Whilst fresh shredded wood looks attractive and it is appealing to think that one is recycling unwanted wood it is not a good idea.

Barks and mulches sold in the professional and retail markets have all undergone a composting process which is crucial for the following reasons:

Nitrogen draw down

As bark and wood degrade they naturally uses up the surrounding nitrogen from the air and soil to feed the bacteria responsible for the decomposition. It is only when the composting process reaches a stable stage that the levels of nitrogen taken up are dramatically reduced (and it is only when barks have reached this stable point that we bag them for sale). Fresh wood and bark take nitrogen from wherever they can get it , which is mainly the border they are put on and therefore remove nutrients available to plants in that area.

Water Uptake

A fully composted bark helps to retain moisture in the ground but fresh bark and wood soak up water as part of the composting process, thereby depriving plants in the area of moisture.

Retardation

Some varieties of tree (Elm in particular) naturally secrete a chemical into the soil surrounding their roots and this chemical acts as a natural inhibitor for other plant varieties as the soil around the tree becomes a hostile environment. Composting these types of trees takes longer as the chemicals naturally present in the wood take a long time to break down and using fresh wood of these varieties as a mulch will introduce these chemicals directly into the soil.

Seeds and Pathogens

The composting process reaches temperatures in excess of 65^oC. This temperature is sufficient to kill off bacterial pathogens and destroy fungi and seeds which may be caught in the grain of the bark so the end product is essentially sterile. Fresh ground bark and wood will contain unwanted seeds, which once introduced to the soil will root as weeds do, and pathogens can be easily spread over large areas.