Erosion control properties of self-seeded forests that appeared in forestless areas of ravine-gully systems

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Statistics of soil permeability in experimental sites_

No TP	Age, years	Soil permeability measurement statistics
		N	χ	σ	m	υ	p
1	8–20		10	15.5	5.99	1.89	38.6	12.2
2	10–25	10	19.0	3.92	1.77	24.1	5.0
3	10–25	10	27.3	9.59	3.03	35.1	11.1
4	10–25	10	21.9	6.63	2.10	30.2	9.56
5	15–16	10	21.6	5.58	1.76	25.8	8.17
6	20–25	10	19.5	2.75	0.43	25.5	5.7
7	20–25	10	11.1	2.02	0.64	18.3	5.7
8	20–25	10	18.7	2.92	0.92	26.1	9.0
9	20–25	10	12.6	2.95	0.93	23.4	7.39
10	20–25	10	10.4	1.42	0.45	13.7	4.32
11	10–17	10	11.6	1.77	0.56	15.3	4.84
12	15–20	10	26.5	10.15	3.21	38.3	12.1

Statistics of soil hardness in experimental sites_

No TP	Age, years	Soil hardness measurement statistics
		N	χ	σ	m	ν	p
1	8–20	15	18.5	0.88	0.23	4.74	1.22
2	10–25	15	17.8	1.01	0.26	5.67	1.46
3	10–25	15	17.1	0.76	0.20	4.45	1.15
4	10–25	15	17.5	0.84	0.22	4.83	1.25
5	15–16	15	17.7	0.98	0.25	5.52	1.43
6	20–25	15	17.8	0.94	0.24	5.29	1.36
7	20–25	15	18.8	0.84	0.22	4.47	1.15
8	20–25	15	18.1	0.93	0.24	5.16	1.33
9	20–25	15	18.5	1.09	0.28	5.92	1.53
10	20–25	15	19.0	0.92	0.22	4.80	1.13
11	10–17	15	18.7	0.49	0.13	2.63	0.68
12	15–20	15	17.4	0.68	0.16	3.93	0.90

Evaluation of the significance of the difference between the average values of permeability indicators_

Pairs of test plots	Number of degrees of freedom	Student’s criterion t0,05	Pairs of test plots	Number of degrees of freedom	Student’s criterion t0,05
1–9	16	1.373	6–9*	16	5.363
2–4	16	1.191	5–12	16	1.338
3–7*	16	5.227	11–12*	16	4.573

Location and orographic characteristics of test plots_

No TP	Geographic coordinates		Steepness of slopes %	Position on the slope	Humus horizon cm
	latitude	longitude
1	49.836796	31.429695	13–14	medium	16
2	49.836483	31.428675	8–10	upper	12
3	49.836220	31.427577	6–8	lower	18
4	49.836417	31.426455	6–8	lower	17
5	49.836582	31.425408	6–8	lower	16
6	49.837010	31.424439	7–9	medium	14
7	49.837471	31.423673	7–9	upper	12
8	49.837997	31.422998	7–9	medium	13
9	49.838524	31.422295	7–9	upper	12
10	49.838952	31.421530	7–9	upper	12
11	49.805334	31.389030	5–7	upper	11
12	49.805618	31.388010	5–7	medium	15

Evaluation of the significance of the difference between the average values of hardness indicators_

Pairs of test plots	Number of degrees of freedom	Student’s criterion t0,05	Pairs of test plots	Number of degrees of freedom	Student’s criterion t0,05
1–9	26	0	6–9	26	1.883
2–4	26	0.884	5–12	26	0.975
3–7*	26	5.812	11–12*	26	6.007

Biometric indicators of natural regeneration of woody plants on eroded ravine-gully lands_

No TP	Composition	Species	Age, years	Amount, pc.	Height, m	Diameter, cm	Components and their cover, %			Index of productivity
							undergrowth	understory	grass cover
1	9Cb1Pt+Sa	Carpinus betulus	8–20	22	8.1	3.6	10	3	0	Ia
		Salix caprea		1	9.0	10.0				Ia
		Populus tremula		3	11.3	8.7				Ia
2	10Bp	Betula pendula	10–25	54	5.2	9.0	15	5	0	III
3	6Pt4Bp+Cb, Fe	Populus tremula	10–25	13	13.6	14.3	18	7	3	Ia
		Betula pendula		10	7.2	5.6				II
		Carpinus betulus		1	6.0	6.0				Ia
		Fraxinus excelsior		1	6.0	4.0				Ia
4	10Bp+Pt, Sc	Betula pendula	10–25	23	10.4	7.0	10	10	80	Ia
		Populus tremula		1	6.5	6.0				Ia
		Salix caprea		1	8.0	18.0				I
5	9Ps1Rp	Pinus sylvestris	15–16	38	4.1	6.4	20	15	65	Ia
		Robinia pseudoacacia		6	3.5	8.0				Ia
6	9Rp1Bp+Pc, Pt	Robinia pseudoacacia	20–25	15	7.6	11.9	6	3	40	III
		Pyrus communis		1	3.5	6.0				V
		Betula pendula		2	6.3	9.0				III
		Populus tremula		2	10.5	20.0				I
7	6Pt1Ps3Bp	Populus tremula	20–25	8	11	12.8	15	0	10	II
		Pinus sylvestris		1	8.0	14.0				II
		Betula pendula		4	7.9	8.0				II
8	6Bp1Pt3Rp	Betula pendula	20–25	8	10.2	12.3	5	9	100	II
		Populus tremula		2	12.5	15.0				I
		Robinia pseudoacacia		4	6.0	7.0				III
9	10Rp+Pa, Ps	Robinia pseudoacacia	20–25	13	4.2	4.5	6	0	100	IV
		Populus alba		1	13.0	22.0				Ia
		Pinus sylvestris		1	5.5	22.0				IV
10	6Rp1Ps3Pt	Robinia pseudoacacia	20–25	8	8.9	8.5	8	0	100	II
		Pinus sylvestris		2	6.0	6.0				III
		Populus tremula		5	9.1	7.6				II
11	10Ps	Pinus sylvestris	10–17	56	5.1	5.9	0	0	0	IV
12	10Ps	Pinus sylvestris	15–20	33	6.0	7.5	0	0	20	III