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Can Scots pine (Pinus sylvestris L.) forests harbour natural regeneration of European ash (Fraxinus excelsior L.)? Cover

Can Scots pine (Pinus sylvestris L.) forests harbour natural regeneration of European ash (Fraxinus excelsior L.)?

Open Access
|Sep 2024

Figures & Tables

Figure 1.

Ash natural regeneration within pine-ash forest (A), soil profile of Arenic Cambisol (B)
Ash natural regeneration within pine-ash forest (A), soil profile of Arenic Cambisol (B)

Figure 2.

Scheme of study plots establishment. Circles indicate study plots (25 m2) established in pine-ash forest (first two plots) and pine forest without ash in overstory but with ash regeneration. The last two plots in pine forest were located up to a maximum distance of 60 m from mature ash trees (seed source) growing in pine-ash forest. Mature ash trees are marked in grey colour
Scheme of study plots establishment. Circles indicate study plots (25 m2) established in pine-ash forest (first two plots) and pine forest without ash in overstory but with ash regeneration. The last two plots in pine forest were located up to a maximum distance of 60 m from mature ash trees (seed source) growing in pine-ash forest. Mature ash trees are marked in grey colour

Figure 3.

Result of Principal Components Analysis for soil chemistry variables
Result of Principal Components Analysis for soil chemistry variables

Figure 4.

Ash saplings density estimated using Poisson generalized linear mixed-effects models (Tab. 1). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction
Ash saplings density estimated using Poisson generalized linear mixed-effects models (Tab. 1). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction

Figure 5.

The proportion of disease-damaged (two first rows) and drought-damaged (third row) saplings estimated using GLMM assuming zero-inflated beta distribution of dependent variable (Tab. 2). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction
The proportion of disease-damaged (two first rows) and drought-damaged (third row) saplings estimated using GLMM assuming zero-inflated beta distribution of dependent variable (Tab. 2). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction

Figure 6.

The proportion of browsed saplings, estimated using generalized linear mixed-effects models assuming zero-inflated Beta distribution of dependent variable (Tab. 3). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction
The proportion of browsed saplings, estimated using generalized linear mixed-effects models assuming zero-inflated Beta distribution of dependent variable (Tab. 3). Dots represent measured values, line – prediction, grey area – 95% confidence interval for prediction

Values of variance inflation factors (VIF) for variables used in models and for all variables

VariableVIF
Proportion of Scots pine in stand4.070
Soil texture1.448
Soil pH4.598
Soil moisture in spring2.113
Soil moisture in spring3.165
Tree layer cover1.699
Shrub layer cover3.042
Herb layer cover5.000
Moss layer cover1.211

Ash regeneration characteristics (ind_/25m2 study plot)

No.PlotDensity of ash <0.6 mDensity of ash 0.6–1.3 mHf damaged ind. <0.6 mHF damaged ind. 0.6–1.3 mDrought-damaged ind. <0.6 mDrought-damaged ind.0.6–1.3 mBrowsed ind. <0.6 mBrowsed ind. 0.6–1.3 m
12345678910
1.1242120062
2151011031
361002010
430000000
2.5170201040
6111001020
7110102020
800000000
3.9223310052
1090000010
1121000000
1200000000
4.1356108490208
143664360106
15174124043
16134013033
5.172853330135
18151103040
19110002010
2040001000
6.213635130163
222902030120
23131002030
2470001010
7.25170201050
26130101020
2750001000
2800000000
8.292912120111
30140102020
3140000000
3250001000
9.33353520093
34121000020
3590001010
3630000000
10.37140001020
3880001010
3940001000
4000000000

Models of ash saplings density (per 25 m2), estimated using Poisson generalized linear mixed-effects models

Independent variablePredictorEstimateSEz valuePr(>|z|)
Saplings <0.6 m height density per 25 m2(intercept)−4.2570.816−5.216<0.001
AICc = 205.6, AICc0 = 480.9proportion of drought-damaged saplings1.2690.5872.1610.031
RE SD < 0.0001proportion of browsed saplings1.4430.5312.7200.007
soil pH1.2930.1558.346<2e-16
tree layer cover0.0140.0081.8810.060
moss layer cover−0.0720.024−2.9660.003
pine proportion−0.0180.010−1.7300.084
Saplings 0.6–1.3 m height density per 25 m2(intercept)−1.1580.986−1.174<0.001
AICc = 91.2, AICc0 = 119.7shrub layer cover0.0910.0312.9270.003
RE SD = 0.8554oine proportion−0.0180.010−1.7300.084

Models of the proportion of damaged saplings estimated using zero-inflated Beta generalized linear mixed-effects models

Independent variablePredictorEstimateSEz valuePr(>|z|)
Proportion of disease-damaged saplings <0.6 m height (count)(intercept)−7.5711.456−5.201<0.001
AICc = −37.8, AICc0 = 10.5tree layer cover0.0240.0121.9960.046
RE SD = 0.0001soil pH0.7900.2353.3630.001
(zero-inflated)(intercept)62.16725.8512.4050.016
RE SD = 0.011soil pH−14.6736.115−2.4000.016
Proportion of disease-damaged saplings 0.6–1.3 m height (count)(intercept)2.0100.6133.0000.001
AICc = −42.4, AICc0 = 47.3soil pH0.8250.000157,341.000<0.001
RE SD = 1.668summer soil moisture−0.6600.000−129,175.000<0.001
herb layer cover0.0210.00088,930.000<0.001
moss layer cover−1.1230.000−546,917.000<0.001
(zero-inflated) RE SD = 1.016(intercept)1.1570.5941.9480.051
Proportion of drought-damaged saplings <0.6 m height (count)(intercept)−1.2560.675−1.8600.063
AICc = −32.0, AICc0 = −11.4summer soil moisture−0.2050.091−2.2640.024
RE SD = 0.1037pine proportion0.0110.0043.0610.002
(zero-inflated)(intercept)8.0444.6031.7480.081
RE SD = 1.414soil pH−2.2271.146−1.9420.052

Study plots characteristics

No.PlotMature pine trees (%)Mature ash trees (%)Other trees in overstory (%)Soil Reference GroupSoil textureSummer groundwater (cm)Summer soil moisture (%)SOM (%)Soil pH
1234567891011
1.1402040QrOchric Dystric CambisolLS1656.72.704.49
250540Qr 5AOchric Dystric CambisolLS>2005.72.254.21
380020QrOchric Brunic ArenosolS>2004.21.693.70
480020QrOchric Brunic ArenosolS>2004.11.603.62
2.5202050Qr 10BArenic Fluvic CambisolS>2006.12.684.50
650530Qr 15BArenic Dystric CambisolS>2006.02.604.14
750030Qr 20BOchric Brunic ArenosolS>2005.12.234.22
890010BOchric Brunic ArenosolS>2003.61.413.38
3.9102040A 30QrColluvic Calcaric CambisolLS1907.73.124.46
10601030QrColluvic Dystric CambisolS>2007.12.164.09
1180020QrOchric Brunic ArenosolS>2004.71.423.67
1290010QrOchric Brunic ArenosolS>2004.41.253.46
4.13504010QrArenic Calcaric CambisolS>2005.43.455.19
14502030QrArenic Calcaric CambisolS>2005.43.194.58
1560030Qr 10TOchric Brunic ArenosolS>2004.92.274.31
1660030Qr 10TOchric Brunic ArenosolS>2004.82.344.26
5.17202050Qr 10BArenic Calcaric CambisolS>2008.72.334.79
1860530Qr 5BOchric Brunic ArenosolS>2005.62.254.12
1970020Qr 10TOchric Brunic ArenosolS>2005.52.034.02
2090010QrOchric Brunic ArenosolS>2004.81.883.68
6.21302040Qr 10AOchric Brunic ArenosolS>2008.33.084.60
22601030QrOchric Brunic ArenosolS>2008.32.984.45
2370030QrOchric Brunic ArenosolS>2005.51.904.00
2490010QrOchric Brunic ArenosolS>2005.21.543.81
7.25101030A 30L 20TColluvic Dystric CambisolS>2008.02.324.51
2660520L 10A 5QrColluvic Dystric CambisolS>2005.51.904.29
2790010QrOchric Brunic ArenosolS>2005.01.843.80
2890010QrOchric Brunic ArenosolS>2004.91.203.40
8.29201040A 30CColluvic Dystric CambisolS>2005.72.664.68
3060520Qr 15AColluvic Dystric CambisolS>2005.62.184.21
3180010Qr 10BOchric Brunic ArenosolS>2004.02.173.90
3280010Qr 10BOchric Brunic ArenosolS>2004.42.013.86
9.33103040Qr 20AArenic Dystric CambisolS1698.33.185.03
3460520Qr 15AOchric Brunic ArenosolS1857.22.294.24
3580020QrOchric Brunic ArenosolS1857.11.704.11
3690010QrOchric Brunic ArenosolS>2006.91.703.60
10.37101050B 30QpOchric Brunic ArenosolS>2006.32.334.28
3860520Qp 15BOchric Brunic ArenosolS>2005.11.904.04
3990010QpOchric Brunic ArenosolS>2004.91,773.59
4090010QpOchric Brunic ArenosolS>2005.01,723.40

Correlation matrix of studied variables, values of |r|>0_7 bolded

VariableAsh proportionPine proportionSOMsoil pHlitter pHsoil NSOCC:N ratiosoil Casoil Ksoil Naspring moisturesummer moisturecanopy covershrub coverherb covermoss cover<0.6 m saplings density0.6–1.3 m saplings density<0.6 m saplings browsed proportion0.6–1.3 m saplings browsed proportion<0.6 m saplings damaged proportion0.6–1.3 m saplings damaged proportion<0.6 m saplings drought damaged proportion
Ash proportion1.00−0.720.840.840.860.710.41−0.600.790.56−0.410.300.560.170.650.72−0.280.890.710.680.640.820.52−0.18
Pine proportion−0.721.00−0.75−0.83−0.88−0.58−0.190.71−0.70−0.390.64−0.30−0.67−0.13−0.55−0.840.45−0.68−0.37−0.74−0.56−0.74−0.520.19
SOM0.84−0.751.000.890.790.850.49−0.760.880.63−0.640.370.570.170.680.78−0.390.900.640.770.650.770.530.02
soil pH0.84−0.830.891.000.890.770.32−0.820.950.70−0.680.360.630.150.700.83−0.530.920.650.860.680.800.590.02
litter pH0.86−0.880.790.891.000.670.35−0.690.780.52−0.540.410.660.200.630.77−0.460.820.510.790.650.840.60−0.20
soil N0.71−0.580.850.770.671.000.74−0.770.840.63−0.440.380.440.120.620.66−0.450.870.640.800.630.660.510.06
SOC0.41−0.190.490.320.350.741.00−0.190.400.32−0.070.280.210.160.380.23−0.220.510.340.410.350.360.28−0.06
C:N ratio−0.600.71−0.76−0.82−0.69−0.77−0.191.00−0.87−0.620.64−0.41−0.520.01−0.55−0.770.60−0.75−0.51−0.82−0.54−0.60−0.47−0.13
soil Ca0.79−0.700.880.950.780.840.40−0.871.000.74−0.630.410.570.120.660.77−0.530.940.700.870.660.730.550.16
soil K0.56−0.390.630.700.520.630.32−0.620.741.00−0.500.340.270.120.390.43−0.340.720.650.580.570.480.550.24
soil Na−0.410.64−0.64−0.68−0.54−0.44−0.070.64−0.63−0.501.00−0.19−0.370.14−0.48−0.640.48−0.48−0.17−0.56−0.28−0.42−0.31−0.11
spring moisture0.30−0.300.370.360.410.380.28−0.410.410.34−0.191.000.520.290.100.28−0.240.360.150.390.390.260.43−0.06
summer moisture0.56−0.670.570.630.660.440.21−0.520.570.27−0.370.521.000.440.340.63−0.230.540.200.650.360.550.29−0.29
canopy cover0.17−0.130.170.150.200.120.160.010.120.120.140.290.441.00−0.14−0.050.310.200.150.180.190.300.10−0.04
shrub cover0.65−0.550.680.700.630.620.38−0.550.660.39−0.480.100.34−0.141.000.61−0.510.680.570.670.550.610.42−0.01
herb cover0.72−0.840.780.830.770.660.23−0.770.770.43−0.640.280.63−0.050.611.00−0.490.720.380.770.460.690.39−0.14
moss cover−0.280.45−0.39−0.53−0.46−0.45−0.220.60−0.53−0.340.48−0.24−0.230.31−0.51−0.491.00−0.38−0.21−0.46−0.23−0.29−0.22−0.09
<0.6 m saplings density0.89−0.680.900.920.820.870.51−0.750.940.72−0.480.360.540.200.680.72−0.381.000.790.850.740.810.600.06
0.6–1.3 m saplings density0.71−0.370.640.650.510.640.34−0.510.700.65−0.170.150.200.150.570.38−0.210.791.000.580.730.570.520.17
<0.6 m saplings browsed proportion0.68−0.740.770.860.790.800.41−0.820.870.58−0.560.390.650.180.670.77−0.460.850.581.000.650.730.550.12
0.6–1.3 m saplings browsed proportion0.64−0.560.650.680.650.630.35−0.540.660.57−0.280.390.360.190.550.46−0.230.740.730.651.000.550.92−0.02
<0.6 m saplings damaged proportion0.82−0.740.770.800.840.660.36−0.600.730.48−0.420.260.550.300.610.69−0.290.810.570.730.551.000.40−0.04
0.6–1.3 m saplings damaged proportion0.52−0.520.530.590.600.510.28−0.470.550.55−0.310.430.290.100.420.39−0.220.600.520.550.920.401.00−0.10
<0.6 m saplings drought damaged proportion−0.180.190.020.02−0.200.06−0.06−0.130.160.24−0.11−0.06−0.29−0.04−0.01−0.14−0.090.060.170.12−0.02−0.04−0.101.00

Models of the proportion of browsed saplings estimated using zero-inflated Beta generalized linear mixed-effects models

Independent variablePredictorEstimateSEz valuePr(>|z|)
Proportion of browsed saplings <0.6 m height (count)(intercept)−4.5261.490−3.0380.002
AICc = −46.3, AICc0 = 6.9shrub layer cover0.0160.0131.2860.198
RE SD = 0.2340soil pH0.7420.3372.2000.028
pine proportion−0.0050.004−1.2080.227
(zero-inflated)(intercept)825.000454.6001.8150.070
RE SD = 150.6pH−208.500114.900−1.8140.070
Proportion of browsed saplings 0.6–1.3 m height (count)(intercept)−1.6801.097−1.5310.126
AICc = −5.7; AICc0 = 25.0moss layer cover−1.5260.426−3.584<0.001
RE SD < 0.0001summer soil moisture0.8230.2113.892<0.001
(zero-inflated)(intercept)337.120292.5601.1520.249
RE SD = 30.35pH−76.87067.800−1.1340.257
DOI: https://doi.org/10.2478/ffp-2024-0015 | Journal eISSN: 2199-5907 | Journal ISSN: 0071-6677
Language: English
Page range: 195 - 214
Submitted on: Jul 11, 2024
Accepted on: Aug 1, 2024
Published on: Sep 12, 2024
Published by: Forest Research Institute
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2024 Krzysztof Turczański, Agnieszka Andrzejewska, Katarzyna Kaźmierczak, Marcin K. Dyderski, published by Forest Research Institute
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.