So, which product is best for your landscaping scheme? Bark chips or wood chips? Well, surely bark chips are the superior product because they are more expensive, right?
Well, no actually. While it is true that bark is certainly more expensive, research trials show that woodchip consistently outperforms bark regarding moisture retention, weed suppression, sustainability and temperature moderation to name a few – all the critical stuff that a good mulch should do.
So, let’s look at each of these factors in turn.
1. Wood chip retains and releases moisture better than bark
The bark is, of course, the outer covering of a tree. It is naturally waterproof and is designed to repel water. It does this because of a waxy coating called Suberin. This explains why fresh bark chips always appear to look dry. Now, a good layer of fresh bark chip on your planted area can create a near-impenetrable barrier that prevents water from reaching the plant roots – this is not good news for plants. Wood chips, on the other hand, are not coated in this wax-like substance and therefore can absorb, retain and release moisture. The woodchips will grab moisture from the air during the night, releasing it into the earth during the day. They will also reduce water evaporation from the soil when it is warm. Moisture is, of course, critical for plant survival and vitality.
Wood chip 1 – Bark Chip 0
2. Wood chip provide excellent weed control
If you want to reduce the need to spend hours and hours hoeing off weeds, and you support a sustainable, herbicide free environment, then natural mulch is the weed-control method of choice. Unlike the uniform nature of bark, wood chip is made up of bark, wood and leaves of varying size and density. This diversity of ingredients means that woodchip is more efficient at light reduction (preventing weed seed germination and the photosynthetic ability of buried leaves), allelopathy (inhibiting seed germination) and reduced nitrogen levels at the mulch/soil interface (reducing seedling survival). It also means that the product resists compaction, and it decomposes at different rates, gradually releasing beneficial nutrients into the soil (resulting in a more diverse colony of soil organisms which improves plant productivity).
Wood chip 2 – Bark Chip 0
Consider where the product you buy comes from and the complex logistics involved in transporting it to your location. Some bark products are imported from forests abroad. Some products are transported between multiple locations; from logging stations to processing plants, held in storage, on to main distributors and then the retailers before finally getting to the end user. All this adds up to many miles travelled. Whereas arborist wood chip can be sourced locally to where you live or work and is made from locally grown trees – trees that have been sustainably managed by local Councils and landowners. Our wood chip comes from essential tree works, is processed into various grades of chip and delivered straight to you. Fewer miles travelled, better for the environment and better for your pocket too!
Wood chip 3 – Bark Chip 0
4. Temperature Moderation
Mulch acts as an effective sunscreen to block the sun and moderate soil temperature, and it seems woodchip appears to be most effective at this job. In winter months soil covered in wood chip will stay warmer longer and may offer protection to plants from sudden changes in temperature, or where plants have not gone into dormancy early enough before the chill sets in. In springtime, the soil will warm faster, helping to extend the plants’ growing season.
Wood chip 4 – Bark Chip 0
So, the question remains, why do some people insist on using bark? It seems that there are two reasons.
1. It is what they have always bought.
2. Aesthetics – bark looks pretty.
Let’s exclude number one straight away because that is not a good reason to do anything, is it?
So we are left with the aesthetic argument – that bark looks nice, it is visually attractive and consistent in size, colour and texture. Okay, maybe – but surely, this must be secondary to the primary function of the product and the health of the plants it is being applied to enhance. As we demonstrated above, not only is wood chip hands-down more effective as a landscape mulch, but bark can be detrimental to the health of plants. Moreover, if you are still concerned about looks, we can produce a wood chip mulch to a consistent uniform grade, or nugget style chip that looks very attractive and will enhance any landscape scheme.