Ouija Board is a better analogy) of forest dynamics.  A species may be represented by a large number of canopy trees at the moment, but if it doesn't have any seedlings or saplings established in the understory, it's days are numbered. Want to assess the sustainability of forest use?  Count seedlings.  Want to make imperceptible, lasting changes to forest composition?  Selectively weed the understory (see Tembawang). 

When you walk through a tropical forest, the natural tendency is to look up.  To scan the crowns for flowers and fruits (if collecting herbarium specimens) or to marvel at the size of the canopy trees (see Size Matters). Nothing wrong with this, but there may be more to be learned by looking down. [NOTE: The sapling with the orange flagging is Grias peruviana (see Grias Predated, Umberto Pacaya, and Varzea Still Life); I still have that machete].

The Importance of Looking Down

I am a firm believer in the idea that if you want to understand the future of a tropical forest - look in the understory (see Regeneration Surveys). Repeated observations of marked seedlings are the crystal ball (maybe Ouija Board is a better analogy) of forest dynamics.  A species may be represented by a large number of canopy trees at the moment, but if it doesn't have any seedlings or saplings established in the understory, it's days are numbered. Want to assess the sustainability of forest use?  Count seedlings.  Want to make imperceptible, lasting changes to forest composition?  Selectively weed the understory (see Tembawang). 

When you walk through a tropical forest, the natural tendency is to look up.  To scan the crowns for flowers and fruits (if collecting herbarium specimens) or to marvel at the size of the canopy trees (see Size Matters). Nothing wrong with this, but there may be more to be learned by looking down. [NOTE: The sapling with the orange flagging is Grias peruviana (see Grias Predated, Umberto Pacaya, and Varzea Still Life); I still have that machete].

Grias Predated

Grias peruviana (Lecythidaceae) is another varzea species that I studied while I was in Peru (see Camu-camu, Jenaro Herrera, Umberto Pacaya, Regeneration Surveys, and Yield Studies). The fruits of this tree, which are produced by caulifory along the trunk, are known locally as "sacha mangua" or faux mango.  They have bright orange pulp like a carrot, and a large football-shaped seed.

To quantify size-specific fruit yield, I marked several adult trees and made daily observations of flower and fruit development. During the period when the young fruits were maturing, I noticed each morning that several of the fruits had small scratches on them.  Just deep enough to cut through the skin and expose the pulp. The scratches continued appearing until the fruit reached maturity, at which point, rather than scratches, I would be greeted by the image above, i.e. a predated fruit with no seed. 

It turned out that the culprits were squirrels, and each morning they would scratch the fruits to see if the pulp had started to turn that bright orange color which would indicate that the fruit, or more importantly, the protein-rich seed, had now reached maturity and was ready to eat.  Like a savvy shopper testing cantaloupes in the produce aisle.