Agriculture Reference
In-Depth Information
Fig. 3.1
Shoots of
Alnus hirsuta
in Bibai, Hokkaido, northern Japan, in mid-June (
a
) and in early
July (
b
). By mid-June four leaves (
1-4
) have fully expanded and a fifth leaf (
5
) has protruded from
the pair of bracts and is just beginning photosynthetic activity. By early July, more leaves have
been produced (
6-8
) and the first and the second leaves (
1
,
2
) have fallen. There are two leaf scars
and six leaves (third to eighth) on the shoot; the ninth leaf is just appearing, but because it is still
enclosed by bracts it is not yet counted (Kikuzawa 1980)
Fig. 3.2
Leaf survival curves for representative deciduous broad-leaved trees:
Alnus hirsuta
(
a
),
Magnolia obovata
(
b
), and
Quercus mongolica
var.
grosseserrata
(
c
).
Open circles
represent the
cumulative number of leaves that have emerged through the growing season;
closed circles
begin
with the onset of leaffall and track the number of leaves still attached at each subsequent census.
The mean leaf longevity over the period of observation is the area under the line showing the
number of attached leaves divided by the total number of emerged leaves
