Teaching art history students about painters' methods and materials for many years, much of my own research was on the technical make-up of paintings by Dutch 17th century painters - Cuyp, Ruisdael, Hobbema etcl. This gave me a love of powerful lowland landscape paintings. I learnt the exact combinations of pigments which had been used to paint clouds, water, woods etc. Now in rural Norfolk, with not dissimilar countryside, I try to use that knowledge in my own paintings.
The woodland sketches were inspired by late 19th century Russian painters' dark trunks and shafts of light in dense forests. Woods in Norfolk are not quite the same, but have allowed painted sketches with a similar focus.