Is leaf tissue fragmented before fungal hyphae (threads) develop?
No not necessarily. Leaves are usually weakened by the growth of fungal hyphae; fragmentation follows either as a result of the activity of soil animals, OR by the weakening of the tissue following the growth of the micro-organisms, OR both. Although for ease of explanation it is the convention to regard the fragmentation of leaves by detritivores as preceding the biochemical decomposition of leaf tissue by microbial decomposers this sequential model is not strictly true. Colonisation by micro-organisms begins as soon as the dead leaves reach the soil surface. Consequently, the physical effects of growing fungal hyphae, and the weakening effects of the initial stages of biochemical action will occur at the same time as the activity of soil animals, and of non-biological processes such as expansion and contraction with temperature changes, oxidation, hydration, and leaching. Nonetheless, the main stage of biochemical decomposition, mediated through the action of microbial enzymes, does
