Agriculture Reference
In-Depth Information
Chapter 3
Quantifying Leaf Longevity
Deciduous broad leaved-forest mixed with some conifers. Midori-numa, Daisetsu-san,
Hokkaido, Japan
Defining Leaf Longevity
Leaf longevity and “leaf lifespan” are sometimes used as equivalent terms, and at other
times “leaf longevity” designates the potential longevity of leaves and “leaf lifespan”
their realized longevity. To keep things simple, we here consistently refer only to leaf
longevity, qualifying the context as may be necessary. With an emphasis on times
when a leaf can carry out its photosynthetic function, we define leaf longevity as the
period from the emergence to the fall of a leaf. Because leaf development is a continu-
ous process, a reasonably consistent operational definition of leaf appearance and
leaffall is necessary. It is impractical to include the period of leaf initiation and early
development before budburst in estimations of leaf longevity, and in any case these
earliest stages in leaf development are not directly relevant to photosynthetic function
