Accuracy of the Copernicus High-Resolution Layer Forest Type (HRL FTY) assessed with domestic NFI sampling plots in Poland

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General characteristics of forest area by forms of forest ownership in 2019

Specification	Grand total	Of which wooded area in % of grand total area
		Total	Tree stands by age classes					Restocking class and of a selection structure
			I (1—20 years)	II (21—40 years)	III (41—60 years)	IV (61—80 years)	V (81years<)
	[ha]	[%]
Total (of which):	9242.4	96.9	11.9	14.8	23.8	20.0	23.1	3.3
1. Public forests (of which)	7460.1	97.3	12.2	14.0	22.2	19.4	25.9	3.6
i) owned by the State Treasury	7375.9	97.3	12.2	14.0	22.2	19.4	25.9	3.6
ii) managed by the State Forests	7110.0	97.4	12.5	14.2	22.2	19.4	25.5	3.6
iii) national parks	185.6	94.9	3.0	8.2	19.6	17.7	40.2	6.2
iv) stock of Treasury Agricultural Property	27.6	89.1	3.7	14.5	24.5	28.7	17.7	-
v) municipally owned	84.2	96.5	6.5	10.7	21.2	20.9	31.9	5.3
2. private forests	1782.3	95.1	10.7	18.2	31.3	22.3	10.9	1.7

UA of HRL FTY based on the Polish NFI sample plots (UA = user’s accuracy, 0 = non-forest, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

UA	HRL FTY code	Country level	Natura 2000	Nature reserves	National parks
		(%)
	non-tree covered areas (0)	31.85	37.38	28.57	30.43
	broad-leaved (1)	70.14	71.32	77.01	67.63
	coniferous (2)	73.73	73.28	65.35	71.15

HRL FTY EO based on the Polish NFI sample plots (EC = error of commission, 0 = non-forest, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

EC	HRL FTY code	Total	Natura 2000	Nature reserves	National parks
		(%)
	non-tree covered areas (0)	68.15	62.62	71.43	69.57
	broad-leaved (1)	29.86	28.68	22.99	32.37
	coniferous (2)	26.27	26.72	34.65	28.85

General confusion matrix of HRL FTY with the NFI plots (0 = non-tree covered areas, 1 = broadleaf dominated forest, 2 = coniferous dominated forest)

Confusion matrix between HRL FTY and NFI Overall forests area		HRL FTY
		non-tree covered areas (0)	broad-leaved (1)	coniferous (2)	Total
NFI	non-tree covered areas (0)	1144	2006	3287	6437
	broad-leaved (1)	1178	11054	3707	15939
	coniferous (2)	1270	2701	19626	23597
	Total	3592	15761	26620	45973

Confusion matrix of HRL FTY with the NFI plots—national parks only (0 = non-tree covered areas, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

Confusion matrix between HRL FTY and NFI National parks		HRL FTY
		non-tree covered areas (0)	broad-leaved (1)	coniferous (2)	Total
NFI	non-tree covered areas (0)	21	43	60	124
	broad-leaved (1)	26	234	75	335
	coniferous (2)	22	69	333	424
	Total	69	346	468	883

Producer’s accuracy (PA) of HRL FTY based on the Polish NFI sample plots (PA = producer’s accuracy, 0 = non-forest, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

PA	HRL FTY code	Country level	Natura 2000	Nature reserves	National parks
		(%)
	non-tree covered areas (0)	17.77	16.25	7.27	16.94
	broad-leaved (1)	69.35	71.76	76.72	69.85
	coniferous (2)	83.17	84.12	80.11	78.54

General characteristic of forest area by forms of forest ownership in 2022

Specification	Grand total	Of which wooded area in % of grand total area
		Total	Tree stands by age classes					Restocking class and of a selection structure
			I (1—20 years)	II (21—40 years)	III (41—60 years)	IV (61—80 years)	V (81years<)
	[ha]	[%]
Total (of which):	9260.3	97.2	11.5	14.2	21.5	21.6	24.4	4.0
1. Public forests (of which)	7474.6	97.5	12.0	13.6	19.9	20.5	26.9	4.6
i) owned by the State Treasury	7390.6	97.5	12.1	13.6	20.0	20.3	26.9	4.6
ii) managed by the State Forests	7121.4	97.6	12.4	13.8	20.1	20.5	26.3	4.5
iii) national parks	183.5	95.0	1.9	7.3	15.2	16.0	45.9	8.7
iv) stock of Treasury Agricultural Property	27.6	91.5	4.1	11.6	23.7	29.5	22.6	-
v) municipally owned	84.0	97.6	4.1	9.7	18.0	25.1	34.5	6.2
2. private forests	1785.7	95.8	9.4	16.5	28.1	26.4	13.6	1.8

Confusion matrix of HRL FTY with the NFI plots – Natura 2000 areas only (0 = non-tree covered areas, 1 = broadleaf dominated forest, 2 = coniferous dominated forest)

Confusion matrix between HRL FTY and NFI Natura 2000		HRL FTY
		non-tree covered areas (0)	broad-leaved (1)	coniferous (2)	Total
NFI	non-tree covered areas (0)	117	245	358	720
	broad-leaved (1)	88	1395	461	1944
	coniferous (2)	108	316	2246	2670
	Total	313	1956	3065	5334

Confusion matrix of HRL FTY with the NFI plots—nature reserves only (0 = non-tree covered areas, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

Confusion matrix between HRL FTY and NFI Nature reserves		HRL FTY
		non-tree covered areas (0)	broad-leaved (1)	coniferous (2)	Total
NFI	non-tree covered areas (0)	4	27	24	55
	broad-leaved (1)	6	201	55	262
	coniferous (2)	4	33	149	186
	Total	14	261	228	503

OA of HRL FTY based on assessment of NFI plots and by age classes (n = number of sample plots, OA = overall accuracy, 0 = non-forest, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

OA	Age class	Country level	Natura 2000	Nature reserves	National parks
	(n) number of plots
	Regeneration phase	6263	809	62	137
	1–10	2883	279	6	44
	11–20	3970	308	19	68
	21–30	3615	323	25	62
	31–40	3359	364	25	55
	41–50	3647	408	34	72
	51–60	5160	576	47	99
	61–70	4561	457	30	92
	71–80	2954	337	34	54
	81–90	3075	381	33	66
	91–100	2148	302	41	30
	101–110	1477	248	36	43
	111–120	980	193	32	18
	121–130	1315	349	79	43
	>130	565	NA	NA	NA
	Total	45973	5334	503	883
	[%]
	Regeneration phase	17.69	16.31	7.27	15.57
	1–10	48.70	45.16	50.00	43.18
	11–20	69.60	74.68	89.47	58.82
	21–30	75.30	77.40	72.00	75.81
	31–40	79.19	83.24	84.00	74.55
	41–50	81.71	80.64	85.29	83.33
	51–60	81.47	79.86	61.70	77.78
	61–70	82.92	80.74	70.00	80.43
	71–80	84.09	85.16	79.41	85.19
	81–90	84.98	88.71	75.76	84.85
	91–100	82.27	81.79	41.67	73.33
	101–110	78.74	79.03	75.00	72.09
	111–120	79.49	82.90	84.38	77.78
	121–130	59.47	56.73	28.57	60.00
	>130	59.47	56.73	28.57	60.00
	Overall accuracy	69.22	70.45	70.38	66.59

HRL FTY EO based on the Polish NFI sample plots (EO = error of omission, 0 = non-forest, 1 = broadleaf dominated forest and 2 = coniferous dominated forest)

EO	HRL FTY code	Country level	Natura 2000	Nature reserves	National parks
		(%)
	non-tree covered areas (0)	82.23	83.75	92.73	83.06
	broad-leaved (1)	30.65	28.24	23.28	30.15
	coniferous (2)	16.83	15.88	19.89	21.46