The impact of forest management on the ecology of natural Chamaecyparis (cypress) forests
previously caused momentous disputes in Taiwan. However, the scientific questions behind this issue
have never been settled and thus require further investigations. This study was conducted in the
Chilanshan area of northeastern Taiwan, where there is a long history of forest management, and
extensive natural Chamaecyparis forests are still preserved. We investigated the ground vegetation
and naturally regenerating seedlings in stands under 4 different management regimes to compare
their plant diversity and tree regeneration. Our results showed that the diversity of ground vegetation
was higher in the old-growth forest where snags and logs had previously been harvested, while
the diversity of tree seedlings was higher in the natural old-growth forest. The lowest diversities of
ground vegetation and seedlings were both observed in the naturally regenerated stand established
after selective cutting. The natural old-growth forest was also distinct from the other stand types
in terms of the species composition. The natural regeneration of seedlings significantly differed
among stand types. The natural old-growth forest contained the greatest amount of both cypress
seedlings (all of which were Chamaecyparis obtusa var. formosana; 87%) and overall seedlings
(77%). Moreover, 91% of cypress seedlings were established on coarse woody debris, revealing a
distinct substrate preference from the other species.
Our study indicated long-term impacts of management regimes on the ground vegetation and
natural regeneration in Chamaecyparis forests. After 20~40 yr of recovery, stands that had experienced
management practices were still dissimilar to natural old-growth forests. Therefore, we
would argue that natural old-growth forests should be protected and ecologically monitored, and
that old-growth forests where snags and logs had previously been removed could offer various
vegetation stages to create more-heterogeneous habitats and thus enhance the overall biological diversity.
As for plantations and naturally regenerated stands, middle- or later-stage tending practices
should promptly be applied to improve tree growth and stand conditions.