Bamboos are often major understory members of Asian coniferous forests in which (among other roles) they can effectively perpetuate the inhibition model of succession for decades. Coniferous forests in the U.S. Pacific Northwest bear striking floristic and physiognomic similarity to these Asian coniferous forests, although they are devoid of native bamboos. With acceleration in the number and extent of commercial importations of temperate Asian bamboos into North America, we asked (i) whether any of these newly introduced species could become invasive in Pacific Northwest forests and (ii) whether potentially invasive bamboos share traits or attributes that would serve as reliable predictors of problematic bamboo importations.
We examined the response of 10 commercially available rhizomatous, monopodial (running) bamboo species native to temperate Asia and one native North American bamboo (Arundinaria gigantea) under light levels (50%, 70% and 90% light reduction) inclusive of the light regimes in late seral Pacific Northwest forest understories. Light response curves for these species were generated with an LI-6400 portable gas exchange system (Li-Cor, Inc).
Results/Conclusions
Several Asian bamboos species (Pleioblastus distichus, Sasa palmata, Sasa kurilensis, Sasaella ramosa) produced photosynthetic rates ranging from 6.91 – 10.56 μmol O2 m-2s-1, even under 90% shade. Other species (Bashania fargesii, Phyllostachys angusta, Phyllostachys nuda) showed no difference in photosynthetic response among treatments. Two temperate Asian bamboo species, Pleioblastus chino, and Pseudosasa japonica showed significantly lower photosynthesis under the lowest light, but no differences between 50% shade and 70% shade. The native Arundinaria gigantea had lower productivity with progressively deeper shade. The shade encountered in a diverse array of Pacific Northwest forest understories does not appear to be a limiting factor for eight of the ten temperate Asian bamboo species we evaluated. If these temperate Asian bamboos were to escape into any of these forests, their fate would depend on factors other than limited light.
