page_title: Carya aquatica
section_title: Reproduction and early growth
hierarchical_section_title: Carya aquatica / Life history / Reproduction and early growth
caption_attribution_description: English: Carya aquatica bud. Arnold Arboretum of Harvard University, accession #32-2013*B.
context_page_description: Carya aquatica, the bitter pecan or water hickory, is a large tree, that can grow over 30 metres tall of the Juglandaceae or walnut family. In the American South it is a dominant plant species found on clay flats and backwater areas near streams and rivers. The species reproduces aggressively both by seed and sprouts from roots and from stumps of cut trees. Water hickory is a major component of wetland forests now in the south eastern US, because of the selective cutting of more desirable tree species for the lumber industry. It is considered important in cleansing drainage waters since the plants slow water flow during flooding, allowing sediments to fall out of the water column. This tree species is tolerant of wet soils but grows best on well draining soils near rivers and other water ways.
context_section_description: Water hickory regenerates aggressively from seeds and sprouts. Seeds germinate and become established on disturbed soil or understory duff. To develop, understory seedlings must be released. Many of our present stands of water hickory, especially on imperfectly drained flats, have been regenerated and released by heavy preferential logging of more valuable species. On poorly drained sites, where competition is not so intense, water hickory grows to fill openings created by windthrow and natural mortality as well as logging.
  Flowering and fruiting- Water hickory is monoecious. Male and female flowers appear during April and May, while the leaves are developing. The male flowers are in stalked catkins on branches of the current or previous year, and the female flowers are in short spikes or stalks. The fruit, covered by a thin husk during development, are thin-shelled, flattened, and have a bitter seed. Nuts fall between October and December of the same year.
  Seed production and dissemination- Seed production begins when the trees are about 20 years old, or about 20 cm (7.9 in) in d.b.h.. Optimum seed-bearing age is from 40 to 75 years, or after the trees reach 51 cm (20 in) in d.b.h. Heavy seed crops are produced in most years, and a thrifty tree may produce up to 70 liters (2 bu) of seeds. There are approximately 440 cleaned seeds per kilogram (200/lb). The seeds are disseminated by water and animals; floodwaters are particularly important in carrying seed to new areas.
  Seedling development- After seedfall in the autumn, the seeds lie dormant until germination in late April through early June. Rarely do they remain viable until the second spring. Germination is hypogeal. Sometimes nearly 80 percent of the seed crop germinates. As a result, thickets and clumps of water hickory are not unusual. The species is tolerant enough to survive in the understory for at least 15 years, but full sunlight is necessary for development into trees. The relatively slow height growth of water hickory requires that it have near freedom from competition to establish itself in the overstory. Because of their extended dormant season, water hickory seedlings are able to survive late-spring floods better than most of their would-be competitors.
  Vegetative reproduction- Stumps less than 61 cm (24 in) and severed roots of water hickory readily sprout. Sprouts grow three or four times faster than seedlings during the first year or two. Even on poorly drained clay soil, first-year sprouts sometimes are 1.5 m (4.9 ft) tall. Sprouts 4.6 m (15 ft) tall at 5 years have been reported.
  Sapling and pole stages to maturityGrowth and yield- Water hickory on a good site may reach 33.5 m (110 ft) tall and 91 cm (36 in) in diameter, with about 16 m (52 ft) of merchantable bole. The tall straight trunk is topped by slender to moderately stout ascending branches. Diameter growth of water hickory is slow for southern species, 2 to 8 mm (0.079 to 0.315 in) per year. At 50 years, dominants might average 35 cm (14 in) in d.b.h. on good sites and only 25 cm (9.8 in) on poor sites. Site index at base age 50 years ranges between 20 and 29 m (66 and 95 ft). Slow growth rates are typical of water hickory in competition with oaks, sugarberry, gum, and other species on good sites.
  Maximum mean annual production of a pure stand (found rarely) on a good site has been established at 10.5 m³/ha (150 ft³/acre). Maximum mean annual production on medium and poor sites was estimated at 7.0 m³/ha (100 ft³/acre) and 3.5 m³/ha (50 ft³/acre), respectively. An average water hickory site might realistically yield 210 m³/ha (3,000 ft³/acre) at maturity. Slow growth and poor sites usually keep yields low.
  Rooting habit- Water hickory, like other hickories, grows a taproot in the seedling stage. The wet clayey soils where water hickory usually is found restricts the entire root system to fairly shallow depths. The taproot eventually becomes the source of a coarse, widespreading but shallow lateral root system. The taproot of a 30-cm (12-in) individual, excavated on moderately well-drained c
caption: Carya aquatica bud
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