Many studies have shown that agroforestry tree prunings can supply suf
ficient nutrients to meet crop demand, with the exception of phosphoru
s. The potential of these organic inputs to supply nutrients depends o
n their resource quality. Various indices have been developed to predi
ct decomposition and nitrogen release patterns of tree prunings. To da
te the (lignin + polyphenol):N ratio seems to be the most robust ratio
for predicting mass loss and nitrogen release. However, no critical v
alue can be given because of the different methods used to analyze pol
yphenols. Suggested areas of future research include development of ro
bust indices for predicting plant litter quality, decomposition patter
ns of belowground litter (roots), residual effects of tree biomass add
itions, and effects of adding mixtures of organic materials of contras
ting quality. The overall challenge is to develop ways of managing org
anic matter decomposition to optimize short-and long-term release of n
utrients and the maintenance of soil organic matter.