Why do we mulch our trees? How being part of the circular economy helps us grow
During early summer at our community tree nursery, we have spent many hours happily mulching our rows of saplings with volunteers. We have been experimenting with a range of organic materials such as wool, wood chip and cardboard. These provide 2-3 inches of protection around the roots. There are a number of reasons why this is an essential part of our growing year.
- Weather Protection & Climate Resilience
Organic mulches keep tree roots warm in winter and cool in summer. This helps to protect trees from extreme temperatures, especially at unusual times of year. Wool, for example, is ideal for warming the soil in spring and insulating the soil from drying winds in summer. We also cover our seep hoses with mulch to protect them from bright sunlight and to keep them at a more constant temperature.
- Reduces Water Evaporation & Soil Erosion
Mulches can reduce water evaporation and soil erosion by as much as 35%. This is hugely important as it reduces how much water we need to give the trees over the summer. This winter we have seen record rainfall, and more intense rain showers, so it is vital that we reduce soil loss via erosion. Heavy rain can also lead to soil compaction which makes it harder for tree roots to grow deeper.
- Fosters Healthy Soil
Organic mulches add nutrients to the soil and encourage better tree growth. Mulches breakdown slowly, releasing nutrients as they decompose. This makes key nutrients such as nitrogen, phosphorus and potassium more available to the trees. Coarse mulches, like wood chip, also improve the soil structure and the amount of organic matter. This helps water retention and supports a whole host of beneficial organisms such as earthworms, nematodes and fungi.
- Suppresses Weed Growth
Mulches restrict light to surface weeds, so trees have light and air, and a greater chance to grow. This makes our nursery maintenance much easier, we can pull most other weeds out by hand, often only once a summer. A good layer of mulch can reduce weeding by 50% and leave us more time to get other tasks completed. (See www.rhs.org.uk for more mulch information).
Where do our mulches come from?
We are hugely grateful for the support of our Stump community and the many offers of mulch material. All our mulch is a ‘waste’ product from the local area, and we can reuse this instead of buying something new.
This gives materials a second life and keeps them in the circular economy (see www.wrapcymru.org.uk for more information). We currently receive wood chip from local tree surgeons and cardboard from a nearby farm.
Our wool comes from several sources; from farmers after shearing, a saddler who uses wool in restoration, and from Wool Insulation Wales, a company who use wool as a low-carbon alternative to insulate homes and offices.
We are always looking for more community partnerships, so if you have material that might be useful to us, please get in touch (hello@stumpupfortrees.org).