Location: Dale Bumpers Small Farms Research Center
Title: Phenological Responses of Juvenile Pecan and White Oak on an Upland Site Authors
Submitted to: Agroforestry Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 7, 2013
Publication Date: February 15, 2014
Citation: Burner, D.M., Brauer, D.K., Snider, J.L., Harrington, C., Moore Jr, P.A. 2014. Phenological Responses of Juvenile Pecan and White Oak on an Upland Site. Agroforestry Systems. 88:141-155. Interpretive Summary: Pecan and white oak produce numerous high-valued products and wildlife values: pecan for short-term income from nuts, and both species for wildlife benefits and long-term timber income. Landowners might consider growing them in mixed-species plantations, but more information is needed if relative timing of growth responses (phenology) is affected by fertilization. We measured tree growth at planting and for six consecutive growing seasons during establishment (2003-2008, Test 1), and measured when trees burst bud, and if trends in leaf area index (LAI), leaf fluorescence, diameter growth, and leaf chlorophyll concentration changed across the growing season in response to three rates of poultry litter (2010-2012, Test 2). The experiment was conducted on an upland site near Booneville, Arkansas. Both species grew well on this site, indicating that they responded to the suite of intensive management practices, including auger planting, competition control, use of containerized seedlings, and irrigation. In general, the various periodic growth parameters tended to be insensitive to fertilization probably because the site had adequate soil nutrients. The study provides additional information on growth responses of these two species that will help growers manage pecan-white oak orchards on upland sites.
Technical Abstract: Pecan (Carya illinoiensis) and white oak (Quercus alba) produce multiple products and wildlife values, but their phenological responses to N fertilization have not been well characterized in an mixed species agroforestry practice. We compared tree height at planting and for six consecutive growing seasons during establishment (2003-2008, Test 1), and determined if phenology of budburst, leaf area index (LAI), quantum yield of photosystem II (Fv/Fm), radial growth, and total chlorophyll concentration (a and b) responded to poultry litter fertilization supplying 0, 50, and 100 kg/ha N (2010-2012, Test 2) in a mixed-species orchard on an upland site near Booneville, Arkansas. Species did not differ significantly in height in Test 1. Budburst tended to occur earlier in white oak than pecan each year, but was significantly earlier by 9 d only in 2010. Budburst for both species could be predicted by accumulating chilling and forcing units throughout the dormant season. Maximum predicted radial growth was comparable for pecan (2.19 mm) and white oak (2.26 mm), but growth peaked 28 d earlier for white oak (3 June) than pecan (1 July). White oak LAI generally exceeded that of pecan during the growing season. Senescence began about 27 October regardless of species, and was better characterized by decreasing Fv/Fm or total chlorophyll concentration than LAI, because white oak was semi-deciduous. Phenology was generally not responsive to N fertilization, perhaps because of adequate soil and foliar N. Results will facilitate decision-making on combining these two high-value species in an orchard for multifunctional purposes on upland sites.