Recensus of the Great Plot at Wytham Woods.

We have just completed a full recensus of our 18 ha plot in Wytham Woods, where we are tracking around 20,000 trees (all trees with greater than 1 cm stem diameter). The plot was set up in 2008, and then remeasured in 2010. Now a team of six people are remeasuring it six years later, working all day five days a week for a couple of months. This measurement is particularly important in establishing the long-term dynamics of the plot (what trees are growing fast, what trees are doing OK, what trees are dying). It is also at a critical time, because ash dieback is likely to arrive in Wytham Woods some time over the next couple of years. Ash trees account for around one third of the trees in the plot, and if many of them die off, as seems likely over the next few years, it will have major consequences for the structure and ecology of the woods. Currently ash is the best performing of the most common tree species, and accounts for a large proportion of the increasing biomass and carbon sink in Wytham, an increase that is large a result of relative "abandonment of the woodlands following intensive use in the first half of the 20th century.. This sink may well turn into a carbon source within the next decade. Waves of pathogen are part of the natural long term ecology of a forest, but the forces of global interconnectedness and movement of goods and people mean that the frequency of arrival of new pathogens has greatly increased. This may well be the most important source of contemporary and future change in temperate woodlands.

The data collected form this census are freely available to researchers. Please contact me if you would like to use these data.

Many thanks to the amazingly thorough and efficient census team, comprising Rebecca Banbury-Morgan, Micol Chiesa, Alex Morrice, Claire Paulus, Cian McGlinchy, Angelica Martinez Bauer and coordinated by Sam Butt.

The Wytham Woods plot forms part of a global network of plots, the Forests Global Earth Observatory (ForestGEO), coordinated by the Smithsonian Institution. There are similar temperate plots across North America, China and other parts of Europe.