Eepr-inted from JOull.NA:t. OF FORESTRY, "\7oL. 55, No. 3, March 1957 Purchased by the Forest Service for Official Use Consistency of Bud Bursting in Douglas-Fir William G. Morris, R.. R.. Silen and H. lrgens-Moller1 POSSIBILITY OF STRONG genetic con­ their progeny can be planted to ad­ Study Areas and Early trol over time of bud bursting in vantage in areas where late spring Observations Douglas-fir has been suggested by frosts are likely to occur. Observa­ In 1915, plantations were estab­ recorded observations extending tions in the early 1930's showed lished at Wind River, Washington, over a period of 22 years. If more that tardiness in beginning annual at an elevation of 1,100 feet, and detailed studies now under way growth apparently does not lessen near Mt. Hood, Oregon, at eleva­ bear out these observations, the a tree's chance of making the same tions of 2,800 and 4,600 feet (Fig. knowledge will have important ap­ height growth as one having an 1). Seed for these plantations came plication in selecting seed for early start. from 120 parent trees at 13 differ- planting forest lands in the Doug­ las-fir region of the Pacific North­ west. Records taken since 1933 on ; three plantations in Oregon and Washington indicate that relative order of vegetative bud bursting is constant between progenies from widely separated seed sources growing in the same plantation. This relationship apparently holds true regardless of altitude of plan­ tation, date when growing season • began, or stand age. Repeated ob­ servations of individual wild trees have further shown that naturally seeded trees growing side by side burst their buds at different dates but in about the same order year after year. " Growth of a Douglas-fir tree both in height and in branch elongation is resumed each spring from the dormant buds formed the previous growing season. If freezing tem­ peratures occur when the buds are in the tender, freshly opened stage, they are usually damaged and no ' growth occurs that year. Late bud bursting protects a tree against this damage. Time of bud bursting in relation to spring frosts is therefore impor­ ., nr tant to tree growth. If late-bud­ '" "' 121• bursting trees transmit this charac­ LEGEND teristic to succeediilg genertions, Principal range of Pacific coast form of Douglas fir in Oregon and Washington 1Morris and Silen are research forest­ 0 Plantations ers, Pacific Northwest Forest and Range Expt. Sta., Forest Service, U. S. Dept. x Seed sources Agrie., Portland, Ore. Irgens-Moller is a graduate student, Oregon State College, FIG. 1.-Locations and elevations 'bf seed sources and test plantations on which Corvallis, Ore. Douglas-:fir bud bursting was observed. 208 MA.Bea 1957 209 ent localities west of the Cascade drainage resulted in warm spring again used at Wind River for sam­ Range, from Darrington in north­ days and cold sprnig nights. (5) ples of three to six trees from each ern Washington to Benton near Time of bud bursting (early or seed source. Due to the lateness of Corvallis, Oregon, 250 miles south. late) had no apparent relation to sampling on the lower Mt. Hood Seed source elevations ranged from annual height growth. plantation, however, terminal shoot 100 to 3,850 feet. Plantation lay­ elongation in inches was estimated out was identical in that progenies Seed Source Ranking for ten branches in the upper from each parent tree were planted crown. Ten trees from each seed Progenies from the 13 seed in the same relative position at the source were used as a sample. On sources have been rated at various three locations. This was <lone to the upper Mt. Hood plantation rel­ times since 1933 for stage of bud eliminate personal bias in the selec­ ative .bud development was deter­ bursting. These ratings are believed tion of planting site. mined through the same scheme of valid for purposes of comparison These plantations, with an eleva­ sampling as on the lower planta­ even though they have differed tional range of 3,500 feet, have fur­ tion. Buds were classified as (1) somewhat in technique and inten­ nished unusual material for com­ tight, (2) slightly swelling, (3) sity of sampling, and though it has parison. From observations in 1933 swelling but not burst, or ( 4) not always been possible to make and 1934, Munger and Morris2 burst. The same system of weight­ observations at the same stage of found that: (1) Bud bursting on ing was applied to data from the growth. the two ·Mt. Hood plantations aver­ 1955 observations as those in the • In 1933, 1934, and 1936, 10 to age 2 to 4 weeks later than at Wind 1930's, except on the lower lift, 15 offspring from each of 4 to 21 River. (2) In some years, buds Hood plantation, where ''inches of parents were classified in one of the burst as much as a month earlier average shoot elongation'' were following groups: (1) All buds than in others. (3) Ranking of the compared to obtain ranking. tight. (2) Buds ·bursting on most 13 seed sources according to date but not all branches; new needles of bursting was nearly the same for Bud Bursting Consistency on greater part of tree not spread the early- as for the late-bursting out in normal brush-like arrange­ Despite the influence of normal years. (4) Trees with earliest ment. (3) New needles spread out sampling error and differences in bursting buds came from localities on entire tree; new shoots noticea­ rating methodology, the rankings having warm spring days and bly elongated. In order to rank the are remarkably consistent (Table nights, such as occur in wide val­ seed sources as to earliness of bud 1). The early-bursting group­ leys. Those with intermediate bursting, the percent of progenies Carson, Portland, and Lakeview­ bursting buds came from higher falling within each classification rank in the upper part of all the elevations, with cold spring days were assigned weights of 1, 2, and lists. The late-bursting group­ and nights. Trees with latest burst­ 3, respectively. The three weighted Hazel, Forston, and Benton-are ing buds came from localities in percentages were then added for always found near the bottom. narrow valleys where cold air each group of seed-source prog­ Records by Morris for several "Munger, Thornton T., and William G. enies, and the sources listed by trees in the Portland area further Morris. Growth 0£ Douglas·fir trees of ranking. support the view that earliness of known seed source. U. S. Dept. Agric. Tech. Bul. 537, 40 pp., illus. 1936. In 1955, these classifications were bud bursting of individual trees TABLE !.-THIRTEEN SEED SOURCES OF DOUGLAS-FIR RANKED ACCORDING TO STAGE OF BUD BURSTING OF PROGENIES ON GIVEN DATES IN THREE PLANTATIONS 1933 1955 (June 9) (June 30) (June 29) 1934 1936 (June 23) (July 7) (July 7) Lower2 Upper8 (May 3) (May 21) Lower' Upper Wind River Mt.Hood Mt. Hood Wind River Wind River Wind River Mt.Hood Mt.Hood Rank' (1,100 feet) (2,800 feet) ( 4,600 feet) (1,100 feet) (1,100 feet) (1,100 feet) (2,800 feet) (4,600 feet) 1 Portland (Portland Carson Portland Carson Carson Lakeview 2 Carson and Carson Portland Carson Portland Portland Portland 3 Lakeview burst Lakeview Lakeview Granite Falls Race Track Carson 4 Gates earliest.) Gates Gates Lakeview Wind River Palmer 5 Santiam Santiam Santiam Race Track Gates Santiam 6 Race Track Race Track Race Track Gates Santiam Darrington 7 Palmer Palmer Palmer Palmer Lakeview Race Track 8 Wind River (Granite Falls, Wind River Wind River Darrington Pahfier Gates 9 Granite Falls _ Darrington, Granite Falls Granite Falls Santiam Darrington Wind River 10 Benton Benton, Fortson -Darrington Benton Wind River Hazel Granite Falls 11 Darrington andHazel burst Benton Darrington Benton Granite Falls Hazel 12 Fortson latest.) Fortson Fortson Hazel Benton Benton 13 Hazel Hazel Hazel Fortson Fortson Fortson 11 is most advanced; 13, least. s:Examined when bursting was too far advanced to permit ranking other than by two broad groups. 8E:xamined when bursting was not sufficiently advanced to permit ranking other than by two broad gr-oups. 'Exa.mined when bursting was too far advanced to accurately recognize differences between the earlier bursting seed sources. 210 JOURNAL OF FORESTRY remains co11Sistent through the TABLE 2.-SELECTED BuD-BURSTING DATES OP' Two DOUGLAS-FI& TREES OBSERVED NEAR PORTLAND, OREGON/ DURING THE PERIOD. 1942-55 years. For 14 years, two trees less than 200 feet apart have, on the Bud-bursting date Iriterval 1 2 average, burst tl;teir buds 7.8 days Item Year Tree Tree (days) apart. This is statistically signif­ Greatest interval 1952 April 29 May 11 12 1943 4 6 2 icant at the 1 percent level, with Least interval May May Earliest season 1947 April 14 April 24 10 standard error of ± 1.07. Tree 1 Latest season 1955 May 18 May 27 9 invariably burst its buds before lg50 feet elevation. Tree 2 (Table 2). The narrow range in interval between bud 3 to 15 years, show the same con­ from more detailed studies. How­ bursting dates, regardless of ex­ sistency. ever, the observations do strength­ tremes in climatic variation during All the above-cited observatio11S en the longheld view that Douglas­ this time, is remarkable. Pheno­ suggest a strong genetic control fir planting stock should be matched logical records irom nine other over time of bud bursting in Doug­ closely in growth period to the area trees, observed over periods of from las-fir. Proof must of course come to be planted.