Interaction between stem damage, crown vitality and growth performance of European yew in Central–East Europe

Denisa Sedmáková; Milan Saniga; Ján Pittner; Jaroslav Vencurik; Robert Sedmák

doi:10.2478/geochr-2020-0029

Figures & Tables

a) Location of the study sites STR (Strazov Mts.), PAV, LAG (Stare Hory Mts.) and VFA (Great Fatra) in Slovakia; b) climate diagrams showing mean monthly courses of temperature and precipitation sums; climate data were derived from KNMI monthly E-OBS 0.25° gridded observations (E-OBS 19.0e); c) number of trees in crown and stem damage classes according to localities.

a) Healthy-looking yew with undamaged stem and crown; b) multiple stem, more than 50% of the stem circumference is stripped by deer, crown with transparency of more than 50%.

Degree of bark stripping damage related to mean height of yew trees in Slovakia. SE—standard error.

Summarisation of mean values and their differences among a) sex categories (non-significant differences in Gnekro and Pbeech between male and female trees are not displayed) and b) localities of the yew trees in surrounding stand characteristics Gtrees, Gnekro, Gt, Gbeech and Pbeech; Gtrees—basal area of living trees, Gnekro—basal area of standing dead trees and stumps, Gbeech—basal area of living beech trees, Pbeech—proportion of beech, LAG (Lackov Grun), PAV (Pavelcovo), STR (Strazov), VFA (Velka Fatra), L and R—left and right y-axis.

Sex-specific mean raw tree-ring width (TRW) chronologies of yew according to four localities. Dashed (male) and dotted (female) lines on left (L) y-axis denote standard error (SE) of the mean TRW chronology value. Dashed (male) and dotted (female) lines on the right (R) y-axis refer to the number of sampled trees, from which the mean chronology was constructed. LAG (Lackov Grun), PAV (Pavelcovo), STR (Strazov) and VFA (Velka Fatra); black arrows point to significant within-site differences in growth between male and female chronologies (sequences of sex-specific mean chronologies, in which curves of SE do not overlap), white arrows show release as a response to known cutting treatment.

Cumulative radial growth of female (blue line) and male (red line) yew trees according to four localities (L-left y-axis): LAG (Lackov Grun), PAV (Pavelcovo), STR (Strazov) and VFA (Velka Fatra). Number of corresponding averaged male (dashed line) and female (dotted line) trees displayed on the right (R) y-axis.

Raw tree-ring width chronologies of damaged/undamaged yew trees according to crown transparency status in four localities: LAG (Lackov Grun), PAV (Pavelcovo), STR (Strazov) and VFA (Velka Fatra). Values of mean TRW (solid lines) and corresponding standard error (dashed line for undamaged and dotted line for damaged trees) are displayed on left (L) y-axis. Right (R) y-axis displays respective values of sampling depth.

Raw tree-ring width chronologies of damaged/undamaged yew trees according to stem status in four localities: LAG (Lackov Grun), PAV (Pavelcovo), STR (Strazov) and VFA (Velka Fatra). Values of mean TRWs (solid lines) and corresponding standard error (dashed line for undamaged and dotted line for damaged trees) are displayed on left (L) y-axis. Right (R) y-axis displays respective values of sampling depth.

Results of the general linear model, which evaluates interactions of stem and crown damage in relation to yew female and male radial growth in selected periods: a) 2010–2015, b) 2005–2015, c) 2000–2015. Main effect (F) calculated for means of independent continuous variables (DBH). Vertical lines denote 0.95 confidence interval.

Plotted A-values against the sines of the included angle for all taller neighbours of central yew at localities a) LAG (Lackov Grun) and b) STR (Strazov). For A-value above 2.0, the sine value of the respective angle reaches Gt mainly of more than 0.8, which allows to select the threshold for selective release cutting of trees i in surrounding of the central yew trees j. In the cutting scheme, trees in the right upper corner are marked to be removed.

Example of cutting scheme (with cross-marked central yew tree in the middle of the three sampling plots) at localities a, b) LAG (Lackov Grun) and c) STR (Strazov). The set criteria of release cut are A-value = 2.5, Tdist < 0 and sineϑ ≥ 0.8. On two sampling plots at locality Lackov Grun with comparable stand basal area (density) a) G = 37.0 m2ha-1b) G = 38.8 m2ha-1, the intensity of release cut is higher (24.35% from basal area) on the plot a) with unfavourable canopy closure (Gt = 20.15), and on the plot b) with more favourable canopy closure (Gt = 11.91), removal of one neighbouring tree is planned. c) In low stand density (G = 17.2 m2ha-1) and low canopy closure (Gt = 4.78), cutting intervention is not indicated. In the figure, circles refer to position of trees on the sampling plot and their size corresponds to DBH of trees; red colour marks trees to be removed by the release cutting, green colour marks living trees, and grey colour marks of standing dead trees and stumps.

Basic statistics of European yew tree-ring series and standardised chronologies for the common periods in four localities of Slovakia

Locality				Raw series				Standardised chronology
	Time span	Nt	MSL	TRW	SD	MSs	AC1	RBT	EPS
LAG	1766^-2015	37	127	0.713	0.44	0.251	0.81	0.526	0.976
PAV	1897^-2015	48	94	0.885	0.52	0.257	0.76	0.303	0.952
STR	1782^-2015	30	204	0.551	0.32	0.236	0.83	0.187	0.869
VFA	1755^-2015	35	185	0.495	0.27	0.270	0.88	0.224	0.967

Parameter estimates and goodness-of-fit statistics of the generalised linear regression model applied to test the relationship of stand canopy closure (shading) and crown damage (transparency) of yew adult trees_

Parameter estimates
Effect	Level of effect	Column	Estimate	SE	p
Intercept n1	1	0.11	0.36	0.77	0.77
Intercept n2	2	2.48	0.44	0.00	0.00
Intercept n3	3	4.94	0.65	0.00	0.00
Gt	4	−30.09	0.02	0.00	0.00
Scale		1.00	0.00
Goodness-of-fit statistics
	Deviance	Scaled deviance	Pearson’s chi²	Scaled P. chi²	AIC	BIC	Loglikelyhood
D_f	359	359	359	359
Statistic	263.04	263.04	383.01	383.01	271.04	282.23	−131.52
Stat/D_f	0.73	0.73	1.07	1.07

Stand characteristics Gtrees, Gnekro, Gt, Gbeech and Pbeech surrounding central yew trees, their mean values and inter-correlations

	Mean	SD	G_nekro(m²ha^-1)	G_trees(m²ha^-1)	Gt	G_Beech(m²ha^-1)	P_Beech (%)
G_nekro	13.0	11.60	1.00	−0.51	−0.41	−0.29	0.01
G_trees	31.1	8.50	−0.51	1.00	0.62	0.67	0.04
Gt	17.0	9.36	−0.41	0.62	1.00	0.44	0.06
G_beech	18.6	6.98	−0.29	0.67	0.44	1.00	0.71
P_beech	59.6	18.54	0.01	0.04	0.06	0.71	1.00

Description of the study sites

Study area	Lackov Grun	Pavelcovo	Strazov	Velka Fatra
Orographic unit	Stare Hory Mts.	Stare Hory Mts.	Strazov Mts	Great Fatra
Name	LAG	PAV	STR	VFA
Type of management	managed forest with the main protection function—soil erosion, water retention	managed forest with the main wood production function, 7% of plots are special purpose forests with main protection function	52%—managed forest with the main protection function—soil erosion, water retention 48%—managed forest with the main wood production function	managed forest with the main protection function—soil erosion, water retention, 10%—managed forest with the main wood production function
Altitude (m asl)	603–688	640–720	710–930	940–1,030
Exposition	NE	S, NE	NW–N–NE	NW–N–NE
Slope inclination	20–40°	10–30°	25–45°	20–40°
Ground surface	sampling plots had no parent rock present on the surface ground	sampling plots had no parent rock present on the surface ground	13% of sampling plots had parent rock present on the surface ground	25% of sampling plots had parent rock present on the surface ground
Canopy cover estimation	0.7–1.0 all plots placed inside the forest stands	0.7–1.0 57% of plots placed inside the forest stand 43% of plots placed in cut forest where yew trees were present in group of trees of remaining mature stand	0.4–1.0 83% of plots placed inside the forest stands 17% of plots placed in cut forest where yew trees grow solitary or in small groups of trees	0.7–1.0 all plots placed inside the forest stands
Sign of disturbance (based on stumps being present on the sampling plot)	all plots	all plots except two	all plots	1/3 of plots were recorded as having no disturbance sign
Relief	93% of plots were established in the middle and upper part of the hill (slope)	except one, all plots were established in the middle and upper part of the hill (slope)	plots were established mainly (74%) in the middle part of the hill (slope)	plots were established in the middle and upper part of the hill (slope)
Number of plots	30	30 (13-fieldmapped)	23	31
Size of the plot (m²)	500	500 (one plot—2,500)	500 (1x300; 2x200)	500
Radius (m)	12.62	12.62	12.62 (1x9.77; 2x7.98)	12.62
Number of tree species	13	10	9	9
Year of the sampling	2017	2015	2016	2017
Disturbance	small scale signs of disturbance—selfthining or windthrow of trees	regeneration cut has begun in forest stands	small scale signs of disturbance—selfthinning 17% of plots—finished regeneration cut	small scale signs of disturbance—selfthining or windthrow of trees 6% of plots—regeneration cut

Two-way table showing no relationship between stem and crown damage of European yew trees expressed in relative frequencies (Pearson’s chi-square = 15_69; Df = 9; p < 0_07)

Degree		Stem damage
Crown transparency	1	2	3	4	All
1	3.33	17.33	8.00	2.00	30.67
2	12.00	13.33	10.67	4.67	40.67
3	2.00	10.67	6.67	4.00	23.33
4	0.67	2.00	2.67	0.00	5.33
All	18.00	43.33	28.00	10.67	100.00

Basic description of sampled male and female trees of European yew at four localities in Slovakia

Locality	Sex	Trees	DBH (cm)		Height (m)		G(cm²)		Crown width (m)		Crown length (m)		Pith age (years)
Locality	Sex
		Nt	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
LAG	♂	16	23.9	3.70	11.2	1.49	0.05	0.01	5.5	0.94	8.0	1.16	137	33.3
	♀	21	21.6	4.79	9.8	2.69	0.04	0.02	5.8	0.95	7.4	2.48	135	22.0
PAV	♂	27	21.1	7.14	10.1	2.07	0.02	0.02	5.1	1.37	7.1	2.05	101	10.8
	♀	21	20.3	5.64	10.6	2.33	0.02	0.02	5.0	1.25	7.6	2.31	102	10.6
STR	♂	17	30.3	7.77	9.6	2.65	0.08	0.04	7.1	1.55	7.4	2.31	206	33.3
	♀	13	26.3	9.25	8.1	2.01	0.06	0.05	6.2	1.30	5.7	1.89	223	11.8
VFA	♂	18	26.1	7.99	9.3	2.24	0.06	0.03	5.0	1.12	7.1	2.14	187	52.9
	♀	15	21.6	4.52	7.7	1.15	0.04	0.02	4.8	0.94	5.3	1.27	199	35.7
	○	2	27.0	4.17	8.8	0.78	0.06	0.02	4.7	0.40	6.2	1.06	235	5.0
ALL		150	23.6	7.12	9.7	2.34	0.04	0.03	5.5	1.37	7.0	2.15	154	53.9

Results of ANOVA showing summary of all effects (locality and sex) of trees in stand characteristics Gtrees, Gnekro, Gt, Gbeech and Pbeech surrounding focal yew trees

			G_nekro (m²ha^-1)				G_trees (m²ha^-1)				Gt
Effect	D_f	SS	MS	F	p	SS	MS	F	p	SS	MS	F	p
Intercept	1	23229	23229	251	0.00	103581	103581	2101	0.00	29759	29759	575	0.00
Locality	3	5299	1766	19.07	0.00	2551	850	17.2	0.00	3690	1230	23.8	0.00
Sex	1	0.21	0.21	0.0	0.96	224	224	4.5	0.04	579	579	11.2	0.00
Error	114	10557	92.6			5619	49.3			5900	51.7
Total	118	15882				8567				10485

		G_Beech (m²ha^-1)							P_Beech (%)

Effect	D_f	SS		MS	F		p	SS	MS		F		p
Intercept	1	36796		36796	849		0.00	391216	391216		1279		0.00
Locality	3	466		155	3.58		0.02	6059	2020		6.6		0.00
Sex	1	267		267	6.1		0.01	168.7	169		0.55		0.46
Error	114	4939		43.3				34859	305.8
Total	118	5697						40973

Interaction between stem damage, crown vitality and growth performance of European yew in Central–East Europe

Figures & Tables

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Fig A1

Fig A2

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Fig 9

Basic statistics of European yew tree-ring series and standardised chronologies for the common periods in four localities of Slovakia

Parameter estimates and goodness-of-fit statistics of the generalised linear regression model applied to test the relationship of stand canopy closure (shading) and crown damage (transparency) of yew adult trees_

Stand characteristics Gtrees, Gnekro, Gt, Gbeech and Pbeech surrounding central yew trees, their mean values and inter-correlations

Description of the study sites

Two-way table showing no relationship between stem and crown damage of European yew trees expressed in relative frequencies (Pearson’s chi-square = 15_69; Df = 9; p < 0_07)

Basic description of sampled male and female trees of European yew at four localities in Slovakia

Results of ANOVA showing summary of all effects (locality and sex) of trees in stand characteristics Gtrees, Gnekro, Gt, Gbeech and Pbeech surrounding focal yew trees

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