Figure 5. K-function envelopes and Diggle-Cressie-Loosmore-Ford
(DCLF) test p-values weighted by diameter of trees for select sites in
the OK all redcedar and oak dataset. Dashed red lines represent
the theoretical Poisson distribution. Grey shaded sections are 95%
acceptance envelopes. The black line illustrates the empirical
K-function. Departure of the black line from the envelope signify a
non-random distribution where points above indicate clustering and below
indicate overdispersion.
Dixon contingency-table and the Monte Carlo segregation tests between
species (redcedar, Quercus , and deciduous trees) and size classes
of trees (DBH < 2.5 cm vs DBH > 2.5 cm) revealed
significant segregation within certain study sites. In the OK all
trees dataset, Monte Carlo tests of overall segregation between types
of species were significant or near significant for site 1 (p = 0.05),
site 3 (p = 0.1), site 4 (p = 0.1), site 6 (p = 0.1), site 7 (p = 0.05),
site 8 (p = 0.1), site 9 (p = 0.05), and site 12 (p = 0.05). Dixon
contingency-table tests for overall segregation largely agreed with the
Monte Carlo tests, with significant or marginally significant findings
in sites 1, 3, 7, 9, 12 (see Table S4). In the OK all treesdataset, deciduous trees tended to be segregated from redcedar andQuercus (sites 3, 7, 9, 12). Similarly, Quercus trees were
segregated away from redcedar and deciduous trees (sites 1, 12).
Redcedar showed no evidence of segregation from either Quercus or
other deciduous trees in the OK all trees dataset. In theOK living trees dataset, deciduous trees tended to aggregate with
other deciduous trees (sites 3, 7, 12). In site 12, redcedar andQuercus tended to be segregated from other species. In theOK living trees dataset, Monte Carlo tests of overall segregation
between types of species were significant for sites 1 (p = 0.005), 3 (p
= 0.015), 4 (p = 0.045), 7 (p = 0.01), and 12 (p = 0.005). Dixon tests
of overall segregation in the OK living trees dataset generally
agreed with these findings, with overall segregation being significant
or marginally significant at sites 3, 7, and 12 (see Table S4; see also
Table S5 In the OK all trees and living trees datasets,
small trees were more commonly found near large trees in sites 2 and 12,
and large trees were repelled from other large trees in site 13. The
Dixon test for overall segregation based on tree size was found to be
marginally significant at sites 2, 12, and 13. Monte Carlo tests of
segregation based on tree size differed slightly different from the
Dixon test results, with no sites having significant segregation.