Silva Fennica

Table 1. Geographical position, altitude (meters above sea level), site index (Hägglund 1974) and year of stand establishment of the study sites used to compare silvicultural regime types (Dense/Sparse = a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning, Dense = a continuous high stand density and Sparse = a continuous low stand density).
Regime type	Site name	Geographical position	Alt. (m.a.s.l.)	SI (H₁₀₀)	Year of stand establishment
Dense/Sparse	Svartberget (SVA)	64°14´N, 19°46´E	210	23	1948
	Svartberget	64°14´N, 19°46´E	210	23	1948
	Norrliden (NOR)	64°21´N, 19°46´E	240	21	1956
Dense	Svartberget	64°14´N, 19°46´E	210	23	1948
Dense	Kulbäcksliden (KUL)	64°10´N, 19°35´E	260	22	1934
Sparse	Åsele (ÅSE)	64°14´N, 17°33´E	330	23	1964
Sparse	Åheden (ÅHE)	64°09´N, 19°40´E	195	19	1948

Table 2. Characteristics of all sample trees included in the study. Site abbreviations are explained in Table 1. D_BH = diameter at breast height; D_GC = diameter at the lowest living branch (not surrounded by two dead branch whorls) of the green crown; D₇₀ = diameter at 70% of total tree height. Dense/Sparse = a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning, Dense = a continuous high stand density, and Sparse = a continuous low stand density. 300L = thinning leaving the 300 largest trees ha^–1; 300S = thinning leaving the 300 smallest trees ha^–1; P600 = PCT to 600 stems ha^–1 at a dominant height of 5m; NT = no thinning; NP = no PCT; 3M = 3 m spacing; 10M = 10 m spacing.
Regime type	Treatment	Site	No. of year rings at breast height	Height (m)	Height to living crown (m)	Height to living crown (% of tree height)	D_BH (cm)	D_GC(cm)	D₇₀(cm)
Dense/ Sparse	300S	SVA	46	14.3	6.1	42.7	19.3	14.6	9.7
		SVA	47	14.7	7.6	51.7	18.2	13.0	9.1
		SVA	46	12.1	6.7	55.4	15.0	10.2	8.1
	300L	SVA	50	16.7	5.5	32.9	23.8	20.4	11.1
		SVA	52	17.1	6.4	37.4	27.0	20.5	12.9
		SVA	46	14.1	6.0	42.5	20.5	16.6	10.3
	P600	NOR	42	17.6	7.2	40.9	22.4	18.5	11.6
		NOR	43	18.6	9.9	53.2	18.5	12.5	9.1
		NOR	43	17.6	8.9	50.6	20.3	14.5	10.2
Dense	NT	SVA	48	18.6	10.5	56.4	16.7	9.7	7.7
		SVA	47	15.9	8.5	53.5	14.1	9.5	6.9
		SVA	46	17.0	9.0	52.9	16.2	10.5	8.1
	NP	KUL	69	20.7	13.9	67.1	19.6	13.2	11.4
		KUL	64	18.2	12.5	68.7	15.2	8.0	7.9
		KUL	65	19.2	12.3	64.1	18.5	9.6	8.5
Sparse	3 M	ÅSE	36	13.9	5.7	41.0	17.5	14.1	8.6
		ÅSE	37	15.2	5.8	38.2	22.2	16.5	9.8
		ÅSE	38	14.5	6.7	46.2	18.1	13.1	9.9
	10M	ÅHE	43	15.2	3.5	23.0	29.3	26.6	10.8
		ÅHE	43	12.9	4.5	34.9	22.0	14.2	7.7
		ÅHE	45	13.9	4.2	30.2	27.0	20.5	10.0

Table 3. Effects of treatments and regimes on transition ages between different fibre length classes at different tree heights, as shown by analysis of variance.
Variable	Treatment			Regime
Variable	df	F	P	df	F	P
Breast height
Age at 1.5 mm	6	3.15	0.036	2	5.13	0.017
Age at 2.5 mm	6	1.81	0.169	2	3.27	0.062
Mean fibre length	6	2.05	0.126	2	4.53	0.025
20% of tree height
Age at 1.5 mm	6	2.14	0.112	2	6.49	0.008
Age at 2.5 mm	6	5.33	0.005	2	19.02	0.000
Mean fibre length	6	3.14	0.036	2	11.29	0.001
70% of tree height
Age at 1.5 mm	6	0.47	0.817	2	0.38	0.690
Age at 2.5 mm	6	0.62	0.711	2	0.65	0.536
Mean fibre length	6	2.72	0.058	2	5.38	0.015

Table 4. Number of year rings and mean ring width within different fibre length classes at breast height (BRH) and 20% of total tree height of the treatments examined. Different letters indicate significant differences. 300L = thinning leaving the 300 largest trees ha^–1; 300S = thinning leaving the 300 smallest trees ha^–1; P600 = PCT to 600 stems ha^–1 at a dominant height of 5m; NT = no thinning; NP = no PCT; 3M = 3 m spacing; 10M = 10 m spacing.
Treatment	0.3–1.5 mm		1.5–2.5 mm			> 2.5 mm
Treatment	No of years	Ring width (mm year^–1)	No of years		Ring width (mm year^–1)	Ring width (mm year^–1)
BRH
300L	5.16^ab	2.98^a	14.30^a	3.21^a		1.60^a
300S	5.35^ab	2.48^a	15.20^a	1.99^a		1.53^ab
P600	4.47^b	2.62^a	12.59^a	2.99^a		1.51^ab
NT	5.40^ab	2.29^a	11.68^a	2.22^a		1.05^ab
NP	7.08^ab	3.21^a	13.40^a	1.74^a		0.73^b
3M	6.75^ab	3.16^a	14.96^a	2.98^a		1.30^ab
10M	10.81^a	3.63^a	17.38^a	2.86^a		1.40^ab
20%
300L	4.42^a	3.56^a	11.35^ab	3.64^a		1.80^a
300S	4.03^a	3.78^a	11.36^ab	2.22^b		1.44^ab
P600	5.45^a	3.01^a	11.62^ab	3.23^ab		1.42^ab
NT	4.60^a	3.56^a	8.28^b	2.45^ab		1.14^ab
NP	4.58^a	3.46^a	8.85^b	2.46^ab		0.82^b
3M	7.05^a	3.72^a	14.64^ab	2.83^ab		1.26^ab
10M	6.82^a	3.57^a	15.72^a	3.75^a		1.46^ab

Table 5. Number of year rings and mean ring width within different fibre length classes at breast height (BRH) and 20% of total tree height of the regime types examined. Different letter indicate significant differences. Dense/Sparse = a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning, Dense = a continuous high stand density and Sparse = a continuous low stand density.
Regime type	0.3–1.5 mm		1.5–2.5 mm			> 2.5 mm
Regime type	No of years	Ring width (mm year^–1)	No of years		Ring width (mm year^–1)	Ring width (mm year^–1)
BRH
Dense	6.24^ab	2.75^a	12.54^a	1.98^b		0.89^b
Dense/Sparse	4.99^b	2.69^a	14.03^a	2.73^ab		1.54^a
Sparse	8.78^a	3.40^a	16.17^a	2.92^a		1.35^a
20%
Dense	4.59^b	3.51^a	8.56^c	2.46^a		0.98^b
Dense/Sparse	4.63^b	3.45^a	11.44^b	3.03^a		1.55^a
Sparse	6.94^a	3.64^a	15.18^a	2.29^a		1.36^a

Fig. 1. Mean fibre length at the sample heights of the management regimes examined. Solid line represents Dense/Sparse (= a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning), dashed line represents Dense (= a continuous high stand stem density) and dotted line denote Sparse (= a continuous low stand stem density); bars denote standard deviations.

Fig. 2. Volume proportions of different fibre length intervals in all trees examined in each regime and mean values for the different principal management regimes (Dense/Sparse = a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning, Dense = a continuous high stand stem density and Sparse = a continuous low stand stem density); bars denote standard deviations. 300L = thinning leaving the 300 largest trees ha^–1; 300S = thinning leaving the 300 smallest trees ha^–1; P600 = PCT to 600 stems ha^–1 at a dominant height of 5 m; NT = no thinning; NP = no PCT; 3M = 3 m spacing; 10M = 10 m spacing.

Fig. 3. Proportions of wood with fibres longer than 2.5 mm in relation to the total wood volume in five investigated stem sections from the base to the top of sample trees (Base = 0 to 1.3 m; Stem 1 = 1.3 m to 20% of total tree height; Stem 2 = 20% of total tree height to the height of the living crown; Stem 3 = height of the living crown to 70% of total tree height; Top = 70% of total tree height to 100% of total tree height). Different letters indicate significant differences between silvicultural regimes (Dense/Sparse = a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning, Dense = a continuous high stand stem density and Sparse = a continuous low stand stem density). Squares denote Dense/Sparse regime, circles represent Dense regime and triangles show Sparse regime.

Fig. 4. Development of mean tree volume and wood volume by fibre length class with tree height in silvicultural management regimes with a high initial stand density followed by high intensity pre-commercial thinning/commercial thinning (a), a continuous high stand stem density (b) and a continuous low stand stem density (c).