TITLE:
Field Performance of Quercus bicolor Established as Repeatedly Air-Root-Pruned Container and Bareroot Planting Stock
AUTHORS:
J. W. Van Sambeek, Larry D. Godsey, William D. Walter, Harold E. Garrett, John P. Dwyer
KEYWORDS:
Afforestation, Root Fibrosity, Root Production Method, Seedling Quality, Swamp White Oak, Whole-Tree Biomass
JOURNAL NAME:
Open Journal of Forestry,
Vol.6 No.3,
June
2,
2016
ABSTRACT: Benefits of repeated air-root-pruning of seedlings when stepping up to progressively
larger containers include excellent lateral root distribution immediately below
the root collar and an exceptionally fibrous root ball. To evaluate long-term
field performance of repeatedly air-root-pruned container stock, three plantings
of swamp white oak (Quercus bicolor Willd.) 10 to 13 years old were located that also included bareroot planting
stock. Initial and final stem diameter and height and above-ground green
weights were determined on randomly selected trees at each site. On a site with
a sandy, excessively drained, high pH soil, trees (age 10) from container stock
were 1.5 times taller, 2.3 times larger in dbh, and 2.8 times greater in green
weight than trees from bareroot stock which averaged only 2.9 m tall, 3.9 cm
dbh, and 16.3 kg green weight. On a site with high clay, poor internal
drainage, and frequent flooding, trees (age 12) from container stock were 1.4
times taller, 1.8 times larger in dbh, and 4.1 times greater in green weight than
trees from bareroot stock which averaged 4 m tall, 7.3 cm dbh, and 28 kg green
weight. On an upland site with deep loess soils, there was a trend for trees
(age 13) from container stock to be only slightly larger than trees from
bareroot stock with each stock type averaging 9.6 m tall, 20 cm dbh, and 177 kg
green weight. Repeated air-root pruning produced lateral roots immediately
below the root collar that resulted in large container stock with large
well-balanced root systems that were competitive on harsh or less than ideal
oak sites. Although the process is relatively labor intensive, propagation of repeatedly
air-root-pruned container stock is readily adaptable internationally to locally
available sources of organic matter and open-bottom containers.