Wood Sample Testing

Photo from left: White PVC board / Cypress / Hoop Pine / Cedar / Merbau / Redwood / Paulownia

Wood Sample Test Exposure to the elements

I thought i’d throw a few samples of different wood together for some weather exposure tests.

Alex of Spicers Hollow Native Bees is trialing some Paulownia and donated a few left over samples and also some PVC board that some box makers use, the rest of the wood is just what i had laying around.

I regularly use Cypress and Hoop Pine so i already know what happens to them over time when used for bee boxes and exposed to the elements. I am more interested to see how the Paulownia holds up when exposed to full weather over time for appearances and what happens to it when exposed to high moisture in the garden.

This might help with how we make native bee boxes, for example if we just use clear coat for a nice timber finish, but then in a few months the box looks terrible, we may just have to use paint.

I made four sample boards,

  1. Placed in the garden where it might have a high chance of rotting
  2. Placed beside a bee hive, full weather exposed to some sun and rain
  3. As above, this one has a clear coating
  4. Placed in the shed, used to compare with the others

Update: 26/12/20203 months from the start

Thoughts so far: A very noticeable difference with the Paulownia. It’s a very light wood, seems very porous, absorbs moisture, starting to mould. Chances are that it might go perfectly well as Native Bee boxes if it’s painted . The bees will coat the inside with propolis so the wood may be sealed off.

All other samples of wood seem unchanged. The Merbau has leached it’s stain everywhere.

Below photo: 1. From Left – In the garden for rot test / 2. Uncoated / 3. Clear Coated / 4. Stored in shed


Update below: April 2021 – 7 Months from the start

All looks fairly well unchanged from the last check

Below photo: 1. From Left – Stored in the shed / 2. Clear Coated / 3. Uncoated / 4. In the garden for rot test


Update below: November 2021 – 13 Months from the start

Below photo: 1. From Left – Stored in the shed / 2. Clear Coated / 3. Uncoated / 4. In the garden for rot test

All samples seem ok, normal sun fade etc. The Paulownia sample placed in the dirt/garden is noticeably soft compared to all the other woods. It’s a bit spongy like you could probably break pieces off. I try to make sure all pieces are evenly exposed to the dirt and moisture. *No bias.

Photo above: Paulownia closest to the camera on the sample board that is placed in the dirt / garden.


Update below: October 2022 – 2 years from the start

It’s been two years since the start of this wood sample test. Top board is the one kept in the shed, middle board is uncoated and left in full weather, rain and sun. The bottom board is up-side-down in contact with the dirt so is kept in a high moisture environment.

All samples on the middle board seem to be in pretty good condition for exposure to full weather for two years so the wood goes ok if it gets wet as long as it can dry out. The bottom board: Hoop pine and cedar looks to be nibbled on by termites? The Paulownia is soft like a sponge and would easily crumble apart.



The Pond Test 11/01/2021

I saw a description for Paulownia that stated it doesn’t absorb water so I couldn’t resist. I placed Cypress, Hoop Pine and Paulownia in the pond.

Below image 14 days in water.

Horizontal end grain image – cross section after being cut – Cypress / Hoop Pine / Paulownia

Below: A little hard to see in a photo, the Cypress has taken on water faster and the piece of wood sunk. The Cypress is heavier to start with so would sink with less amount of water absorbed. It looks like the fibres/grain have drawn water further in to the wood and faster than the others . The Hoop Pine has taken on more water than the Paulownia, though both have drawn in a fair bit. It looks like the Paulownia may just have held water within the outside few millimetres and resists drawing water further in.

Update: 15/04/2021: 3 months in the water

The Cypress took 14 days to sink, Hoop Pine took two months to sink and the Paulownia three months. Photo below shows the Paulownia on the right with a small dry area in the center. A pretty impressive result for the Paulownia.

Horizontal end grain image – cross section after being cut – Cypress / Hoop Pine / Paulownia



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