F. Hapla et J. Saborowski, QUANTIFICATION OF HEARTWOOD VOLUMES IN CO NIFERS WITH OBLIGATORY HEARTWOOD FORMATION, Holz als Roh- und Werkstoff, 52(3), 1994, pp. 205-209
The determination of the heartwood portion in trees is often the subje
ct of biological research. So far the most frequent methodical startin
g point was generally limited to the measuring of cross sections in di
fferent stem heights. The aim of the present study was to determine as
accurately as possible the volume of heartwood in the stem by means o
f a small number of disks. In the course of our investigation the rota
tion volumes of stem and heartwood curves of young Douglas-fir trees w
ere calculated and compared by means of higher grade polynomes as well
as spline-functions. The presented mathematical formulation proved as
specially suited to conifers with obligatory coloured heartwood, beca
use these species have certain symmetric properties of heartwood forma
tion in contrast to the trees with optional heartwood formation. most
of the harvesting activities in Douglas-fir stands in Germany concern
young plantations. Therefore, the knowledge about the heartwood propor
tion as a result of silvicultural treatments and of harvesting strateg
ies could promote the market of this problematic small-sized Douglas-f
ir grade.