Studies of tree recruitment are many, but they provide few general insights
into the role of recruitment limitation for population dynamics. That role
depends on the vital rates (transitions) from seed production to sapling s
tages and on overall population growth. To determine the state of our under
standing of recruitment limitation we examined how well we can estimate par
ameters corresponding to these vital rates. Our two-part analysis consists
of (1) a survey of published literature to determine the spatial and tempor
al scale of sampling that is basis for parameter estimates, and (2) an anal
ysis of extensive data sets to evaluate sampling intensity found in the lit
erature. We find that published studies focus on fine spatial scales, empha
sizing large numbers of small samples within a single stand, and tend not t
o sample multiple stands or variability across landscapes. Where multiple s
tands are sampled, sampling is often inconsistent. Sampling of seed rain, s
eed banks, and seedlings typically span <1 yr and rarely last 5 yr. Most st
udies of seeding establishment and growth consider effects of a single vari
able and a single life history stage. By examining how parameter estimates
are affected by the spatial and temporal extent of sampling we find that fe
w published studies are sufficiently extensive to capture the variability i
n recruitment stages. Early recruitment stages are especially variable and
require samples across multiple years and multiple stands. Ironically, the
longest duration data sets are used to estimate mortality rates, which are
less variable tin time) than are early life history stages. Because variabl
es that affect recruitment rates interact, studies of these interactions ar
e needed to assess their full impacts. We conclude that greater attention t
o spatially extensive and longer duration sampling for early life history s
tages is needed to assess the role of recruitment limitation in forests.