Silva Fennica

Table 1. Description of the pixel data from Central and Eastern Norway used in the case study. The table shows the number of pixels for each site index / initial rot level combination and its cumulative distribution in the last row.
Site Index spruce	Rot level (%)
Site Index spruce	0	5	10	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	90	100	Total
10	321	131	148	129	106	61	43	27	19	21	11	4	4	2	1	1	1	1	1	0	1032
12	895	365	290	253	135	114	81	47	42	22	19	8	5	6	1	2	1	1	1	0	2288
14	1235	583	468	399	319	228	208	133	129	102	48	43	21	20	14	6	3	0	1	0	3960
16	816	281	225	145	104	80	54	37	35	28	27	20	11	5	3	3	2	0	0	1	1877
18	523	286	202	162	112	72	55	43	23	22	13	14	6	4	3	0	0	1	1	0	1542
20	697	290	226	190	110	75	48	34	26	18	3	8	1	2	0	0	0	0	0	0	1728
22	13	9	7	7	3	2	5	1	0	0	1	0	0	0	0	0	0	0	0	0	48
Total	4500	1945	1566	1285	889	632	494	322	274	213	122	97	48	39	22	12	7	3	4	1	12 475
Distr.	36%	52%	64%	75%	82%	87%	91%	93%	95%	97%	98%	99%	99%	100%	100%	100%	100%	100%	100%	100%

Fig. 1. Pixel data distribution regarding site index and rot level within the 71 stands analysed in central and eastern Norway. (a) Site index distribution when aggregating the stands by its dominant site index (heterogeneous areas). (b) Rot level intervals distribution when aggregating the stands by their dominant site index (heterogeneous areas).

Table 2. Optimal tree species for each combination of site index, initial rot level, and rotation length. P stands for Pinus sylvestris (pine) and S for Picea abies (spruce). The economically optimal rotation age (NPV based considering an interest rate of 3%) for each site index given a homogenous rot level is indicated in bold. The brackets indicate negative NPVs, while the lack indicates positive NPVs.

H40 Site
Index

Rotation
length
(years)

Initial rot level (%)

100

Spruce -10

55–80

(P)

Pine -12

(P)

(P)

Spruce - 12

55–75

(P)

Pine - 13

(P)

(P)

(S)

(P)

(S)

(S)

(P)

Spruce - 14

(P)

Pine - 14

(S)

(P)

65–70

(S)

(P)

(S)

(P)

(P)

(P)

(P)

(S)

(P)

(P)

(P)

(P)

(S)

(P)

(S)

(P)

Spruce - 16

(S)

(P)

Pine - 16

(P)

85–90

Spruce - 18

(P)

Pine - 17

60–65

80–90

Spruce - 20

55–65

Pine - 18

75–90

Spruce - 22

55–60

Pine - 20

75–85

Spruce - 24

55–60

Pine - 21

80–85

Fig. 2. Precision forestry method results. (a) Share of stands where the most profitable option was planting Picea abies (spruce) only or planting mixed species according to the site index and rot level (Precision forestry). (b) Increase in LEV (€ ha^–1) observed in the stands where Precision forestry yields the best results. The values are obtained by comparing the results of the Precision forestry method to the best single species (only Picea abies or Pinus sylvestris – whichever is the best) alternative.

Fig. 3. Decrease in NPV (€ ha^–1), considering the economically optimal rotation age when choosing the non-optimal species. The bulleted part of the graph refers to the losses when planting Pinus sylvestris (pine) instead of Picea abies (spruce) in a homogeneous area. The non-bulleted part of the graph refers to the losses when planting Picea abies (spruce) instead of Pinus sylvestris (pine) in a homogeneous area. The lines refer to different site indexes.