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Report of 31 October 20013 Seed Harvest
1. CLINTON, NORTH CAROLINA
CONNIE BARLOW COLLECTED 102 SEEDS AND 4 SEEDLINGS during this site visit on 31 October 2013 (with the permission of the landowner, Mrs. Kennedy).
Only one tree (composed of one main stem and two mature basal stems) still lives on the property of Mrs. Kennedy at 613 College St. in Clinton, North Carolina. Until a hurricane in 1998, an even larger specimen grew nearby, but was knocked over when a big pine toppled onto it. (pers. comm. A.J. Bullard; click to read Connie Barlow's notes of a 2009 phone interview with Mr. Bullard on the full history of the Clinton Torreya trees.)
ABOVE LEFT: The multi-stemmed Torreya taxifolia is near the center of the photo. The photographer, Connie Barlow, is standing NE of the tree. At the far left is a basswood tree, with large yellow leaves adorning its basal sprouts. Next inward is the trunk of an evergreen Southern Magnolia, whose location directly south of the Torreya protects the tree from summer heat and drought, but reduces its opportunities for photosynthesis during clement times. At the right edge of the photo is the very big trunk of a Chestnut Oak, whose western location protects the Torreya from late afternoon summer heat, but whose deciduous character enhances the passage of sunlight during the winter months. (Immediately to the left of the oak is the slender trunk of a healthy Dogwood tree.)
ABOVE RIGHT: The main stem of Torreya with 2 mature basal stems that support a great deal of foliage but very few male or female "cones". Notice the fresh young basal growth, which is almost always present even in fully healthy Torreya specimens.
ABOVE LEFT: Standing in front of Mrs. Kennedy's house, looking toward College St. The man in the background left is standing just left of the Torreya tree. The big tree foreground right is another Chestnut Oak.
ABOVE RIGHT: Michael Dowd uses a walking stick to dislodge some ripe Torreya "fruits" (technically, cones covered by a fleshy sarcotesta) still hanging from the branches of the main Torreya stem. The large Chestnut Oak featured in the previous photograph is visible at the far right of this photo.
ABOVE: Some of the ripe "fruits" (orange to purplish in color) are still hanging from their branchlets. The photo left shows the main stem of the Torreya at far right (which is bearing these fruiting branches). Connie observed that, as with the Torreyas she observed in shady Redwood forests in California, only the branches well exposed to sunlight bear prolific fruit. South-facing branches shaded by the evergreen Southern Magnolia had no visible fruit on the branches nor directly beneath them on the ground.
ABOVE: Three whole fallen "fruits" visible in photo left and 2 in photo right. Both photos show remnant casings from which squirrels have removed and buried the seeds. The fleshy casing around the ripe fruit tends to crack apart, even when moist, and thus make seed removal easy. A chestnut oak leaf is visible in photo right; basswood seeds at top of photo left. Connie Barlow estimates, based on the ratio of whole seeds on the ground to seed casings, that the squirrels had peeled (and then eaten or buried) 70 to 90 percent of the fallen "fruit".
ABOVE LEFT: Connie could not reach high enough to touch any of the branches emanating from the main Torreya stem (where she photographed "fruits" growing). But she could reach a few branches of the two mature basal stems. Here she sees the typical series of buds placed laterally along a stem, which she surmises as the buds of the male cones for next year. The smaller three-pointed bud at the tip of the branchlet is the bud for next year's vegetative growth. It is conceivable that one or both of the "mature basal stems" actually began as distinct seedlings — not as true clones of the parent stem. But the far more likely possibility is that a single Torreya tree (whether "male" or "female") will produce both sexes of reproductive organs on distinct branches, especially if it is isolated from other individuals and thus needs to self-fertilize. Note: See this topic explored below in the Mt. Olive photo-essay.
ABOVE RIGHT: A seedling Torreya grows where a squirrel planted a seed: 10 to 20 feet beyond the southern, crimped canopy of the parent tree, in the deep shade of an evergreen Southern Magnolia (slightly overtopped by a Chestnut Oak). Notice both the smooth-edged magnolia leaves and the wavy Chestnut oak margins. A magnolia fruit (with one red seed still protruding) is visible at right. At least 20 seedlings were easily visible in this region — none taller than 8 inches. This area never needs to be mowed, so the absence of taller seedlings suggests either that they have been harvested by collectors or the more likely prospect that, once the large seed has used up all its food stores while producing early roots and above-ground growth, the seedlings simply die from lack of sunlight. Crucially, the fact that there are any seedlings at all confirms that at least some of the seeds produced by this lone individual have been self-fertilized and are thus capable of developing into trees.
ABOVE: Two more examples of seedlings growing beneath the dense Southern Magnolia and Chestnut Oak canopies.
ADDENDUM: A month after Connie collected the above seedlings and gave them to Jeff Morris to tend and propagate in North Carolina, Jeff made this crucial observation:
500+ SEEDS HARVESTED NOVEMBER 2014: Torreya Guardians was thrilled to harvest more than 500 seeds on 11 November 2014. We were happy that by delaying our harvest until well into November, more of the seeds had already dropped than remained in the tree. (The tree is too tall to be able to harvest seeds that have not yet fallen.) Squirrels in Ms. Kennedy's yard preferred the Chestnut Oak acorns and the pecans, at least this early in the season, so we did not have to worry about the squirrels hiding many Torreya seeds before we got there. As well, because Torreya grows its seeds near the prickly branchlet tips, squirrels are precluded from plucking seeds still hanging on the tree.
ADDITIONAL ONSITE 2014 OBSERVATIONS BELOW. NOVEMBER 2014 OBSERVATIONS: There were once two trees on this property in Clinton NC. It appears that a larger tree used to grow about 70 feet from the remaining 'fruiting' Torreya taxifolia. Fortunately, this remaining tall tree is not alone:
(2) There are two 4-ft-tall volunteers that the late Mr. Kennedy moved from under the now-gone tree, and planted in the backyard some years back. It is possible that they provide pollen to the 'fruiting' Torreya.
(3) There is at least one additional volunteer about 3-ft-tall along the driveway, bordering a neighbor's property.
(4) Finally, we learned that there used to be two additional mature Torreya taxifolia trees, larger than either of the Kennedy's pair, about a block away. They produced fruit for a number of years until the property last changed hands (within the past six years or so). The new owner didn't know what they were, and had them cut down before even occupying the residence. But, they likely produced volunteers, even within only a hundred or so feet, in shaded areas. On our next visit, we need to look carefully at prospects in the neighborhood.
OVERALL 2014: It is exciting to know that assisted migration may already be underway, even if on a small scale (squirrels dispersing seeds which then germinate), in Clinton, North Carolina. And it is possible that seeds we collected from the tall tree in 2013 and 2014 might not be as genetically isolated (inbred) as we had feared. Another speculation: Since the tall tree appears rather old, perhaps it was planted from seeds collected in the wild in Florida (not from the recently dead Norlina tree, which we know is the ancestor of seedlings dispersed by certain nurseries). Only genetic testing would confirm this possibility, but the existence of more than one isolated tree is a very encouraging bit of new knowledge.
CONNIE BARLOW COLLECTED 41 SEEDS during this site visit on 31 October 2013.
ABOVE LEFT: A.J. Bullard, one of the most knowledgeable self-taught botanists and horticulturalists in North Carolina, stands in front of the tallest of his same-age Torreya taxifolia trees. This tree produced relatively few "fruit" this year. The more squat tree at right edge of photo produced a lot of "fruit". (Technically, conifer trees bear cones, not fruit — but the female cones of Torreya look like figs, though they contain but a single big seed. The fleshy covering over the single seed is a sarcotesta.) The tree branches at the top of photo are of the large Darlington Oak (an upland variety/species of Laurel Oak), which he planted there in 1967.
ABOVE RIGHT: Bullard labels his specimens. These two trees growing at his home in Mt. Olive are identified by where he collected them as seedlings: offspring of the two Torreyas then-standing on the Kennedy property in the nearby town of Clinton NC (see photo-essay above).
Background information on the two trees: In a 6 December 2013 phone conversation with A.J. Bullard, Connie collected details on the history of the two specimens. In approx. 1995 A.J. and his cousin dug up (with the permission of the owner) 75 seedlings that were growing in the unmoved areas of the Kennedy property on which the trees stood. The seedlings were primarily found along the hedgerows and in the flower garden. Of the 75 seedlings, he gave away (or traded for other plants to conserve on his property) 73 seedlings. He planted only two on his own land: the two seen in these photos. The two seedlings he kept and planted were each about 3 feet tall, so he estimates that they probably sprouted from a seed crop approx. 1988 - 1990. It is impossible to know whether these two specimens contain significant genes from the tallest Torreya on the Clinton NC property, but because A.J. estimates from his 1995 visit that the tallest tree produced about 2/3 of the entire seed crop (of perhaps more than 5,000 seeds from the two trees combines) there is strong likelihood that these two specimens contain genes no longer found in the seedlings and seeds that I (Connie Barlow) collected beneath the one remaining (smaller) Clinton Torreya in October 2013.
ABOVE: Both photos are of a fruit-bearing section of the squat Torreya tree. Notice that the fleshy covering of some of the very ripe seeds is beginning to split on its own, exposing the seed for easy removal by squirrels. Notice, too, the agricultural land in the background. Thus, these Torreya specimens are helpful for (a) species preservation, (b) generation of seeds, and (c) studying the growth patterns and ecology of this species. But this is not a site contributing to the study of this species' performance in wild forests ("rewilding"), nor can squirrels be expected to assist the local population in expanding — at least so long as humans manage the surroundings as lawns and farm fields.
Maturation takes 18 - 20 years: The seeds photographed here in 2013 were only the sixth year that seeds were evident, as one of the trees began bearing seeds in 2008. (Read more details from the 2009 phone conversation between Bullard and Barlow.)
Calculating future squirrel-assisted range expansion rates: Because Bullard did not artificially nurture the trees beyond initial watering after planting, and because the trees experience partial shade (from the tall oak south of them) during the summer, a 20 year time span between generations would be a reasonable estimate for partial shade (Torreyas do not produce female cones in deep shade). Bullard estimates 250 feet as the most distant squirrel-planted seedling that he spied at and near the Clinton site.
ABOVE LEFT: Although thick growths of green-leaved branches extend all the way to the ground in both specimens, each rises from a single stem.
ABOVE RIGHT: Notice the drying, fallen fruits in the foreground of the right photo (with Torreya trunk behind). A.J. says there are 2 or 3 local fox squirrels, and that the nearby Darlington Oak produced only a few acorns this year. Experience elsewhere is that Torreya seeds are highly prized by squirrels, and so we need to protect out-planted seeds that we try to germinate. And yet, there was little evidence that squirrels were hastily taking and burying the seeds for the winter.
ABOVE LEFT: Torreya vegetative buds always grow at the apex or tips of the branchlets. The male and female cones grow farther back up the stem. A.J.'s left hand holds a pair of vegetative buds; his right hand holds a set of 3 female cone-buds. Notice the pair of light-colored lines of air-exchanging pores, stomates, on the underside of all the Torreya leaves (very similar to what appears on the underside of Hemlock leaves).
ABOVE RIGHT: Here A.J. compares 3 branchlets, all growing on the squat specimen. From top to bottom: female cone-buds, a series of male cone-buds along a branchlet, and a pair of vegetative buds at the branchlet's tip. Notice that the female buds are the largest and most angular; the male buds are most numerous in a series; and the vegetative buds are the scaliest (least smooth).
THIS IS CONCLUSIVE EVIDENCE THAT INDIVIDUAL TREES WILL PRODUCE BOTH MALE AND FEMALE REPRODUCTIVE CONES.
Note added September 2014: For those who may be skeptical that Torreya sp. can possibly produce male and female cones on the same individual (as the bulk of the literature refutes this), please google the terms "facultatively dioecious" and "geitonogamous selfing". The latter will get you to a pdf overview: "The Role of Geitonogamy in the Gradual Evolution towards Dioecy in Cosexual Plants", 2001, Jong and Geritz.
On p. 127 of "Conifer Reproductive Biology" by Claire G. Williams, one finds: "Selfing, only possible for monoecious conifers, can only be geitonogamous because conifers are monosporangiate. Geitonogamy refers to the case where male and female strobili occur on the same plant but not in a single strobilus. Conifers do not have autogamy."
ABOVE LEFT: Superb vegetative growth on all sides of both individual trees.
ABOVE RIGHT: A.J. Bullard with Torreya seeds and branches in foreground.
ABOVE LEFT: Seeds dropped in place beneath the tree show no evidence of harvesting by squirrels (in contrast to the intense squirrel activity evident at the Clinton Torreya site the same day). Note the abundance of fallen leaves from the nearby Darlington (aka Laurel) Oak.
ABOVE RIGHT: The drying fleshy covering of the Torreya seed cracks on its own, making the seed easy for a squirrel to remove and carry away.
Click above image for the Clinton / Mt. Olive section in the VIDEO
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