Savoring the Final Moments of Autumn, as Discussed by Nigel Slater
Exploring Autumn's Colourful Canvas: A Guide to Tree Leaves
Autumn is a spectacle of colours, and the trees in our gardens play a significant role in this seasonal art exhibition. The hues of red, orange, and yellow that grace our landscapes are the result of various pigments in the leaves, responding to environmental factors like light, temperature, and soil conditions.
Leaves contain multiple pigments, with chlorophyll being the most dominant during the growing season, giving leaves their green colour. As daylight shortens and temperatures drop in autumn, chlorophyll breaks down, allowing other pigments to become visible.
Carotenoids, which show yellow and orange hues, are present throughout the growing season but are masked by chlorophyll. On the other hand, anthocyanins, which produce red and purple colours, are synthesized in some species in response to sugar accumulation in the leaves during cooler temperatures.
Three key environmental factors influencing autumn colouration are light, temperature, and soil and moisture. Shorter days and less direct sunlight reduce chlorophyll production, revealing underlying pigments. Cooler temperatures, especially cold nights, help break down chlorophyll and promote the formation of red pigments (anthocyanins). However, early frost can dull colours by killing leaves prematurely. Soil conditions affect nutrient uptake and tree stress, influencing pigment development and colour vibrancy. Both drought and excess water can cause premature yellowing or leaf drop, affecting fall colours.
Different tree species vary in pigment composition and production. Acer (maple) species often exhibit vibrant reds due to anthocyanin production, whereas cherry trees may display more subtle reds or yellows depending on species and conditions. Wisteria, being a vine with different leaf chemistry, typically shows more muted autumn colours, often yellow tones from carotenoids.
In the speaker's garden, the leaves of the small trees, such as the Cornus kousa and Acer palmatum, provide vibrant autumn colours. The ornamental cherry outside the house is shedding its leaves in shades of butter and rust. The beech 'bee-hives' are currently being attempted to be brought back into shape.
The speaker enjoys throwing handfuls of leaves into the air each autumn, longing for windy days to watch the leaves dance and flutter on the breeze. The leaves of the robinia are tiny and stick to the broom, and the stems lodge in the tines of the rake. The leaves of the wisteria, chestnut, and jasmine are also falling. However, the leaves are unsightly due to Guinardia, a chestnut leaf blotch.
The leaves can create piles that children can kick before street sweepers get to them. A hedgehog might find a winter home in the leaf piles. The speaker collects leaves for his compost heap, still picking up exceptional autumn leaves to press under the weight of a book. The leaves of the fig tree fall in a dramatic manner, like an avalanche. The horse chestnut trees' leaves are left to crumble to dust, enriching the root-packed ground underneath.
The amelanchier and the orange edges of the witch hazel leaves are unexpected highlights of the autumn season. The speaker has chosen the small trees in the garden with half-a-mind to autumn colour. Last year, the leaves of the beech topiaries were lost due to a stiff pruning in late autumn, but they may be left be this year. The leaves fall slowly and take a while to break down, particularly their stems.
In conclusion, the vibrant colours of autumn are a testament to the intricate interplay between tree species, pigment composition, and environmental factors. By understanding these elements, we can appreciate the beauty of autumn even more.
- The small trees in the speaker's garden, such as the Cornus kousa and Acer palmatum, are sources of vibrant autumn colors, contributing to the home-and-garden landscape during this season.
- Carotenoids, which are present in various plants and flowers, are responsible for the yellow and orange hues seen in the leaves during autumn, while anthocyanins produce red and purple colors.
- A combination of light, temperature, and soil and moisture affect the autumn colouration of trees, with cooler temperatures and optimal soil conditions promoting the formation of vibrant autumn colours.
