Table 1. Characteristics of the Scots pine field trials in Sweden and Russia.
Country Name Latitude, longitude Altitude
(m a.s.l.) 		Continentality index Area
(ha) 		Plot size Spacing
(m) 		No. of
seedlings
2007a Normalb
Sweden Bäcksjön 63°56´N, 20°21´E 75 25.5 18.6 1.3 1×1 2.2×2 2785
Russia Syktyvkar 61°40´N, 51°03´E 132 38.5 31.9 1.1 1×1 2×2 2128
a Continentality index calculated per Lockwood (1985).
b Average over 10-year period 1998–2007 from SMHI (2018) at Bäcksjön and Novakovskiy and Elsakov (2014) at Syktyvkar.
Table 2. Geographic origin of the populations studied.
Provenance designation Latitude, longitude Altitude (m a.s.l.)
Populations from Sweden
Almajärvi 68°02´N, 23°08´E 320
Lainio 67°40´N, 22°22´E 350
Tärendö 67°05´N, 22°40´E 250
Harads 66°10´N, 18°54´E 200
Arvidsjaur 65°35´N, 19°40´E 400
Skellefteå 65°00´N, 20°30´E 150
Ramsele 63°30´N, 16°25´E 400
Sollefteå 63°00´N, 17°00´E 200
Stöde 62°25´N, 16°37´E 200
Ånge 62°15´N, 15°55´E 300
Edsbyn 61°30´N, 15°30´E 400
Malung 60°30´N, 13°45´E 450
Populations from Russia
Ertom 63°33´N, 47°50´E 130
Ertom 63°31´N, 47°45´E 130
Mitrofanovo 63°12´N, 56°03´E 140
Kyltovo 62°12´N, 51°00´E 160
Komsomolsk 62°07´N, 56°36´E 170
Ust-Kulom 61°41´N, 53°40´E 190
Vilgort 61°39´N, 50°46´E 120
Sherjg 61°36´N, 54°19´E 110
Kuratovo 60°55´N, 49°30´E 180
Koygorodok 60°27´N, 51°00´E 150
1

Fig. 1. Location of the Scots pine populations (●), stands with selected plus trees (■) and field trials (*).

Table 3. Geographic origin of the open-pollinated families studied.
Stand designation Number of OP families Latitude, longitude Altitude (m a.s.l.)
Half-sib families from Sweden
Ranesvare 6 66°37´N, 20°27´E 200
Moskosel 7 66°00´N, 19°59´E 290
Arvidsjaur 6 65°46´N, 20°03´E 375
Half-sib families from Russia
Ust-Chilma 11 65°23´N, 52°21´E 50
Usinsk 9 66°05´N, 57°30´E 75
2

Fig. 2. Relationships between heat sum and relative shoot elongation estimated from the sigmoid function y = 1/(1 + be(rx+c/x)) based on: (a) populations at (1) Bäcksjön and (2) Syktyvkar test sites; and (b) Swedish (3, 5) and Russian (4, 6) material in Bäcksjön (3, 4) and Syktyvkar (5, 6) field trials, respectively.

3

Fig. 3. Temperature sum accumulation over Julian days for populations at Bäcksjön (1) and Syktyvkar (2) test sites. The temperature sum at 10% (○, ●) and 90% (□, ■) estimated shoot elongation is indicated by symbols in Bäcksjön (○, □) and Syktyvkar (●, ■) field trials, respectively.

Table 4. Selected date and corresponding actual mean shoot elongation representing growth onset and cessation.
Onset Cessation
Field trial Date Degree days (%) Date Degree days (%)
Syktyvkar May 20 50.4 8.7 July 1 360.4 93.1
Bäcksjön May 24 36.6 11.1 June 27 296.3 88.2
Table 5. Onset of growth, parameter estimates from Model 1 with p-values.
Source Parameter Estimate Standard error p-value
Site s –0.02363a 0.00559 <0.0001
Region of origin r 0.02013 0.00613 0.0012
Regression coefficient for latitude d  0.00728 0.00131 <0.0001
a differences between Russian and Swedish test sites include dates of measurement and other site-specific environmental effects.
Table 6. Cessation of growth, parameter estimates from Model 1 with p-values.
Source Parameter Estimate Standard error p-value
Site s 0.04869a 0.008523 <0.0001
Region of origin r 0.02685 0.00937 0.0045
Regression coefficient for latitude d 0.00932 0.00199 <0.0001
a differences between Russian and Swedish test sites include dates of measurement and other site-specific environmental effects.
Table 7. Narrow-sense heritabilities (h2 ± S.E.) of Scots pine phenological traits.
Model 2 Model 3
Field trial Onset Cessation Onset Cessation
Syktyvkar (Russia) Not estimable 0.021 ± 0.052 0.084 ± 0.251 Not estimable
Bäcksjön (Sweden) Not estimable 0.061 ± 0.151 0.482 ± 0.181 0.501 ± 0.165