In Wolong Reserve there are a total of seven species: Phyllostachys nidularia, P. heteroclada, Sinarundinaria confusa, S. ferax, S. chungii, S. fangiana and Fargesia robustal. Of these, only two, Fargesia robusta (umbrella bamboo) and Sinarundinaria (arrow bamboo), are important to Panda ecology.

Umbrella bamboo covers a little under 25 per cent of the area 'held' by all bamboo species. It is a lover of low altitudes, being found between 1600m (5250 ft) and 2400 m (8000 ft) on the slopes and stripped plains of the mountains. Umbrella bamboo is quite a tall plant, with stems averaging 2.5 m in height, occasional specimens are over 5 m. Stem diameter can be anything up to 2.5 cm at the base, but average widths are just under 1 cm. Umbrella bamboo grows in dense clumps, with thirty to forty stems crowding into a square meter. Because of this, and the way in which its long stems become tangled as they grow, moving through umbrella bamboo stands can be very difficult, at least for humans.

By contrast, arrow bamboo is slender, rarely thicker than 0.5 cm, and much shorter than umbrella bamboo, with an average height of 1.4 m. But what it lacks in height and girth, arrow bamboo makes up for in vigour. Stems are twice as dense as those of umbrella bamboo, seventy to seventy-five stems per m sq., and its rhizomes are phenomenally active, sending out long runners that can colonise suitable habitat with surprising swiftness. In the Wolong area, arrow bamboo normally grows between 2600 and 3200 m. It grows thinly, if at all, in the more densely shaded areas, and can be entirely absent from ridges covered in rhododendron, but it flourishes almost everywhere else, standing in wide swathes of swaying stems that can blanket extensive areas. Coverage in most areas averages between 50 and 60 per cent, and can reach 90 per cent in certain areas, so dense that it may seriously impede the regeneration of the forest over long periods, denying the seedling trees light. In the most densely growing areas not even moss can grow beneath the tightly packed stems.

Evidence from other parts of China indicates that there is probably competition between the two species: in the Min Mountains of Sichuan, where arrow bamboo is absent, umbrella bamboo ma); colonize the slopes to a height of 3300 m (10 800 ft). This is a far higher altitudinal range than the species enjoys at Wolong and indicates that, where they coexist, the two species probably do compete for space.