There have been many changes in the acoustic guitarindustry through the years,some good,some not so good and some were really bad. For the most part the old adage that "necessity breeds invention" holds true. Take the use of Mahogany wood for example. Mahogany wood was once viewed as inferior tone wood to be used on acoustic guitars, but was accepted and used as a replacement for Brazilian rosewood at times.One large guitar maker even used birch wood ( although called maple) for the sides and back of some of its guitars. But, back to mahogany. This wood was found to have properties to better the construction of guitar necks , because at one point in history acoustic guitar necks were made of cedar, spliced together. So instead of several pieces of cedar to make a guitar neck one piece of mahogany wood because of its strength could now be used and made it possible to construct the neck and peg head out of one piece. Mahogany also gained acceptance for the back and sides of acoustic guitars.

Another replacement or change that happened was the replacement of Ivory ,also a widely used material for bridge pins, binding,bridge saddles, and nuts,decoration and sometimes complete custom fret boards. this was slowly replaced with a celluloid material commonly referred to today as " ivoryoid".
 With the advent of longer fret boards to facilitate players needs and demands and with the wider usage of steel strings Acoustic guitar builders slowly adapted to the placement of interior neck reinforcement. This helped keep the neck straight due to the tension created by steel strings. Using everything from ebony to steel and finally the adjustable "truss rod " we know as a standard feature on guitars today. Which are still being refined on modern guitars.

 The change from "gut" or "Nylon" strings to steel strings also created other changes in acoustic guitars. The greater tension placed on the guitar tops,bracing and bridges on guitars of "oldie" required makers to change or alter the interior body bracing for the acoustic guitars tops and also change the size " footprint" that the bridge made on the top of the guitar as well, all leading to a better built and sometimes better sounding acoustic guitar.

During the late 1960's and early 1970's the tone wood from Brazil became harder to get and after it came under government control it became quite expensive also. Acoustic guitar makers scrambled to get as much as they could  and started to utilize the remaining Brazilian rosewood that they already had. Such is the case for the emergence of smaller pieces being used to create the backs of some acoustic guitars( 3 pieces instead of 2 larger pieces), and a shift to Indian rosewood as well.
As in regards to experiments with tone woods, builders used and are still doing so,more laminates,exotic woods and indigenous wood species in an attempt to replace the lost Brazilian rosewoods,But hey that is another edition of the vintage guitar news and views altogether. This article is not meant to be all inclusive or the  definite last word on the subjects covered,but rather an informative and entertain look at the different aspects of guitars and the vintage guitar market as I see it and as usual this is just my guitar news and views. So until next month may all your days be memorable,all your friends stay true and all your riffs be killer,Greg at gregsguitars.net