Langbar Loop #12: Phenology 101 - It's All About Timing!
The 12th cache in the series, is hidden at an obvious place along the footpath running along the edge of the farmland at the top of the steep western bank of Holden Gill.
See Langbar Loop #1 for background info on the series including a map.
At the time of placing the cache, and throughout my walk around the loop I was particularly aware of the growth of plants coming into leaf and flower with the onset and progression of spring.
So here, at this fallen giant on the edge of this lovely deciduous woodland, it may be a suitable place to sit and consider some phenology!
Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation).
The word is derived from the Greek φαίνω (phainō), 'to show, to bring to light, make to appear'+ λόγος (logos), 'study, discourse, reasoning' and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle.
Examples include the date of emergence of leaves and flowers, the first flight of butterflies, the first appearance of migratory birds, the date of leaf colouring and fall in deciduous trees, the dates of egg-laying of birds and amphibia, or the timing of the developmental cycles of temperate-zone honey bee colonies.
In the scientific literature on ecology, the term is used more generally to indicate the time frame for any seasonal biological phenomena, including the dates of last appearance (eg. the seasonal phenology of a species may be from April through September).
Because many such phenomena are very sensitive to small variations in climate, especially to temperature, phenological records can be a useful proxy for temperature in historical climatology, especially in the study of climate change and global warming. For example, viticultural records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years.
In addition to providing a longer historical baseline than instrumental measurements, phenological observations provide high temporal (real-time) resolution of ongoing changes related to global warming - see short explanatory video here and see here more details of this critical phenomenon.
See also here for a fascinating presentation on the importance of phenology in the timing of tree pruning.
In relation to tree phenology . . . while much research has focused on the timing of individual plant phenological events, the sequence of such events has received considerably less attention.
Fascinating research 'Sequence of flower and leaf emergence in deciduous trees is linked to ecological traits, phylogenetics, and climate' reported in 2018 investigated the drivers and patterns of flower and leaf emergence sequence (FLS) in deciduous tree species.
It evaluated 5 hypotheses proposed to explain possible factors affecting this: cold tolerance, water dynamics, seed mass, pollination syndrome, and xylem anatomy type.
It was found that those related to species’ water dynamics and seed mass had the greatest support. The spatial pattern of FLS was found to be strongly related to minimum monthly temperature and the phylogenetic pattern was clustered among species. It was also found that species’ fruiting characteristics were the most important variables in explaining FLS.
FLS was shown to be related to a combination of plant traits and environmental tolerances. The need to expand such research to include both the timing and sequence of plant's entire phenology, in particular in relation to plant physiology and global climatic and environmental changes.
