Jl. Innes, AN ASSESSMENT OF THE USE OF CROWN STRUCTURE FOR THE DETERMINATION OF THE HEALTH OF BEECH (FAGUS-SYLVATICA), Forestry, 71(2), 1998, pp. 113-130
Considerable difficulties exist with the standardization and interpret
ation of assessments of crown defoliation, the most commonly used inde
x of tree health in Europe. A variety of other measures of crown condi
tion exist and one that has received considerable attention, particula
rly for beech (Fagus sylvatica L.), is crown architecture. Four stages
of crown development are generally recognized, termed the exploration
, degeneration, stagnation and resignation phases. An analysis of the
available literature suggests that there are a number of problems surr
ounding the use of these classes to describe trees. Although the class
es probably reflect the progressive deterioration of the crown of a tr
ee, there are many factors that affect the assessment and interpretati
on of the scores, as is the case for defoliation estimates. Measuremen
ts of shoot elongation in the upper crown provide a more useful measur
e, but involve destructive sampling and are very time-consuming. Conse
quently, while crown architectural assessments should only be incorpor
ated into large-scale inventories of forest health with great care, th
ey may be useful for case studies involving the detailed examination o
f a small number of sites.