Forest Genetic Resources No 23.
J. E. Kuser, A. Bailly, A. Franclet, W. J. Libby, J. Martin, J. Rydelius, R. Schoenike, and N. Vagle
180 clones of Sequoia sempervirens, representing 90 provenance locations throughout the natural range and elevations from 24 m to 945 m, are being tested for survival and height growth at 3 plantation sites in the U.S., 2 in France, and plots in Spain, Britain, and New Zealand. Early results indicate that provenances from the north end of the range survive best in South Carolina and suffer less frost damage in northern France. Provenances from Humboldt County have grown relatively tall at Brookings, Oregon; Lafayette, California; and Etançon, France. Although there are no full scale plantations of the test at warmer locations, hedge orchards at Davis, California and Malissard, France indicate that more southern provenances (Santa Cruz and Monterey counties) may grow as fast or faster on warm sites. Preliminary recommendations for seed collections in Del Norte and Napa counties are made for further testing of cold tolerance, but it is not yet possible to recommend sources for warmer areas.
Figure 1. Range of coast redwood, Sequoia sempervirens (Little, 1971)
Redwood is one of the world's botanical wonders. The tallest tree in the world is a 110 m redwood in Redwood National Park, near Orick, California (American Forests, 1990). Redwood is a fire-adapted species with thick, fire-resistant bark and the ability to stump-sprout from a ring of burl tissue which surrounds the root-collar zone. It is
unlike most conifers in this sprouting ability, and can grow new branches along its entire trunk to replace any killed by fire (Burns and Honkala, 1990).Coast redwood, Sequoia sempervirens (D.Don.) Endl. is one of the temperate zone's fastest growing trees. On the best sites, redwood can produce 30 m3 of wood per hectare per year (Fritz, 1945). Because redwood heartwood is decay-resistant, it is used for outdoor products such as siding, decking, garden furniture, stakes, shakes, and slatsfor air-conditioning cooling towers. Its decay resistance and beauty make redwood lumber worth more than pine or Douglas-fir. In California, for example, late 1992 retail lumber yard prices for "construction" grade redwood averaged 77 percent higher than those for comparable Douglas-fir; and for "clear" grades, redwood prices were 20 percent higher than Douglas-fir's.
California State Tax Board values for second-growth redwood logs averaged 148 percent of the value of Douglas-fir logs of the same dimensions, 230 percent of those for sugar and ponderosa pine (Pinus lambertiana and P. ponderosa) and 1148 percent of those for radiata (P. radiata) and shore pine (P. contorta var. contorta) (Libby, 1993).
Besides being valuable for timber, redwood is a spectacular tree which attracts many visitors to 100,000 hectares of state and national parks (Dewitt, 1985).
Before the Pleistocene, redwood or its close relatives were widespread, occurring in Europe, Asia, and North America (Chaney, 1934). Today, however, Sequoia sempervirens is confined to a narrow 720-km strip of the California and Oregon coast, extending 30 to 60 km inland. (Little, 1971) (see Figure 1). It was once thought that redwood grew in this belt because it needed the region's summer fog in order to survive; but more than 100 years ago, it was being successfully grown at Placerville, in the foothills of the Sierra Nevada, and outside California at Seattle, Washington, Victoria, British Columbia, and Hawkinsville, Georgia (Kuser, 1981). It is now known that redwood can be grown in many parts of western Europe and in the Crimea, Turkey, Japan, New Zealand, Chile, South Africa, Tasmania, and in the tropics at high enough elevation to provide temperate climate. As efforts to grow redwood in many parts of the world get underway, information on provenance differences becomes urgent. Use of the right or wrong seed source can spell the difference between success and failure with exotics (Zobel et al., 1988). The earliest provenance test of redwood was started in 1961 by Muelder and Hansen with seed of 10 populations from the central and north coast of California (Millar et al., 1985). It was evident to us by 1983 that a rangewide collection was warranted, with testing at locations in the temperate zones wherever there was interest in growing this species.
MATERIALS AND METHODS
In 1984, we made a 180-clone collection of redwood funded by the American Philosophical Society. Originally we intended to collect seeds for the test, but soon realized that this would be impossible in many parts of the range where the trees rely on stump-sprout regeneration and produce cone crops infrequently. We then decided to collect seedlings and use vegetative propagation to produce ramets for test plantations. This strategy had the advantage of removing one source of variation from analysis of results. As far as possible, we collected juvenile seedlings, no larger than 50 cm tall, in order to avoid cyclophysis.
Because redwood's range is too irregular to use a grid system for collecting, we chose representative collection sites in all the main groves, outlying groves on the continental side of the main range, and as complete a range of elevations and soil types as possible.
Elevations ranged from near sea level to 945 m; soil types included sand and rendzina as well as the common, acid brown soils. The most unusual soil/site was at Limekiln Creek, where redwoods had naturally regenerated in blocks of limestone at the top of an abandoned kiln.
Seedlings were taken to Simpson Forest Tree Nursery at Korbel, California, potted, and allowed to grow new tops.
Occasionally collection locations were unique enough to warrant representation, but no seedlings were available; in these cases, cuttings were taken from stump sprouts or saplings.
To the 180 collected clones, others were added as follows: 1) 14 clones of plus trees and plus-tree crosses selected by Simpson Timber in Humboldt County, and 2) ramets propagated from crown cuttings of three large, famous trees: Father of the Forest (height 75 m, dbh 5.09 m), Prairie Creek Big Tree (92.7 m x 6.55 m), and Stout Tree (105.8 m x 5.45 m).
Each clone was propagated by cuttings to produce four plants, which were established in a hedge orchard at Korbel, California. After the initial hedge orchard was producing plants, we established additional hedge orchards at the University of California's Russell Reservation, Lafayette, CA, 1987; California Department of Forestry, Davis, California, 1989; and AFOCEL (Association Forêt-Cellulose), Etançon, Angers, Dijon, and Malissard, France, beginning 1986. Propagation is now also being done by Investigaciones Forestales, Pontevedra, Spain, and Tasman Forests, Rotorua, New Zealand.
After all test clones were growing vigorously in the hedge orchard, with shoots 0.5 m to 1.2 m tall by October 1985, the orchard was hedged to approximately 10 cm high. In November 1986 and subsequently, cuttings were rooted for test plantations. Plantations were established at Clemson, South Carolina (1988); Russell Reservation, Lafayette, California (1989); Pontevedra, Spain (1989), Brookings, Oregon (1989), St. Fargeau, France (1990), and Etançon, France (1992). Partial tests were established in Britain (10 clones, 1989) and South Africa (19 clones, 1988), and cuttings of 49 clones were sent to New Zealand in 1990.
Survival of plantations has varied from 95% after 2 field seasons at Brookings, Oregon to only 5% after 6 seasons at Clemson, South Carolina. Differences in growth rates and winter hardiness have begun to show. At Clemson, 47 out of 50 survivors were from 6 northern counties and only 3 from 6 southern counties. At Brookings, clones from mid-range (Napa and Humboldt counties) were taller than those from the extreme north (Curry, Del Norte), where the plantation is. At St. Fargeau,
France, after the cold winter of 1990-91, 14 clones out of 180 were in excellent condition on 23 May 1991, with stems, branches, and tips rated green. All 14 originated in Humboldt, Mendocino, and Napa counties.
Ramets of 59 clones from 6 northern counties were over 2m tall at St. Fargeau in October 1993, while none from 6 southern counties exceeded this height (c2=16.67**); and at Etançon, France, after 3 field seasons, mean height of 173 northern-county ramets was 2.18m vs. 2.00m for 147 southern county ramets.
The tallest plantation was at the University of California's Russell Reservation, near Berkeley, where mean height of trees in the best block after 4 field seasons was 2.70m. Here, as at Brookings, the tallest clones were from regions south of the plantation (Santa Clara and Santa Cruz counties), but clones from Humboldt, Mendocino, and Monterey counties were nearly as tall and not statistically distinct. Of the total variance in this block, 9.9% was due to clone, 6.7% to stand, 0.6% to county, 3.4% to region, and 79.0% to experimental error (P>F 0.0016).
At Malissard, France, where a hedge orchard but not a randomized plantation had been established, the tallest one-year sprouts were from San Mateo, Santa Clara, and Santa Cruz counties.
At Davis, California, a warm site in the Central Valley where a hedge orchard but not a randomized plantation had been established, there appeared to be an inverse correlation between height of one-year sprouts and their latitude of origin. The tallest sprouts were those of 10 clones from Monterey county at the extreme south end of the range, with 6 plants of one clone producing sprouts >2m tall.
At Westonbirt Arboretum in Britain, where only a few ramets were planted, mean height after 5 field seasons was 4.1m. At Bedgebury and Derby, also in Britain, mean heights after 3 seasons were 1.44m at Bedgebury and 0.86m at Derby. At all 3 arboreta in Britain, as well as at Brookings, Oregon, plus-tree clones selected by Simpson Timber outgrew ordinary provenance clones from Humboldt County, their region of origin.
The results of this experiment indicate that provenance differences probably exist in coast redwood, but not as great as those in Pseudotsuga menziesii (Ching and Bever 1960, Rowe and Ching 1973) or Tsuga heterophylla (Kuser and Ching 1980).
Variation in redwood is likely commensurate with the smaller latitudinal extent occupied by Sequoia's native range (Little 1971).
At test plantations in cooler areas such as Brookings, Etançon, and St. Fargeau, clones from the northern part of the native range have grown faster on average than those from the south. At warmer sites such as Russell, on the other hand, Santa Cruz and Monterey clones grow comparatively better; and our limited evidence from Davis and Malissard appears to substantiate this. Neither Davis nor Malissard results are significant on their own because of lack of randomization and replication, but taken together they indicate that redwoods from the warmer portions of the range may grow faster on warm test sites. If so, that agrees with Anekonda's findings linking growth rates to metabolic heat measured by microcalorimetry, and predicting that Monterey clones have the potential to grow faster on average (Anekonda et al., 1993, 1994a, 1994b).
Lack of cold tolerance is a major factor limiting the use of Sequoia outside the
warm-temperate areas where it can be grown successfully. On the west coast of North America, the northern limit for growing redwood appears to be Vancouver, British Columbia, (January mean T = 2.0ºC); and on the east coast, the limit is Williamsburg, Virginia, (January mean T = 4.7ºC.) (Kuser 1981 & U.S.D.A., 1941).
In this experiment, clones from the southern part of the range (particularly Monterey) experienced more winter injury and higher mortality after a hard freeze at St. Fargeau, France; and southern clones nearly all died at Clemson, South Carolina where a north-south clinal pattern of survival occurred. Considering these results, one might reasonably search for more cold-tolerant clones of Sequoia around French Hill Road, Del Norte county (site of the tallest surviving tree at Clemson), and Lokoya, Napa county (site of the most frost resistant clone at St. Fargeau).
Results at Brookings and growth of a limited number of trees in Britain confirm that identification of certain Humboldt county clones as plus trees has probably been valid. Humboldt clones in general have grown relatively fast at Brookings, Russell, St.Fargeau, and Etançon.
The ease of propagating redwood vegetatively insures that any genetic variation in growth rate or cold hardiness which is discovered in provenance experiments, or bred in tree improvement programs, can be used to its full extent in plantations.
Stecklings of this rangewide provenance test of coast redwood, Sequoia sempervirens (D. Don.) Endl. are available from Simpson Timber Co., Korbel, California, U.S.A., at a cost of $US 1.25 each. These are vigorous 20 cm plants grown in containers for 6 months after rooting.
Contact Mark Diegan at Simpson Forest Tree Nursery, P.O. Box 68, Korbel, California 95550 (Tel. 707-668-4501, Fax. 707-668-4502). For those with phytosanitary restrictions, unrooted cuttings sterilized in NaOCl are available at a cost of US cents 25 each, and tissue culture plantlets can be produced on request.
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