Crown architecture in Quercus petraea and Q. robur: the fate of buds and shoots in relation to age, position and environmental perturbation
作者:G.H. Bicl-Sorlin
DOI:10.1093/forestry/73.4.331
日期:2000.4.1
Shoot and bud dynamics of peripheral crown portions of mature pedunculate and
sessile oak trees ( Quercus robur L., Q.
petraea (Matt.) Liebl.) were monitored over almost three vegetation
periods. The formation and shedding of buds and extension units (eus) was mapped
in the form of simplified drawings. Branches were additionally subjected to
manipulative treatments simulating herbivore (defoliation at different times,
loss of certain bud types) and abiotic damage (artificial acid rain) and the
effects on branch architecture analysed. Branch characteristics, such as
branching order and age structure, had a large influence on the growth and
dynamics of peripheral branch portions, even greater than that of the
manipulative treatments, with the exception of spring defoliation and shoot tip
removal, which led to increased shoot shedding. In order to quantify the
observed changes in crown structure with time, new measures were introduced: the shedding ratio corresponds to the number of shed eus
divided by the total number of eus present and produced since a given starting
point. The vitality ratio was defined as the total number of eus produced in 1
year, divided by the total number of eus shed during the same time. The vitality ratio could thus be – on a small scale – the
quantitative measure of Roloff's vitality classes (Roloff, 1987, 1988,
1989).
成熟的白栎(Quercus robur L.)和山栎(Q. petraea (Matt.) Liebl.)树木周边树冠部分的抽枝和芽动态在近三个生长季内进行了监测。芽的形成和脱落以及延伸单位(eu)的变化以简化的图形形式进行了记录。枝条还受到模拟 herbivore(在不同时间进行的落叶、某些芽类型的丧失)和非生物损伤(人工酸雨)的操作性处理,并分析了对枝条结构的影响。枝条特征,如分枝顺序和年龄结构,对周边枝条部分的生长和动态有很大影响,甚至超过了操作性处理的影响,春季落叶和顶芽去除除外,这两者导致了芽的脱落增加。为了定量观察到的树冠结构随时间变化的新措施被提出:脱落比率对应于脱落的eu数量与自给定起点以来存在和产生的eu总数的比值。活力比率被定义为在1年内产生的eu总数除以同一时间内脱落的eu总数。因此,活力比率可以在小范围内作为Roloff的活力等级的定量衡量标准(Roloff, 1987, 1988, 1989)。