God has cared for these trees, saved them from drought, disease, avalanches, and a thousand tempests and floods. But He cannot save them from fools. 
John Muir

Mulch Images - When Mulch Kills!

Links

Future Mulch - Distributor for Rubberific Mulch

Every time I learn something "new" and "beneficial" for trees it turns out to be something that simulates conditions normally found in natural forests. This is certainly the case with mulching.

This is what I'm talking about (image on left). Here's a happy walnut tree (left) in the arboretum. Depth around 3 inches. Mulch all the way to the dripline if you really want to minimize the influence of turf (allelopathic & competition for nutrients/water/space).  Make sure the trunk is making contact with the soil, NOT the mulch (image on right). You should be able to still see the root flare and a little bit of the soil line around the trunk after mulching. (Walnut. June 13, 2001)

Just a few things to remember, 

• AVOID volcano mulch (see below)
• AVOID applying over 3 inches
• AVOID contact with the trunk
• AVOID "sour mulch" (see below)

Volcano Mulch

Virginia's Urban & Community Forestry Coordinator pointing out a typical volcano mulching job.	Close up (above)
1. The roots are not benefiting from the mulch.	Other than these three problems everything else is just fine :-)
2. It's suffocating the lower portion of the trunk.	3. It's about 16 inches too deep.

Sour Mulch. Symptoms may resemble those caused by drought, excess water, pesticide injury, fertilizer burn (i.e. marginal leaf chlorosis, leaf scorch, leaf drop.... If these symptoms appear within 24 - 36 hours after mulching - suspect sour mulch. The plant is suffering from a cocktail of fermentation products (methane, alcohol, ammonia gas, and hydrogen sulfide gas) that have accumulated when a pocket of the mulch has experienced low levels of oxygen and high levels of water (over 40%).  These conditions can occur when piles of mulch haven't been turned over (i.e. lumber yards). When handling sour mulch you will probably smell something resembling old gym socks that have been dipped in vinegar. If you have the ability to test sour mulch you will record a low (acidic) pH in the range between 1.8 to 3.6, while properly composted mulch will have a pH in the range between 6.0 to 7.2. It's important to identify sour mulch before applying it to trees. By the time symptoms appear it will be too late to identify the mulch and repair the damage.

Keeping the string trimmers away.... geez, mulch should probably be placed around these sign posts!