Database of Benchmark Values (DBV)

The real power of Arborcheck lies in its ability to analyse recorded data from a particular tree against a species-specific Database of Benchmark Values (DBV) for chlorophyll fluorescence and chlorophyll content.

Independent collection of the DBV data has taken place annually since 2009 by Bartlett Tree Research Laboratories from trees at Barcham Trees Nursery, the largest containerised tree nursery in Europe. Barcham originally began collecting data to offer an additional level of quality assurance to customers by providing evidence of good physiological tree health.

Leaves from several individual trees within a species/cultivar are tested for both chlorophyll fluorescence and chlorophyll content before being sent to a lab where they undergo an additional procedure known as electrolyte leakage which tests for cell wall integrity. The results of these measurements are analysed by Dr. Glynn Percival and his colleagues at Bartlett to determine the overall health and vitality of the stock on the nursery. Thanks to the strict production models employed by Barcham, the stock has been verified by Bartlett as being in optimum physiological condition.

This extensive data set is collated and integrated into Arborcheck to provide the DBV. The current database contains benchmark values for almost 400 individual species/cultivar.

Strict data collection policy

Data is collected using robust, peer reviewed research techniques according to a strict set of procedures so that we are able to guarantee that the DBV can be described as optimum. We only collect data from containerised trees since this method of nursery production offers as near as possible a perfectly controlled growth environment. For all tree types, we collect 2 years worth of data for chlorophyll fluorescence, chlorophyll content and an additional laboratory research technique called electrolyte leakage before adding the species/cultivar to the DBV. Data collection is overseen at every stage by researchers from Bartlett Tree Research Laboratories in the UK with data analysis carried out by some of the worlds leading researchers in arboriculture to ensure that the consistency and integrity of the DBV is maintained.

Ongoing data collection

Each year, the data collection exercise not only adds to the list of supported trees as new species are added to the Barcham stock list but also serves to increase the robustness of the existing datasets. The DBV currently contains almost 400 individual tree species/cultivar that Barcham Trees are able to grow in the temperate British climate. Whilst this covers a large geographical area (UK and much of Europe), as a commitment to supply Arborcheck to arborists all over the world, we have commissioned reputable independent consultants to collect data from hand-picked nurseries with projects currently ongoing in Australia, New Zealand, Hong Kong and the United States of America to screen species from different climatic regions.