Predicting wood density of growth increments of Douglas-fir stands in New Zealand

Table 2 Outerwood basic density of 50-mm core samples, mean ring number from pith, predicted basic density of ring 30 from pith, and environmental variables at 32 Douglas-fir sites used to develop sub-model 1

Site number	Mean ring number from pith	Measured outerwood density (kg m⁻³)	Predicted wood density of reference ring (ring 30 from pith) (kg m⁻³)	Mean annual temperature (°C)	Soil C (%)	Soil N (%)	Soil C/(N − 0.014)
1	19.2	384	399	8.9	2.53	0.200	13.6
2	20.1	386	398	7.9	4.36	0.307	14.9
3	21.8	393	399	10.3	3.09	0.214	15.5
4	18.8	319	333	7.8	5.57	0.380	15.2
5	16.9	408	430	10.1	3.56	0.235	16.1
6	36.8	426	423	10.9	11.56	0.749	15.7
7	18.1	381	397	9.6	5.46	0.342	16.6
8	27.4	491	491	12.0	13.15	0.757	17.7
9	15.8	493	526	12.2	6.14	0.352	18.2
10	21.8	369	376	8.1	5.17	0.295	18.4
11	42.1	444	440	11.7	10.85	0.612	18.1
12	29.2	489	489	12.5	4.64	0.262	18.7
13	40.3	454	450	11.5	5.99	0.334	18.7
14	38.1	497	494	13.3	6.51	0.361	18.8
15	19.9	406	420	9.8	1.99	0.107	21.4
16	24.2	461	466	11.3	3.12	0.166	20.5
17	19.6	421	437	9.5	5.18	0.262	20.9
18	43.3	420	415	9.8	5.61	0.279	21.2
19	14.3	446	482	12.9	4.43	0.217	21.8
20	23.3	369	372	8.3	4.25	0.205	22.3
21	20.6	411	422	9.4	4.94	0.230	22.9
22	15.9	419	447	10.8	6.70	0.290	24.3
23	31.3	366	361	7.3	11.09	0.452	25.3
24	34.7	420	415	7.9	3.57	0.144	27.5
25	34.1	401	396	7.6	4.15	0.166	27.3
26	34.4	418	413	7.6	4.19	0.156	29.5
27	21.1	485	495	11.6	3.38	0.117	32.8
28	39.5	505	501	10.4	3.79	0.129	33.0
29	12.8	373	412	9.3	6.86	0.322	22.3
30	13.6	362	403	8.2	3.99	0.234	18.1
31	23.7	488	493	11.9	6.25	0.328	19.9
32	26.5	462	463	12.0	8.04	0.424	19.6