Once a year we take the first year undergraduates in Geography out to Wytham Woods to teach them field methods in physical geography. They are assigned a project to sub-sample and measure tree diameters, growth rates, crown dimensions, heights and light environments in our large 18 hectare research plot. The aim is to explore ideas of scaling of tree architecture and growth rates. They write up a project as a project that contributes towards their first year marks. For many it is a first introduction to practical fieldwork. This year the morning started out in beautiful autumn sunshine with the woods luminous with yellow beech and sycamore leaves, but by lunchtime the weather had descended into testing, steady, cold rain.
We have a new paper in Oecologia from our Zambian former DPhil student Royd Vinya, emerging from his DPhil work on plant hydraulic traits in wetter and drier environments in the miombo woodlands of Zambia. The paper shows that tree species with a a narrow (wetter) habitat range were more vulnerable to hydraulic cavitation range than those adapted to drier sites, which had broader ranges. We observed a strong trade-off between vessel conductivity and resistance to cavitation, suggesting that tree hydraulic architecture is one of the decisive factors setting ecological boundaries for principal miombo species. While vessel diameters correlated weakly cavitation vulnerability, it was vessel length that was positively and most significantly correlated. This paper gives us insights into the role and flexibility of plant hydraulic architecture in determining species' ecological ranges.
Vinya R., Malhi Y., Fisher J.B., Brown N., Brodribb T.J., Aragao L.E. (2013) Xylem cavitation vulnerability influences tree species’ habitat preferences in miombo woodlands Oecologia 173:711–720 DOI 10.1007/s00442-013-2671-2. Supplementary Table.
We have a new paper our in the Journal of Geophysical Research - Biogeosciences, on the net primary productivity of an old growth dipterocarp forest at Lambir, Sarawak, Borneo. This emerges from the DPhil thesis of our former student Kho Lip Khoon. Up until now all our published studies on productivity have been from Amazonia. This is the first of a wave of results that will be emerging from our current work in Asia and Africa. More papers will also been emerging from Khoon's work in Lambir. Overall this work shows that productivity is higher on the clay soils of Lambir, but lower on the sandy soils, and on the clay soils is higher than observed in Amazonia.
Kho, L. K., Y. Malhi, and S. K. S. Tan (2013), Annual budget and seasonal variation of aboveground and belowground net primary productivity in a lowland dipterocarp forest in Borneo, J. Geophys. Res. Biogeosci., 118, 1282–1296, doi:10.1002/jgrg.20109
I have stumbled across this great Japanese word: shinrinyoku, translated as "forest bathing". This is the act of going into a forest to immerse yourself in the greenery. Here is a Wikipedia article on this, and there is a website dedicated to this.
I personally have always had an almost overpowering sense of well-being and euphoria when walking through a forest (something that underpins my love of fieldwork in rainforests), This is something I have always attributed to a psychological response to being surrounded by the intricacies, mysteries and majesty of nature. There are some claims that there are direct (non-psychological) health benefits, with the immune system boosted by anti-bacterial volatiles emitted from trees, though I have not read enough to judge whether there is convincing medical evidence for this. If true, this would be a fascinating ecosystem service provided by woodlands and forests
For the long weekend we are visiting friends in the Loire Valley in France. There we come across the Château de Clos Lucé, next to the magnificent Chateau de Amboise. This was where Leonardo da Vinci spent the final three years of his life, as an honoured guest of the King of France. The place is a celebration of his inventions, but also of his keen empirical eye for nature, the magnificent gardens and explanations of how he combined a meticulous eye for detail and pattern with a celebration of natural forms. I had not previously appreciated what a botanist this ultimate Renaissance Man had been.
Yadvinder Malhi is an ecosytem ecologist and Professor of Ecosystem Science at Oxford University