The best rosewood, in terms of quality, is typically sourced from Central and South America. This region is renowned for producing the highest grade of rosewood, characterized by its rich color, dense grain, and exceptional durability. The most prized species within this category include Brazilian rosewood (Dalbergia nigra) and Honduran rosewood (Dalbergia stevensonii).

The superior quality of rosewood from Central and South America can be attributed to several factors. Firstly, the climate and soil conditions in these regions are ideal for the growth of rosewood trees, leading to robust and healthy trees that produce high-quality wood. Secondly, the dense and tight grain of the wood makes it highly resistant to warping and cracking, which is crucial for maintaining the structural integrity of furniture and musical instruments made from rosewood.

Data from the Forest Products Laboratory at the United States Department of Agriculture (USDA) supports this assessment. A study conducted in 2016 analyzed the physical properties of rosewood from various origins and concluded that Brazilian rosewood had the highest density and modulus of elasticity, making it the most suitable for high-end applications. Additionally, the study found that Honduran rosewood also exhibited excellent mechanical properties, further solidifying its status as a premium rosewood species.

Furthermore, the rarity and endangered status of rosewood species from these regions contribute to their premium value. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates the trade of rosewood to prevent overexploitation. As a result, rosewood from Central and South America is subject to strict import and export controls, which further enhance its desirability among collectors and craftsmen.

In conclusion, the best rosewood in terms of quality is sourced from Central and South America, primarily due to the exceptional physical properties and rarity of the species found in these regions. The combination of ideal growing conditions, dense grain, and endangered status makes rosewood from this origin the gold standard for high-end applications.