Selection from the list of topics

Estimates and standard error of the estimates

The results published in the NFI tables are estimates for variables in the Swiss forest (population parameters) whose true values are not known and must therefore be extrapolated (estimated) from the NFI sample data.

The extrapolations carry uncertainties. However, the accuracy of the extrapolations can be reliably estimated from the NFI sample, which is designed to be a random sample. To this end, all NFI tables include a second figure in addition to the estimate itself, namely the standard error of the estimate.

In most tables the percent standard error is reported (±%), but the absolute standard error (±) is also reported occasionally, especially for estimated percentages. The relationship between absolute and percent standard error is as follows:

percent standard error = absolute standard error / estimate × 100

absolute standard error = percent standard error × estimate / 100

Information on the forest road network is based on a full survey of all forest roads. In this case, there is no need to specify a standard error because there is no uncertainty caused by sampling.

Confidence interval of the estimate

With the estimate and the standard error of the estimate, the limits of the so-called confidence interval of the estimate can be calculated as:

lower limit = estimate – tQ × absolute standard error

upper limit = estimate + tQ × absolute standard error

If the simple standard error is used for the calculation (tQ = 1), then the 68% confidence interval is formed. In this case, the true value of the population parameter has a 68% probability of lying within this confidence interval of the estimate. If the double standard error is used (tQ = 2), then there is a 95% probability that the true value lies within this 95% confidence interval.

Significance of the estimate

The confidence interval can be used to statistically test whether the estimated population parameter is larger or smaller than a specific reference or target value, or whether two estimated population parameters truly differ (in the real population). For practical applications, proceed as follows: if a reference value lies outside the confidence interval, the estimated population value can be interpreted as being significantly different from it; if it lies within the confidence interval, the difference between the estimated population parameter and the reference value can be interpreted as random or not significant. When two population parameters are compared, they can be interpreted as differing significantly if their confidence intervals do not overlap.

Dealing with missing values

When calculating a results table, data are not always available for all combinations of characteristics^* of the classification variables and regional demarcation applied. In most cases, this indicates that the attribute estimated with the respective target variable does not occur or occurs only very rarely. Usually, the value 0 is used (imputed). However, as this value is not based on direct measurements, the associated standard error is represented with a full stop [.]. If the imputed value of 0 is referred to in the calculation, e.g. in the case of percentages or certain change estimates, no value can be entered. In this case, the estimated value and standard error are both represented with a full stop [.].

For example, no Arolla pines have been found and measured in the Swiss Plateau to date (growing stock of Arolla pines by production region). The values can be assumed to be missing because Arolla pine does not occur in the Swiss Plateau and therefore the growing stock there must be 0.

^* e.g. ‘Arolla pine’ characteristic of the classification variable ‘tree species’ and ‘Swiss plateau’ characteristic of the ‘regional demarcation’

Changes

There are two types of changes in the NFI:

The first type involves specific target variables relating to components of change, such as increment, fellings, mortality and losses. These target variables are only available for two consecutive inventory cycles, e.g. NFI3–NFI4. In the evaluation of components of change, the classification variable characteristic of the second inventory cycle is assigned to the first inventory cycle. These evaluations therefore do not take into account potential changes in a classification variable characteristic from the earlier to the later inventory (e.g. from private to public ownership).

With the second type of change, the difference in target variables, such as number of stems, growing stock or forest area, is used to assess the change between two inventory cycles. Target variables are generally used to represent states, such as that in NFI4, but can also indicate the net change between any two inventory cycles, e.g. NFI1–NFI4. In evaluations of change using these target variables, the change in a classification variable characteristic is considered in the analysis. Consequently, one can detect, for example, that the forest area without shrub forest increased between the two inventory cycles. This only has an effect on classification variables whose characteristic (class) can actually change, e.g. the affiliation with a forest area or the tree condition.

NFI5
total number of stems with two most important forms of damages
altitude (in 200 m classes) · cause of damage to trees (10 classes)
regional demarcation: economic region
unit: 1000 n
evaluation area: accessible forest without shrub forest
grid: 1.4 km grid, subgrids 1-5
state 2018/26
		economic region
		Western Jura		Eastern Jura		Western Plateau		Central Plateau		Eastern Plateau		Western Pre-Alps		Central Pre-Alps		Eastern Pre-Alps		Northwestern Alps		Central Alps		Northeastern Alps		Southwestern Alps		Southeastern Alps		Southern Alps		Switzerland
altitude (in 200 m classes)	cause of damage to trees (10 classes)	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%	1000 n	±%
n/a	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	rockfall	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	various	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	indeterminable	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	wood harvest	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	other human activity	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	weather	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	lying living trees	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	dead trees	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
>1800 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	0	.	0	.	0	.	0	.	0	.	496	100	69	100	0	.	769	50	255	100	71	100	5873	16	11610	12	3932	17	23075	8
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	7	100	7	100
	rockfall	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	333	26	154	43	343	53	830	26
	various	0	.	0	.	0	.	0	.	0	.	0	.	17	100	0	.	33	63	0	.	28	100	243	36	630	25	215	26	1166	16
	indeterminable	0	.	0	.	0	.	0	.	0	.	15	100	66	100	0	.	337	44	55	100	60	100	2149	18	4627	13	1481	18	8789	9
	wood harvest	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	79	53	20	76	0	.	100	45
	other human activity	0	.	0	.	0	.	0	.	0	.	0	.	14	100	0	.	9	100	0	.	0	.	293	46	84	54	63	69	462	33
	weather	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	18	100	427	26	290	26	615	39	1350	20
	lying living trees	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	140	56	452	39	93	49	684	29
	dead trees	0	.	0	.	0	.	0	.	0	.	0	.	222	100	0	.	237	53	18	100	0	.	1827	21	2994	16	876	29	6175	11
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
1601-1800 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	0	.	0	.	0	.	0	.	0	.	771	51	3174	35	272	100	2396	22	262	48	1073	52	6706	18	8661	14	4947	17	28262	8
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	rockfall	0	.	0	.	0	.	0	.	0	.	32	71	163	53	0	.	144	55	0	.	0	.	163	36	325	35	206	52	1033	20
	various	0	.	0	.	0	.	0	.	0	.	16	71	146	44	0	.	229	63	154	84	90	58	196	30	424	29	355	33	1611	17
	indeterminable	0	.	0	.	0	.	0	.	0	.	339	57	693	33	0	.	964	26	290	50	292	63	2402	17	2797	15	1145	21	8921	9
	wood harvest	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	55	100	0	.	0	.	7	100	41	46	27	100	130	50
	other human activity	0	.	0	.	0	.	0	.	0	.	8	100	37	100	0	.	35	61	0	.	95	93	227	52	222	40	43	61	667	27
	weather	0	.	0	.	0	.	0	.	0	.	0	.	62	62	0	.	177	40	0	.	24	77	453	42	328	32	293	23	1337	18
	lying living trees	0	.	0	.	0	.	0	.	0	.	0	.	101	75	22	100	35	100	0	.	0	.	68	48	53	74	16	100	294	34
	dead trees	0	.	0	.	0	.	0	.	0	.	237	51	661	47	127	100	1042	36	93	58	96	54	2251	25	1410	18	659	24	6577	12
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
1401-1600 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	680	34	0	.	386	53	0	.	0	.	2465	34	3260	22	1622	34	4523	19	1923	31	923	34	6067	17	9563	14	7423	17	38834	7
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	rockfall	13	100	0	.	0	.	0	.	0	.	85	76	203	62	0	.	537	52	25	77	57	59	388	41	519	44	402	34	2227	20
	various	138	47	0	.	0	.	0	.	0	.	111	55	22	75	149	76	167	36	49	54	69	70	231	31	192	42	495	24	1623	14
	indeterminable	185	36	0	.	61	61	0	.	0	.	864	31	1263	21	195	39	1393	18	563	34	361	42	1818	18	2769	15	1556	18	11030	7
	wood harvest	8	100	0	.	0	.	0	.	0	.	15	72	42	100	7	100	48	55	37	100	0	.	37	56	131	42	18	100	342	26
	other human activity	0	.	0	.	0	.	0	.	0	.	143	64	102	62	15	100	93	53	71	100	0	.	673	75	199	37	42	71	1340	40
	weather	26	78	0	.	0	.	0	.	0	.	43	48	125	42	12	100	166	38	134	63	25	76	337	30	279	29	419	25	1564	13
	lying living trees	0	.	0	.	0	.	0	.	0	.	37	72	0	.	0	.	18	100	58	100	104	71	198	60	88	53	102	52	605	28
	dead trees	51	54	0	.	134	84	0	.	0	.	947	33	901	30	607	55	1436	23	308	39	357	49	1568	20	2385	23	1486	20	10182	9
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
1201-1400 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	5587	17	0	.	253	66	40	100	0	.	4035	20	3635	21	3234	19	3347	24	1953	29	1403	30	5784	19	3860	21	5148	18	38280	6
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	33	100	33	100
	rockfall	21	100	0	.	0	.	129	100	0	.	337	60	351	41	178	45	252	43	408	67	543	45	459	40	265	54	699	27	3641	15
	various	305	30	0	.	0	.	0	.	0	.	216	41	160	61	347	37	126	42	125	61	197	45	743	47	114	47	445	29	2779	16
	indeterminable	886	19	0	.	59	72	66	100	0	.	898	24	1247	22	808	22	824	24	450	32	503	32	931	23	1593	22	1475	18	9741	7
	wood harvest	111	44	0	.	0	.	0	.	0	.	37	60	43	62	74	83	77	74	0	.	118	55	0	.	109	45	60	50	629	21
	other human activity	83	41	0	.	0	.	0	.	0	.	269	50	19	100	136	49	23	75	7	100	0	.	18	100	159	49	26	76	739	24
	weather	253	45	0	.	7	100	0	.	0	.	150	42	119	37	36	83	98	56	131	71	107	48	101	51	186	47	340	28	1526	15
	lying living trees	0	.	0	.	0	.	0	.	0	.	0	.	36	71	6	100	0	.	158	81	90	60	78	47	0	.	125	39	493	31
	dead trees	813	26	0	.	15	71	30	100	0	.	1105	26	1263	30	949	22	650	29	463	43	898	39	1331	22	1237	24	1133	24	9886	9
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
1001-1200 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	12302	10	0	.	575	58	198	74	140	67	3494	23	7162	15	3920	18	2521	26	2075	29	1640	37	4041	19	2940	24	6511	17	47520	6
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	6	100	72	91	78	84
	rockfall	352	39	0	.	46	100	0	.	0	.	90	78	724	37	102	71	415	50	477	50	246	46	328	52	447	44	854	27	4080	14
	various	460	28	0	.	7	100	0	.	20	74	129	63	158	32	264	36	123	46	438	44	50	49	218	37	281	48	440	40	2587	14
	indeterminable	1664	13	0	.	76	92	7	100	7	100	791	31	1075	21	1056	21	488	25	462	30	507	34	886	26	1285	28	1669	19	9972	7
	wood harvest	742	20	0	.	0	.	0	.	23	100	101	59	309	33	273	38	7	100	22	100	135	54	7	100	33	81	7	100	1660	14
	other human activity	184	38	0	.	0	.	0	.	7	100	111	80	105	58	160	60	0	.	50	77	103	63	15	71	55	58	25	100	817	22
	weather	167	39	0	.	0	.	0	.	33	100	177	53	318	35	118	45	111	46	69	62	35	62	144	35	172	63	377	26	1721	14
	lying living trees	0	.	0	.	0	.	0	.	0	.	15	100	37	100	61	76	18	100	71	100	0	.	139	66	18	100	169	60	527	32
	dead trees	1487	18	0	.	59	75	34	100	0	.	690	29	1326	20	1211	31	551	37	537	36	394	43	1096	26	694	28	1217	25	9295	8
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
801-1000 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	11430	11	1445	31	1824	29	2445	30	1679	37	1971	31	8836	15	7180	16	2171	25	1285	38	1007	29	2952	25	2055	27	6609	23	52887	6
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	rockfall	1017	35	38	100	0	.	0	.	52	100	0	.	293	68	7	100	134	58	442	57	903	32	362	64	88	60	592	30	3928	16
	various	303	30	0	.	34	65	81	47	65	64	117	56	457	22	393	28	98	84	64	60	80	39	84	53	116	44	502	40	2394	13
	indeterminable	2123	16	201	41	275	39	301	31	301	36	387	34	1055	21	1185	21	446	35	284	41	386	33	844	27	838	28	1934	23	10559	7
	wood harvest	608	29	66	59	97	77	171	37	31	81	41	54	482	33	394	34	0	.	22	100	71	55	33	100	87	48	0	0	2103	14
	other human activity	252	38	19	100	0	.	8	100	82	82	39	81	235	53	188	40	26	76	18	100	19	100	7	100	50	74	90	43	1033	19
	weather	328	30	48	63	26	78	0	.	37	61	0	0	205	41	189	33	96	63	25	78	100	50	40	71	227	45	549	54	1870	19
	lying living trees	0	.	0	.	0	.	0	.	0	.	0	.	94	55	0	.	8	100	18	100	22	77	18	100	18	100	204	58	382	35
	dead trees	1666	16	226	53	115	42	212	43	65	62	298	39	1496	23	1236	25	582	32	406	41	646	29	765	30	452	28	1945	24	10111	8
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
601-800 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	10686	13	2142	23	5283	21	9513	14	8036	13	923	46	5872	16	3857	22	1526	28	520	60	884	45	1196	46	2132	25	4541	19	57111	5
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	424	69	424	69
	rockfall	328	40	323	60	0	.	24	78	0	.	60	100	336	70	57	71	218	52	128	71	151	76	147	62	147	71	391	30	2310	18
	various	310	31	45	54	497	36	157	39	449	29	68	100	614	47	456	35	100	55	18	100	0	0	76	81	171	31	1238	40	4200	16
	indeterminable	1618	17	380	30	533	32	1321	21	1216	19	122	59	1023	21	1032	23	331	32	165	72	142	59	300	46	570	31	2052	20	10803	7
	wood harvest	507	24	125	46	280	39	706	22	563	24	0	.	402	32	75	51	32	100	6	100	17	73	0	.	33	100	90	100	2836	11
	other human activity	107	49	26	100	125	59	168	58	95	42	0	.	69	50	26	75	15	100	0	.	0	.	0	.	14	71	28	77	674	22
	weather	216	26	60	59	49	43	85	54	308	30	0	.	84	52	78	56	46	58	18	100	15	100	42	61	38	83	774	43	1812	20
	lying living trees	0	.	35	100	0	.	0	.	50	58	0	.	36	71	60	57	0	.	0	.	15	100	36	71	0	.	98	44	330	25
	dead trees	2169	16	425	36	544	26	797	24	859	23	153	77	829	29	882	27	357	35	0	.	299	41	477	37	413	35	2317	21	10522	8
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
=600 m	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	5254	15	8058	14	4042	19	11583	11	17558	8	0	.	699	56	994	38	648	62	896	48	180	60	1289	36	35	100	6550	18	57786	5
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	126	100	126	100
	rockfall	191	100	108	87	0	.	0	.	0	.	0	.	0	.	373	82	7	100	22	100	18	100	48	73	0	.	479	34	1247	33
	various	339	41	342	29	297	31	202	30	695	21	0	.	0	.	79	100	74	72	44	62	0	.	112	59	0	.	831	34	3015	13
	indeterminable	1009	19	1356	16	579	24	975	16	3021	10	0	.	79	71	341	44	153	84	102	54	34	73	203	47	0	.	3027	18	10879	7
	wood harvest	281	29	342	31	128	39	989	21	1146	18	0	.	52	100	51	65	18	100	7	100	0	.	18	100	0	.	0	.	3034	11
	other human activity	88	52	142	37	96	49	222	38	253	64	0	.	0	.	36	65	0	0	16	100	0	.	75	100	0	.	192	41	1120	20
	weather	204	35	232	30	150	48	84	39	425	23	0	.	0	.	70	68	44	72	18	100	0	.	36	71	0	.	430	28	1695	12
	lying living trees	62	53	90	44	0	.	0	.	97	41	0	.	0	.	21	74	15	100	0	.	0	.	18	100	0	.	323	41	627	24
	dead trees	1285	24	1356	19	851	28	725	20	1784	15	0	.	64	52	298	42	148	56	127	54	68	80	431	42	0	.	3335	17	10471	8
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
total	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	no visible damage	45940	4	11645	11	12364	12	23778	8	27414	6	14156	12	32708	7	21078	8	17901	9	9168	14	7180	15	33908	7	40856	6	45661	5	343756	2
	fire	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	6	100	662	50	669	49
	rockfall	1922	23	469	46	46	100	153	85	52	100	603	39	2069	22	717	45	1707	23	1501	30	1918	21	2226	18	1945	19	3967	11	19297	6
	various	1855	13	387	27	835	24	440	21	1229	16	657	25	1575	21	1687	17	951	22	891	28	514	24	1903	20	1929	14	4520	14	19374	5
	indeterminable	7485	6	1936	13	1583	16	2669	13	4544	9	3416	14	6501	9	4617	10	4936	10	2370	15	2284	16	9531	8	14480	7	14339	6	80692	2
	wood harvest	2258	12	533	24	505	28	1866	14	1764	14	194	35	1330	18	874	21	238	39	94	52	340	31	183	34	454	21	202	50	10834	5
	other human activity	714	20	188	33	220	40	398	32	436	41	571	33	581	28	562	25	203	31	162	52	217	51	1308	42	783	20	510	22	6852	10
	weather	1194	15	340	24	232	34	169	33	803	17	370	31	912	18	503	22	737	19	394	35	324	25	1581	16	1519	15	3797	14	12875	6
	lying living trees	62	53	125	42	0	.	0	.	147	34	52	59	303	34	170	37	93	49	304	52	231	40	696	26	629	30	1132	20	3943	11
	dead trees	7472	8	2007	16	1717	17	1799	14	2708	12	3431	15	6763	11	5310	13	5002	12	1951	18	2758	18	9747	9	9585	9	12967	7	73219	3
	total	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.

Table citation

Abegg, M.; Ahles, P.; Allgaier Leuch, B.; Cioldi, F.; Didion, M.; Düggelin, C.; Fischer, C.; Herold, A.; Meile, R.; Rohner, B.; Rösler, E.; Speich, S.; Temperli, C.; Traub, B.,
2023: Swiss national forest inventory - Result table No. 1346984. Birmensdorf, Swiss Federal Research Institute WSL

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