Survival strategy of the endangered tree Rehd., based on C fractionation.

We conducted a field investigation and evaluation of C natural abundance to determine the growth habit and propagation strategy of Rehd., a tree species native to China that is highly endangered. The results showed that . is a K-selected strategist and pioneer species. Its narrow ecological range limits its geographical distribution, and poor fecundity limits its population size. The analysis of C natural abundance showed that . does not use organic matter for reproduction when its stand volume is less than 1.08 × 10 cm or it is less than 18.6 m tall, but it does use this strategy when it has a sufficient 1.08 × 10 cm stand volume or more or is taller than 18.6 m. If environmental conditions are not conducive (e.g., severe human disturbance, cliff edges, or fierce interspecific competition) to the continued growth of the tree, . may allocate organic matter for reproduction. Human disturbance seems to promote the population expansion of .. We provide our suggestions for the promotion and protection of . as a species.