Genetic consequences of harvest in a mature second-growth stand of black walnut (Juglans nigra L.)

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Table II

Effect of simulated diameter limit harvests on genetic diversity and their level of significance. Before treatment level of allelic richness for the Long Hollow walnut population was 18.08 across all loci with a total 217 alleles.

	Treatment intensity of diameter-limit harvests (cm)

	> 60	> 50	> 40	> 30
Trees harvested (%)	7	23	44	70
Allelic richness^a	17.8^b^NS	17.5 ^NS	17.1^NS	15.4^NS
Alleles retained (%)	99	97	94	85
F _ST ^c	0.0004	0.0006	0.0011	0.0007
D ^d	0.0505	0.0238	0.0198	0.0211

Allelic richness among the residual black walnuts after the simulated removal of the treatment trees.

NS = not significant (α = 0.05); one tailed T-test for the observed reduction in allelic richness under the null hypothesis that the diameter-limit harvest did not differ from a random harvest of equal intensity (based upon the distribution of outcomes from 10000 random harvests).

Estimated F_ST between the pre- and post-harvest populations.

Nei’s 1972 genetic distance values between the pre- and post-harvest populations.