In Helaman 3:5 we find that as the Nephites spread northward, they went into "whatever parts it had not been rendered desolate and without timber, because of the many inhabitants who had before inherited the land." According to Hugh Nibley, the deforestation of the land doesn't suit the vast forests of the north, but was a very serious problem in ancient Mesoamerica, as it is today in Mesoamerica. . . . We are told that in the valley of Oaxaca [in the fifth to ninth centuries] over-population "created a growing shortage of timber for construction and firewood and for cooking, apparently reaching such an alarming extent that the hills were completely stripped of forest."
According to W.T. Sanders, among the major causes contributing to the rapid decline and collapse both in the highlands of Mexico and the Mayan country was the necessity of bringing more land under cultivation with "a corresponding decline in forest products."
Nobody worried about deforestation in Joseph Smith's day. They thought the woods were endless. [Hugh W. Nibley, Teachings of the Book of Mormon, Semester 4, p. 237]
Helaman 3:5 They did spread for into all parts of the land, into whatever parts it had not been rendered desolate and without timber, because of the many inhabitants who had before inherited the land ([Illustration]): When the dried vegetation on the corn plots that are being prepared is set ablaze, typically in March or April, the atmosphere over wide regions is obscured by smoke. If this manner of burning was widely carried out in Jaredite times, it may have been a cause of the lack of timber noted by their successors (see Helaman 3:5-6). This scene is in southern Chiapas. [John L. Sorenson, Images of Ancient America, p. 35]
“Whatever Parts It Had Not Been Rendered Desolate and Without Timber”
The Book of Mormon mentions that the land northward had been "rendered desolate and without timber, because of the many inhabitants who had before inherited the land" (Helaman 3:5). This made timber "exceedingly scarce in the land northward" (Helaman 3:10). As to some possibilities on how this Jaredite environmental disaster happened, Jerry Ainsworth notes a report in the New York Times by Richard Hansen of the University of California at Los Angeles, which was presented in the Thirteenth Annual Maya Conference at the University of Pennsylvania on April 11, 1995:
You have to burn about twenty big trees and all their branches in order to make only a little pile of lime (to produce stucco) about one meter high. So they hacked down the forests. The deforestation led to soil erosion and that filled in the seasonal swamps where they had been collecting peat to fertilize their terraced agricultural gardens. They made these areas uninhabitable.
Hansen added that the Olmec [Jaredites] made canals for waterways by raking muck from swamplands adjoining the Gulf of Mexico and using it to build agricultural terraces (see illustration). The practice of building with bricks and "slime" (stucco), of course, was known from the Tower of Babel (Genesis 11:3). Nephites who emigrated to the land northward also learned the practice. They "became exceedingly expert in the working of cement" (Helaman 3:7). [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, p. 119]
Helaman 3:5 Whatever parts it had not been rendered desolate without timber ([Illustration]-agricultural terraces): 67. Aerial view showing terraces and canals off the coast of Belize [but resembling those in Veracruz adjoining the Gulf of Mexico], now mostly filled by erosion. Used by permission of Science Magazine and B. L. Turner. 68. Artist's drawing of canals and terraces and how they were used by pre-Columbian cultures. Drawing by Terry Rutledge. [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, p. 120]