West Virginia Seed Sources of Balsam Fir

Research Bulletin 1191-99

Spring Bud Break

Foliage of single-needled conifers, including Abies sp., can be severely damaged if buds break dormancy and new foliage is exposed before the last frosts/freezes occur in the spring. Earlier studies found that trees of a Canaan Valley seed source of balsam fir broke dormancy somewhat later in the spring than did trees of a North Carolina (Fraser fir) origin and considerably later than Pennsylvania, New York, and Nova Scotia origins (Brown 1983, Brown 1998, Brown 1999). For this study, all trees in the experimental planting were rated for bud break and shoot development at weekly intervals from May 7 to May 29, 1996, and again in 1997, beginning on May 1 and continuing until May 29. In those ratings, a five-point scale was used: 1 = buds not expanded, 2 = buds swelling, 3 = minor foliage exposed, 4 = major foliage exposed, and 5 = foliage fully exposed (Figure 14). Details are presented for the May 14, 22, and 29, 1996, ratings. Evaluations for the May 1 rating are not included because buds on most trees showed little expansion, and there were only minor differences in observations.

Figure 14. Stages of bud break on trees: 1 = tight, buds not swelling; 2 = buds swelling; 3 = slight exposure of new needles; 4 = major exposure of new needles; 5 = needles fully exposed.

Differences Between Locations
There were no significant differences (at the 5% probability level) in average bud development of trees from different areas for the three evaluations reported, apparently because of wide variation between individual trees and seed sources within areas. On May 14, trees from all collections showed obvious signs of bud enlargement, with averages for the five West Virginia collections ranging from 2.14 to 2.20 and those from North Carolina averaging slightly higher at 2.45. By May 22, development of buds had progressed to the point where North Carolina origin trees were showing minor foliage exposure (rating 3.27), while average development for the five West Virginia origins had not progressed quite so far, with ratings of 2.72 to 2.94. On May 29 when the last set of evaluations was made in 1996, trees from all locations had progressed to the point where there was exposed foliage on trees of all seed sources from each area, with the average being highest for North Carolina trees (Table 7; Figure 14).

Table 7. Means, Standard Deviations, and Ranking of Bud Break/Bud Development on Trees of Individual Half-Sib Families (West Virginia) and Stand Collections (North Carolina).
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Blister Run, WV
350	2.10	9	17	2.67	13	13	3.57	14	12
351	2.12	6	21	2.81	9	24	3.83	14	22
352	2.06	8	12	2.69	24	15	3.59	15	13
353	2.11	10	19	2.73	12	19	3.72	13	19
355	2.03	13	4	2.54	15	4	3.48	12	5
356	2.08	9	13	2.70	13	16	3.68	13	15
360	2.14	12	25	2.92	13	28	3.92	14	26
361	2.41	16	49	3.19	17	48	4.40	17	48
363	2.09	16	15	2.70	15	16	3.65	14	14
364	2.00	6	1	2.29	13	1	3.03	16	1
Mean	2.14	12	1	2.72	17	1	3.69	16	1
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Blister Swamp, WV
366	2.04	12	7	2.59	15	7	3.50	16	6
367	2.03	13	4	2.57	12	6	3.40	11	3
368	2.08	10	13	2.66	18	12	3.68	18	15
369	2.05	13	10	2.65	19	8	3.51	16	8
372	2.11	13	30	2.87	15	27	4.00	15	29
373	2.16	16	28	2.84	18	26	3.92	16	26
375	2.13	17	23	2.78	20	23	3.91	16	25
378	2.35	20	46	3.17	18	46	4.35	16	47
379	2.12	17	21	2.78	16	22	3.89	15	24
380	2.13	12	23	2.75	17	20	3.70	19	17
Mean	2.20	15	4	2.76	17	3	3.79	18	2
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Stone Coal Run, WV
381	2.11	12	19	2.76	16	21	3.82	11	22
384	2.18	11	31	2.98	16	35	4.05	13	35
385	2.30	11	42	3.07	13	42	4.01	12	31
386	2.21	14	35	3.02	13	37	4.10	12	39
387	2.14	15	26	2.81	21	25	3.81	17	21
389	2.31	18	43	3.17	19	46	4.20	19	45
390	2.20	36	34	3.00	14	36	4.05	14	35
393	2.15	19	27	2.92	18	29	4.02	15	32
394	2.22	14	38	2.98	18	34	4.02	15	32
395	2.10	11	17	2.68	21	14	3.71	21	18
Mean	2.19	15	3	2.94	15	5	3.98	17	5
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Canaan Valley-State Park, WV
397	2.04	16	7	2.62	21	8	3.52	21	9
398	2.00	6	1	2.38	16	2	3.22	20	2
399	2.19	17	32	2.93	14	31	4.09	15	37
400	2.04	15	7	2.64	17	10	3.50	16	6
402	2.02	12	3	2.52	19	3	3.41	14	4
403	2.36	15	47	3.12	21	45	4.40	12	48
404	2.21	16	35	2.96	19	33	4.02	17	32
406	2.26	18	41	3.05	18	40	4.09	18	37
408	2.03	14	4	2.55	23	5	3.52	22	9
409	2.21	14	35	3.05	16	40	4.10	14	39
Mean	2.14	15	1	2.78	19	4	3.79	20	2
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Canaan Valley-Cortland Road, WV
416	2.09	17	15	2.71	16	18	3.75	16	20
417	2.32	20	44	3.11	18	44	4.00	12	29
418	2.19	15	32	2.94	14	32	4.00	12	29
419	2.24	17	40	3.04	21	38	4.12	17	41
424	2.04	8	10	2.64	9	10	3.54	9	11
425	2.22	11	38	3.04	16	39	4.13	17	42
426	2.16	19	28	2.93	16	30	3.93	15	28
428	2.33	13	45	3.09	17	43	4.17	13	43
Mean	2.17	17	5	2.75	16	2	3.96	17	4
SS No.1	5/14/96			5/22/96			5/29/96
	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2	Mean Rtng3	S.D. % Mean	Rank2
Roan Mountain, North Carolina
24	2.37	13	48	3.33	15	50	4.24	16	46
410	2.52	15	50	3.21	10	49	4.42	19	50
Mean	2.45	13	6	3.27	19	6	4.33	19	6
Variable
Mean	2.18	-	-	2.86	-	-	3.81	-	-
Mean Comparisons Among Locations
4pF	0.241	-	-	0.058	-	-	0.108	-	-
5LSD0.05	-	-	-	-	-	-	-	-	-
Mean Comparisons Among Individual Seed Sources
4pF	<0.001	-	-	<0.001	-	-	<0.001	-	-
5LSD0.05	0.17	-	-	0.27	-	-	0.34	-	-
1OARDC Seed-Source Accession/Identification Number. 2Ranking in array of means (from lowest to highest) for seed sources for trait indicated. 3Bud Break Rating: 1 = Buds Tight (not swelling); 2 = Buds Swelling; 3 = Slight Exposure of New Needles; 4 = Major Exposure of New Needles; 5 = Needles Fully Exposed. 4pF: probability of statistical significance for analysis of variance F test. 5LSD0.05: Least Significant Difference at the 5% probabililty level for comparing differences between location and seed source means.

Differences Between Seed Sources
There were highly significant differences in bud development/bud break for individual seed sources for all times of evaluation. For all rating periods, trees of the two North Carolina collections had bud development that was at or near the most advanced, with rankings of 48 and 50, 50 and 49, and 46 and 50, for the three rating periods for SS-24 and SS-410, respectively. Of the West Virginia origins, trees of SS-361 from Blister Run showed the earliest bud development and foliage exposure for all three rating times; however, trees of six of 10 seed sources from that area were also among the one-third showing the slowest development, including SS-364 which was the slowest to develop for all ratings. As a group, approximately half of the trees from Blister Swamp collections were among the slowest developing and only one among the fastest, while approximately half of Stone Coal Run half-sib families were among the first to break dormancy and only one was among the slowest one-third (Tables 3, 4, 7; Figure 14). A comparison of bud break/foliage exposure data for the May 14, 22, and 29, 1996, evaluations with those for May 15, 23, and 30, 1997, showed correlations of r = 0.76, 0.81, and 0.82,respectively, all of which were significant at less than the 0.001 probability level. Comparisons also showed that the appearance of new growth was somewhat earlier in 1996 than in 1997. Similar results were noted in another study in which evaluations were made between stand collections of balsam fir from Canaan Valley and Roan Mountain (Brown 1998).

Differences Within Seed Sources
Standard deviations within individual seed sources for time of bud break/foliage exposure ranged from 6 to 36 percent, 9 to 24 percent, and 9 to 22 percent, respectively, for the May 14, 22, and 29 dates (Table 7). For individual trees, stage of bud development for North Carolina trees ranged from 2.00 to 3.00 for the May 14 rating, 2.00 to 4.00 for May 22, and 2.50 to 5.00 for the May 29 date. For trees of SS-364, which were slowest to develop, ratings were 2.00 to 2.50 on May 14, 2.00 to 3.00 on May 22, and 2.00 to 4.00 on May 29. For SS-361, the earliest to develop, ratings were 2.00 to 3.00, 2.00 to 4.00, and 2.50 to 5.00, respectively, for the three rating periods.