The trend in forestry is toward shorter rotations and more complete
utiliza- tion of trees. The reasons are: (1) financial pressures to
obtain rapid returns on the forestry investment made possible by an
earlier harvest; (2) enforced harvest of young plantations to maintain a
continuing supply of cellulose for mills where wood shortages are
experienced; (3) thinning young plantations, both because they were
planted too densely initially and because thinning is done where long
rotation quality trees are the forestry goal; (4) more intensive
utilization is being done using tops and small diameter trees; and (5)
there is interest in using young (juvenile) wood for special products
because of its unique characteristics and the development of new
technologies. The largest present-day source of conifer juvenile wood is
from thinnings of plantations where millions of hectares of pine were
planted too densely. Because of the better growth rate resulting from
improved silviculture and good genetic stock, plantations will need to
be thinned heavily. As a result of this trend, young wood makes up an
increasingly larger proportion of the total conifer wood supply each
year. Large amounts of juvenile wood from hard- woods are also currently
available, especially in the tropics and subtropics, because of the fast
growth rate of the species used, which results in shorter rotations and
ess ntially all juvenile wood.