Fungi are important drivers of ecosystem function. Pathogens however can impair productivity stability. We are interested in determining whether there is an effect of tree species diversity on regulating foliar fungal pathogens in Suceava, Romania. We hypothesize that higher diversity mixture plots will have a lower incidence of pathogens and pathogen damage than monoculture plots. Leaf samples from selected target trees were collected between July 8 and July 18, 2013 with tree climbers and shooters. Target tree species include: Acer pseudoplatanus, Fagus sylvatica, Picea abies, and Abies alba. Leaves from two levels of the canopy were sampled; 30 from the sun-exposed upper and 30 from the lower part of the canopy, both branches from the south exposition. For conifers, 10 shoots were sampled for each of the first two years' cohorts (20 shoots total) for the upper branch and similarly for the lower branch from the south exposition. Damages were assessed based on two categories, powdery mildew and leaf spots for the broadleaved trees and two categories for the conifers, rust and needle cast.

Two objectives in task 4.6 were achieved with the sampling of fresh leaves and needles from target trees: performing damage assessment (this workbook) and collecting leaves and needles (from the 2013, current year cohort and from the 2012, previous year cohort) for molecular analysis (not in this workbook, but the leaves and needles were from the same selected trees described below) Leaves and needles were sampled from trees along gradients like diversity. From provided tree size data, the trees sorted based on DBH. The 12 largest trees based on DBH were selected from monoculture plots and 6 trees for the those trees in mixture plots. From these, 6 trees were randomly selected (Excel random number generator) in the monoculture plots and 3 trees were selected from mixture plots. Sometimes the pre-selected tree needed to be changed in the field. Leaves from broadleaved trees were selected randomly from cut branches; 30 leaves from the sun-exposed upper canopy and 30 leaves from the lower part of the canopy. Needles from conifers were selected randomly from cut branches with 10 shoots from the current year cohort and 10 shoots from the previous year cohort from the sun-exposed upper canopy, and the same scheme for the lower part of the canopy.

Exploratory Region: Romania

Between July 8, 2013 and July 18, 2013

Leaves from Acer pseudoplatanus and Fagus sylvatica, and needles from Picea abies and Abies alba

Are there circumstances that explain the precision of your measurements? Could it be that a sandstorm destroyed part of the plots in a given year?

Columns A-D provide the unique identification for each focal tree. Column E indicates the branch from which the leaves were sampled for that particular focal tree. Columns F-H indicate the number of leaves with powdery mildew (mildew), the number of leaves without powdery mildew (m.healthy), and the total number of leaves assessed for powdery mildew (m.total), respectively. Columns I-K indicate the number of leaves with leaf spots (spots), the number of leaves without leaf spots (s.healthy), and the total number of leaves assessed for leaf spots (s.total), which are the same leaves assessed for powdery mildew, respectively. Columns L and M indicate the number of shoots with rust (rust.current) and needle cast (cast.current), respectively for the current year needles (i.e. from 2013). Columns N and O indicate the number of healthy shoots (healthy.current) and total number of shoots sampled (ndl.tot.current) for that cohort of shoots, respectively. Columns P-S have the same notes the same as columns L-O, except for data from the previous year needle cohorts (indicated with ".prev") (i.e. from 2012). Column T indicates the overall number of healthy leaves or healthy current year shoots. Column U indicates the total number of leaves or current year shoots sampled. Column V indicates the number of leaves with tar spots, a subset of spots. These leaves have already been accounted for in the number of leaves with spots in Column I.