Early farmers, woodworking, and climate change

From the press release:

"Intensive woodworking and tree-felling was a phenomenon that only appeared with the onset of the major changes in human life, including the transition to agriculture and permanent villages," says Dr. Barkai, whose research was published in the journal PLoS One. Prior to the Neolithic period, there is no evidence of tools that were powerful enough to cut and carve wood, let alone fell trees. But new archaeological evidence suggests that as the Neolithic age progressed, sophisticated carpentry developed alongside agriculture.

...

The early part of the Neolithic age is divided into two distinct eras — Pre-Pottery Neolithic A (PPNA) and Pre-Pottery Neolithic B (PPNB). Agriculture and domesticated plants and animals appear only in PPNB, so the transition between these two periods is a watershed moment in human history. And these changes can be tracked in the woodworking tools which belong to each period, says Dr. Barkai.

Within PPNA, humans remained gatherers but lived in more permanent settlements for the first time, he says. Axes associated with this period are small and delicate, used for light carpentry but not suited for felling trees or other massive woodworking tasks. In PPNB, the tools have evolved to much larger and heavier axes, formed by a technique called polishing. The researchers' in-depth analysis of these tools shows that they were used to cut down trees and complete various building projects. 

Beyond the change from a hunter-gatherer to an agricultural economy, a new form of architecture also emerged. Not only did people begin to live in permanent villages, but the buildings in which they lived literally took a different shape. The round and oval structures of earlier domiciles were replaced by rectangular structures in PPNB, explains Dr. Barkai. "Evidence tells that us that for each home, approximately 10 wooden beams were needed. Prior to this, there were no homes with wooden beams." In addition, humans began to produce limestone-based plaster floors for their homes — which also represented a growing use of wood, since plaster is manufactured by heating limestone.

These architectural developments, along with building pens and fences for domesticated animals, also necessitated the felling of trees in large quantities.

PLoS ONE 7(8): e42442. doi:10.1371/journal.pone.0042442

Form and Function of Early Neolithic Bifacial Stone Tools Reflects Changes in Land Use Practices during the Neolithization Process in the Levant

Richard W. Yerkes et al.

For many, climate change is no longer recognized as the primary cause of cultural changes in the Near East. Instead, human landscape degradation, population growth, socioeconomic adjustments, and conflict have been proposed as the mechanisms that shaped the Neolithic Revolution. However, as Bar-Yosef noted, even if there is chronological correlation between climate changes and cultural developments, what is important is to understand how Neolithic societies dealt with these improving or deteriorating environments. Changes in bifacial stone tools provide a framework for examining some of these interactions by focusing on changing land use practices during the Neolithization process. The results of microwear analysis of 40 bifacial artifacts from early Pre-Pottery Neolithic (EPPNB) levels at Motza in the Judean hills document changes during the PPNA–PPNB transition at the onset of the Levantine Moist Period (ca. 8000 cal B.C.) when conditions for agriculture improved. EPPNB villagers added heavy-duty axes to a toolkit they had used for carpentry and began to clear forests for fields and grazing lands. Sustainable forest management continued for the duration of the PPN until the cumulative effects of tree-felling and overgrazing seem to have led to landscape degradation at end of the Pre-Pottery Neolithic C (PPNC), when a cold, dry climatic anomaly (6600–6000 cal B.C.) may have accelerated the reduction of woodlands. Early PPNB components at sites like Motza, with data from nearly five millennia of Neolithic occupations, show how complex hunter–gatherers and early food producers were able to establish sustainable resource management systems even as climate changed, population increased, and social relations were redefined.

Link