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
number of stems
conifers and broadleaves · diameter at breast height (10 classes)
regional demarcation: canton
unit: 1000 n
evaluation area: accessible forest without shrub forest NFI4/NFI5
grid: 1.4 km grid, subgrids 1-5
state 2018/26
		canton
		AG		AI		AR		BE		BL/BS		FR		GE		GL		GR		JU		LU		NE		NW		OW		SG		SH		SO		SZ		TG		TI		UR		VD		VS		ZG		ZH		Switzerland
conifers and broadleaves	diameter at breast height (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	±%	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	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	12-20 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	21-30 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	31-40 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	41-50 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	51-60 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	61-70 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	71-80 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	81-90 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	91-100 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	>100 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	total	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
conifers	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	12-20 cm	1730	21	262	36	664	39	16291	8	915	33	3496	20	86	82	997	32	22789	7	2076	17	6049	16	2527	21	774	64	3336	24	3794	18	445	45	1777	32	2230	23	1545	24	6607	15	2467	21	7789	13	13388	9	271	50	2473	24	104779	3
	21-30 cm	1230	24	367	36	519	40	9564	8	365	32	2373	20	0	.	544	33	14314	7	1065	21	3128	14	1846	17	647	42	2030	23	2413	16	379	35	833	25	1372	22	1253	24	4271	13	1806	20	4440	13	9520	10	336	38	1606	22	66223	3
	31-40 cm	527	27	544	29	532	30	6279	8	239	31	1869	18	45	100	341	32	9081	7	657	24	1720	14	1031	21	425	41	1265	24	1744	16	338	35	618	26	1106	21	655	33	2567	13	1097	21	3012	11	5751	9	249	36	1150	18	42843	3
	41-50 cm	388	24	344	28	321	30	4726	7	164	31	1199	16	14	100	419	25	6091	6	651	20	1170	14	832	16	222	38	601	23	1085	15	191	30	363	21	827	19	385	21	1579	13	687	25	2139	11	3511	9	166	41	986	15	29062	3
	51-60 cm	256	22	279	31	333	31	2999	8	126	36	749	16	0	.	264	24	3498	7	462	21	975	15	639	16	61	48	304	25	945	14	92	33	191	26	588	18	154	29	1073	16	303	25	1213	11	2059	10	98	45	468	17	18127	3
	61-70 cm	127	31	107	36	77	46	1447	10	49	42	244	20	0	.	124	36	1449	9	202	27	427	19	281	23	91	42	91	37	595	18	63	40	68	48	248	26	103	30	388	15	138	28	773	15	866	13	14	100	250	22	8221	4
	71-80 cm	80	31	22	58	29	50	648	12	35	60	120	30	0	.	112	39	592	12	79	41	165	24	134	24	26	50	111	38	302	21	28	61	21	58	100	30	47	55	215	24	64	46	245	20	424	18	14	71	117	30	3728	5
	81-90 cm	27	61	7	100	0	.	196	21	7	100	55	42	0	.	35	45	312	19	15	71	37	45	60	39	0	.	21	77	103	30	0	.	14	71	35	51	33	53	78	35	7	100	59	36	145	26	11	100	51	38	1305	8
	91-100 cm	7	100	0	.	0	.	66	34	0	.	9	100	0	.	29	50	102	29	7	100	0	.	8	100	0	.	0	.	14	71	0	.	7	100	7	100	13	71	29	59	0	.	31	50	73	31	0	.	0	.	401	14
	>100 cm	0	.	0	.	0	.	28	50	0	.	7	100	0	.	7	100	59	35	14	71	7	100	8	100	0	.	0	.	21	58	0	.	0	.	7	100	0	.	25	71	0	.	7	100	14	71	0	.	0	.	205	20
	total	4371	17	1932	28	2475	27	42244	6	1899	24	10122	14	145	71	2872	25	58286	5	5227	14	13679	12	7366	13	2247	42	7759	19	11016	12	1535	27	3891	20	6520	15	4189	19	16831	11	6569	18	19707	9	35752	7	1158	34	7102	15	274895	2
broadleaves	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	12-20 cm	3895	15	48	73	435	36	12610	9	2418	22	2921	18	221	61	950	26	6760	15	2549	19	2834	16	2240	20	911	33	1117	30	4166	16	1328	27	3433	21	2122	22	1983	21	22009	8	1488	29	8934	12	8004	12	182	47	4318	15	97874	3
	21-30 cm	1747	16	54	74	414	35	6549	9	1208	23	2157	16	121	65	675	28	3514	16	1359	20	1318	18	1041	18	738	43	613	35	2956	16	688	30	1839	17	1258	26	1046	20	12342	8	999	28	4198	12	3010	15	128	58	2276	16	52247	3
	31-40 cm	898	18	79	49	296	33	3732	9	822	22	1208	19	66	65	356	30	1477	17	1067	18	1025	18	424	29	348	48	471	31	1996	15	510	26	1290	19	458	23	676	25	4527	10	395	42	2307	12	832	19	101	42	1232	14	26592	3
	41-50 cm	741	17	69	55	124	43	2074	10	371	25	532	20	43	52	239	27	552	19	766	19	554	20	332	21	136	39	181	31	1143	15	344	25	760	17	313	26	373	20	1733	10	146	32	1414	12	233	27	91	51	677	15	13938	3
	51-60 cm	464	18	0	.	38	45	1248	11	195	27	314	22	22	100	145	37	214	23	259	23	406	24	83	35	36	66	114	50	509	18	98	33	380	23	206	30	275	21	707	15	57	52	652	14	81	41	37	45	525	14	7069	4
	61-70 cm	131	27	14	71	14	71	372	17	59	42	61	33	7	100	40	53	112	26	137	30	84	33	8	100	7	100	35	59	181	30	58	39	88	33	20	58	118	32	211	22	42	62	215	22	34	51	13	100	216	23	2280	7
	71-80 cm	116	27	0	.	7	100	84	37	33	51	41	41	7	100	0	.	39	46	22	58	42	52	7	100	0	.	7	100	37	51	23	58	61	46	34	68	13	71	117	28	0	.	68	32	15	72	0	.	60	33	834	10
	81-90 cm	27	50	0	.	0	.	7	100	0	.	8	100	0	.	0	.	7	100	0	.	0	.	0	.	0	.	0	.	43	45	0	.	0	.	0	.	22	58	75	34	25	58	8	100	0	0	0	.	14	71	235	18
	91-100 cm	13	71	0	.	0	.	17	72	0	.	0	.	0	.	6	100	0	.	0	.	0	.	0	.	0	.	0	.	12	100	0	.	0	.	7	100	8	100	38	60	0	.	7	100	7	100	0	.	14	71	128	27
	>100 cm	0	.	0	.	0	.	7	100	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	30	71	50	51	0	.	7	100	0	.	0	.	0	.	94	37
	total	8032	12	263	50	1328	28	26700	7	5106	17	7243	14	487	48	2411	22	12674	13	6160	14	6263	13	4134	15	2175	34	2539	25	11043	12	3048	21	7851	14	4418	18	4543	16	41810	6	3152	25	17810	9	12216	11	552	39	9333	11	201292	2
indeterminable	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	12-20 cm	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	0
	21-30 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	0
	31-40 cm	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	0	0	0
	41-50 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	51-60 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	61-70 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	71-80 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	81-90 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	91-100 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	>100 cm	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	total	0	.	0	.	0	.	0	0	0	0	0	.	0	.	0	.	0	0	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	.	0	.	0	.	0	.	0	0	0	.	0	0	0	0
total	n/a	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.	0	.
	12-20 cm	5625	14	310	35	1099	33	28900	7	3332	20	6417	14	307	54	1947	22	29549	7	4624	14	8884	13	4767	15	1685	35	4454	20	7959	14	1773	27	5210	18	4352	19	3528	17	28616	7	3955	20	16723	10	21392	8	453	36	6791	14	202653	2
	21-30 cm	2976	15	421	35	933	29	16113	7	1573	20	4530	14	121	65	1219	23	17828	6	2424	15	4446	12	2887	14	1385	32	2643	20	5369	13	1067	24	2672	15	2630	18	2299	17	16613	7	2805	17	8638	10	12530	8	464	35	3883	13	118470	2
	31-40 cm	1425	16	623	28	828	26	10010	6	1061	20	3078	14	110	60	697	22	10558	6	1723	16	2745	12	1455	18	773	32	1736	19	3741	12	848	23	1909	17	1564	17	1331	21	7094	8	1492	20	5319	9	6582	8	350	32	2382	12	69435	2
	41-50 cm	1129	14	413	28	445	27	6800	6	535	22	1731	13	57	58	657	21	6643	6	1418	15	1725	12	1164	13	358	30	783	20	2228	12	534	21	1123	14	1140	16	758	18	3312	8	833	22	3552	9	3744	9	256	34	1663	12	43001	2
	51-60 cm	720	15	279	31	371	30	4247	7	321	22	1063	14	22	100	410	22	3713	7	721	16	1381	13	722	15	97	39	418	24	1454	12	189	25	571	18	794	16	429	19	1780	13	360	23	1865	9	2141	9	135	36	993	13	25195	2
	61-70 cm	259	20	121	34	91	42	1819	9	108	30	305	18	7	100	164	30	1561	9	339	20	511	18	289	22	98	39	126	35	776	16	121	29	155	29	268	25	220	23	599	12	180	26	988	13	901	13	28	71	466	16	10501	3
	71-80 cm	195	21	22	58	36	45	732	11	68	39	162	25	7	100	112	39	631	12	101	36	206	22	141	23	26	50	118	36	339	19	51	42	82	37	134	31	60	45	332	18	64	46	313	17	438	17	14	71	177	24	4562	5
	81-90 cm	53	39	7	100	0	.	203	21	7	100	62	39	0	.	35	45	319	19	15	71	37	45	60	39	0	.	21	77	146	25	0	.	14	71	35	51	55	43	152	24	32	51	67	34	145	26	11	100	65	34	1541	8
	91-100 cm	20	58	0	.	0	.	83	30	0	.	9	100	0	.	35	45	102	29	7	100	0	.	8	100	0	.	0	.	26	60	0	.	7	100	14	71	21	58	66	42	0	.	37	45	80	30	0	.	14	71	529	12
	>100 cm	0	.	0	.	0	.	35	45	0	.	7	100	0	.	7	100	59	35	14	71	7	100	8	100	0	.	0	.	21	58	0	.	0	.	7	100	30	71	76	42	0	.	14	71	14	71	0	.	0	.	299	18
	total	12403	11	2195	28	3803	24	68944	5	7005	16	17365	11	632	48	5283	18	70961	5	11387	12	19942	10	11500	11	4422	28	10298	16	22059	10	4584	19	11742	13	10938	13	8732	14	58641	5	9721	16	37517	7	47968	6	1710	29	16434	10	476187	1

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. 1348726. Birmensdorf, Swiss Federal Research Institute WSL

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