Measuring forest phenology

Helping to establish two new International Phenology Gardens (IPGs) at Westonbirt Arboretum and Bedgebury Pinetum

News from Forest Research: June 2010

Photos of the forest canopy in a research forest in the south of England taken in May 2010 and May 2009 from a camera mounted on a tower with a hemispherical lens pointing downwards Phenology is the study of the timing of natural growth events; for example budburst, flowering, fruiting and autumn leaf fall. As weather conditions affect these processes, the changes in their timing have provided evidence of the effects of climate change. We established an IPG at our Headley research nursery in 1967 and have a large phenological dataset.

Phenological observations also play an important role in the EU-funded FutMon long-term monitoring programme and in our other climate change adaptation research work.

Daily manual observation of trees is often impractical, particularly in remote locations, resulting in a lack of precision about the timing of events. In 2009, a project using automatic digital cameras was started with Toshie Mizunuma of the University of Edinburgh. Two different camera systems have been mounted on a tower in a research forest in the south of England, one with a hemispherical lens pointing downwards and the second using a conventional lens looking across the top of the canopy. Both systems capture hourly images throughout the growing season.

At this stage, important differences between the two systems are clear: whilst the hemispherical lens is ideal for the quantitative assessments, the conventional lens seems better suited as a replacement for manual observations. We are also measuring the uptake or loss of carbon dioxide and other greenhouse gases (GHG) at the same site. This will allow us to examine the relationship between GHG fluxes and the variation in forest phenology, helping to improve our understanding of the environmental factors controlling forest/atmosphere GHG exchange.

More information on FutMon and phenology.

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This and other news stories can be found in the June 2010 issue of FR News, our online newsletter.