Economic losses caused by butt rot in Norway spruce trees in Norway

Figures & data

Figure 1. Map showing locations of the assessed stands in Norway, colors indicating the seven contractors that provided the harvester data.

Table 1. Summary statistics of diameters at breast height (DBH) and tree volumes under bark (including cut-offs/waste) recorded by the harvesters, and tree values according to the assumed assortment prices (Table 2) for the harvested Norway spruce trees (n = 385,766).

	Min	Mean	Max	Std. dev
DBH (mm)	51	190	767	84
Volume (m^3)	0.00	0.37	7.88	0.48
Value (€)	0.13	8.07	133.46	10.70

Table 2. Norway spruce log assortments used in the bucking simulations, assumed prices (€/m³ under bark), and permitted log dimensions (over bark).

Assortment	Price (€)	Min length (cm)	Max length (cm)	Min diameter (mm)	Max diameter (mm)
Saw	52.80	370	610	120	550
Pulp	24.00	300	490	50	700
Rotten pulp	19.20	300	490	50	700
Energy	14.40	300	490	50	700
Waste	0	10	100	0	-

Figure 2. Density plot of diameters at breast height (DBH) of trees without butt rot and trees with butt rot. Rotten and non-rotten are here considered different populations.

Table 3. Proportions of log assortments obtained from the bucking simulations.

Assortment	Bucking simulation 1 - butt rot included	Bucking simulation 2 - trees assumed free of butt rot
Saw log (%)	49	58
Pulp (%)	34	36
Rotten pulp (%)	5	0
Energy (%)	11	4
Waste (%)	2	1

Figure 3. Diameter at breast height (DBH) of harvested trees plotted against value losses.

Figure 4. Violin plot of value losses of trees affected by rot. Dots indicate mean values calculated for contractors and whiskers indicate corresponding standard deviations.

Figure 5. Density plots of saw log volume losses in percent of total tree volume (left panel) and in m³ (right panel), obtained for trees affected by butt rot. Dashed lines indicate mean values.

Table 4. Number of trees, mean value loss per tree, mean saw log length and no. of saw logs per tree obtained in the simulations, calculated for five diameter at breast height (DBH) classes.

			DBH class
	0-100 mm	100-200 mm	200-300 mm	300-400 mm	>400 mm
Number of trees	49274	186998	108498	34067	6929
Mean value loss (%)	1	3	6	8	11
Mean value loss (€/m^3)	0.19	1.35	3.52	5.04	6.05
Mean saw log length when rot was included in dataset (cm)	0	145	693	1005	1000
Mean saw log length when trees were assumed free of rot (cm)	2	169	775	1136	1172
Mean no. of saw logs when rot was included in dataset	0.00	0.34	1.67	2.45	2.44
Mean no. of saw logs when trees were assumed free of rot	0.00	0.40	1.87	2.78	2.87

Figure 6. Stand-wise mean value losses plotted against mean proportions of butt rot, mean diameter at breast height (DBH) and mean loss in saw log length obtained for the harvested stands.

Data availability statement

For privacy reasons, the contractors and forest owners’ cooperatives that own the harvester data did not agree for the data to be shared publicly.