Or when you visit a nursery — “vivero” in Spanish — ask about trees native to Yucatan. So much is lost during the annual fires. If more trees could be planted, it would help restore some of the balance of nature.

Some researchers and archeologists believe Yucatan once had quite a thick cover of trees, but had become heavily deforested by Mayans as early as the 900s AD, causing a permanent shift to a drier climate. A lengthy drought around 1000 to 1100 led to the final collapse of largest city-states and a more decentralized existence for the remaining Mayans.
http://adsabs.harvard.edu/abs/2005AGUFM.B33F..07R
http://adsabs.harvard.edu/abs/1995Natur.375..391H
http://adsabs.harvard.edu/abs/1979Sci…206..298D

http://www.ncdc.noaa.gov/paleo/drought/drght_mayan.html
http://news.nationalgeographic.com/news/2003/03/0313_030313_mayadrought.html
http://www.amazon.com/Great-Maya-Droughts-Water-Death/dp/0826327745/ref=sr_1_1?ie=UTF8&s=books&qid=1240331562&sr=1-1

Following the arrival of the Spanish, a second deforestation began from the 1500s to 1600s, as land was cleared for sugar plantations, cattle ranching and anything else the Conquistadores thought could earn money. Henequen eventually became the cash crop of choice as other ideas failed over the next 200 years. From the 1800s through World War II, henequen brought riches to Merida, but resulted in yet more vigorous and permanent deforestation.

Today, the scrub brush that we see over the countryside is secondary and tertiary growth. Large trees are too rare.

Establishing a sturdy new tree is a gift for those who come after you. Planting a tree is an act of the heart more than muscle.