. 2012 Jun 11;109(26):10398–10402. doi: 10.1073/pnas.1204157109

Table 1.

Nitrogen stocks and dynamics in plantations in lowland Costa Rica after 16 y of forest development

		Species
Stock or flux	Units	Hieronyma	Pentaclethra	Virola	Vochysia	Mean	P > F
N in plant biomass	kg⋅ha⁻¹	674 ± 53	967 ± 152	790 ± 127	1,065 ± 81	874 ± 176	0.125
Total N in detritus	kg⋅ha⁻¹	142 ± 4	147 ± 15	114 ± 8	144 ± 14	137 ± 15	0.264
Total N in soil	kg⋅ha⁻¹	14,498 ± 481^AB	12,777 ± 915^B	14,175 ± 498^B	15,914 ± 146^A	14,341 ± 1,288	0.034
Detrital N production	kg⋅ha⁻¹⋅y⁻¹
Canopy		155 ± 10^AB	197 ± 18^A	126 ± 3^B	157 ± 11^AB	159 ± 29	0.010
Fine roots		127 ± 9^A	94 ± 10^AB	75 ± 9^B	122 ± 22^AB	105 ± 24	0.038
Woody tissues		25 ± 3^BC	44 ± 9^A	13 ± 2^C	34 ± 3^AB	29 ± 13	0.004
ΔBiomass-N	kg⋅ha⁻¹⋅y⁻¹	35 ± 4^B	75 ± 11^A	51 ± 9^AB	57 ± 1^AB	54 ± 17	0.055
Total plant N uptake	kg⋅ha⁻¹⋅y⁻¹	341 ± 11^AB	409 ± 35^A	265 ± 18^B	371 ± 21^A	347 ± 61	0.011
N use efficiency	g DW⋅g N⁻¹	98 ± 6^A	74 ± 4^B	88 ± 1^AB	94 ± 2^A	88 ± 11	0.008
ΔSoil N stocks^*	kg⋅ha⁻¹⋅16 y	−1,633 ± 481^AB	−3,354 ± 915^B	−1,956 ± 498^AB	−217 ± 146^A	−1,790 ± 1,288	0.035
ΔN in plantations^†	kg⋅ha⁻¹⋅16 y	−817 ± 524^AB	−2,240 ± 1,032^B	−1,053 ± 398^AB	+992 ± 230^A	−779 ± 1,335	0.039
Soil N MRT^‡	y	43 ± 3^AB	32 ± 5^B	54 ± 5^A	43 ± 2^AB	43 ± 9	0.027

Means (±SE) within a row followed by the same superscript letter do not differ significantly among species (Tukey’s HSD, P = 0.05). Statistical test results are reported in Table S4. DW, dry weight.

*Mineral soil to 1-m depth.

^†All N in vegetation, detritus, and soil to 1-m depth.

^‡Mean residence time of N in soil, calculated as the quotient of soil N stocks (0–1 m) and total plant N uptake.