Wood density and carbon and nitrogen concentrations in deadwood of Chamaecyparis obtusa and Cryptomeria japonica

Figures & data

Figure 1. Locations of the sampling prefectures for Chamaecyparis obtusa (Sieb. et Zucc.) Endl. (squares) and Cryptomeria japonica D. Don (circles).

Table 1. Location, management history, and climate conditions of the study stands in 12 prefectures

Tree species	Region	Number of sites	Sampling area		Elevation (m a.s.l.)	Stand age (years)	Years since death	Mean annual temperature (°C)	Mean annual precipitation (mm)	Maximum snow depth (cm)
			Latitude, N.	Longitude, E.	Min∼Max		Min∼Max	Min∼Max	Min∼Max	Min∼Max
Chamaecyparis obtusa (Sieb. et Zucc.) Endl.
	Niigata	15	37°37′ ∼ 38°32′	138°49′ ∼ 139°38′	60 ∼ 155	12 ∼ 25	1 ∼ 6	11.1 ∼ 12.8	1786 ∼ 2654	5 ∼ 186
	Saitama	8	36°00′ ∼ 36°05′	138°52′ ∼ 139°09′	430 ∼ 930	20 ∼ 46	1 ∼ 15	8.5 ∼ 11.5	1150 ∼ 1495	9 ∼ 11
	Kyoto	8	35°14′ ∼ 35°20′	135°05′ ∼ 135°30′	80 ∼ 450	27 ∼ 38	1 ∼ 20	11.1 ∼ 13.4	1450 ∼ 1596	21 ∼ 26
	Hiroshima	8	34°31′ ∼ 35°03′	132°51′ ∼ 133°10′	295 ∼ 748	17 ∼ 41	1 ∼ 13	9.3 ∼ 12.7	1284 ∼ 2079	8 ∼ 75
	Mie	8	34°20′ ∼ 34°24′	136°20′ ∼ 136°24′	135 ∼ 693	29 ∼ 53	0 ∼ 13	10.8 ∼ 14.0	2132 ∼ 2682	2 ∼ 3
	Nagasaki	19	32°49′ ∼ 32°58′	130°01′ ∼ 130°11′	50 ∼ 820	24 ∼ 44	1 ∼ 18	10.9 ∼ 16.0	2156 ∼ 2837	1 ∼ 9
Cryptomeria japonica D. Don
	Akita	10	39°42′ ∼ 40°16′	140°24′ ∼ 140°41′	110 ∼ 450	28 ∼ 76	1 ∼ 20	7.4 ∼ 9.5	1738 ∼ 2279	67 ∼ 205
	Ibaraki	15	36°35′ ∼ 36°36′	140°30′ ∼ 140°34′	130 ∼ 390	32 ∼ 46	1 ∼ 17	10.9 ∼ 12.2	1321 ∼ 1487	16 ∼ 17
	Toyama	8	36°33′ ∼ 36°33′	137°10′ ∼ 137°11′	165 ∼ 210	23 ∼ 26	0 ∼ 6	8.2 ∼ 12.3	1367 ∼ 2486	30 ∼ 106
	Chiba	24	35°09′ ∼ 35°15′	139°57′ ∼ 140°03′	110 ∼ 300	19 ∼ 50	1 ∼ 10	13.3 ∼ 14.0	1709 ∼ 1895	11 ∼ 12
	Yamaguchi	8	34°05′ ∼ 34°14′	131°22′ ∼ 131°32′	150 ∼ 390	21 ∼ 46	1 ∼ 18	12.4 ∼ 14.1	1707 ∼ 2122	7 ∼ 20
	Oita	8	33°08′ ∼ 32°54′	131°33′ ∼ 131°54′	130 ∼ 470	24 ∼ 34	1 ∼ 13	12.6 ∼ 15.5	1673 ∼ 2257	2 ∼ 4
a.s.l., above sea level.

Table 2. Criteria determining the decay classes of fallen logs

Decay class	Appearance of decaying fallen logs
1	No decay
	Fine twigs remaining
	Bark completely remaining
	Wood is clear or blue, slightly stained
	No moss
2	Slightly decayed
	No fine twigs
	Most bark present
	Sapwood rotted but heartwood mostly sound
3	Moderately decayed, but fallen log could support itself
	Branch stubs remaining
	Some bark present
	Sapwood and heartwood show strong signs of decay
4	Fallen log could no longer support itself
	All bark often absent
	Sapwood often absent and deep red-brown heartwood could be crumbled manually
5	Wood resembles red powder with a disassembled structure
	The bark is completely absent
	The cross section of the bole is no longer round, but elliptical

Figure 2. Wood density of fallen logs of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. (squares) and Cryptomeria japonica D. Don (circles) in decay classes 1–4. Bars are standard deviations. Different letters indicate significant differences (P < 0.05).

Table 3. Results of a two-way analysis of variance for the wood density of fallen logs by decay class and tree species, and their interaction

Dependent variable	Fixed factor	Df	Mean Sq	F value	P value
Wood density	Decay class	3	1304965	403.95	<0.001
	Tree species	1	635571	196.74	<0.001
	Decay class × Tree species	3	22449	6.95	0.001
	Residuals	1515	3231
Df, degrees of freedom.

Figure 3. Wood density of fallen logs changed with log diameter in decay class 1 (filled circles), decay class 2 (open circles) and decay class 3 (triangles) of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. and Cryptomeria japonica D. Don.

Table 4. Results of an analysis of covariance for the wood density of fallen logs by region and log diameter, and their interaction, in each decay class and tree species

Tree species	Decay class	Factor	Df	Mean Sq	F value	P value
Chamaecyparis obtusa (Sieb. et Zucc.) Endl.	1	Region	5	7115	2.82	0.017
		Diameter	1	127373	50.54	<0.001
		Region × Diameter	5	2473	0.98	0.433
		Residuals	376	2520
	2	Region	5	10688	3.46	0.004
		Diameter	1	34548	11.18	0.001
		Region × Diameter	5	2079	0.67	0.639
		Residuals	181	3091
	3	Region	4	46305	14.41	<0.001
		Diameter	1	6407	1.99	0.160
		Region × Diameter	4	7271	2.26	0.104
		Residuals	35	3214
	4	Region	3	11701	15.74	0.018
		Diameter	1	3937	5.30	0.101
		Region × Diameter	1	20191	27.16	0.011
		Residuals	3	744
Cryptomeria japonica D. Don	1	Region	5	5892	2.44	0.032
		Diameter	1	68447	28.29	<0.001
		Region × Diameter	5	3834	1.59	0.162
		Residuals	577	2420
	2	Region	5	10523	3.11	0.010
		Diameter	1	14047	4.16	0.046
		Region × Diameter	5	5561	1.65	0.160
		Residuals	186	3381
	3	Region	5	15668	5.14	0.001
		Diameter	1	562	0.19	0.678
		Region × Diameter	5	3308	1.09	0.365
		Residuals	65	3048
	4	Region	4	11286	1.42	0.277
		Diameter	1	2783	0.35	0.553
		Region × Diameter	3	7249	0.91	0.449
		Residuals	15	7950
Df, degrees of freedom.

Figure 4. Fallen log carbon concentrations of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. (squares) and Cryptomeria japonica D. Don (circles) in decay classes 1–4. Bars are sample standard deviations. Different letters indicate significant differences (P < 0.05).

Table 5. Results of a two-way analysis of variance for the carbon concentrations of fallen logs by decay class and tree species, and their interaction

Dependent variable	Fixed factor	Df	Mean Sq	F value	P value
Carbon concentration	Decay class	3	0.85	4.53	0.005
	Tree species	1	12.15	64.98	<0.001
	Decay class × Tree species	3	2.11	11.28	<0.001
	Residuals	424	0.19
Df, degrees of freedom.

Figure 5. Concentrations of (a) carbon and (b) nitrogen changed with diameter in decay class 1 (filled circles), decay class 2 (open circles) and decay class 3 (triangles) of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. and Cryptomeria japonica D. Don.

Table 6. Results of an analysis of covariance for the carbon concentrations of fallen logs by region and log diameter, and their interaction, in each decay class and tree species

Tree species	Decay class	Factor	Df	Mean Sq	F value	P value
Chamaecyparis obtusa (Sieb. et Zucc.) Endl.	1	Region	5	1.76	61.19	<0.001
		Diameter	1	0.66	23.04	<0.001
		Region × Diameter	5	0.04	1.33	0.260
		Residuals	94	0.03
	2	Region	5	0.12	2.43	0.054
		Diameter	1	0.01	0.11	0.743
		Region × Diameter	4	0.03	0.58	0.674
		Residuals	43	0.05
	3	Region	3	0.34	0.87	0.502
		Diameter	1	0.04	0.10	0.724
		Region × Diameter	3	0.09	0.23	0.756
		Residuals	8	0.40
Cryptomeria japonica D. Don	1	Region	5	6.82	135.81	<0.001
		Diameter	1	1.02	20.33	<0.001
		Region × Diameter	5	0.04	0.88	0.511
		Residuals	157	0.05
	2	Region	5	1.84	54.35	< 0.001
		Diameter	1	0.47	13.83	<0.001
		Region × Diameter	4	0.08	2.32	0.068
		Residuals	47	0.03
	3	Region	4	0.80	12.87	<0.001
		Diameter	1	0.00	0.01	0.946
		Region × Diameter	3	0.01	0.19	0.920
		Residuals	12	0.06
Df, degrees of freedom.

Figure 6. Fallen log nitrogen concentrations of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. (squares) and Cryptomeria japonica D. Don (circles) in decay classes 1–4. Bars are sample standard deviations. Different letters indicate significant differences (P < 0.05).

Table 7. Results of a two-way analysis of variance for the nitrogen concentrations of fallen logs by decay class and tree species, and their interaction

Dependent variable	Fixed factor	Df	Mean Sq	F value	P value
Nitrogen concentration	Decay class	3	2.05 E−02	40.86	<0.001
	Tree species	1	3.62 E−04	0.72	0.399
	Decay class × Tree species	3	2.30 E−03	4.59	0.007
	Residuals	424	5.02 E−04
Df, degrees of freedom.

Table 8. Results of an analysis of covariance for the nitrogen concentrations of fallen logs by region and log diameter, and their interaction, in each decay class and tree species

Tree species	Decay class	Factor	Df	Mean Sq	F value	P value
Chamaecyparis obtusa (Sieb. et Zucc.) Endl.	1	Region	5	2.71 E−03	21.09	<0.001
		Diameter	1	4.30 E−03	33.52	<0.001
		Region × Diameter	5	1.52 E−04	1.18	0.319
		Residuals	94	1.28 E−04
	2	Region	5	2.95 E−03	34.31	<0.001
		Diameter	1	2.05 E−03	23.81	<0.001
		Region × Diameter	4	2.60 E−04	3.02	0.033
		Residuals	43	8.60 E−05
	3	Region	3	2.33 E−03	2.70	0.119
		Diameter	1	3.57 E−03	4.14	0.078
		Region × Diameter	3	9.25 E−04	1.07	0.404
		Residuals	8	8.62 E−04
Cryptomeria japonica D. Don	1	Region	5	3.79 E−03	20.79	<0.001
		Diameter	1	4.23 E−03	23.20	<0.001
		Region × Diameter	5	2.01 E−04	1.10	0.369
		Residuals	157	1.82 E−04
	2	Region	5	5.51 E−03	47.59	<0.001
		Diameter	1	2.91 E−03	25.17	<0.001
		Region × Diameter	4	2.37 E−04	2.05	0.111
		Residuals	47	1.16 E−04
	3	Region	4	6.02 E−04	0.49	0.721
		Diameter	1	1.46 E−03	1.18	0.301
		Region × Diameter	3	9.20 E−04	0.74	0.478
		Residuals	12	1.24 E−03
Df, degrees of freedom.

Number of disks collected in each decay class and region for the measurement of wood density. Numbers of samples submitted to carbon (C) and nitrogen (N) analysis are presented in parentheses

		Decay class
Tree	Region	1	2	3	4	5
Chamaecyparis obtuse (Sieb. et Zucc.) Endl.	Niigata	115(30)	8(1)	0(0)	0(0)	0(0)
	Saitama	16(5)	37(11)	2(0)	5(3)	0(0)
	Kyoto	45(13)	21(6)	15(4)	1(0)	0(0)
	Hiroshima	42(13)	15(5)	6(2)	0(0)	0(0)
	Mie	52(16)	31(9)	5(3)	1(1)	0(0)
	Nagasaki	118(30)	81(22)	17(7)	2(1)	0(0)
Cryptomeria japonica D. Don	Akita	56(18)	35(10)	13(4)	4(1)	0(0)
	Ibaraki	175(48)	10(3)	7(1)	0(0)	0(0)
	Toyama	70(19)	39(9)	3(0)	4(1)	0(0)
	Chiba	163(54)	99(31)	34(9)	1(0)	0(0)
	Yamaguchi	57(17)	5(1)	10(4)	4(0)	0(0)
	Oita	68(16)	10(4)	10(3)	11(2)	5(0)