The body of a tree, cut up or intact, is a valuable source of carbon and other nutrients, and a whole crew of decomposers large and microscopically small are ready to transform this bounty into food and habitat.
Of course, we would rather preserve a precious resource - actually I'm not even sure if it's okay to call forests a "resource". So what wood treatment options does an organic gardener have for protecting wooden structures?
There is good reason to avoid conventionally treated wood. Chemical wood treatments contain a wide array of pesticides to kill any fungus or insect that might like to dine on that 2x4. In the past, products were made with arsenic; today we usually encounter copper, zinc, chrome, and boron at toxic levels.
Or else, I'm sure you're familiar with the characteristic tar-like smell of creosote. Many of these wood treatment products create problems as they leach into soil and water, poisoning the soil food web and the plants we grow. Even skin contact is harmful, and we are advised not to compost or burn this toxic wood.
Fortunately a number of alternatives exist. First off, we can save ourselves a whole lot of trouble by avoiding direct contact of wood and soil. Posts set in metal brackets secured in a concrete foundation, will outlive their buried counterparts by many years. Charring (lightly burning) the outer surface also works well for a while, especially if combined with a coat of linseed oil.
Theoretically we could choose tree species that have a high natural resistance to rotting in the first place. In practice however, few of us have ready access to black locust or honey locust trees, Eastern or Western red cedars, or princess trees (Paulownia). And I am definitely not going to suggest cutting down the last of the majestic redwoods!
It comes down to finding environmentally sound wood treatment products. They exist, and while they are not always cheap, they offer long lasting benefits.
One of them is called "Wood Bliss" and I have decided to offer it through the Pantry. What convinced me to try it was the "Eco-Test" seal on the bottle. This is a rigorous and prestigious consumer safety test in Germany and anything that passes with "very good" results is certainly plenty good for organic gardens.
Produced "with sustainable mineral and plant resources", Wood-Bliss is effective against insects and fungus attacks on all indoor and outdoor wooden structures. This makes it particularly suitable for use on raised planter beds, compost bins, trellises and arbours, fences, decks, cold frames and greenhouses, dog houses, chicken coops and bee hives. It will also act as fire protection, and will even lock existing toxins into wood previously treated with harmful chemicals, preventing further leaching and off-gassing.
Wood-Bliss concentrate is diluted 1:3 with water (one part product to three parts water). It can be applied by painting, rolling on, dipping, flooding, or pressure treatment. To obtain good protection, two coats are recommended which will provide 200ml of diluted product to one square meter of wood surface. This translates into about 20 square meters (215 square feet) coverage for one litre of concentrate.
Stir well before dilution. Clean wood of any dirt, old paint, or water repellent substances before treating the wood. Allow to dry completely before use or between applications. Protect glass or metal parts from contact with Wood-Bliss. In high moisture situations, extra wood protection such as an oil coating may be necessary.
By the way, where did I learn about all of this wood preservation stuff? Why, of course through the fabulous education programs offered by Gaia College!
Have a great season and drop me a line with feedback if you feel like.