It’s that time of year again, when the weather turns cooler, the evenings close in and the leaves fall off the trees in our towns and cities. But in catchments where we have nutrient pollution in our lakes and rivers, do these fallen leaves contribute to pollution?
Certainly when leaves fall onto grass and gardens, they should be left in place to break down and to nourish the soil. But when they fall on streets, paths and car-parks, would it be better to sweep them up and to take them away for composting?
Our Director of Operations, Jo Bradley decided to do a little investigation of her own to find out. She took a sample of fallen leaves from a sycamore tree in a small suburb of Preston. She weighed the sample and sent it off to the laboratory for nutrient analysis. She estimated how many leaves had fallen from that one tree and what proportion had fallen into the road, where they will wash into the stream.
The results of analysis came back and revealed that the sample contained phosphorus and nitrogen. This means that these trees are contributing a load of nutrients to the river in the Autumn. Although this isn’t a particular concern in Preston, as the River Ribble isn’t badly affected by nutrient pollution, in other parts of the Country, where rivers are struggling with high nutrient loads, this may be a significant problem.
At least it is an easy problem to solve though. Leaves can be swept up easily from streets and car-parks and taken away for composting somewhere away from the river catchment, where the leaf-mould can be useful. What do you do with the leaves around your home? Does anyone sweep them up and take them away? Or do you have a garden where you can keep a pile of leaves for hedgehogs and insects to spend the winter?
