Autumn leaf colours as indicators of decomposition rate in sycamore (Acer pseudoplatanus L.)

We tested the hypothesis that there is a causal connection between autumn c olour, nutrient concentration and decomposibility of fresh leaf litter. Sam ples from patches of different autumn colours within the leaves of the deci duous tree sycamore (Acer pseudoplatanus) were sealed into litter bags and incubated for one winter in an outdoor leaf mould bed. Green leaf patches w ere decomposed faster than yellow or brown patches and this corresponded wi th the higher N and P concentrations in the former. Black patches, indicati ng colonisation by the tar spot fungus Rhytisma acerinum, were particularly high in P, but were decomposed very slowly, owing probably to resource imm obilisation by the fungus. The results supported the hypothesis and were co nsistent with a previous study reporting an interspecific link between autu mn coloration and decomposition rate. Autumn leaf colour of deciduous woody plants may serve as a useful predictor of litter decomposibility in ecosys tem or biome scale studies where extensive direct measurements of litter ch emistry and decomposition are not feasible.