An important aspect of the sustainable management of tropical rain
forests is the maintenance of genetic diversity within populations of
commercial tree species. Logging may reduce genetic variation directly
and may also affect genetic processes, leading possibly to genetic
erosion and ultimately even species extinction. It is, however,
impractical for the forest manager to make meaningful measurements of
genetic variation and they are therefore inappropriate for use as
indicators of sustainable forest management. We propose that the
application of well-known silvicultural principles is the most practical
way of preventing rapid loss of genetic diversity.
Most tropical rain forest tree species have many more individuals below
the minimum size for commercial exploitation than above. The genetic
diversity of these species will be little affected by logging, as the
stems removed form only a small fraction of the total population.
Similarly, for most species, disruption of normal mating patterns will
either not occur or be transient, because reproduction commences at
sizes well below felling limits, or because, after logging, juveniles
will be recruited to the sexually mature size classes.
Strongly light-demanding species with a commercial value are most likely
to suffer loss of genetic diversity from logging. Characteristically,
these have populations in which only a small proportion of the total
population lies in small size classes. In order to conserve genetic
diversity, pre-felling silvicultural treatments will be required to
increase the survival and growth of juveniles. Ecological and genetic
research needs to focus on these light-demanding species.
Jennings, S.B.; Brown, N.D.; Boshier, D.H.; Whitmore, D.C.; Lopez, J.do C.A. Ecology provides a pragmatic solution to the maintenance of genetic diversity in sustainably managed tropical rain forests. Forest Ecology and Management (2001) 154 (1-2) 1-10. [DOI: 10.1016/S0378-1127(00)00637-X]
Ecology provides a pragmatic solution to the maintenance of genetic diversity in sustainably managed tropical rain forests