Variability of Cypress Rot Resistance

Old growth Cypress has more natural rot resistance than younger trees. May 15, 2011

Is there any difference between a swamp cypress and an upland cypress in decay resistance? A claim is being made that upland cypress is more rot resistant.

Forum Responses
(Architectural Woodworking Forum)
From contributor U:
We use a fair amount of cypress for exterior shutters, and we find there is a wide range of terms used to describe the different types. What we find to be in cypress that is referred to as swamp cypress is that there is a lesser quality in the stability and rot resistance of the wood. That being said, cypress is like most other woods in that the best material comes from the more mature trees, whether it is swamp or upland cypress. That being said, neither compares to "old growth cypress".

I have finally developed the attitude that when I use cypress, I prime, seal and paint with the best products I can, then I encourage my customers to repaint on a regular schedule and hopefully never really test the rot resistance of the wood. I believe that swamp cypress grows out faster due to the higher availability of water, and that due to this, the wood is not as good. By the time we consider availability, cost and workability, plus whatever rot resistance there is, we like using cypress on most outdoor projects over most other woods.

From Gene Wengert, forum technical advisor:
I have not heard of variations due to growing site. However, old growth has much more decay resistance versus new grown trees and this is documented.

From contributor U:
Gene, is it possible that there is a difference in the actual types of cypress that are found growing in the two different locations? When I say location, I mean a wetland environment versus a drier woodland area. I have been working around and with cypress in my business for 20 plus years, but I confess I am no expert and stay somewhat confused by the terminology used from one place to the next, to describe the types of cypress. Most of my suppliers just list their wood as cypress, should I be specifying a certain type when ordering the common newer growth cypress that is being sold today? I am in the southeast and a lot of the local wood that is cut and sold here comes from the Appalachicola river basin and adjoining areas.