That is true,
but what most people think about is a Flex Tree that mixes, wood, rubber and plastic.
You cannot start mixing dissimilar material like that and expect it to last, Solid Wood Trees have been covered/reinforced with Rawhide for 100's of years, many of those trees are as good today as they were 50-75 years ago. Today to save 4-5 lbs, they cover them with a Fiberglass Matte and Resin which makes them just as strong as rawhide but lighter.
There is a reason some Flex Trees are on Version/Generation II ... the 1st version failed miserably, I am not a fan of the 2nd version either.
Instead of Fancy Fads like a Flex Tree, spend the extra Money on a Very Good Saddle pad, your Horse will be Happy and so will you.
May all your Trails be happy and safe ones